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Zeng ZL, Wang XQ, Zhang SB, Huang W. Mesophyll conductance limits photosynthesis in fluctuating light under combined drought and heat stresses. PLANT PHYSIOLOGY 2024; 194:1498-1511. [PMID: 37956105 DOI: 10.1093/plphys/kiad605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 10/18/2023] [Accepted: 10/23/2023] [Indexed: 11/15/2023]
Abstract
Drought and heat stresses usually occur concomitantly in nature, with increasing frequency and intensity of both stresses expected due to climate change. The synergistic agricultural impacts of these compound climate extremes are much greater than those of the individual stresses. However, the mechanisms by which drought and heat stresses separately and concomitantly affect dynamic photosynthesis have not been thoroughly assessed. To elucidate this, we used tomato (Solanum lycopersicum) seedlings to measure dynamic photosynthesis under individual and compound stresses of drought and heat. Individual drought and heat stresses limited dynamic photosynthesis at the stages of diffusional conductance to CO2 and biochemistry, respectively. However, the primary limiting factor for photosynthesis shifted to mesophyll conductance under the compound stresses. Compared with the control, photosynthetic carbon gain in fluctuating light decreased by 38%, 73%, and 114% under the individual drought, heat, and compound stresses, respectively. Therefore, compound stresses caused a greater reduction in photosynthetic carbon gain in fluctuating light conditions than individual stress. These findings highlight the importance of mitigating the effects of compound climate extremes on crop productivity by targeting mesophyll conductance and improving dynamic photosynthesis.
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Affiliation(s)
- Zhi-Lan Zeng
- Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiao-Qian Wang
- Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Shi-Bao Zhang
- Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
| | - Wei Huang
- Department of Economic Plants and Biotechnology, Yunnan Key Laboratory for Wild Plant Resources, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, China
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Soualiou S, Duan F, Li X, Zhou W. Nitrogen supply alleviates cold stress by increasing photosynthesis and nitrogen assimilation in maize seedlings. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:3142-3162. [PMID: 36847687 DOI: 10.1093/jxb/erad073] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2022] [Accepted: 02/23/2023] [Indexed: 05/21/2023]
Abstract
Cold stress inhibits the early growth of maize, leading to reduced productivity. Nitrogen (N) is an essential nutrient that stimulates maize growth and productivity, but the relationship between N availability and cold tolerance is poorly characterized. Therefore, we studied the acclimation of maize under combined cold stress and N treatments. Exposure to cold stress caused a decline in growth and N assimilation, but increased abscisic acid (ABA) and carbohydrate accumulation. The application of different N concentrations from the priming stage to the recovery period resulted in the following observations: (i) high N supply alleviated cold stress-dependent growth inhibition, as shown by increased biomass, chlorophyll and Rubisco content and PSII efficiency; (ii) cold stress-induced ABA accumulation was repressed under high N, presumably due to enhanced stomatal conductance; (iii) the mitigating effects of high N on cold stress could be due to the increased activities of N assimilation enzymes and improved redox homeostasis. After cold stress, the ability of maize seedlings to recover increased under high N treatment, indicating the potential role of high N in the cold stress tolerance of maize seedlings.
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Affiliation(s)
- Soualihou Soualiou
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences Beijing 100081, China
| | - Fengying Duan
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences Beijing 100081, China
| | - Xia Li
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences Beijing 100081, China
| | - Wenbin Zhou
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences Beijing 100081, China
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Chen X, Han H, Cong Y, Li X, Zhang W, Wan W, Cui J, Xu W, Diao M, Liu H. The Protective Effect of Exogenous Ascorbic Acid on Photosystem Inhibition of Tomato Seedlings Induced by Salt Stress. PLANTS (BASEL, SWITZERLAND) 2023; 12:1379. [PMID: 36987066 PMCID: PMC10052531 DOI: 10.3390/plants12061379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 03/16/2023] [Accepted: 03/16/2023] [Indexed: 06/19/2023]
Abstract
This study investigated the protective effects of exogenous ascorbic acid (AsA, 0.5 mmol·L-1) treatment on salt-induced photosystem inhibition in tomato seedlings under salt stress (NaCl, 100 mmol·L-1) conditions with and without the AsA inhibitor lycorine. Salt stress reduced the activities of photosystem II (PSII) and PSI. AsA treatment mitigated inhibition of the maximal photochemical efficiency of PSII (Fv/Fm), maximal P700 changes (Pm), the effective quantum yields of PSII and I [Y(II) and Y(I)], and non-photochemical quenching coefficient (NPQ) values under salt stress conditions both with and without lycorine. Moreover, AsA restored the balance of excitation energy between two photosystems (β/α-1) after disruption by salt stress, with or without lycorine. Treatment of the leaves of salt-stressed plants with AsA with or without lycorine increased the proportion of electron flux for photosynthetic carbon reduction [Je(PCR)] while decreasing the O2-dependent alternative electron flux [Ja(O2-dependent)]. AsA with or without lycorine further resulted in increases in the quantum yield of cyclic electron flow (CEF) around PSI [Y(CEF)] while increasing the expression of antioxidant and AsA-GSH cycle-related genes and elevating the ratio of reduced glutathione/oxidized glutathione (GSH/GSSG). Similarly, AsA treatment significantly decreased the levels of reactive oxygen species [superoxide anion (O2-) and hydrogen peroxide (H2O2)] in these plants. Together, these data indicate that AsA can alleviate salt-stress-induced inhibition of PSII and PSI in tomato seedlings by restoring the excitation energy balance between the photosystems, regulating the dissipation of excess light energy by CEF and NPQ, increasing photosynthetic electron flux, and enhancing the scavenging of reactive oxygen species, thereby enabling plants to better tolerate salt stress.
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Affiliation(s)
- Xianjun Chen
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi 832003, China
- Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization of Xinjiang Production and Contruction Crops, Shihezi 832003, China
| | - Hongwei Han
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi 832003, China
- Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization of Xinjiang Production and Contruction Crops, Shihezi 832003, China
- Key Laboratory of Horticulture Crop Genomics and Genetic Improvement in Xinjiang, Institute of Horticultural Crops, Xinjiang Academy of Agricultural Sciences, Urumqi 830000, China
| | - Yundan Cong
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi 832003, China
- Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization of Xinjiang Production and Contruction Crops, Shihezi 832003, China
| | - Xuezhen Li
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi 832003, China
- Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization of Xinjiang Production and Contruction Crops, Shihezi 832003, China
| | - Wenbo Zhang
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi 832003, China
- Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization of Xinjiang Production and Contruction Crops, Shihezi 832003, China
| | - Wenliang Wan
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi 832003, China
- Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization of Xinjiang Production and Contruction Crops, Shihezi 832003, China
| | - Jinxia Cui
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi 832003, China
- Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization of Xinjiang Production and Contruction Crops, Shihezi 832003, China
| | - Wei Xu
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi 832003, China
- Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization of Xinjiang Production and Contruction Crops, Shihezi 832003, China
| | - Ming Diao
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi 832003, China
- Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization of Xinjiang Production and Contruction Crops, Shihezi 832003, China
| | - Huiying Liu
- Department of Horticulture, Agricultural College, Shihezi University, Shihezi 832003, China
- Key Laboratory of Special Fruits and Vegetables Cultivation Physiology and Germplasm Resources Utilization of Xinjiang Production and Contruction Crops, Shihezi 832003, China
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Drought Tolerance Assessment of Okra (Abelmoschus esculentus [L.] Moench) Accessions Based on Leaf Gas Exchange and Chlorophyll Fluorescence. Life (Basel) 2023; 13:life13030682. [PMID: 36983840 PMCID: PMC10052028 DOI: 10.3390/life13030682] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 02/27/2023] [Accepted: 02/28/2023] [Indexed: 03/06/2023] Open
Abstract
Physiological and complementary phenotypic traits are essential in the selection of drought-adapted crop genotypes. Understanding the physiological response of diverse okra genotypes under drought stress conditions is critical to the selection of drought-tolerant accessions for production or breeding. The objective of this study was to assess the levels of drought tolerance in preliminarily selected okra accessions based on leaf gas exchange and chlorophyll fluorescence to determine best-performing genotypes for drought-tolerance breeding. Twenty-six genetically diverse okra accessions were screened under non-stressed (NS) and drought-stressed (DS) conditions under a controlled glasshouse environment using a 13 × 2 alpha lattice design in three replicates, in two growing seasons. Data were subjected to statistical analyses using various procedures. A significant genotype × water condition interaction effect was recorded for transpiration rate (T), net CO2 assimilation (A), intrinsic water use efficiency (WUEi), instantaneous water use efficiency (WUEins), minimum fluorescence (Fo′), maximum fluorescence (Fm′), maximum quantum efficiency of photosystem II photochemistry (Fv′/Fm′), the effective quantum efficiency of PSII photochemistry (ɸPSII), photochemical quenching (qP), nonphotochemical quenching (qN) and relative measure of electron transport to oxygen molecules (ETR/A). The results suggested variable drought tolerance of the studied okra accessions for selection. Seven principal components (PCs) contributing to 82% of the total variation for assessed physiological traits were identified under DS conditions. Leaf gas exchange parameters, T, A and WUEi, and chlorophyll fluorescence parameters such as the ɸPSII, Fv′/Fm′, qP, qN, ETR and ETR/A had high loading scores and correlated with WUEi, the ɸPSII, qP and ETR under DS conditions. The study found that optimal gas exchange and photoprotection enhance drought adaptation in the assessed okra genotypes and tested water regimes. Using the physiological variables, the study identified drought-tolerant accessions, namely LS05, LS06, LS07 and LS08 based on high A, T, Fm′, Fv′/Fm′ and ETR, and LS10, LS11, LS18 and LS23 based on high AES, Ci, Ci/Ca, WUEi, WUEins, ɸPSII and AES. The selected genotypes are high-yielding (≥5 g/plant) under drought stress conditions and will complement phenotypic data and guide breeding for water-limited agro-ecologies.
