Strobilurin fungicides induce changes in photosynthetic gas exchange that do not improve water use efficiency of plants grown under conditions of water stress

2007 ◽  
Vol 63 (12) ◽  
pp. 1191-1200 ◽  
Author(s):  
Mark A Nason ◽  
John Farrar ◽  
David Bartlett
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Use ◽  
Photosynthetic Gas Exchange ◽  
Strobilurin Fungicides ◽  
Use Efficiency

scholarly journals Interaction of CO<sub>2</sub> concentrations and water stress in semiarid plants causes diverging response in instantaneous water use efficiency and carbon isotope composition

2017 ◽  
Vol 14 (14) ◽  
pp. 3431-3444 ◽  
Author(s):  
Na Zhao ◽  
Ping Meng ◽  
Yabing He ◽  
Xinxiao Yu
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Use ◽  
Environmental Changes ◽  
Isotope Composition ◽  
Water Soluble ◽  
Severe Drought ◽  
Semiarid Areas ◽  
Use Efficiency

Abstract. In the context of global warming attributable to the increasing levels of CO2, severe drought may be more frequent in areas that already experience chronic water shortages (semiarid areas). This necessitates research on the interactions between increased levels of CO2 and drought and their effect on plant photosynthesis. It is commonly reported that 13C fractionation occurs as CO2 gas diffuses from the atmosphere to the substomatal cavity. Few researchers have investigated 13C fractionation at the site of carboxylation to cytoplasm before sugars are exported outward from the leaf. This process typically progresses in response to variations in environmental conditions (i.e., CO2 concentrations and water stress), including in their interaction. Therefore, saplings of two typical plant species (Platycladus orientalis and Quercus variabilis) from semiarid areas of northern China were selected and cultivated in growth chambers with orthogonal treatments (four CO2 concentration ([CO2])  ×  five soil volumetric water content (SWC)). The δ13C of water-soluble compounds extracted from leaves of saplings was determined for an assessment of instantaneous water use efficiency (WUEcp) after cultivation. Instantaneous water use efficiency derived from gas-exchange measurements (WUEge) was integrated to estimate differences in δ13C signal variation before leaf-level translocation of primary assimilates. The WUEge values in P. orientalis and Q.  variabilis both decreased with increased soil moisture at 35–80 % of field capacity (FC) and increased with elevated [CO2] by increasing photosynthetic capacity and reducing transpiration. Instantaneous water use efficiency (iWUE) according to environmental changes differed between the two species. The WUEge in P. orientalis was significantly greater than that in Q. variabilis, while an opposite tendency was observed when comparing WUEcp between the two species. Total 13C fractionation at the site of carboxylation to cytoplasm before sugar export (total 13C fractionation) was species-specific, as demonstrated in the interaction of [CO2] and SWC. Rising [CO2] coupled with moistened soil generated increasing disparities in δ13C between water-soluble compounds (δ13CWSC) and estimates based on gas-exchange observations (δ13Cobs) in P. orientalis, ranging between 0.0328 and 0.0472 ‰. Differences between δ13CWSC and δ13Cobs in Q. variabilis increased as [CO2] and SWC increased (0.0384–0.0466 ‰). The 13C fractionation from mesophyll conductance (gm) and post-carboxylation both contributed to the total 13C fractionation that was determined by δ13C of water-soluble compounds and gas-exchange measurements. Total 13C fractionation was linearly dependent on stomatal conductance, indicating that post-carboxylation fractionation could be attributed to environmental variation. The magnitude and environmental dependence of apparent post-carboxylation fractionation is worth our attention when addressing photosynthetic fractionation.

Sensitivity of leaf gas exchange to atmospheric drought, soil drought, and water-use efficiency in some Mediterranean Abies species

1991 ◽  
Vol 21 (10) ◽  
pp. 1507-1515 ◽  
Author(s):  
J. M. Guehl ◽  
G. Aussenac ◽  
J. Bouachrine ◽  
R. Zimmermann ◽  
J. M. Pennes ◽  
...  
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Use ◽  
Leaf Gas Exchange ◽  
Soil Drought ◽  
Drought Adaptation ◽  
Internal Water ◽  
Annual Growth Rings ◽  
Use Efficiency

The responses of CO2 assimilation rate (A), transpiration rate (E), and leaf conductance (g) to increasing leaf to air water vapor concentration difference (ΔW) were investigated (i) using excised shoots from mature trees of Abiesalba, Abiescephalonica, Abiesmarocana, and Abiesnordmanniana and (ii) in situ on a mature tree of Abiesbornmulleriana. Gas-exchange responses to increasing soil drought were also studied in plants of A. bornmulleriana, A. cephalonica, and Cedrusatlantica. Stable carbon isotope composition measurements were carried out on annual growth rings of A. bornmulleriana to estimate the time-integrated values of the ratio of intercellular leaf (Ci) to ambient (Ca) CO2 concentration. Increasing ΔW around the shoots reduced A and g in such a way that either Ci remained constant or its decrease was not pronounced enough for the changes in A to be accounted for by changes in g only. This suggests a direct effect of ΔW on photosynthesis. The different Abies species showed clear differences in water-use efficiency. Abiescephalonica and A. marocana had lower water costs of CO2 assimilation (E/A) than A. nordmanniana and A. alba. It has also been shown that A. cephalonica and A. marocana are characterized by an optimal stomatal control of leaf gas exchange. Stomata closed very rapidly in A. bornmulleriana in response to water supply being withheld, even prior to there being any important decrease in leaf predawn water potential. The stomatal response in C. atlantica was more gradual. In A. bornmulleriana, drought adaptation appears to be linked to the ability to avoid internal water stress, whereas drought adaptation in C. atlantica involves the ability to tolerate internal water stress. The high stomatal sensitivity mA. bornmulleriana is also supported by the isotopic carbon composition data, as shown by the substantial interannual variations in the estimates of Ci/Ca, ranging from 0.48 for the dryest years to 0.61 for the rainy years.

Seasonal photosynthetic gas exchange and water-use efficiency in a constitutive CAM plant, the giant saguaro cactus (Carnegiea gigantea)

Oecologia ◽  
2011 ◽  
Vol 167 (3) ◽  
pp. 861-871 ◽  
Author(s):  
Dustin R. Bronson ◽  
Nathan B. English ◽  
David L. Dettman ◽  
David G. Williams
Keyword(s):  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Use ◽  
Photosynthetic Gas Exchange ◽  
Carnegiea Gigantea ◽  
Use Efficiency ◽  
Cam Plant

Effect of water stress on leaf level gas exchange capacity and water-use efficiency of wheat cultivars

2016 ◽  
Vol 21 (3) ◽  
pp. 300-305 ◽  
Author(s):  
Sripati Sikder ◽  
Yunzhou Qiao ◽  
Dong Baodi ◽  
Changhai Shi ◽  
Mengyu Liu
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Use ◽  
Exchange Capacity ◽  
Wheat Cultivars ◽  
Effect Of Water ◽  
Leaf Level ◽  
Use Efficiency
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