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Sun YH, Gu CX, Li GZ, Han AH, Hao L. Arbuscular mycorrhizal fungus-mediated amelioration of NO 2-induced phytotoxicity in tomato. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 205:111350. [PMID: 32961487 DOI: 10.1016/j.ecoenv.2020.111350] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/26/2020] [Accepted: 09/11/2020] [Indexed: 06/11/2023]
Abstract
Atmospheric nitrogen dioxide (NO2) negatively affects plant (crop) growth and development, as well the yield and quality in some regions or environments. Arbuscular mycorrhizal fungus (AMF)-mediated amelioration of NO2-induced plant damage has been reported, but the underlying mechanisms remained unclear. This study explored the beneficial effect of AMF symbiosis on tomato plant responses to NO2 at physiology, biochemistry, and gene expression, with an emphasis on nitrate metabolism, antioxidative defense, and photosynthetic performance. Pot-grown plants were used in the experiments, which were performed in laboratory from February to November 2019. NO2 fumigation with a dose of 10 ± 1 ppm was carried out after 50 d of plant growth, and data were collected following 8 h of fumigation. NO2 fumigation (+NO2) and AMF inoculation (+AMF), alone and especially in combination (NO2 + AMF), increased the gene expression of nitrate- and nitrite reductase, and their enzymatic activity in leaves, such as by 61%, 27%, and 126% for the activity of nitrate reductase, and by 95%, 37%, and 188% for nitrite reductase, respectively, in +NO2, +AMF, and AMF + NO2 plants relative the control (-NO2, -AMF) levels. Following NO2 exposure, +AMF leaves displayed stronger activities of superoxide dismutase, peroxidase and catalase, and higher content of glutathione and ratio of its reduced form to oxidized form, as compared with -AMF ones. Correspondingly, lesser oxidative damage was detected in +AMF than in -AMF plants, as indicated by the contents of H2O2 and malondialdehyde, electrolyte leakage, also by in situ visualization for the formation of H2O2, superoxide anion, and dead cells. The increased antioxidative capacity in +AMF plants was correlated with enhanced expression of antioxidation-related genes. Exposure to NO2 substantially impaired photosynthetic processes in both + AMF and -AMF plants, but an obvious mitigation was observed in the former than in the latter. For example, the total chlorophyll, net photosynthetic rate, stomatal conductance, and ribulose-1,5-bisphosphate carboxylase activity were 18%, 27%, 26%, and 40% higher, respectively, in +AMF than in -AMF plants under NO2 stress. The differential photosynthetic performance was also revealed by chlorophyll fluorescence imaging. We analyzed the expression patterns of some genes related to photosynthesis and carbon metabolisms, and found that all of them exclusively presented a higher expression level in +AMF plants relative to -AMF ones under NO2 stress. Taken together, this study provided evidence that AMF symbiosis played a positively regulatory role in host plant responses to NO2, probably by increasing leaf nitrate metabolism and antioxidative defense, and maintaining the photosynthetic efficiency to some extent, wherein the transcription regulation might be a main target.
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Affiliation(s)
- Yue-Hang Sun
- College of Life Science, Shenyang Normal University, Shenyang, 110034, China
| | - Chun-Xiu Gu
- College of Life Science, Shenyang Normal University, Shenyang, 110034, China
| | - Guang-Zhe Li
- College of Life Science, Shenyang Normal University, Shenyang, 110034, China
| | - Ai-Hong Han
- College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, 110034, China.
| | - Lin Hao
- College of Life Science, Shenyang Normal University, Shenyang, 110034, China.