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Yang J, Kuang MT, Yang L, Huang W, Hu JM. Modern interpretation of the traditional application of Shihu - A comprehensive review on phytochemistry and pharmacology progress of Dendrobium officinale. JOURNAL OF ETHNOPHARMACOLOGY 2023; 302:115912. [PMID: 36351476 DOI: 10.1016/j.jep.2022.115912] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 10/20/2022] [Accepted: 11/01/2022] [Indexed: 06/16/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The traditional Chinese medicine (TCM) "Shihu" has a long history of medicinal use in China from some species of Dendrobium. D. officinale is a major source of "Shihu" and is widely cultivated in south of China and listed separately as "Tiepi Shihu" by the Chinese Pharmacopoeia in now time. Traditionally, D. officinale has been widely used in daily health care and the treatment of diabetes and gastrointestinal diseases. AIM OF THIS REVIEW In order to better develop and utilize D. officinale, we conducted this systematic review of previous studies, showed clear structure of all isolates from D. officinale together with pharmacological progress, hoping to provide references for further research and utilization. In addition, specific display of the chemical components and the research progress of related activities can help to better understand the traditional records and modern pharmaceutical applications of the plant medicine. MATERIALS AND METHODS Information on phytochemistry and pharmacological studies of D. officinale was collected from various scientific databases including Web of Science, SciFinder, ACS, Springer, Scopus, PubMed, ScienceDirect, Google Scholar and CNKI. RESULTS More than 180 compounds isolated from D. officinale, including bibenzyls, phenols, phenylpropanoids, lignans, flavonoids and polysaccharides are listed in this review. Furthermore, modern pharmacological researches such as hypoglycemia, immune regulation, antioxidant, cardiovascular regulation and gastrointestinal protection are summarized. CONCLUSION Based on the summary of the research work of D. officinale, we systematically show the chemical composition of the plant, and concluded the relationship of those composition with plant habitat together with the relationship between the structure of chemical components and pharmacological activity. Moreover, we suggest that some of small molecule compounds could also be quality control of D. officinale besides polysaccharides.
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Affiliation(s)
- Jie Yang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of Chinese Academy of Science, Beijing, 100049, China
| | - Meng-Ting Kuang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; Bio-Innovation Center of DR PLANT, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Liu Yang
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; Bio-Innovation Center of DR PLANT, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
| | - Jiang-Miao Hu
- State Key Laboratory of Phytochemistry and Plant Resources in West China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; Bio-Innovation Center of DR PLANT, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of Chinese Academy of Science, Beijing, 100049, China.
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Perera-Castro AV, Flexas J. The ratio of electron transport to assimilation (ETR/A N): underutilized but essential for assessing both equipment's proper performance and plant status. PLANTA 2023; 257:29. [PMID: 36592261 DOI: 10.1007/s00425-022-04063-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
ETR/AN ratios should be in the range 7.5-10.5 for non-stressed C3 plants. Ratios extremely out of this range can be reflecting both uncontrolled plant status and technical mistakes during measurements. We urge users to explicitly refer to this ratio in future studies as a proof for internal data quality control. For the last few decades, the use of infra-red gas-exchange analysers (IRGAs) coupled with chlorophyll fluorometers that allow for measurements of net CO2 assimilation rate and estimates of electron transport rate over the same leaf area has been popularized. The evaluation of data from both instruments in an integrative manner can result in additional valuable information, such as the estimation of the light respiration, mesophyll conductance and the partitioning of the flux of electrons into carboxylation, oxygenation and alternative processes, among others. In this review, an additional and more 'straight' use of the combination of chlorophyll fluorescence and gas exchange-derived parameters is presented, namely using the direct ratio between two fully independently estimated parameters, electron transport rate (ETR)-determined by the fluorometer-and net CO2 assimilation rate (AN)-determined by the IRGA, i.e., the ETR/AN ratio, as a tool for fast detection of incongruencies in the data and potential technical problems associated with them, while checking for the study plant's status. To illustrate this application, a compilation of 75 studies that reported both parameters for a total of 178 species under varying physiological status is presented. Values of ETR/AN between 7.5 and 10.5 were most frequently found for non-stressed C3 plants. C4 species showed an average ETR/AN ratio of 4.7. The observed ratios were larger for species with high leaf mass per area and for plants subjected to stressful factors like drought or nutritional deficit. Knowing the expected ETR/AN ratio projects this ratio as a routinary and rapid check point for guaranteeing both the correct performance of equipment and the optimal/stress status of studied plants. All known errors associated with the under- or overestimation of ETR or AN are summarized in a checklist that aims to be routinely used by any IRGA/fluorometer user to strength the validity of their data.
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Affiliation(s)
- Alicia V Perera-Castro
- Department of Botany, Ecology and Plant Physiology, Universidad de La Laguna, Av. Astrofísico Francisco Sánchez, S/N, 38200, La Laguna, Canary Islands, Spain.
| | - Jaume Flexas
- Department of Biology, Agro-Environmental and Water Economics Institute (INAGEA), Universitat de LES Illes Balears, Carretera de Valldemossa Km 7.5, 07122, Palma, Illes Balears, Spain
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Du P, Cao Y, Yin B, Zhou S, Li Z, Zhang X, Xu J, Liang B. Improved tolerance of apple plants to drought stress and nitrogen utilization by modulating the rhizosphere microbiome via melatonin and dopamine. Front Microbiol 2022; 13:980327. [DOI: 10.3389/fmicb.2022.980327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 10/19/2022] [Indexed: 11/11/2022] Open
Abstract
This study explored the contributions of melatonin and dopamine to the uptake and utilization of nitrogen and the formation of rhizosphere microbial communities in ‘Tianhong 2’/M. hupehensis, with the goal improving plant resistance to drought stress. Drought stress was formed by artificially controlling soil moisture content. And melatonin or dopamine solutions were applied to the soil at regular intervals for experimental treatment. After 60 days of treatment, plant indices were determined and the structure of the rhizosphere microbial community was evaluated using high-throughput sequencing technology. The findings revealed two ways through which melatonin and dopamine alleviate the inhibition of growth and development caused by drought stress by promoting nitrogen uptake and utilization in plants. First, melatonin and dopamine promote the absorption and utilization of nitrogen under drought stress by directly activating nitrogen transporters and nitrogen metabolism-related enzymes in the plant. Second, they promote the absorption of nitrogen by regulating the abundances of specific microbial populations, thereby accelerating the transformation of the soil nitrogen pool to available nitrogen that can be absorbed directly by plant roots and utilized by plants. These findings provide a new framework for understanding how melatonin and dopamine regulate the uptake and utilization of nitrogen in plants and improve their ability to cope with environmental disturbances.
