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Gregory LM, Roze LV, Walker BJ. Increased activity of core photorespiratory enzymes and CO 2 transfer conductances are associated with higher and more optimal photosynthetic rates under elevated temperatures in the extremophile Rhazya stricta. PLANT, CELL & ENVIRONMENT 2023; 46:3704-3720. [PMID: 37667571 DOI: 10.1111/pce.14711] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 06/26/2023] [Accepted: 08/23/2023] [Indexed: 09/06/2023]
Abstract
Increase photorespiration and optimising intrinsic water use efficiency are unique challenges to photosynthetic carbon fixation at elevated temperatures. To determine how plants can adapt to facilitate high rates of photorespiration at elevated temperatures while also maintaining water-use efficiency, we performed in-depth gas exchange and biochemical assays of the C3 extremophile, Rhazya stricta. These results demonstrate that R. stricta supports higher rates of photorespiration under elevated temperatures and that these higher rates of photorespiration correlate with increased activity of key photorespiratory enzymes; phosphoglycolate phosphatase and catalase. The increased photorespiratory enzyme activities may increase the overall capacity of photorespiration by reducing enzymatic bottlenecks and allowing minimal inhibitor accumulation under high photorespiratory rates. Additionally, we found the CO2 transfer conductances (stomatal and mesophyll) are re-allocated to increase the water-use efficiency in R. stricta but not necessarily the photosynthetic response to temperature. These results suggest important adaptive strategies in R. stricta that maintain photosynthetic rates under elevated temperatures with optimal water loss. The strategies found in R. stricta may inform breeding and engineering efforts in other C3 species to improve photosynthetic efficiency at high temperatures.
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Affiliation(s)
- Luke M Gregory
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
| | - Ludmila V Roze
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
| | - Berkley J Walker
- Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, Michigan, USA
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, USA
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2
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Wall CB, Swift SOI, D’Antonio CM, Gebauer G, Hynson NA. Isoscapes of remnant and restored Hawaiian montane forests reveal differences in biological nitrogen fixation and carbon inputs. PeerJ 2023; 11:e15468. [PMID: 37304880 PMCID: PMC10252893 DOI: 10.7717/peerj.15468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 05/05/2023] [Indexed: 06/13/2023] Open
Abstract
Deforestation and subsequent land-use conversion has altered ecosystems and led to negative effects on biodiversity. To ameliorate these effects, nitrogen-fixing (N2-fixing) trees are frequently used in the reforestation of degraded landscapes, especially in the tropics; however, their influence on ecosystem properties such as nitrogen (N) availability and carbon (C) stocks are understudied. Here, we use a 30-y old reforestation site of outplanted native N2-fixing trees (Acacia koa) dominated by exotic grass understory, and a neighboring remnant forest dominated by A. koa canopy trees and native understory, to assess whether restoration is leading to similar N and C biogeochemical landscapes and soil and plant properties as a target remnant forest ecosystem. We measured nutrient contents and isotope values (δ15N, δ13C) in soils, A. koa, and non-N2-fixing understory plants (Rubus spp.) and generated δ15N and δ13C isoscapes of the two forests to test for (1) different levels of biological nitrogen fixation (BNF) and its contribution to non-N2-fixing understory plants, and (2) the influence of historic land conversion and more recent afforestation on plant and soil δ13C. In the plantation, A. koa densities were higher and foliar δ15N values for A. koa and Rubus spp. were lower than in the remnant forest. Foliar and soil isoscapes also showed a more homogeneous distribution of low δ15N values in the plantation and greater influence of A. koa on neighboring plants and soil, suggesting greater BNF. Foliar δ13C also indicated higher water use efficiency (WUEi) in the plantation, indicative of differences in plant-water relations or soil water status between the two forest types. Plantation soil δ13C was higher than the remnant forest, consistent with greater contributions of exotic C4-pasture grasses to soil C pools, possibly due to facilitation of non-native grasses by the dense A. koa canopy. These findings are consequential for forest restoration, as they contribute to the mounting evidence that outplanting N2-fixing trees produces different biogeochemical landscapes than those observed in reference ecosystems, thereby influencing plant-soil interactions which can influence restoration outcomes.