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Takahashi M, Shigeto J, Sakamoto A, Morikawa H. Selective nitration of PsbO1 inhibits oxygen evolution from isolated Arabidopsis thylakoid membranes. PLANT SIGNALING & BEHAVIOR 2017; 12:e1304342. [PMID: 28323554 PMCID: PMC5437824 DOI: 10.1080/15592324.2017.1304342] [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: 02/03/2017] [Revised: 03/05/2017] [Accepted: 03/06/2017] [Indexed: 05/19/2023]
Abstract
Treatment of isolated Arabidopsis thaliana thylakoid membranes with nitrogen dioxide (NO2) induces selective nitration of the tyrosine residue at the ninth amino acid (9Tyr) of PsbO1. This selective nitration is triggered by light and is inhibited by photosynthetic electron transport inhibitors. Therefore, we postulated that, similar to 161Tyr of D1 (YZ), 9Tyr of PsbO1 is redox active and is selectively oxidized by photosynthetic electron transport in response to illumination to a tyrosyl radical that is highly susceptible to nitration. This tyrosyl radical may combine rapidly at diffusion-controlled rates with NO2 to form 3-nitrotyrosine. If this postulation is correct, the nitration of 9Tyr of PsbO1 should decrease oxygen evolution activity. We investigated the effects of PsbO1 nitration on oxygen evolution from isolated thylakoid membranes, and found that nitration decreased oxygen evolution to ≥ 0% of the control. Oxygen evolution and nitration were significantly negatively correlated. This finding is consistent with redox active properties of the 9Tyr gene of PsbO1, and suggests that PsbO1 9Tyr acts as an electron relay, such as YZ in the photosystem II oxygenic electron transport chain.
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Affiliation(s)
- Misa Takahashi
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
- CONTACT Misa Takahashi , Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama,Higashi-Hiroshima, Hiroshima 739–8526, Japan
| | - Jun Shigeto
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Atsushi Sakamoto
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
| | - Hiromichi Morikawa
- Department of Mathematical and Life Sciences, Graduate School of Science, Hiroshima University, Higashi-Hiroshima, Hiroshima, Japan
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Adrees M, Ibrahim M, Shah AM, Abbas F, Saleem F, Rizwan M, Hina S, Jabeen F, Ali S. Gaseous pollutants from brick kiln industry decreased the growth, photosynthesis, and yield of wheat (Triticum aestivum L.). ENVIRONMENTAL MONITORING AND ASSESSMENT 2016; 188:267. [PMID: 27048492 DOI: 10.1007/s10661-016-5273-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 03/29/2016] [Indexed: 06/05/2023]
Abstract
Gaseous pollutant emissions from brick kiln industries deteriorate the current state of ambient air quality in Pakistan and worldwide. These gaseous pollutants affect the health of plants and may decrease plant growth and yield. A field experiment that was conducted to monitor the concentration of gaseous pollutants emitted mainly from brick kilns in the ambient air and associated impacts on the growth and physiological attributes of the two wheat (Triticum spp.) cultivars. Plants were grown at three sites, including control (Ayub Agriculture Research Institute, AARI), low pollution (LP) site (Small Estate Industry), and high pollution (HP) site (Sidar Bypass), of Faisalabad, Pakistan. Monitoring of ambient air pollution at experimental sites was carried out using the state-of-art ambient air analyzers. Plants were harvested after 120 days of germination and were analyzed for different growth attributes. Results showed that the hourly average concentration of gaseous air pollutants CO, NO2, SO2, and PM10 at HP site were significantly higher than the LP and control sites. Similarly, gaseous pollutants decreased plant height, straw and grain yield, photosynthesis and increased physical injury, and metal concentrations in the grains. However, wheat response toward gaseous pollutants did not differ between cultivars (Galaxy and 8173) studied. Overall, the results indicated that brick kiln emissions could reduce the performance of wheat grown in the soils around kilns and confirm the adverse impacts of pollutants on the growth, yield, and quality of the wheat.