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Sun H, Wang XQ, Zeng ZL, Yang YJ, Huang W. Exogenous melatonin strongly affects dynamic photosynthesis and enhances water-water cycle in tobacco. FRONTIERS IN PLANT SCIENCE 2022; 13:917784. [PMID: 35991431 PMCID: PMC9381976 DOI: 10.3389/fpls.2022.917784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 07/11/2022] [Indexed: 06/09/2023]
Abstract
Melatonin (MT), an important phytohormone synthesized naturally, was recently used to improve plant resistance against abiotic and biotic stresses. However, the effects of exogenous melatonin on photosynthetic performances have not yet been well clarified. We found that spraying of exogenous melatonin (100 μM) to leaves slightly affected the steady state values of CO2 assimilation rate (A N ), stomatal conductance (g s ) and mesophyll conductance (g m ) under high light in tobacco leaves. However, this exogenous melatonin strongly delayed the induction kinetics of g s and g m , leading to the slower induction speed of A N . During photosynthetic induction, A N is mainly limited by biochemistry in the absence of exogenous melatonin, but by CO2 diffusion conductance in the presence of exogenous melatonin. Therefore, exogenous melatonin can aggravate photosynthetic carbon loss during photosynthetic induction and should be used with care for crop plants grown under natural fluctuating light. Within the first 10 min after transition from low to high light, photosynthetic electron transport rates (ETR) for A N and photorespiration were suppressed in the presence of exogenous melatonin. Meanwhile, an important alternative electron sink, namely water-water cycle, was enhanced to dissipate excess light energy. These results indicate that exogenous melatonin upregulates water-water cycle to facilitate photoprotection. Taking together, this study is the first to demonstrate that exogenous melatonin inhibits dynamic photosynthesis and improves photoprotection in higher plants.
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Affiliation(s)
- Hu Sun
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiao-Qian Wang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- School of Life Sciences, Northwest University, Xi’an, China
| | - Zhi-Lan Zeng
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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Yang YJ, Shi Q, Sun H, Mei RQ, Huang W. Differential Response of the Photosynthetic Machinery to Fluctuating Light in Mature and Young Leaves of Dendrobium officinale. FRONTIERS IN PLANT SCIENCE 2022; 12:829783. [PMID: 35185969 PMCID: PMC8850366 DOI: 10.3389/fpls.2021.829783] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 12/27/2021] [Indexed: 06/14/2023]
Abstract
A key component of photosynthetic electron transport chain, photosystem I (PSI), is susceptible to the fluctuating light (FL) in angiosperms. Cyclic electron flow (CEF) around PSI and water-water cycle (WWC) are both used by the epiphytic orchid Dendrobium officinale to protect PSI under FL. This study examined whether the ontogenetic stage of leaf has an impact on the photoprotective mechanisms dealing with FL. Thus, chlorophyll fluorescence and P700 signals under FL were measured in D. officinale young and mature leaves. Upon transition from dark to actinic light, a rapid re-oxidation of P700 was observed in mature leaves but disappeared in young leaves, indicating that WWC existed in mature leaves but was lacking in young leaves. After shifting from low to high light, PSI over-reduction was clearly missing in mature leaves. By comparison, young leaves showed a transient PSI over-reduction within the first 30 s, which was accompanied with highly activation of CEF. Therefore, the effect of FL on PSI redox state depends on the leaf ontogenetic stage. In mature leaves, WWC is employed to avoid PSI over-reduction. In young leaves, CEF around PSI is enhanced to compensate for the lack of WWC and thus to prevent an uncontrolled PSI over-reduction induced by FL.
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Affiliation(s)
- Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Qi Shi
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hu Sun
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Ren-Qiang Mei
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- Bio-Innovation Center of DR PLANT, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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Alteration of Metabolites Accumulation in Maize Inbreds Leaf Tissue under Long-Term Water Deficit. BIOLOGY 2021; 10:biology10080694. [PMID: 34439927 PMCID: PMC8389289 DOI: 10.3390/biology10080694] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 07/15/2021] [Accepted: 07/16/2021] [Indexed: 01/16/2023]
Abstract
Simple Summary As sessile organisms, plants are constantly exposed to diverse environmental stresses of which water deficit is the most significant because it limits plant growth, development, and productivity. In this work, we showed the influence of non-irrigation treatment on changes in maize leaf metabolite content. We argued that the different susceptibility of maize inbred lines to long-term water deficit will result in different patterns of change in metabolite accumulation. We emphasized the need for the careful interpretation of the level and type of accumulated metabolites in order to assess the drought tolerance status of maize inbred lines in terms of improved grain yield exhibited under severe water deficit conditions. Leaf metabolites that have contributed to higher grain yield under the condition of long-term water deficit could be considered as biochemical markers useful in breeding drought-tolerant maize. Abstract Plants reconfigure their metabolic pathways to cope with water deficit. The aim of this study was to determine the status of the physiological parameters and the content of phenolic acids in the upper most ear leaf of maize inbred lines contrasting in drought tolerance in terms of improved plant productivity e.g., increased grain yield. The experiment was conducted under irrigation and rain-fed conditions. In drought-tolerant lines, the effect of water deficit was reflected through a chlorophyll and nitrogen balance index increase followed by a flavonols index decrease. The opposite trend was noticed in drought susceptible inbreds, with the exception of the anthocyanins index. Moreover, in comparison to irrigation treatment, opposite trends in the correlations between grain yield and physiological parameters found under water deficit conditions indicated the activation of different metabolic pathways in defense against water deficit stress. Concerning phenolic acid content, water deficit caused the reduction of protocatechuic, caffeic, and sinapic acid in all inbreds evaluated. However, the highly pronounced increase of ferulic and especially cinnamic acid content under water deficit conditions indicated possible crucial role of these secondary metabolites in preventing the harmful effects of water deficit stress, which, in turn, might be useful in maize breeding selection for drought tolerance.
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Hessini K, Jeddi K, Siddique KHM, Cruz C. Drought and salinity: A comparison of their effects on the ammonium-preferring species Spartina alterniflora. PHYSIOLOGIA PLANTARUM 2021; 172:431-440. [PMID: 33063846 DOI: 10.1111/ppl.13241] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 10/06/2020] [Accepted: 10/12/2020] [Indexed: 05/14/2023]
Abstract
Drought and salinity are the most serious environmental factors affecting crop productivity worldwide; hence, it is important to select and develop both salt- and drought-tolerant crops. The perennial smooth cordgrass Spartina alterniflora Loisel is unusual in that it is highly salt-tolerant and seems to prefer ammonium (NH4 + ) over nitrate (NO3 - ) as an inorganic N source. In this study, we determined whether Spartina's unique preference for NH4 + enhances performance under salt and drought stress. Greenhouse experiments were conducted to compare the interactive effects of N source, salinity, and low water availability on plant performance (growth and antioxidant metabolism). Drought significantly reduced growth and photosynthetic activity in S. alterniflora, more so with NH4 + than NO3 - ; in contrast, NH4 + enhanced growth under high salinity. The increased tolerance of S. alterniflora to salt stress in the presence of NH4 + was linked to a high level of antioxidant enzyme activity, combined with low MDA content, EL, and H2 O2 production. In contrast, drought stress negated the growth advantages for S. alterniflora exposed to salt stress in the presence of NH4 + . The susceptibility of S. alterniflora to drought was partly due to reduced antioxidant enzyme activities, thereby reducing the defense against the oxidative damages induced by osmotic stress. In conclusion, in contrast to salt stress, drought stress negates the beneficial effects of ammonium as an N source in the C4 plant Spartina alterniflora.
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Affiliation(s)
- Kamel Hessini
- Department of Biology, College of Sciences, Taif University, Taif, Saudi Arabia
- Laboratory of Extremophile Plants, Centre of Biotechnology of Borj-Cedria, Tunis, Tunisia
| | - Kaouthar Jeddi
- Laboratory of Plant Biodiversity and Dynamic of Ecosystems in Arid Area, Faculty of Sciences of Sfax, Sfax, Tunisia
- Department of Biology, Faculty of Sciences of Gabès, Tunis, Tunisia
| | - Kadambot H M Siddique
- The UWA Institute of Agriculture, The University of Western Australia, Perth, Western Australia, Australia
| | - Cristina Cruz
- Departamento de Biologia Vegetal, Faculdade de Ciencias de Lisboa, Centro de Ecologia, Evolução e Alterações Ambientais - cE3c, Lisbon, Portugal
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12
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Huang W, Sun H, Tan SL, Zhang SB. The water-water cycle is not a major alternative sink in fluctuating light at chilling temperature. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2021; 305:110828. [PMID: 33691962 DOI: 10.1016/j.plantsci.2021.110828] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 11/30/2020] [Accepted: 01/12/2021] [Indexed: 05/13/2023]
Abstract
The water-water cycle (WWC) has the potential to alleviate photoinhibition of photosystem I (PSI) in fluctuating light (FL) at room temperature and moderate heat stress. However, it is unclear whether WWC can function as a safety valve for PSI in FL at chilling temperature. In this study, we measured P700 redox state and chlorophyll fluorescence in FL at 25 °C and 4 °C in the high WWC activity plant Dendrobium officinale. At 25 °C, the operation of WWC contributed to the rapid re-oxidation of P700 upon dark-to-light transition. However, such rapid re-oxidation of P700 was not observed at 4 °C. Upon a sudden increase in light intensity, WWC rapidly consumed excess electrons in PSI and thus avoided an over-reduction of PSI at 25 °C. On the contrary, PSI was highly reduced within the first seconds after transition from low to high light at 4 °C. Therefore, in opposite to 25 °C, the WWC is not a major alternative sink in FL at chilling temperature. Upon transition from low to high light, cyclic electron transport was highly stimulated at 4 °C when compared with 25 °C. These results indicate that D. officinale enhances cyclic electron transport to partially compensate for the inactivation of WWC in FL at 4 °C.