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Affiliation(s)
- Christopher B. Wall
- University of California, San Diego, San Diego, CA, United States
- University of Hawaii at Manoa, Honolulu, HI, United States
| | | | - Carla M. D’Antonio
- University of California, Santa Barbara, Santa Barbara, CA, United States
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Yang D, Wang YSD, Wang Q, Ke Y, Zhang YB, Zhang SB, Zhang YJ, McDowell NG, Zhang JL. Physiological response and photosynthetic recovery to an extreme drought: Evidence from plants in a dry-hot valley savanna of Southwest China. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 868:161711. [PMID: 36682563 DOI: 10.1016/j.scitotenv.2023.161711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 01/15/2023] [Accepted: 01/15/2023] [Indexed: 06/17/2023]
Abstract
The frequency of extreme drought events has been rising worldwide, but due to its unpredictability, how plants will respond remains poorly understood. Here, we aimed to characterize how the hydraulics and photosynthesis of savanna plants respond to extreme drought, and tested whether they can subsequently recover photosynthesis after drought. There was an extreme drought in 2019 in Southwest (SW) China. We investigated photosynthetic gas exchange, leaf-, stem-, and whole-shoot hydraulic conductance of 18 plant species with diverse leaf habits (deciduous, semi-deciduous and evergreen) and growth forms (tree and shrub) from a dry-hot valley savanna in SW China for three rainy seasons from 2019 to 2021. We also compared photosynthetic gas exchange to those of a regular year (2014). We found that leaf stomatal and hydraulic conductance and maximum photosynthetic rate were significantly lower during the drought in 2019 than in the wetter years. In 2019, all studied plants maintained stomatal conductance at their minimum level observed, which could be related to high vapor pressure deficits (VPD, >2 kPa). However, no significant difference in stem and shoot hydraulic conductance was detected across years. The reductions in leaf hydraulic conductance and stomatal regulation under extreme drought might help keep the stem hydraulic function. Stomatal conductance and photosynthesis after drought (2020 and 2021) showed comparable or even higher values compared to that of 2014, suggesting high recovery of photosynthetic gas exchange. In addition, the response of hydraulic and photosynthetic traits to extreme drought was convergent across leaf habits and growth forms. Our results will help better understand the physiological mechanism underlying the response of savanna ecosystems to climate change.
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Affiliation(s)
- Da Yang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
| | - Yang-Si-Ding Wang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qin Wang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yan Ke
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yun-Bing Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, 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
| | - Yong-Jiang Zhang
- School of Biology and Ecology, University of Maine, Orono, ME 04469, USA.
| | - Nate G McDowell
- Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, Richland, WA, USA; School of Biological Sciences, Washington State University, PO Box 644236, Pullman, WA 99164-4236, USA
| | - Jiao-Lin Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China.
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Moore ER, Carter KR, Heneghan JP, Steadman CR, Nachtsheim AC, Anderson-Cook C, Dickman LT, Newman BD, Dunbar J, Sevanto S, Albright MBN. Microbial Drivers of Plant Performance during Drought Depend upon Community Composition and the Greater Soil Environment. Microbiol Spectr 2023:e0147622. [PMID: 36943043 PMCID: PMC10101012 DOI: 10.1128/spectrum.01476-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023] Open
Abstract
The increasing occurrence of drought is a global challenge that threatens food security through direct impacts to both plants and their interacting soil microorganisms. Plant growth promoting microbes are increasingly being harnessed to improve plant performance under stress. However, the magnitude of microbiome impacts on both structural and physiological plant traits under water limited and water replete conditions are not well-characterized. Using two microbiomes sourced from a ponderosa pine forest and an agricultural field, we performed a greenhouse experiment that used a crossed design to test the individual and combined effects of the water availability and the soil microbiome composition on plant performance. Specifically, we studied the structural and leaf functional traits of maize that are relevant to drought tolerance. We further examined how microbial relationships with plant phenotypes varied under different combinations of microbial composition and water availability. We found that water availability and microbial composition affected plant structural traits. Surprisingly, they did not alter leaf function. Maize grown in the forest-soil microbiome produced larger plants under well-watered and water-limited conditions, compared to an agricultural soil community. Although leaf functional traits were not significantly different between the watering and microbiome treatments, the bacterial composition and abundance explained significant variability in both plant structure and leaf function within individual treatments, especially water-limited plants. Our results suggest that bacteria-plant interactions that promote plant performance under stress depend upon the greater community composition and the abiotic environment. IMPORTANCE Globally, drought is an increasingly common and severe stress that causes significant damage to agricultural and wild plants, thereby threatening food security. Despite growing evidence of the potential benefits of soil microorganisms on plant performance under stress, decoupling the effects of the microbiome composition versus the water availability on plant growth and performance remains a challenge. We used a highly controlled and replicated greenhouse experiment to understand the impacts of microbial community composition and water limitation on corn growth and drought-relevant functions. We found that both factors affected corn growth, and, interestingly, that individual microbial relationships with corn growth and leaf function were unique to specific watering/microbiome treatment combinations. This finding may help explain the inconsistent success of previously identified microbial inocula in improving plant performance in the face of drought, outside controlled environments.