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Affiliation(s)
- Muhammad Adrees
- Department of Environmental Sciences and Engineering, Government College University Faisalabad, Faisalabad-38000, Faisalabad, Pakistan
| | - Muhammad Ibrahim
- Department of Environmental Sciences and Engineering, Government College University Faisalabad, Faisalabad-38000, Faisalabad, Pakistan
| | - Aamir Mehmood Shah
- Department of Environmental Sciences and Engineering, Government College University Faisalabad, Faisalabad-38000, Faisalabad, Pakistan
| | - Farhat Abbas
- Department of Environmental Sciences and Engineering, Government College University Faisalabad, Faisalabad-38000, Faisalabad, Pakistan
| | - Farhan Saleem
- Department of Environmental Sciences and Engineering, Government College University Faisalabad, Faisalabad-38000, Faisalabad, Pakistan
| | - Muhammad Rizwan
- Department of Environmental Sciences and Engineering, Government College University Faisalabad, Faisalabad-38000, Faisalabad, Pakistan.
| | - Saadia Hina
- Department of Environmental Sciences and Engineering, Government College University Faisalabad, Faisalabad-38000, Faisalabad, Pakistan
| | - Fariha Jabeen
- Department of Environmental Sciences and Engineering, Government College University Faisalabad, Faisalabad-38000, Faisalabad, Pakistan
| | - Shafaqat Ali
- Department of Environmental Sciences and Engineering, Government College University Faisalabad, Faisalabad-38000, Faisalabad, Pakistan
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Liu X, Hou F, Li G, Sang N. Effects of nitrogen dioxide and its acid mist on reactive oxygen species production and antioxidant enzyme activity in Arabidopsis plants. J Environ Sci (China) 2015; 34:93-9. [PMID: 26257351 DOI: 10.1016/j.jes.2015.03.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 02/07/2015] [Accepted: 03/03/2015] [Indexed: 05/10/2023]
Abstract
Nitrogen dioxide (NO2) is one of the most common and harmful air pollutants. To analyze the response of plants to NO2 stress, we investigated the morphological change, reactive oxygen species (ROS) production and antioxidant enzyme activity in Arabidopsis thaliana (Col-0) exposed to 1.7, 4, 8.5, and 18.8 mg/m(3) NO2. The results indicate that NO2 exposure affected plant growth and chlorophyll (Chl) content, and increased oxygen free radical (O2(-)) production rate in Arabidopsis shoots. Furthermore, NO2 elevated the levels of lipid peroxidation and protein oxidation, accompanied by the induction of antioxidant enzyme activities and change of ascorbate (AsA) and glutathione (GSH) contents. Following this, we mimicked nitric acid mist under experimental conditions, and confirmed the antioxidant mechanism of the plant to the stress. Our results imply that NO2 and its acid mist caused pollution risk to plant systems. During the process, increased ROS acted as a signal to induce a defense response, and antioxidant status played an important role in plant protection against NO2/nitric acid mist-caused oxidative damage.
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Affiliation(s)
- Xiaofang Liu
- College of Environment and Resource, Research Center of Environment and Health, Shanxi University, Taiyuan 030006, China
| | - Fen Hou
- College of Environmental Science and Engineering, Nankai University, Tianjin 300071, China
| | - Guangke Li
- College of Environment and Resource, Research Center of Environment and Health, Shanxi University, Taiyuan 030006, China.
| | - Nan Sang
- College of Environment and Resource, Research Center of Environment and Health, Shanxi University, Taiyuan 030006, China.