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Affiliation(s)
- Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; Bio-Innovation Center of DR PLANT, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China.
| | - Hu Sun
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shun-Ling Tan
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, China
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13
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Role of Suillus placidus in Improving the Drought Tolerance of Masson Pine (Pinus massoniana Lamb.) Seedlings. FORESTS 2021. [DOI: 10.3390/f12030332] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Masson pine is an important afforestation species in southern China, where seasonal drought is common. The present study focused on the effects of Suillus placidus, an ectomycorrhizal fungus, inoculation on the growth and physiological and biochemical performance of masson pine seedlings under four different watering treatments (well-watered, mild drought, moderate drought, and severe drought) to evaluate the symbiotic relationship between S. placidus and masson pine seedlings. Ectomycorrhizal-inoculated (ECM) and non-inoculated (NM) seedlings were grown in pots and maintained for 60 days using the weighing method. Results showed that seedlings’ growth, dry weight, RWC, chlorophyll content, PSII efficiency, and photosynthesis decreased as drought stress intensified in both ECM and NM plants. This suggests that drought stress significantly limits the growth and photosynthetic performance of masson pine seedlings. Nevertheless, increased An/gs and proline contents in both NM and ECM prevented oxidative damage caused by drought stress. In addition, increased peroxidase (POD) activity is an essential defense mechanism of ECM seedling under drought stress. Compared with NM, ECM seedlings showed faster growth, higher RWC, and photosynthetic performance, and lower lipid peroxidation in cell membranes under drought stress, as indicated by higher POD activity and lower proline and malondialdehyde (MDA). Our experiment found that S. placidus inoculation can enhance the drought resistance of masson pine seedlings by increasing antioxidant enzyme activity, water use efficiency, and proline content, thereby enhancing growth under water-deficiency conditions. S. placidus can be used to cultivate high-quality seedlings and improve their survival in regions that experience seasonal droughts.
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Optimal Nitrogen Supply Ameliorates the Performance of Wheat Seedlings under Osmotic Stress in Genotype-Specific Manner. PLANTS 2021; 10:plants10030493. [PMID: 33807753 PMCID: PMC7999466 DOI: 10.3390/plants10030493] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/26/2021] [Accepted: 03/02/2021] [Indexed: 11/17/2022]
Abstract
Strategies and coping mechanisms for stress tolerance under sub-optimal nutrition conditions could provide important guidelines for developing selection criteria in sustainable agriculture. Nitrogen (N) is one of the major nutrients limiting the growth and yield of crop plants, among which wheat is probably the most substantial to human diet worldwide. Physiological status and photosynthetic capacity of two contrasting wheat genotypes (old Slomer and modern semi-dwarf Enola) were evaluated at the seedling stage to assess how N supply affected osmotic stress tolerance and capacity of plants to survive drought periods. It was evident that higher N input in both varieties contributed to better performance under dehydration. The combination of lower N supply and water deprivation (osmotic stress induced by polyethylene glycol treatment) led to greater damage of the photosynthetic efficiency and a higher degree of oxidative stress than the individually applied stresses. The old wheat variety had better N assimilation efficiency, and it was also the one with better performance under N deficiency. However, when both N and water were deficient, the modern variety demonstrated better photosynthetic performance. It was concluded that different strategies for overcoming osmotic stress alone or in combination with low N could be attributed to differences in the genetic background. Better performance of the modern variety conceivably indicated that semi-dwarfing (Rht) alleles might have a beneficial effect in arid regions and N deficiency conditions.
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15
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Sun H, Yang YJ, Huang W. The water-water cycle is more effective in regulating redox state of photosystem I under fluctuating light than cyclic electron transport. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148235. [PMID: 32485160 DOI: 10.1016/j.bbabio.2020.148235] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/12/2020] [Accepted: 05/26/2020] [Indexed: 11/28/2022]
Abstract
Photosynthetic electron flux from water via photosystem II (PSII) and PSI to oxygen (water-water cycle) may act as an alternative electron sink under fluctuating light in angiosperms. We measured the P700 redox kinetics and electrochromic shift signal under fluctuating light in 11 Camellia species and tobacco leaves. Upon dark-to-light transition, these Camellia species showed rapid re-oxidation of P700. However, this rapid re-oxidation of P700 was not observed when measured under anaerobic conditions, as was in experiment with tobacco performed under aerobic conditions. Therefore, photo-reduction of O2 mediated by water-water cycle was functional in these Camellia species but not in tobacco. Within the first 10 s after transition from low to high light, PSI was highly oxidized in these Camellia species but was over-reduced in tobacco leaves. Furthermore, such rapid oxidation of PSI in these Camellia species was independent of the formation of trans-thylakoid proton gradient (ΔpH). These results indicated that in addition to ΔpH-dependent photosynthetic control, the water-water cycle can protect PSI against photoinhibition under fluctuating light in these Camellia species. We here propose that the water-water cycle is an overlooked strategy for photosynthetic regulation under fluctuating light in angiosperms.
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Affiliation(s)
- Hu Sun
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ying-Jie Yang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wei Huang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
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16
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Huang W, Yang YJ, Wang JH, Hu H. Photorespiration is the major alternative electron sink under high light in alpine evergreen sclerophyllous Rhododendron species. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2019; 289:110275. [PMID: 31623777 DOI: 10.1016/j.plantsci.2019.110275] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 08/08/2019] [Accepted: 09/13/2019] [Indexed: 06/10/2023]
Abstract
Owing to the high leaf mass per area, alpine evergreen sclerophyllous Rhododendron have low values of mesophyll conductance (gm). The resulting low chloroplast CO2 concentration aggravates photorespiration, which requires a higher ATP/NADPH ratio. However, the significance of photorespiration and underlying mechanisms of energy balance in these species are little known. In this study, eight alpine evergreen sclerophyllous Rhododendron species grown in a common garden were tested for their gm, electron flow to photorespiration, and energy balancing. Under saturating light, gm was the most limiting factor for net photosynthesis (AN) in all species, and the species differences in AN were primarily driven by gm rather than stomatal conductance. The total electron flow through photosystem II (ETRII) nearly equaled the electron transport required for Rubisco carboxylation and oxygenation. Furthermore, blocking electron flow to photosystem I with appropriate inhibitors showed that electron flow to plastic terminal oxidase was not observed. As a result, these studied species showed little alternative electron flow mediated by water-water cycle or plastic terminal oxidase. By comparison, the ratio of electron transport consumed by photorespiration to ETRII (JPR/ETRII), ranging from 43%∼55%, was negatively correlated to AN and gm. Furthermore, the increased ATP production required by enhanced photorespiration was regulated by cyclic electron flow around photosystem I. These results indicate that photorespiration is the major electron sink for dissipation of excess excitation energy in the alpine evergreen sclerophyllous Rhododendron species. The coordination of gm, photorespiration and cyclic electron flow is important for sustaining leaf photosynthesis.
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Affiliation(s)
- Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, PR China
| | - Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Ji-Hua Wang
- Flower Research Institute of Yunnan Academy of Agricultural Sciences, Kunming, Yunnan, PR China.
| | - Hong Hu
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan, 650201, PR China.
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17
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Zhang L, Li G, Dong G, Wang M, Di D, Kronzucker HJ, Shi W. Characterization and comparison of nitrate fluxes in Tamarix ramosissima and cotton roots under simulated drought conditions. TREE PHYSIOLOGY 2019; 39:628-640. [PMID: 30566674 DOI: 10.1093/treephys/tpy126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 09/13/2018] [Accepted: 11/23/2018] [Indexed: 05/24/2023]
Abstract
Tamarix ramosissima Ledeb., a major host plant for the parasitic angiosperm Cistanche tubulosa, and known for its unique drought tolerance, has significant ecological and economic benefits. However, the mechanisms of nitrogen acquisition by the T. ramosissima root system under drought have remained uncharacterized. Here, uptake of nitrate (NO3-) in various regions of the root system was measured in T. ramosissima using Non-invasive Micro-test Technology at the cellular level, and using a 15NO3--enrichment technique at the whole-root level. These results were compared with responses in the model system cotton (Gossypium hirsutum L.). Tamarix ramosissima had lower net NO3- influx and a significantly lower Km (the apparent Michalis-Menten constant; 8.5 μM) for NO3- uptake than cotton under normal conditions. Upon simulated drought conditions, using polyethylene glycol (PEG), NO3- flux in cotton switched from net influx to net efflux, with a substantive peak in the white zone (WZ) of the root. There were no significant NO3- influx signals observed in the WZ of T. ramosissima under control conditions, whereas PEG treatment significantly enhanced NO3- influx in the WZ of T. ramosissima. The effect of PEG application on NO3- fluxes was highly localized, and the increase in net NO3- influx in response to PEG stimulation was also found in C. tubulosa-inoculated T. ramosissima. Consistently, root nitrogen (N) content and root biomass were higher in T. ramosissima than in cotton under PEG treatment. Our study provides insights into NO3- uptake and the influence of C. tubulosa inoculation in T. ramosissima roots during acclimation to PEG-induced drought stress and provides guidelines for silvicultural practice and for breeding of T. ramosissima under coupled conditions of soil drought and N deficiency.