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Affiliation(s)
- Eric R Moore
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Kelsey R Carter
- Earth and Environmental Science Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - John P Heneghan
- Earth and Environmental Science Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Christina R Steadman
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
- Earth and Environmental Science Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Abigael C Nachtsheim
- Statistical Sciences Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | | | - L Turin Dickman
- Earth and Environmental Science Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Brent D Newman
- Earth and Environmental Science Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - John Dunbar
- Bioscience Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
| | - Sanna Sevanto
- Earth and Environmental Science Division, Los Alamos National Laboratory, Los Alamos, New Mexico, USA
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5
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Lin X, Wu B, Wang J, Wang G, Chen Z, Liang Y, Liu J, Wang H. Effects of Geographical and Climatic Factors on the Intrinsic Water Use Efficiency of Tropical Plants: Evidence from Leaf 13C. PLANTS (BASEL, SWITZERLAND) 2023; 12:951. [PMID: 36840299 PMCID: PMC9962877 DOI: 10.3390/plants12040951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/11/2023] [Accepted: 02/13/2023] [Indexed: 06/18/2023]
Abstract
Understanding the water use efficiency (WUE) and adaptation strategies of plants in high-temperature and rainy areas is essential under global climate change. The leaf carbon content (LCC) and intrinsic WUE of 424 plant samples (from 312 plant species) on Hainan Island were measured to examine their relationship with geographical and climatic factors in herbs, trees, vines and ferns. The LCC ranged from 306.30 to 559.20 mg g-1, with an average of 418.85 mg g-1, and decreased with increasing mean annual temperature (MAT). The range of intrinsic WUE was 8.61 to 123.39 μmol mol-1 with an average value of 60.66 μmol mol-1. The intrinsic WUE decreased with increasing altitude and relative humidity (RH) and wind speed (WS), but increased with increasing latitude, MAT and rainy season temperature (RST), indicating that geographical and climatic factors affect the intrinsic WUE. Stepwise regression suggested that in tropical regions with high temperature and humidity, the change in plant intrinsic WUE was mainly driven by WS. In addition, the main factors affecting the intrinsic WUE of different plant functional types of plants are unique, implying that plants of different plant functional types have distinctive adaptive strategies to environmental change. The present study may provide an insight in water management in tropical rainforest.
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Affiliation(s)
- Xiaoyan Lin
- School of Forestry, Hainan University, Haikou 570228, China
- Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
- Opening Project Fund of Key Laboratory of Biology and Genetic Resources of Rubber Tree/State Key Laboratory Breeding Base of Cultivation and Physiology for Tropical Crops/Danzhou Investigation and Experiment Station of Tropical Crops, Ministry of Agriculture and Rural Affairs, Danzhou 571700, China
| | - Bingsun Wu
- Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
- Opening Project Fund of Key Laboratory of Biology and Genetic Resources of Rubber Tree/State Key Laboratory Breeding Base of Cultivation and Physiology for Tropical Crops/Danzhou Investigation and Experiment Station of Tropical Crops, Ministry of Agriculture and Rural Affairs, Danzhou 571700, China
| | - Jingjing Wang
- School of Forestry, Hainan University, Haikou 570228, China
- Opening Project Fund of Key Laboratory of Biology and Genetic Resources of Rubber Tree/State Key Laboratory Breeding Base of Cultivation and Physiology for Tropical Crops/Danzhou Investigation and Experiment Station of Tropical Crops, Ministry of Agriculture and Rural Affairs, Danzhou 571700, China
| | - Guoan Wang
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Department of Environmental Sciences and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Zixun Chen
- Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, Department of Environmental Sciences and Engineering, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193, China
| | - Yongyi Liang
- School of Forestry, Hainan University, Haikou 570228, China
- Rubber Research Institute, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China
| | - Jiexi Liu
- School of Forestry, Hainan University, Haikou 570228, China