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Hu Y, Fernández V, Ma L. Nitrate transporters in leaves and their potential roles in foliar uptake of nitrogen dioxide. FRONTIERS IN PLANT SCIENCE 2014; 5:360. [PMID: 25126090 PMCID: PMC4115617 DOI: 10.3389/fpls.2014.00360] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 07/04/2014] [Indexed: 05/07/2023]
Abstract
While plant roots are specialized organs for the uptake and transport of water and nutrients, the absorption of gaseous or liquid mineral elements by aerial plant parts has been recognized since more than one century. Nitrogen (N) is an essential macronutrient which generally absorbed either as nitrate (NO(-) 3) or ammonium (NH(+) 4) by plant roots. Gaseous nitrogen pollutants like N dioxide (NO2) can also be absorbed by plant surfaces and assimilated via the NO(-) 3 assimilation pathway. The subsequent NO(-) 3 flux may induce or repress the expression of various NO(-) 3-responsive genes encoding for instance, the transmembrane transporters, NO(-) 3/NO(-) 2 (nitrite) reductase, or assimilatory enzymes involved in N metabolism. Based on the existing information, the aim of this review was to theoretically analyze the potential link between foliar NO2 absorption and N transport and metabolism. For such purpose, an overview of the state of knowledge on the NO(-) 3 transporter genes identified in leaves or shoots of various species and their roles for NO(-) 3 transport across the tonoplast and plasma membrane, in addition to the process of phloem loading is briefly provided. It is assumed that a NO2-induced accumulation of NO(-) 3/NO(-) 2 may alter the expression of such genes, hence linking transmembrane NO(-) 3 transporters and foliar uptake of NO2. It is likely that NRT1/NRT2 gene expression and species-dependent apoplastic buffer capacity may be also related to the species-specific foliar NO2 uptake process. It is concluded that further work focusing on the expression of NRT1 (NRT1.1, NRT1.7, NRT1.11, and NRT1.12), NRT2 (NRT2.1, NRT2.4, and NRT2.5) and chloride channel family genes (CLCa and CLCd) may help us elucidate the physiological and metabolic response of plants fumigated with NO2.
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Affiliation(s)
- Yanbo Hu
- College of Life Science, Northeast Forestry UniversityHarbin, China
| | - Victoria Fernández
- Forest Genetics and Ecophysiology Research Group, School of Forest Engineering, Technical University of MadridMadrid, Spain
| | - Ling Ma
- School of Forestry, Northeast Forestry UniversityHarbin, China
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Hu Y, Bellaloui N, Sun G, Tigabu M, Wang J. Exogenous sodium sulfide improves morphological and physiological responses of a hybrid Populus species to nitrogen dioxide. JOURNAL OF PLANT PHYSIOLOGY 2014; 171:868-75. [PMID: 24635903 DOI: 10.1016/j.jplph.2013.10.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 10/29/2013] [Accepted: 10/29/2013] [Indexed: 05/08/2023]
Abstract
Gaseous nitrogen dioxide (NO2) can disturb normal plant growth and trigger complex physiological responses. NO2-induced responses are influenced by biotic or abiotic factors. In this study, we investigated the effects of exogenous sodium sulfide (Na2S, 5mmolL(-1)) on epidermis and stomata related physico-chemical responses of hybrid poplar cuttings (Pouplus alba×P. berolinensis) to gaseous NO2 (4μl1(-1)) for three time periods (0, 14 and 48h). We also investigated hydrogen sulfide (H2S), nitrate-nitrogen and nitrate reductase activity (NR) in control and Na2S treated plants. Our results showed that NO2 exposure for 48h led to the decline of NR, maximal PSII quantum yield (Fv/Fm), net photosynthetic rate (Pn), and dark respiration rate (Rd). The maximum rate for the post-illumination carbon dioxide burst (PIB) occurred in 48-h exposed leaves 13-15s after darkening. Moreover, NO2 exposure resulted in a significant increase in nitrogen percentage (from 0 to 33%) and a decrease in the macro and micro-elements of leaf surface. Spraying Na2S aqueous solution on the leaf surfaces significantly increased the thicknesses of palisade/spongy tissue and H2S content. Na2S pretreatment alleviated NO2-caused toxic effects as indicated by increased NR and higher values of Pn, Fv/Fm, and actual photochemical efficiency in light (ФPSII) compared with the control. Na2S pretreatment had no significant impacts on PIB-based photorespiration or elements composition of a leaf surface.