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Affiliation(s)
- Lin Zhang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, China
- University of the Chinese Academy of Sciences, No.19(A) Yuquan Road, Shijingshan District, Beijing , China
| | - Guangjie Li
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, China
| | - Gangqiang Dong
- Amway (China) Botanical R&D Center, Wuxi, Jiangsu, China
| | - Meng Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, China
| | - Dongwei Di
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, China
| | - Herbert J Kronzucker
- School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, VIC, Australia
| | - Weiming Shi
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, No. 71 East Beijing Road, Nanjing, China
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18
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Huang W, Yang YJ, Zhang SB. The role of water-water cycle in regulating the redox state of photosystem I under fluctuating light. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2019; 1860:383-390. [PMID: 30890407 DOI: 10.1016/j.bbabio.2019.03.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 12/18/2018] [Accepted: 03/14/2019] [Indexed: 10/27/2022]
Abstract
The regulation of photosystem I (PSI) redox state under fluctuating light was investigated for four species using P700 measurement and electrochromic shift analysis. Species included the angiosperms Camellia japonica, Bletilla striata and Arabidopsis thaliana and the fern Cyrtomium fortunei. For the first seconds after transition from low to high light, all species showed relatively low levels of the proton gradient (ΔpH) across the thylakoid membranes. At this moment, PSI was highly oxidized in C. japonica and C. fortunei but was over-reduced in B. striata and A. thaliana. In B. striata and A. thaliana, the redox state of PSI was largely dependent on ΔpH. In contrast, the rapid oxidation of P700 in C. japonica was relatively independent of ΔpH, but was mainly dependent on the outflow of electrons to O2 via the water-water cycle. In the fern C. fortunei, PSI redox state was rapidly regulated by the fast photo-reduction of O2 rather than the ΔpH. These results indicate that mechanisms regulating PSI redox state under fluctuating light differ greatly between species. We propose that the water-water cycle is an important mechanism regulating the PSI redox state in angiosperms.
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Affiliation(s)
- Wei Huang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Ying-Jie Yang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shi-Bao Zhang
- Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
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19
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Cao X, Zhong C, Zhu C, Zhu L, Zhang J, Wu L, Jin Q. Ammonium uptake and metabolism alleviate PEG-induced water stress in rice seedlings. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2018; 132:128-137. [PMID: 30189416 DOI: 10.1016/j.plaphy.2018.08.041] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 07/27/2018] [Accepted: 08/30/2018] [Indexed: 05/01/2023]
Abstract
Ammonium (NH4+) can enhance the water stress induced drought tolerance of rice seedlings in comparison to nitrate (NO3-) nutrition. To investigate the mechanism involved in nitrogen (N) uptake, N metabolism and transcript abundance of associated genes, a hydroponic experiment was conducted in which different N sources were supplied to seedlings growing under water stress. Compared to nitrate, ammonium prevented water stress-induced biomass, leaf SPAD and photosynthesis reduction to a significantly larger extent. Water stress significantly increased root nitrate reductase (NR) and nitrite reductase (NiR) activities, but decreased leaf NiR and glutamate synthetase (GS) activities under NO3- supply, causing lower nitrate content in roots and higher in leaves. In contrast, under NH4+ supply root GS and glutamine oxoglutarate aminotransferase (GOGAT) activities were significantly decreased under water stress, but remained higher in leaves, compared to NO3- treatment, which was beneficial for the transport and assimilation of ammonium in leaves. 15N tracing assays demonstrated that rice 15N uptake rate and accumulation were significant reduced under water stress, but were higher in plants supplied with NH4+ than with NO3-. Therefore, the formers showed higher leaf soluble sugar, proline and amino acids contents, and in turn, associated with a higher photosynthesis rate and biomass accumulation. Most genes related to NO3- uptake and reduction in roots and leaves were down-regulated; however, two ammonium transporter genes closely related to NH4+ uptake (AMT1;2 and AMT1;3) were up-regulated in response to water stress. Overall, our findings suggest that ammonium supply alleviated waters tress in rice seedlings, mainly by increasing root NH4+ uptake and leaf N metabolism.
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Affiliation(s)
- Xiaochuang Cao
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China
| | - Chu Zhong
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China
| | - Chunquan Zhu
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China
| | - Lianfeng Zhu
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China
| | - Junhua Zhang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China
| | - Lianghuan Wu
- Ministry of Education Key Laboratory of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Qianyu Jin
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, China.
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20
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Singh SK, Reddy VR. Co-regulation of photosynthetic processes under potassium deficiency across CO 2 levels in soybean: mechanisms of limitations and adaptations. PHOTOSYNTHESIS RESEARCH 2018; 137:183-200. [PMID: 29478203 DOI: 10.1007/s11120-018-0490-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Accepted: 02/18/2018] [Indexed: 06/08/2023]
Abstract
Plants photosynthesis-related traits are co-regulated to capture light and CO2 to optimize the rate of CO2 assimilation (A). The rising CO2 often benefits, but potassium (K) deficiency adversely affects A that contributes to the majority of plant biomass. To evaluate mechanisms of photosynthetic limitations and adaptations, soybean was grown under controlled conditions with an adequate (control, 5.0 mM) and two K-deficient (moderate, 0.50 and severe, 0.02 mM) levels under ambient (aCO2; 400 µmol mol-1) and elevated CO2 (eCO2; 800 µmol mol-1). Results showed that under severe K deficiency, pigments, leaf absorption, processes of light and dark reactions, and CO2 diffusion through stomata and mesophyll were down co-regulated with A while light compensation point increased and photorespiration, alternative electron fluxes, and respiration were up-regulated. However, under moderate K deficiency, these traits were well co-regulated with the sustained A without any obvious limitations amid ≈ 50% reduction in leaf K level. Primary mechanism of K limitation to A was either biochemical processes (Lb ≈ 60%) under control and moderate K deficiency or the CO2 diffusion limitations (DL ≈ 70%) with greater impacts of mesophyll than stomatal pathways under severe K deficiency. The eCO2 increased DL while lessened the Lb under K deficiency. Adaptation strategies to severe K deficiency included an enhanced K utilization efficiency (KUE), and reduction of photosystem II excitation pressure by decreasing photosynthetic pigments, light absorption, and photochemical quenching while increasing photorespiration and alternative electron fluxes. The eCO2 also stimulated A and KUE when K deficiency was not severe. Thus, plants responded to K deficiency by a coordinated regulation of photosynthetic processes to optimize A, and eCO2 failed to alleviate the DL in severely K-deficient plants.
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Affiliation(s)
- Shardendu K Singh
- Adaptive Cropping Systems Laboratory, USDA-ARS, Beltsville, MD, 20705, USA.
- Wye Research and Education Center, University of Maryland, College Park, MD, USA.
| | - Vangimalla R Reddy
- Adaptive Cropping Systems Laboratory, USDA-ARS, Beltsville, MD, 20705, USA
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21
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Zhong C, Cao X, Bai Z, Zhang J, Zhu L, Huang J, Jin Q. Nitrogen metabolism correlates with the acclimation of photosynthesis to short-term water stress in rice (Oryza sativa L.). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2018; 125:52-62. [PMID: 29413631 DOI: 10.1016/j.plaphy.2018.01.024] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/18/2018] [Accepted: 01/23/2018] [Indexed: 05/12/2023]
Abstract
Nitrogen metabolism is as sensitive to water stress as photosynthesis, but its role in plant under soil drying is not well understood. We hypothesized that the alterations in N metabolism could be related to the acclimation of photosynthesis to water stress. The features of photosynthesis and N metabolism in a japonica rice 'Jiayou 5' and an indica rice 'Zhongzheyou 1' were investigated under mild and moderate soil drying with a pot experiment. Soil drying increased non-photochemical quenching (NPQ) and reduced photon quantum efficiency of PSII and CO2 fixation in 'Zhongzheyou 1', whereas the effect was much slighter in 'Jiayou 5'. Nevertheless, the photosynthetic rate of the two cultivars showed no significant difference between control and water stress. Soil drying increased nitrate reducing in leaves of 'Zhongzheyou 1', characterized by enhanced nitrate reductase (NR) activity and lowered nitrate content; whereas glutamate dehydrogenase (GDH), glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) were relative slightly affected. 'Jiayou 5' plants increased the accumulation of nitrate under soil drying, although its NR activity was increased. In addition, the activities of GDH, GOT and GPT were typically increased under soil drying. Besides, amino acids and soluble sugar were significantly increased under mild and moderate soil drying, respectively. The accumulation of nitrate, amino acid and sugar could serve as osmotica in 'Jiayou 5'. The results reveal that N metabolism plays diverse roles in the photosynthetic acclimation of rice plants to soil drying.