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institutes of Plant Physiology and Ecology, Shanghai 200032, China
| | - Hao Wang
- School of Forestry, Hainan University, Haikou 570228, China
- College of International Studies, Yangzhou University, Yangzhou 225009, China
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6
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Li C, Gao T, Wang X, Qu S, Yang Y, Zuo M, Wang J, Wang H, Zhou G, Liu Y. Phytoremediation Potential and Physiological Mechanisms Underlying Metallic Extraction of Suaeda glauca, Artemisia desertorum, and Atriplex canescens. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:16035. [PMID: 36498118 PMCID: PMC9736508 DOI: 10.3390/ijerph192316035] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 11/23/2022] [Accepted: 11/24/2022] [Indexed: 06/17/2023]
Abstract
Mining activities have led to serious environmental (soil erosion, degradation of vegetation, and groundwater contamination) and human health (musculoskeletal problems, diarrheal conditions, and chronic diseases) issues at desert mining areas in northwest China. Native plant species grown naturally in desert regions show a unique tolerance to arid and semiarid conditions and are potential candidates for soil phytoremediation. Here, an ex situ experiment involving pot planting of seedlings of three native plant species (Suaeda glauca, Artemisia desertorum, and Atriplex canescens) was designed to explore their phytoremediation potential and the underlying physiological mechanism. For Zn and Cu, the three plants were all with a biological accumulation coefficient (BAC) greater than 1. For Cd, Ni, and Pb, Atriplex canescens had the highest bioaccumulation concentrations (521.52, 862.23, and 1734.59 mg/kg), with BAC values (1.06, 1.30, 1.25) greater than 1, which indicates that Atriplex canescens could be a broad-spectrum metal extraction plant. Physiological analysis (antioxidation, extracellular secretions, photosynthesis, and hydraulics) showed that the three desert plants exploited their unique strategy to protect against the stress of complex metals in soils. Moreover, the second growing period was the main heavy metal accumulation and extraction stage concomitant with highest water use efficiency (iWUE). Taken together, the three desert plants exhibited the potent heavy metal extraction ability and physiological and ecological adaptability to a harsh polluted environment in arid desert areas, providing potential resources for the bioremediation of metal-contaminated soils in an arid and semiarid desert environment.
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Affiliation(s)
- Changming Li
- College of Chemistry and Chemical Engineering, Qinghai Normal University, Xining 810008, China
- Research Center of Pollution Control and Ecological Restoration Engineering in Mining Area of Gansu Province, Lanzhou 730001, China
| | - Tianpeng Gao
- Research Center of Pollution Control and Ecological Restoration Engineering in Mining Area of Gansu Province, Lanzhou 730001, China
- College of Biological and Environmental Engineering, Xi’an University, Xi’an 710065, China
| | - Xueying Wang
- Xi’an Institute of Environment Sanitation Sciences, Xi’an 710065, China
| | - Shipeng Qu
- Research Center of Pollution Control and Ecological Restoration Engineering in Mining Area of Gansu Province, Lanzhou 730001, China
- Gansu Jinchang Environmental Monitoring Center, Jinchang 737100, China
| | - Yingli Yang
- Research Center of Pollution Control and Ecological Restoration Engineering in Mining Area of Gansu Province, Lanzhou 730001, China
- College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China
| | - Mingbo Zuo
- Research Center of Pollution Control and Ecological Restoration Engineering in Mining Area of Gansu Province, Lanzhou 730001, China
- College of Life Science, Northwest Normal University, Lanzhou 730070, China
| | - Juan Wang
- Research Center of Pollution Control and Ecological Restoration Engineering in Mining Area of Gansu Province, Lanzhou 730001, China
- College of Life Science, Northwest Normal University, Lanzhou 730070, China
| | - Haoming Wang
- Research Center of Pollution Control and Ecological Restoration Engineering in Mining Area of Gansu Province, Lanzhou 730001, China
- College of Biological and Pharmaceutical Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
| | - Guixiang Zhou
- Research Center of Pollution Control and Ecological Restoration Engineering in Mining Area of Gansu Province, Lanzhou 730001, China
- Nanjing Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210018, China
| | - Yubing Liu
- Research Center of Pollution Control and Ecological Restoration Engineering in Mining Area of Gansu Province, Lanzhou 730001, China
