scholarly journals Drought stress strengthens the link between chlorophyll fluorescence parameters and photosynthetic traits

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10046 ◽  
Author(s):  
Jie Zhuang ◽  
Yonglin Wang ◽  
Yonggang Chi ◽  
Lei Zhou ◽  
Jijing Chen ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Drought Stress ◽  
Terrestrial Ecosystems ◽  
Stomatal Limitation ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Total Chlorophyll Content ◽  
Leaf Level ◽  
Photosynthetic Traits ◽  
Quantum Efficiency Of Psii

Chlorophyll fluorescence (ChlF) has been used to understand photosynthesis and its response to climate change, particularly with satellite-based data. However, it remains unclear how the ChlF ratio and photosynthesis are linked at the leaf level under drought stress. Here, we examined the link between ChlF ratio and photosynthesis at the leaf level by measuring photosynthetic traits, such as net CO2 assimilation rate (An), the maximum carboxylation rate of Rubisco (Vcmax), the maximum rate of electron transport (Jmax), stomatal conductance (gs) and total chlorophyll content (Chlt). The ChlF ratio of the leaf level such as maximum quantum efficiency of PSII (Fv/Fm) is based on fluorescence kinetics. ChlF intensity ratio (LD685/LD740) based on spectrum analysis was obtained. We found that a combination of the stomatal limitation, non-stomatal limitation, and Chlt regulated leaf photosynthesis under drought stress, while Jmax and Chlt governed the ChlF ratio. A significant link between the ChlF ratio and An was found under drought stress while no significant correlation in the control, which indicated that drought stress strengthens the link between the ChlF ratio and photosynthetic traits. These results suggest that the ChlF ratio can be a powerful tool to track photosynthetic traits of terrestrial ecosystems under drought stress.

scholarly journals Chlorophyll fluorescence response of wheat to exogenous application of growth regulators under terminal drought stress

2015 ◽  
Vol 70 (1) ◽  
pp. 13
Author(s):  
Hamid Mohammadi ◽  
Mohsen Janmohammadi ◽  
Naser Sabaghnia
Keyword(s):  
Chlorophyll Fluorescence ◽  
Drought Stress ◽  
Electron Transport ◽  
Quantum Yield ◽  
Photochemical Quenching ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Exogenous Application ◽  
Terminal Drought ◽  
Terminal Drought Stress

<p>Drought stress negatively affects plant photosynthesis and disturbs the electron transport activity. Evaluation of the chlorophyll fluorescence parameters might reflect influence of the environmental stress on plants and can be applied as an indicator of the primary photochemistry of photosynthesis. In current study the effect of foliar application of benzylaminopurine (BAP, a synthetic cytokinin) and abscisic acid (ABA) on chlorophyll fluorescence parameters of relatively drought tolerant (Pishtaz) and susceptible (Karaj3) bread wheat genotypes under well watered and terminal water deficit condition have been evaluated. Terminal drought was induced by withholding water at anthesis stage (Zadoks scale 65). Results showed that coefficient of non-photochemical quenching of variable fluorescence (qN), quantum yield of PS II photochemistry (ΦPSII) and photochemical quenching (qP) were affected by hormone spray treatments. So that evaluation of parameters at 7 day after foliar treatments revealed that ABA significantly increased electron transport rate (ETR) and qN while considerably decreased ΦPSII, gs and maximum quantum yield of photosystem II (Fv/Fm). However exogenous application of cytokinin could increase gs, Fv/Fm and ΦPSII and the highest value of these parameters was recorded in <em>cytokinin </em>treated plants of Pishtaze cv. under well watered condition. Nevertheless, evaluation of the parameters in different periods after spraying showed that with approaching the maturity stage some traits like as gs, Fv/Fm and ETR significantly decreased in both genotypes. Evaluation of gs and Chlorophyll fluorescence parameters of genotypes between different irrigation levels showed that although cv. Pishtaz showed higher performance of PSII under well watered condition, it failed to maintain its superiority under stress condition. This finding suggests that some more responsive parameter like gs, Fv/Fm and ΦPSII can be considered as reliable indicator for understanding the biochemical and physiological effects of exogenous application of phytohormones under terminal drought stress.</p>

Relationships between chlorophyll fluorescence parameters and photochemical reflectance index of tree species adapted to different temperature regimes

2006 ◽  
Vol 33 (3) ◽  
pp. 241 ◽  
Author(s):  
Jen-Hsien Weng ◽  
Yaw-Nan Chen ◽  
Tien-Szu Liao
Keyword(s):  
Chlorophyll Fluorescence ◽  
Mangifera Indica ◽  
Photochemical Quenching ◽  
Weak Correlation ◽  
Tropical Fruit ◽  
Chlorophyll Fluorescence Parameters ◽  
Psii Efficiency ◽  
Photochemical Reflectance Index ◽  
Fluorescence Parameters ◽  
Leaf Level

Chlorophyll fluorescence parameters and spectral reflectance at leaf level were measured at both predawn and noon, under different temperatures and natural light conditions from autumn to winter. Predawn Fv / Fm of both mango (Mangifera indica L.), a tropical fruit tree, and Podocarpus nagi Zoll. et Moritz., a subtropical conifer, decreased with decreasing temperature, with the former to a greater extent than the latter. Yet, predawn Fv / Fm of Taiwan alder (Alnus formosana Makino), a broadleaf tree widely distributed from the lowlands to 3000 m above sea level in Taiwan, was less influenced by temperature. Nevertheless, taking all three species into consideration, predawn Fv / Fm showed a strong correlation with predawn photochemical reflectance index [(PRIp), PRI = (R531 − R570) / (R531 + R570), where R = reflectance]. For the data obtained at noon, ΔF / Fm′ showed a significant but weak correlation with PRI (PRIn). However, stronger correlation between ΔF / Fm′ and ΔPRI (PRIp − PRIn) was found. In addition, while a non-significant or weak correlation between non-photochemical quenching (NPQ) and PRIn was observed in species sensitive to low temperature, their NPQ was significantly correlated with ΔPRI. We conclude that PRIp can serve as an indicator of the seasonal variation of potential PSII efficiency; and ΔPRI reflects the actual photodissipation as well as actual PSII efficiency during illumination. For the three species in this study, the PRI provides a more consistent measure of the variation in predawn fluorescence values than for steady-state values measured under normal seasonally varying daylight illumination.

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