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Affiliation(s)
- Chu Zhong
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China; Crop Physiology and Production Center, Huazhong Agricultural University, Wuhan 420007, China
| | - Xiaochuang Cao
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Zhigang Bai
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Junhua Zhang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Lianfeng Zhu
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Jianliang Huang
- Crop Physiology and Production Center, Huazhong Agricultural University, Wuhan 420007, China
| | - Qianyu Jin
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China.
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22
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Chen Z, Tao X, Khan A, Tan DKY, Luo H. Biomass Accumulation, Photosynthetic Traits and Root Development of Cotton as Affected by Irrigation and Nitrogen-Fertilization. FRONTIERS IN PLANT SCIENCE 2018; 9:173. [PMID: 29497435 PMCID: PMC5819319 DOI: 10.3389/fpls.2018.00173] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 01/30/2018] [Indexed: 05/12/2023]
Abstract
Limitations of soil water and nitrogen (N) are factors which cause a substantial reduction in cotton (Gossypium hirsutum L.) yield, especially in an arid environment. Suitable management decisions like irrigation method and nitrogen fertilization are the key yield improvement technologies in cotton production systems. Therefore, we hypothesized that optimal water-N supply can increase cotton plant biomass accumulation by maintaining leaf photosynthetic capacity and improving root growth. An outdoor polyvinyl chloride (PVC) tube study was conducted to investigate the effects of two water-N application depths, i.e., 20 cm (H20) or 40 cm (H40) from soil surface and four water-N combinations [deficit irrigation (W55) and no N (N0) (W55N0), W55 and moderate N (N1) (W55N1), moderate irrigation (W75) and N0 (W75N0), W75N1] on the roots growth, leaf photosynthetic traits and dry mass accumulation of cotton crops. H20W55N1 combination increased total dry mass production by 29-82% and reproductive organs biomass by 47-101% compared with other counterparts. Root protective enzyme and nitrate reductase (NR) activity, potential quantum yield of photosystem (PS) II (Fv/Fm), PSII quantum yield in the light [Y(II)] and electron transport rate of PSII were significantly higher in H20W55N1 prior to 82 days after emergence. Root NR activity and protective enzyme were significantly correlated with chlorophyll, Fv/Fm, Y(II) and stomatal conductance. Hence, shallow irrigation (20 cm) with moderate irrigation and N-fertilization application could increase cotton root NR activity and protective enzyme leading to enhance light capture and photochemical energy conversion of PSII before the full flowering stage. This enhanced photoassimilate to reproductive organs.
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Affiliation(s)
- Zongkui Chen
- Key Laboratory of Oasis Eco-Agriculture, Xinjiang Production and Construction Group, College of Agriculture, Shihezi University, Shihezi, China
| | - Xianping Tao
- Key Laboratory of Oasis Eco-Agriculture, Xinjiang Production and Construction Group, College of Agriculture, Shihezi University, Shihezi, China
- Center of Agricultural Technique Extension of Manasi County, Manasi, China
| | - Aziz Khan
- Key Laboratory of Plant Genetics and Breeding, College of Agriculture, Guangxi University, Nanning, China
| | - Daniel K. Y. Tan
- Faculty of Science, Plant Breeding Institute, Sydney Institute of Agriculture, School of Life and Environmental Sciences, The University of Sydney, Sydney, NSW, Australia
| | - Honghai Luo
- Key Laboratory of Oasis Eco-Agriculture, Xinjiang Production and Construction Group, College of Agriculture, Shihezi University, Shihezi, China
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23
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Yi XP, Zhang YL, Yao HS, Han JM, Chow WS, Fan DY, Zhang WF. Changes in activities of both photosystems and the regulatory effect of cyclic electron flow in field-grown cotton (Gossypium hirsutum L) under water deficit. JOURNAL OF PLANT PHYSIOLOGY 2018; 220:74-82. [PMID: 29156245 DOI: 10.1016/j.jplph.2017.10.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 09/28/2017] [Accepted: 10/29/2017] [Indexed: 05/26/2023]
Abstract
To clarify the influence of water deficit on the functionality of the photosynthetic apparatus of cotton plants, leaf gas exchange, chlorophyll a fluorescence, and P700 redox state were examined in field-grown cotton Gossypium hirsutum L. cv. Xinluzao 45. In addition, we measured changes in the P515 signal and analyzed the activity of ATP synthase and the trans-thylakoid proton gradient (ΔpH). With increasing water deficit, the net CO2 assimilation rate (AN) and stomatal conductance (gs) significantly decreased, but the maximum quantum efficiency of PSII photochemistry (Fv/Fm) did not change. The photochemical activity of photosystem II (PSII) was reflected by the photochemical quenching coefficient (qP), quantum efficiency of photosystem II [Y(II)], and electron transport rate through PSII [ETR(II)], while the activity of photosystem I (PSI) was reflected by the quantum efficiency of photosystem I [Y(I)] and the electron transport rate through PSI [ETR(I)]. Both activities were maintained under mild water deficit, but were slightly decreased under moderate water deficit. Under moderate water deficit, cyclic electron flow (CEF), the fraction of absorbed light dissipated thermally via the ΔpH- and xanthophyll-regulated process [Y(NPQ)], and the fraction of P700 oxidized under a given set of conditions [Y(ND)] increased. Our results suggest that the activities of both photosystems are stable under mild water deficit and decrease only slightly under moderate water deficit. Moderate water deficit stimulates CEF, and the stimulation of CEF is essential for protecting PSI and PSII against photoinhibition.
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Affiliation(s)
- Xiao-Ping Yi
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China
| | - Ya-Li Zhang
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China
| | - He-Sheng Yao
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China
| | - Ji-Mei Han
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China
| | - Wah Soon Chow
- Division of Plant Sciences, Research School of Biology, College of Science, The Australian National University, Acton, ACT, 2601, Australia
| | - Da-Yong Fan
- Division of Plant Sciences, Research School of Biology, College of Science, The Australian National University, Acton, ACT, 2601, Australia
| | - Wang-Feng Zhang
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi, 832003, PR China.
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Zhong C, Cao X, Hu J, Zhu L, Zhang J, Huang J, Jin Q. Nitrogen Metabolism in Adaptation of Photosynthesis to Water Stress in Rice Grown under Different Nitrogen Levels. FRONTIERS IN PLANT SCIENCE 2017; 8:1079. [PMID: 28690622 PMCID: PMC5481364 DOI: 10.3389/fpls.2017.01079] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/06/2017] [Indexed: 05/09/2023]
Abstract
To investigate the role of nitrogen (N) metabolism in the adaptation of photosynthesis to water stress in rice, a hydroponic experiment supplying with low N (0.72 mM), moderate N (2.86 mM), and high N (7.15 mM) followed by 150 g⋅L-1 PEG-6000 induced water stress was conducted in a rainout shelter. Water stress induced stomatal limitation to photosynthesis at low N, but no significant effect was observed at moderate and high N. Non-photochemical quenching was higher at moderate and high N. In contrast, relative excessive energy at PSII level (EXC) was declined with increasing N level. Malondialdehyde and hydrogen peroxide (H2O2) contents were in parallel with EXC. Water stress decreased catalase and ascorbate peroxidase activities at low N, resulting in increased H2O2 content and severer membrane lipid peroxidation; whereas the activities of antioxidative enzymes were increased at high N. In accordance with photosynthetic rate and antioxidative enzymes, water stress decreased the activities of key enzymes involving in N metabolism such as glutamate synthase and glutamate dehydrogenase, and photorespiratory key enzyme glycolate oxidase at low N. Concurrently, water stress increased nitrate content significantly at low N, but decreased nitrate content at moderate and high N. Contrary to nitrate, water stress increased proline content at moderate and high N. Our results suggest that N metabolism appears to be associated with the tolerance of photosynthesis to water stress in rice via affecting CO2 diffusion, antioxidant capacity, and osmotic adjustment.