- State Key Laboratory of Grassland Agro-Ecosystems, Lanzhou University, Lanzhou 730020, China
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7
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Ehleringer JR, Driscoll AW. Intrinsic water-use efficiency influences establishment in Encelia farinosa. Oecologia 2022; 199:563-578. [PMID: 35819533 DOI: 10.1007/s00442-022-05217-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 06/21/2022] [Indexed: 11/25/2022]
Abstract
We describe establishment of Encelia farinosa, a drought-deciduous shrub common to the Mojave and Sonoran Deserts, based on annual observations of two populations between 1980 and 2020. Only 11 establishment events of 50 + yearlings (0.02-0.03 individuals m-2) occurred during this monitoring period; in 68% of the years fewer than 10 yearlings were established. Yearling survival to adulthood (age 4) ranged from 88 to 5% and was significantly related to cumulative precipitation. Juvenile survival rates were lowest during the current megadrought period. We calculated intrinsic water-use efficiency (iWUE) and observed the widest variations in iWUE values among the youngest plants. Among juveniles, surviving yearlings with the lowest iWUE values exhibited upward ontogenetic shifts in iWUE values, whereas those yearlings with the highest initial iWUE values exhibited little if any change. Juvenile size, higher iWUE values, and greater likelihood of surviving were all positively related with each other over the past several decades. Furthermore, iWUE and photosynthetic capacity were positively related to each other, providing a mechanistic explanation for why increased iWUE values among juveniles could lead to greater survival rates and to larger plants under water-deficit conditions. We posit that there is bi-directional selection for genotypic variations in iWUE values among E. farinosa and that this variation is selected for because of interannual environmental heterogeneity in precipitation and VPD associated with both high- and low-frequency climate cycles. Extreme drought cycles may favor plants with higher iWUE values, whereas more mesic periods may allow for greater persistence of lower iWUE genotypes.
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Affiliation(s)
- James R Ehleringer
- School of Biological Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT, 84112, USA.
| | - Avery W Driscoll
- School of Biological Sciences, University of Utah, 257 South 1400 East, Salt Lake City, UT, 84112, USA
- Present Address: Department of Soil and Crop Sciences, Colorado State University, 301 University Avenue, Fort Collins, CO, 80523, USA
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Strongly Active Responses of Pinus tabuliformis Carr. and Sophora viciifolia Hance to CO2 Enrichment and Drought Revealed by Tree-Ring Isotopes on the Central China Loess Plateau. FORESTS 2022. [DOI: 10.3390/f13070986] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Understanding the water-use strategy of human-planted species used in response to climate change is essential to optimize afforestation programs in dry regions. Since 2000, trees on the central Loess Plateau have experienced a shift from strengthening drought to weakening drought. In this study, we combined tree-ring δ13C and δ18O records from Pinus tabuliformis (syn. tabulaeformis) Carr. (a tree) and Sophora viciifolia Hance (a shrub) on the central Loess Plateau to investigate species-specific responses to rising atmospheric CO2 (Ca) and drought. We found summer relative humidity controlled the fractionation of tree-ring δ18O, but the magnitude of the climate influence on δ13C differed between the species. The intrinsic water-use efficiency (iWUE) trends of both species suggested a strongly active response to maintain constant intercellular CO2 concentrations as Ca rose. The tree-ring δ13C and δ18O of both species using first-difference data were significantly and positively correlated, with stronger relationships for the shrub. This indicated the dominant regulation of iWUE by stomatal conductance in both species, but with greater stomatal control for the shrub. Moreover, the higher mean iWUE value of S. viciifolia indicated a more conservative water-use strategy than P. tabuliformis. Based on our commonality analysis, the main driver of the increased iWUE was the joint effect of Ca and vapor-pressure deficit (25.51%) for the tree, while it was the joint effect of Ca and the self-calibrated Palmer drought severity index (39.13%) for the shrub. These results suggest S. viciifolia will be more drought-tolerant than P. tabuliformis and as Ca continually rises, we should focus more on the effects of soil drought than atmospheric drought on the water-use strategy of S. viciifolia.