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Affiliation(s)
- Yanbo Hu
- College of Life Science, Northeast Forestry University, China.
| | | | - Guangyu Sun
- College of Life Science, Northeast Forestry University, China.
| | - Mulualem Tigabu
- Swedish University of Agricultural Sciences, Southern Swedish Forest Research Centre, P.O.Box 49, SE-230 50, Alnarp, Sweden
| | - Jinghong Wang
- College of Landscape, Northeast Forestry University, China
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Takahashi M, Furuhashi T, Ishikawa N, Horiguchi G, Sakamoto A, Tsukaya H, Morikawa H. Nitrogen dioxide regulates organ growth by controlling cell proliferation and enlargement in Arabidopsis. THE NEW PHYTOLOGIST 2014; 201:1304-1315. [PMID: 24354517 DOI: 10.1111/nph.12609] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 10/20/2013] [Indexed: 05/08/2023]
Abstract
• To gain more insight into the physiological function of nitrogen dioxide (NO₂), we investigated the effects of exogenous NO₂ on growth in Arabidopsis thaliana. • Plants were grown in air without NO₂ for 1 wk after sowing and then grown for 1-4 wk in air with (designated treated plants) or without (control plants) NO₂. Plants were irrigated semiweekly with a nutrient solution containing 19.7 mM nitrate and 10.3 mM ammonium. • Five-week-old plants treated with 50 ppb NO₂ showed a ≤ 2.8-fold increase in biomass relative to controls. Treated plants also showed early flowering. The magnitude of the effects of NO₂ on leaf expansion, cell proliferation and enlargement was greater in developing than in maturing leaves. Leaf areas were 1.3-8.4 times larger on treated plants than corresponding leaves on control plants. The NO₂-induced increase in leaf size was largely attributable to cell proliferation in developing leaves, but was attributable to both cell proliferation and enlargement in maturing leaves. The expression of different sets of genes for cell proliferation and/or enlargement was induced by NO₂, but depended on the leaf developmental stage. • Collectively, these results indicated that NO₂ regulates organ growth by controlling cell proliferation and enlargement.
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Affiliation(s)
- Misa Takahashi
- Department of Mathematical and Life Sciences, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
| | - Takamasa Furuhashi
- Department of Mathematical and Life Sciences, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
| | - Naoko Ishikawa
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Gorou Horiguchi
- Department of Life Science, College of Science, Rikkyo University, 3-34-1 Nishi-Ikebukuro, Toshima-ku, Tokyo, 171-8501, Japan
| | - Atsushi Sakamoto
- Department of Mathematical and Life Sciences, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
| | - Hirokazu Tsukaya
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Hiromichi Morikawa
- Department of Mathematical and Life Sciences, Hiroshima University, Higashi-Hiroshima, 739-8526, Japan
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Takahashi M, Morikawa H. Nitrogen dioxide is a positive regulator of plant growth. PLANT SIGNALING & BEHAVIOR 2014; 9:e28033. [PMID: 24525764 PMCID: PMC4091254 DOI: 10.4161/psb.28033] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Accepted: 01/29/2014] [Indexed: 05/19/2023]
Abstract
Atmospheric nitric oxide (NO) and nitrogen dioxide (NO₂) have long been recognized as either detrimental or beneficial for plant development. Recent research has established that NO is a phytohormone. Our present knowledge of the physiological role of NO₂ is incomplete. We do know, however, that exogenous NO₂ positively regulates the vegetative and reproductive growth of plants. We may therefore postulate that NO₂ is a positive growth regulator for plants. We are now in a position to coherently summarize what is known of NO₂ physiology; collated information on the topic is presented here.