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Affiliation(s)
- Chu Zhong
- National Key Laboratory of Rice Biology, China National Rice Research InstituteHangzhou, China
- Crop Physiology and Production Center, Huazhong Agricultural UniversityWuhan, China
| | - Xiaochuang Cao
- National Key Laboratory of Rice Biology, China National Rice Research InstituteHangzhou, China
| | - Jijie Hu
- National Key Laboratory of Rice Biology, China National Rice Research InstituteHangzhou, China
| | - Lianfeng Zhu
- National Key Laboratory of Rice Biology, China National Rice Research InstituteHangzhou, China
| | - Junhua Zhang
- National Key Laboratory of Rice Biology, China National Rice Research InstituteHangzhou, China
| | - Jianliang Huang
- Crop Physiology and Production Center, Huazhong Agricultural UniversityWuhan, China
| | - Qianyu Jin
- National Key Laboratory of Rice Biology, China National Rice Research InstituteHangzhou, China
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Hessini K, Kronzucker HJ, Abdelly C, Cruz C. Drought stress obliterates the preference for ammonium as an N source in the C 4 plant Spartina alterniflora. JOURNAL OF PLANT PHYSIOLOGY 2017; 213:98-107. [PMID: 28342331 DOI: 10.1016/j.jplph.2017.03.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 03/06/2017] [Accepted: 03/07/2017] [Indexed: 06/06/2023]
Abstract
The C4 grass Spartina alterniflora is known for its unique salt tolerance and strong preference for ammonium (NH4+) as a nitrogen (N) source. We here examined whether Spartina's unique preference for NH4+ results in improved performance under drought stress. Manipulative greenhouse experiments were carried out to measure the effects of variable water availability and inorganic N sources on plant performance (growth, photosynthesis, antioxidant, and N metabolism). Drought strongly reduced leaf number and area, plant fresh and dry weight, and photosynthetic activity on all N sources, but the reduction was most pronounced on NH4+. Indeed, the growth advantage seen on NH4+ in the absence of drought, producing nearly double the biomass compared to growth on NO3-, was entirely obliterated under both intermediate and severe drought conditions (50 and 25% field capacity, respectively). Both fresh and dry weight became indistinguishable among N sources under drought. Major markers of the antioxidant capacity of the plant, the activities of the enzymes superoxide dismutase, catalase, ascorbate peroxidase, and glutathione reductase, showed higher constitutive levels on NH4+. Catalase and glutathione reductase were specifically upregulated in NH4+-fed plants with increasing drought stress. This upregulation, however, failed to protect the plants from drought stress. Nitrogen metabolism was characterized by lower constitutive levels of glutamine synthetase in NH4+-fed plants, and a rise in glutamate dehydrogenase (GDH) activity under drought, accompanied by elevated proline levels in leaves. Our results support postulates on the important role of GDH induction, and its involvement in the synthesis of compatible solutes, under abiotic stress. We show that, despite this metabolic shift, S. alterniflora's sensitivity to drought does not benefit from growth on NH4+ and that the imposition of drought stress equalizes all N-source-related growth differences observed under non-drought conditions.
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Affiliation(s)
- Kamel Hessini
- Laboratory of Extremophiles Plants, Center of Biotechnology of Borj Cedria, University of Tunis El Manar, Tunisia; Biology Department, Faculty of Science, Taif University, Taif 888, Saudi Arabia.
| | - Herbert J Kronzucker
- Department of Biological Sciences & Canadian Centre for World Hunger Research, University of Toronto, 1265 Military Trail, Toronto, ON, M1C 1A4, Canada; School of BioSciences, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Chedly Abdelly
- Laboratory of Extremophiles Plants, Center of Biotechnology of Borj Cedria, University of Tunis El Manar, Tunisia
| | - Cristina Cruz
- Departamento de BiologiaVegetal, Faculdade de Ciencias de Lisboa, Centro de Biologia Ambiental-CBA, Campo Grande, Bloco C-2, Piso 4, 1749-016 Lisboa, Portugal
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The water-water cycle is a major electron sink in Camellia species when CO 2 assimilation is restricted. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2017; 168:59-66. [PMID: 28171808 DOI: 10.1016/j.jphotobiol.2017.01.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 01/22/2017] [Accepted: 01/30/2017] [Indexed: 01/30/2023]
Abstract
The water-water cycle (WWC) is thought to dissipate excess excitation energy and balance the ATP/NADPH energy budget under some conditions. However, the importance of the WWC in photosynthetic regulation remains controversy. We observed that three Camellia cultivars exhibited high rates of photosynthetic electron flow under high light when photosynthesis was restricted. We thus tested the hypothesis that the WWC is a major electron sink in the three Camellia cultivars when CO2 assimilation is restricted. Light response curves indicated that the WWC was strongly increased with photorespiration and was positively correlated with extra ATP supplied from other flexible mechanisms excluding linear electron flow, implying that the WWC is an important alternative electron sink to balance ATP/NADPH energy demand for sustaining photorespiration in Camellia cultivars. Interestingly, when photosynthesis was depressed by the decreases in stomatal and mesophyll conductance, the rates of photosynthetic electron flow through photosystem II declined slightly and the rates of WWC was enhanced. Furthermore, the increased electron flow of WWC was positively correlated with the ratio of Rubisco oxygenation to carboxylation, supporting the involvement of alternative electron flow in balancing the ATP/NADPH energy budget. We propose that the WWC is a crucial electron sink to regulate ATP/NADPH energy budget and dissipate excess energy excitation in Camellia species when CO2 assimilation is restricted.
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Huang W, Tong YG, Yu GY, Yang WX. The Sclerophyllous Eucalyptus camaldulensis and Herbaceous Nicotiana tabacum Have Different Mechanisms to Maintain High Rates of Photosynthesis. FRONTIERS IN PLANT SCIENCE 2016; 7:1769. [PMID: 27933083 PMCID: PMC5121285 DOI: 10.3389/fpls.2016.01769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 11/10/2016] [Indexed: 06/06/2023]
Abstract
It is believed that high levels of mesophyll conductance (gm) largely contribute to the high rates of photosynthesis in herbaceous C3 plants. However, some sclerophyllous C3 plants that display low levels of gm have high rates of photosynthesis, and the underlying mechanisms responsible for high photosynthetic rates in sclerophyllous C3 plants are unclear. In the present study, we examined photosynthetic characteristics in two high-photosynthesis plants (the sclerophyllous Eucalyptus camaldulensis and the herbaceous Nicotiana tabacum) using measurements of gas exchange and chlorophyll fluorescence. Under saturating light intensities, both species had similar rates of CO2 assimilation at 400 μmol mol-1 CO2 (A400). However, E. camaldulensis exhibited significantly lower gm and chloroplast CO2 concentration (Cc) than N. tabacum. A quantitative analysis revealed that, in E. camaldulensis, the gm limitation was the most constraining factor for photosynthesis. By comparison, in N. tabacum, the biochemical limitation was the strongest, followed by gm and gs limitations. In conjunction with a lower Cc, E. camaldulensis up-regulated the capacities of photorespiratory pathway and alternative electron flow. Furthermore, the rate of alternative electron flow was positively correlated with the rates of photorespiration and ATP supply from other flexible mechanisms, suggesting the important roles of photorespiratory pathway, and alternative electron flow in sustaining high rate of photosynthesis in E. camaldulensis. These results highlight the different mechanisms used to maintain high rates of photosynthesis in the sclerophyllous E. camaldulensis and the herbaceous N. tabacum.