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Farahat E, Cherubini P, Saurer M, Gärtner H. Wood anatomy and tree-ring stable isotopes indicate a recent decline in water-use efficiency in the desert tree Moringa peregrina. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2022; 66:127-137. [PMID: 34633523 DOI: 10.1007/s00484-021-02198-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 09/22/2021] [Accepted: 09/25/2021] [Indexed: 06/13/2023]
Abstract
The ability of desert plants to adapt to future climate changes and maximize their water-use efficiency will determine their survival. This study uses wood anatomy and δ13C and δ18O isotope analyses to investigate how Moringa peregrina trees in the Egyptian desert have responded to the environment over the last 10 years. Our results show that M. peregrina tree-ring widths (TRWs) have generally declined over the last decade, although individual series are characterized by high variability and low Rbars. Vessel lumen area percentages (VLA%) are low in wet years but increase significantly in dry years, such as the period 2017-2020. Stable δ13C isotope values decrease between 2010 (- 23.4‰) and 2020 (- 24.9‰), reflecting an unexpected response to an increase in drought conditions. The mean δ18O value (± standard error, SE) for the first ten rings of each tree from bark to pith (2020-2010) is 33.0 ‰ ± 0.85 with a range of 29.2-36.3‰, which indicates a common drought signal. The intrinsic water-use efficiency (iWUE) declines gradually with time, from 130.0 µmol mol-1 in 2010 to 119.4 µmol mol-1 in 2020. The intercellular carbon concentration (Ci) and Ci/Ca ratio increase over the same period, likely as a result of decreasing iWUE. The results show that M. peregrina trees seem to cool their leaves and the boundary air at the cost of saving water.
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Affiliation(s)
- Emad Farahat
- Botany and Microbiology Department, Faculty of Science, Helwan University, P.O. 11790, Cairo, Egypt.
| | - Paolo Cherubini
- Swiss Federal Research Institute WSL, Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Matthias Saurer
- Swiss Federal Research Institute WSL, Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
| | - Holger Gärtner
- Swiss Federal Research Institute WSL, Zürcherstrasse 111, CH-8903, Birmensdorf, Switzerland
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10
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Rapid increases in shrubland and forest intrinsic water-use efficiency during an ongoing megadrought. Proc Natl Acad Sci U S A 2021; 118:2118052118. [PMID: 34930849 DOI: 10.1073/pnas.2118052118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2021] [Indexed: 11/18/2022] Open
Abstract
Globally, intrinsic water-use efficiency (iWUE) has risen dramatically over the past century in concert with increases in atmospheric CO2 concentration. This increase could be further accelerated by long-term drought events, such as the ongoing multidecadal "megadrought" in the American Southwest. However, direct measurements of iWUE in this region are rare and largely constrained to trees, which may bias estimates of iWUE trends toward more mesic, high elevation areas and neglect the responses of other key plant functional types such as shrubs that are dominant across much of the region. Here, we found evidence that iWUE is increasing in the Southwest at one of the fastest rates documented due to the recent drying trend. These increases were particularly large across three common shrub species, which had a greater iWUE sensitivity to aridity than Pinus ponderosa, a common tree species in the western United States. The sensitivity of both shrub and tree iWUE to variability in atmospheric aridity exceeded their sensitivity to increasing atmospheric [CO2]. The shift to more water-efficient vegetation would be, all else being equal, a net positive for plant health. However, ongoing trends toward lower plant density, diminished growth, and increasing vegetation mortality across the Southwest indicate that this increase in iWUE is unlikely to offset the negative impacts of aridification.
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Liu X, Ziaco E, Biondi F. Water-Use Efficiency of Co-occurring Sky-Island Pine Species in the North American Great Basin. FRONTIERS IN PLANT SCIENCE 2021; 12:787297. [PMID: 34925427 PMCID: PMC8678526 DOI: 10.3389/fpls.2021.787297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 11/02/2021] [Indexed: 06/14/2023]
Abstract
Water-use efficiency (WUE), weighing the balance between plant transpiration and growth, is a key characteristic of ecosystem functioning and a component of tree drought resistance. Seasonal dynamics of tree-level WUE and its connections with drought variability have not been previously explored in sky-island montane forests. We investigated whole-tree transpiration and stem growth of bristlecone (Pinus longaeva) and limber pine (Pinus flexilis) within a high-elevation stand in central-eastern Nevada, United States, using sub-hourly measurements over 5 years (2013-2017). A moderate drought was generally observed early in the growing season, whereas interannual variability of summer rains determined drought levels between years, i.e., reducing drought stress in 2013-2014 while enhancing it in 2015-2017. Transpiration and basal area increment (BAI) of both pines were coupled throughout June-July, resulting in a high but relatively constant early season WUE. In contrast, both pines showed high interannual plasticity in late-season WUE, with a predominant role of stem growth in driving WUE. Overall, bristlecone pine was characterized by a lower WUE compared to limber pine. Dry or wet episodes in the late growing season overrode species differences. Our results suggested thresholds of vapor pressure deficit and soil moisture that would lead to opposite responses of WUE to late-season dry or wet conditions. These findings provide novel insights and clarify potential mechanisms modulating tree-level WUE in sky-island ecosystems of semi-arid regions, thereby helping land managers to design appropriate science-based strategies and reduce uncertainties associated with the impact of future climatic changes.