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Khandaker MM, Boyce AN, Osman N. The influence of hydrogen peroxide on the growth, development and quality of wax apple (Syzygium samarangense, [Blume] Merrill & L.M. Perry var. jambu madu) fruits. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2012; 53:101-110. [PMID: 22349652 DOI: 10.1016/j.plaphy.2012.01.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 01/23/2012] [Indexed: 05/31/2023]
Abstract
The present study represents the first report of the effect of hydrogen peroxide (H(2)O(2)) on the growth, development and quality of the wax apple fruit, a widely cultivated fruit tree in South East Asia. The wax apple trees were spray treated with 0, 5, 20 and 50 mM H(2)O(2) under field conditions. Photosynthetic rates, stomatal conductance, transpiration, chlorophyll and dry matter content of the leaves and total soluble solids and total sugar content of the fruits of wax apple (Syzygium samarangense, var. jambu madu) were significantly increased after treatment with 5 mM H(2)O(2). The application of 20 mM H(2)O(2) significantly reduced bud drop and enhanced fruit growth, resulting in larger fruit size, increased fruit set, fruit number, fruit biomass and yield compared to the control. In addition, the endogenous level of H(2)O(2) in wax apple leaves increased significantly with H(2)O(2) treatments. With regard to fruit quality, 20 mM H(2)O(2) treatment increased the K(+), anthocyanin and carotene contents of the fruits by 65%, 67%, and 41%, respectively. In addition, higher flavonoid, phenol and soluble protein content, sucrose phosphate synthase (SPS), phenylalanine ammonia lyase (PAL) and antioxidant activities were recorded in the treated fruits. There was a positive correlation between peel colour (hue) and TSS, between net photosynthesis and SPS activity and between phenol and flavonoid content with antioxidant activity in H(2)O(2)-treated fruits. It is concluded that spraying with 5 and 20 mM H(2)O(2) once a week produced better fruit growth, maximising the yield and quality of wax apple fruits under field conditions.
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Hu Y, Sun G. Leaf nitrogen dioxide uptake coupling apoplastic chemistry, carbon/sulfur assimilation, and plant nitrogen status. PLANT CELL REPORTS 2010; 29:1069-77. [PMID: 20628880 DOI: 10.1007/s00299-010-0898-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2010] [Revised: 07/03/2010] [Accepted: 07/04/2010] [Indexed: 05/08/2023]
Abstract
Emission and plant uptake of atmospheric nitrogen oxides (NO + NO(2)) significantly influence regional climate change by regulating the oxidative chemistry of the lower atmosphere, species composition and the recycling of carbon and nutrients, etc. Plant uptake of nitrogen dioxide (NO(2)) is concentration-dependent and species-specific, and covaries with environmental factors. An important factor determining NO(2) influx into leaves is the replenishment of the substomatal cavity. The apoplastic chemistry of the substomatal cavity plays crucial roles in NO(2) deposition rates and the tolerance to NO(2), involving the reactions between NO(2) and apoplastic antioxidants, NO(2)-responsive germin-like proteins, apoplastic acidification, and nitrite-dependent NO synthesis, etc. Moreover, leaf apoplast is a favorable site for the colonization by microbes, which disturbs nitrogen metabolism of host plants. For most plant species, NO(2) assimilation in a leaf primarily depends on the nitrate (NO(3) (-)) assimilation pathway. NO(2)-N assimilation is coupled with carbon and sulfur (sulfate and SO(2)) assimilation as indicated by the mutual needs for metabolic intermediates (or metabolites) and the NO(2)-caused changes of key metabolic enzymes such as phosphoenolpyruvate carboxylase (PEPc) and adenosine 5'-phosphosulfate sulfotransferase, organic acids, and photorespiration. Moreover, arbuscular mycorrhizal (AM) colonization improves the tolerance of host plants to NO(2) by enhancing the efficiency of nutrient absorption and translocation and influencing foliar chemistry. Further progress is proposed to gain a better understanding of the coordination between NO(2)-N, S and C assimilation, especially the investigation of metabolic checkpoints, and the effects of photorespiratory nitrogen cycle, diverse PEPc and the metabolites such as cysteine, O-acetylserine (OAS) and glutathione.
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Affiliation(s)
- Yanbo Hu
- College of Life Science, Northeast Forestry University, 26# Hexing Road, Xiangfang District, Harbin 150040, People's Republic of China.
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