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Affiliation(s)
- Wei Huang
- Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of SciencesMengla, China
- Department of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
| | - You-Gui Tong
- Forestry Bureau of Dongchuan CountyKunming, China
| | - Guo-Yun Yu
- Forestry Bureau of Dongchuan CountyKunming, China
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Huang W, Yang YJ, Hu H, Zhang SB. Seasonal variations in photosystem I compared with photosystem II of three alpine evergreen broad-leaf tree species. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2016; 165:71-79. [PMID: 27768955 DOI: 10.1016/j.jphotobiol.2016.10.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/09/2016] [Accepted: 10/12/2016] [Indexed: 12/22/2022]
Abstract
Low temperature associated with high light can induce photoinhibition of photosystem I (PSI) and photosystem II (PSII). However, the photosynthetic electron flow and specific photoprotective responses in alpine evergreen broad-leaf plants in winter is unclear. We analyzed seasonal changes in PSI and PSII activities, and energy quenching in PSI and PSII in three alpine broad-leaf tree species, Quercus guyavifolia (Fagaceae), Rhododendron decorum (Ericaceae), Euonymus tingens (Celastraceae). In winter, PSII activity remained stable in Q. guyavifolia but decreased significantly in R. decorum and E. tingens. Q. guyavifolia showed much higher capacities of cyclic electron flow (CEF), water-water cycle (WWC), non-photochemical quenching (NPQ) than R. decorum and E. tingens in winter. These results indicated that in alpine evergreen broad-leaf tree species the PSII activity in winter was closely related to these photoprotective mechanisms. Interestingly, unlike PSII, PSI activity was maintained stable in winter in the three species. Meanwhile, photosynthetic electron flow from PSII to PSI (ETRII) was much higher in Q. guyavifolia, suggesting that the mechanisms protecting PSI activity against photoinhibition in winter differed among the three species. A high level of CEF contributed the stability of PSI activity in Q. guyavifolia. By comparison, R. decorum and E. tingens prevented PSI photoinhibition through depression of electron transport to PSI. Taking together, CEF, WWC and NPQ played important roles in coping with excess light energy in winter for alpine evergreen broad-leaf tree species.
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Affiliation(s)
- Wei Huang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China.
| | - Ying-Jie Yang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Hong Hu
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
| | - Shi-Bao Zhang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, Yunnan 650201, China
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Yi XP, Zhang YL, Yao HS, Luo HH, Gou L, Chow WS, Zhang WF. Rapid recovery of photosynthetic rate following soil water deficit and re-watering in cotton plants (Gossypium herbaceum L.) is related to the stability of the photosystems. JOURNAL OF PLANT PHYSIOLOGY 2016; 194:23-34. [PMID: 26948982 DOI: 10.1016/j.jplph.2016.01.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Revised: 12/17/2015] [Accepted: 01/04/2016] [Indexed: 05/20/2023]
Abstract
The responses of gas exchange, chlorophyll fluorescence and the anti-oxidative system of cotton leaves were studied during water deficit and recovery. The results show that water deficit led to a reversible reduction in the photosynthetic rate. This reduction was mainly accompanied by stomatal limitation. The activity of photosystem II (PSII) and photosystem I (PSI) was relatively stable during water deficit and recovery. Water deficit caused an enhanced production of reactive oxygen species (ROS) and increased lipid peroxidation. Proline accumulation and the anti-oxidative enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX) and peroxidase (POD), along with the antioxidant ascorbate (AsA), increased during water deficit. On re-watering, the ROS generation rate, anti-oxidative enzymes activities and the extent of the lipid peroxidation returned to near control values. Overall, rapid recovery of the photosynthetic rate is related to the stability of the photosystems which appears to be a critical mechanism allowing cotton plants to withstand and survive drought environments.
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Affiliation(s)
- Xiao-Ping Yi
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi 832003, PR China
| | - Ya-Li Zhang
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi 832003, PR China
| | - He-Sheng Yao
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi 832003, PR China
| | - Hong-Hai Luo
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi 832003, PR China
| | - Ling Gou
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi 832003, PR China
| | - Wah Soon Chow
- Division of Plant Sciences, Research School of Biology, College of Medicine, Biology and Environment, The Australian National University, ACTON ACT 2601, Australia
| | - Wang-Feng Zhang
- The Key Laboratory of Oasis Eco-agriculture, Xinjiang Production and Construction Group, Shihezi University, Shihezi 832003, PR China.
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Huang W, Yang YJ, Hu H, Zhang SB. Response of the water-water cycle to the change in photorespiration in tobacco. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2016; 157:97-104. [PMID: 26896885 DOI: 10.1016/j.jphotobiol.2016.02.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 01/26/2016] [Accepted: 02/03/2016] [Indexed: 01/20/2023]
Abstract
Photosynthetic electron transport produces ATP and NADPH, which are used by the primary metabolism. The production and consumption of ATP and NADPH must be balanced to maintain steady-state rates of CO2 assimilation and photorespiration. It has been indicated that the water-water cycle (WWC) is indispensable for driving photosynthesis via increasing ATP/NADPH production. However, the relationship between the WWC and photorespiration is little known. We tested the hypothesis that the WWC responds to change in photorespiration by balancing ATP/NADPH ratio. Measurements of gas exchange and chlorophyll fluorescence were conducted in tobacco plants supplied with high (HN-plants) or low nitrogen concentration (LN-plants). The WWC was activated under high light but not low light in both HN-plants and LN-plants. HN-plants had significantly higher capacities of the WWC and photorespiration than LN-plants. Under high light, the relative high WWC activation in HN-plants was accompanied with relative low levels of NPQ compared LN-plants, suggesting that the main role of the WWC under high light was to favor ATP synthesis but not to activate NPQ. Interestingly, the activation of WWC was positively correlated to the electron flow devoted to RuBP oxygenation, indicating that the WWC plays an important role in energy balancing when photorespiration is high. We conclude that the WWC is an important flexible mechanism to optimize the stoichiometry of the ATP/NADPH ratio responding to change in photorespiration. Furthermore, HN-plants enhance the WWC activity to maintain higher rates of CO2 assimilation and photorespiration.
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Affiliation(s)
- Wei Huang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China; Yunnan Key Laboratory for Wild Plant Resources, Kunming 650201, Yunnan, China
| | - Ying-Jie Yang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China; Yunnan Key Laboratory for Wild Plant Resources, Kunming 650201, Yunnan, China
| | - Hong Hu
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China; Yunnan Key Laboratory for Wild Plant Resources, Kunming 650201, Yunnan, China.
| | - Shi-Bao Zhang
- Key Laboratory of Economic Plants and Biotechnology, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming 650201, Yunnan, China; Yunnan Key Laboratory for Wild Plant Resources, Kunming 650201, Yunnan, China.
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31
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Singh SK, Reddy VR. Response of carbon assimilation and chlorophyll fluorescence to soybean leaf phosphorus across CO2: Alternative electron sink, nutrient efficiency and critical concentration. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 2015; 151:276-84. [PMID: 26343044 DOI: 10.1016/j.jphotobiol.2015.08.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 08/14/2015] [Accepted: 08/17/2015] [Indexed: 12/27/2022]
Abstract
To evaluate the response of CO2 assimilation rate (PN) and various chlorophyll fluorescence (CF) parameters to phosphorus (P) nutrition, soybean plants were grown in controlled environment with sufficient (0.50mM) and deficient (0.10 and 0.01 mM) phosphate (P) supply under ambient and elevated CO2 (aCO2, 400 and eCO2, 800 μmol mol(-1), respectively). Measurements were made at ambient (21%) and low (2%) O2 concentrations. Results showed strong correlation of leaf P concentration with PN and CF parameters. The P deficiency showed parallel decreases in PN, and CF parameters including quantum efficiency (Fv'/Fm'), quantum yield of photosystem II (ΦPSII), electron transport rate (JF), and photochemical quenching (qP). The Fv'/Fm' decreased as a result of greater decline in maximal (Fm') than minimal (Fo') fluorescence. The eCO2 stimulated PN especially under higher leaf P concentrations. Low O2 also stimulated PN but only at aCO2. The photosynthetic carbon reduction (PCR, signified by PN) and photorespiratory carbon oxidation cycles (PCO, signified photorespiration as indicated by ratio of JF to gross PN and % increase in PN at 2% O2) was the major electron sinks. However, the presence of alternative electron sink was also evident as determined by the difference between the electron transport calculated from chlorophyll fluorescence and gas exchange measurements. Alternative electron sink declined at lower leaf P concentration suggesting its minor role in photochemical energy consumption, thus dissipation of the excess excitation pressure of PSII reaction center under P deficiency. The JF/PG and % increase in PN at 2 versus 21% O2 remained consistent across leaf P concentration suggesting PCO cycle as an important mechanism to dissipate excess excitation energy in P deficient leaves. The severe decline of Fv'/Fm', ΦPSII, JF and qP under P deficiency also suggested the occurrences of excess radiant energy dissipation by non-photochemical quenching mechanisms. Critical leaf P concentration (CLPC) needed to achieve 90% of the maximum value was greater for PN than CF parameters. Moreover, CLPC was always higher at eCO2 suggesting increased sensitivity of soybean to P deficiency under eCO2. An increased phosphorus utilization efficiency of PN and CF parameters was also achieved but with the expense of net CO2 assimilation in P-deficient leaves.
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Affiliation(s)
- Shardendu K Singh
- Crop Systems and Global Change Laboratory, USDA-ARS, Beltsville, MD 20705, USA; Wye Research and Education Center, University of Maryland, MD, USA.
| | - Vangimalla R Reddy
- Crop Systems and Global Change Laboratory, USDA-ARS, Beltsville, MD 20705, USA
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