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Affiliation(s)
- Xinsheng Liu
- School of Geography and Tourism, Anhui Normal University, Wuhu, China
- DendroLab, Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV, United States
- College of Tourism and Geography, Jiujiang University, Jiujiang, China
| | - Emanuele Ziaco
- Department of Ecology and Genetics, Plant Ecology and Evolution, University of Uppsala, Uppsala, Sweden
| | - Franco Biondi
- DendroLab, Department of Natural Resources and Environmental Science, University of Nevada, Reno, NV, United States
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12
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Yu L, Dong H, Huang Z, Korpelainen H, Li C. Elevated CO2 causes different growth stimulation, water- and nitrogen-use efficiencies, and leaf ultrastructure responses in two conifer species under intra- and interspecific competition. TREE PHYSIOLOGY 2021; 41:2082-2095. [PMID: 33891044 DOI: 10.1093/treephys/tpab054] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 04/14/2021] [Indexed: 06/12/2023]
Abstract
The continuously increasing atmospheric carbon dioxide concentration ([CO2]) has substantial effects on plant growth, and on the composition and structure of forests. However, how plants respond to elevated [CO2] (e[CO2]) under intra- and interspecific competition has been largely overlooked. In this study, we employed Abies faxoniana Rehder & Wilson and Picea purpurea Mast. seedlings to explore the effects of e[CO2] (700 p.p.m.) and plant-plant competition on plant growth, physiological and morphological traits, and leaf ultrastructure. We found that e[CO2] stimulated plant growth, photosynthesis and nonstructural carbohydrates (NSC), affected morphological traits and leaf ultrastructure, and enhanced water- and nitrogen (N)- use efficiencies in A. faxoniana and P. purpurea. Under interspecific competition and e[CO2], P. purpurea showed a higher biomass accumulation, photosynthetic capacity and rate of ectomycorrhizal infection, and higher water- and N-use efficiencies compared with A. faxoniana. However, under intraspecific competition and e[CO2], the two conifers showed no differences in biomass accumulation, photosynthetic capacity, and water- and N-use efficiencies. In addition, under interspecific competition and e[CO2], A. faxoniana exhibited higher NSC levels in leaves as well as more frequent and greater starch granules, which may indicate carbohydrate limitation. Consequently, we concluded that under interspecific competition, P. purpurea possesses a positive growth and adjustment strategy (e.g. a higher photosynthetic capacity and rate of ectomycorrhizal infection, and higher water- and N-use efficiencies), while A. faxoniana likely suffers from carbohydrate limitation to cope with rising [CO2]. Our study highlights that plant-plant competition should be taken into consideration when assessing the impact of rising [CO2] on the plant growth and physiological performance.
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Affiliation(s)
- Lei Yu
- Department of Ecology, College of Life and Environmental Sciences, Hangzhou Normal University, Yuhangtang Road 2318, Hangzhou 311121, China
| | - Haojie Dong
- Department of Ecology, College of Life and Environmental Sciences, Hangzhou Normal University, Yuhangtang Road 2318, Hangzhou 311121, China
| | - Zongdi Huang
- Department of Ecology, College of Life and Environmental Sciences, Hangzhou Normal University, Yuhangtang Road 2318, Hangzhou 311121, China
| | - Helena Korpelainen
- Department of Agricultural Sciences, Viikki Plant Science Centre, University of Helsinki, PO Box 27, Latokartanonkaari 5 FI-00014, Helsinki, Finland
| | - Chunyang Li
- Department of Ecology, College of Life and Environmental Sciences, Hangzhou Normal University, Yuhangtang Road 2318, Hangzhou 311121, China
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13
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Driscoll AW, Kannenberg SA, Ehleringer JR. Long-term nitrogen isotope dynamics in Encelia farinosa reflect plant demographics and climate. THE NEW PHYTOLOGIST 2021; 232:1226-1237. [PMID: 34352127 DOI: 10.1111/nph.17668] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 08/02/2021] [Indexed: 06/13/2023]
Abstract
While plant δ15 N values have been applied to understand nitrogen (N) dynamics, uncertainties regarding intraspecific and temporal variability currently limit their application. We used a 28 yr record of δ15 N values from two Mojave Desert populations of Encelia farinosa to clarify sources of population-level variability. We leveraged > 3500 foliar δ15 N observations collected alongside structural, physiological, and climatic data to identify plant and environmental contributors to δ15 N values. Additional sampling of soils, roots, stems, and leaves enabled assessment of the distribution of soil N content and δ15 N, intra-plant fractionations, and relationships between soil and plant δ15 N values. We observed extensive within-population variability in foliar δ15 N values and found plant age and foliar %N to be the strongest predictors of individual δ15 N values. There were consistent differences between root, stem, and leaf δ15 N values (spanning c. 3‰), but plant and bulk soil δ15 N values were unrelated. Plant-level variables played a strong role in influencing foliar δ15 N values, and interannual relationships between climate and δ15 N values were counter to previously recognized spatial patterns. This long-term record provides insights regarding the interpretation of δ15 N values that were not available from previous large-scale syntheses, broadly enabling more effective application of foliar δ15 N values.
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Affiliation(s)
- Avery W Driscoll
- School of Biological Sciences, University of Utah, 257 S 1400 E, Salt Lake City, UT, 84112, USA
| | - Steven A Kannenberg
- School of Biological Sciences, University of Utah, 257 S 1400 E, Salt Lake City, UT, 84112, USA
| | - James R Ehleringer
- School of Biological Sciences, University of Utah, 257 S 1400 E, Salt Lake City, UT, 84112, USA
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14
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Driscoll AW, Bitter NQ, Ehleringer JR. Interactions among intrinsic water-use efficiency and climate influence growth and flowering in a common desert shrub. Oecologia 2021; 197:1027-1038. [PMID: 33387007 DOI: 10.1007/s00442-020-04825-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 12/05/2020] [Indexed: 12/16/2022]
Abstract
Plants make leaf-level trade-offs between photosynthetic carbon assimilation and water loss, and the optimal balance between the two is dependent, in part, on water availability. "Conservative" water-use strategies, in which minimizing water loss is prioritized over assimilating carbon, tend to be favored in arid environments, while "aggressive" water-use strategies, in which carbon assimilation is prioritized over water conservation, are often favored in mesic environments. When derived from foliar carbon isotope ratios, intrinsic water-use efficiency (iWUE) serves as a seasonally integrated indicator of the balance of carbon assimilation to water loss at the leaf level. Here, we used a multi-decadal record of annual iWUE, growth, and flowering from a single population of Encelia farinosa in the Mojave Desert to evaluate the effect of iWUE on plant performance across interannual fluctuations in water availability. We identified substantial variability in iWUE among individuals and found that iWUE interacted with water availability to significantly influence growth and flowering. However, the relationships between iWUE, water availability, and plant performance did not universally suggest that "conservative" water-use strategies were advantageous in dry years or that "aggressive" strategies were advantageous in wet years. iWUE was positively related to the odds of growth regardless of water availability and to the odds of flowering in dry years, but negatively related to growth rates in dry years. In addition, we found that leaf nitrogen content affected interannual plant performance and that an individual's iWUE plasticity in response to fluctuations in aridity was negatively related to early life drought survival and growth.
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Affiliation(s)
- Avery W Driscoll
- School of Biological Sciences, University of Utah, 257 S 1400 E, Salt Lake City, UT, 84112, USA.
| | - Nicholas Q Bitter
- School of Biological Sciences, University of Utah, 257 S 1400 E, Salt Lake City, UT, 84112, USA
| | - James R Ehleringer
- School of Biological Sciences, University of Utah, 257 S 1400 E, Salt Lake City, UT, 84112, USA
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Profile of James R. Ehleringer. Proc Natl Acad Sci U S A 2020; 117:20348-20350. [DOI: 10.1073/pnas.2015163117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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