Effects of Heat Stress after Anthesis on PSII Photochemical Efficiency and the Antioxidant Activity of Wheat Cultivars

Gas exchange and chlorophyll a fluorescence measurements were performed simultaneously on leaves of Phillyrea angustifolia L. to assess the effects of heat stress (30 min at 40 °C) on photosynthesis and photosystem II (PSII) photochemical efficiency of plants grown at ambient CO2 and exposed to an elevated CO2 concentration (800 µmol·mol–1) and 300 µmol photons·m–2·s–1. No significant difference was found in the heat-induced decreases of net photosynthesis (PN), quantum yield of PSII electron transport (ΦPSII), and maximum PSII photochemical efficiency (Fv/Fm) between plants exposed to ambient and elevated CO2 concentrations, showing that elevated CO2 was not able to reduce the potential for photoinhibition at high temperatures under moderate light conditions. The heat-induced decrease of PN was higher than that of ΦPSII indicating that reductive power was more utilized in non-assimilatory processes than in CO2 fixation at both CO2 treatments. This result suggested that impairment of the Calvin cycle rather than electron transport inhibition was the main cause of the limitation in CO2 fixation.

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Phenotyping of wheat cultivars for heat tolerance using chlorophyll a fluorescence

Functional Plant Biology ◽

10.1071/fp12100 ◽

2012 ◽

Vol 39 (11) ◽

pp. 936 ◽

Cited By ~ 53

Author(s):

Dew Kumari Sharma ◽

Sven Bode Andersen ◽

Carl-Otto Ottosen ◽

Eva Rosenqvist

Keyword(s):

Heat Stress ◽

Chlorophyll Fluorescence ◽

Mass Screening ◽

Heat Tolerance ◽

Global Climate ◽

Genetic Difference ◽

Photochemical Efficiency ◽

Wheat Cultivars ◽

Genetic Determination ◽

Chlorophyll Fluorescence Parameters

In view of the global climate change, heat stress is an increasing constraint for the productivity of wheat (Triticum aestivum L.). Our aim was to identify contrasting cultivars in terms of heat tolerance by mass screening of 1274 wheat cultivars of diverse origin, based on a physiological trait, the maximum quantum efficiency of PSII (Fv/Fm). A chlorophyll fluorescence protocol was standardised and used for repeated screening with increased selection pressure with a view to identifying a set of cultivars extreme for the trait. An initial mass screening of 1274 wheat cultivars with a milder heat stress of 38°C in 300 µmol m–2 s–1 for 2 h with preheating at 33–35°C for 19 h in 7–14 µmol m–2 s–1 light showed a genetic determination of 8.5 ± 2.7%. A heat treatment of 40°C in 300 µmol m–2 s–1 for 72 h in the second screening with 138 selected cultivars resulted in larger differentiation of cultivars with an increased genetic component (15.4 ± 3.6%), which was further increased to 27.9 ± 6.8% in the third screening with 41 contrasting cultivars. This contrasting set of cultivars was then used to compare the ability of chlorophyll fluorescence parameters to detect genetic difference in heat tolerance. The identification of a set of wheat cultivars contrasting for their inherent photochemical efficiency may aid future studies to understand the genetic and physiological nature of heat stress tolerance in order to dissect quantitative traits into simpler genetic factors.

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Characterization and Functional Analysis of FaHsfC1b from Festuca arundinacea Conferring Heat Tolerance in Arabidopsis

International Journal of Molecular Sciences ◽

10.3390/ijms19092702 ◽

2018 ◽

Vol 19 (9) ◽

pp. 2702 ◽

Cited By ~ 13

Author(s):

Lili Zhuang ◽

Wei Cao ◽

Jian Wang ◽

Jingjin Yu ◽

Zhimin Yang ◽

...

Keyword(s):

Heat Stress ◽

Transgenic Plants ◽

Heat Tolerance ◽

Festuca Arundinacea ◽

Photochemical Efficiency ◽

Grass Species ◽

Pcr Analysis ◽

Plant Tolerance ◽

Qrt Pcr ◽

Class C

Heat transcription factors (Hsfs) belong to a large gene family classified into A, B, and C groups, with classes A and B Hsfs being well-characterized and known for their roles in plant tolerance to abiotic stresses. The functions and roles of Class C Hsfs are not well-documented. The objectives of this study were to characterize a class C Hsf gene (FaHsfC1b) cloned from tall fescue (Festuca arundinacea), a perennial grass species, and to determine the physiological functions of FaHsfC1b in regulating heat tolerance by overexpressing FaHsfC1b in Arabidopsis thaliana. Full length cDNA of FaHsfC1b was cloned and the sequence alignment showed that it had high similarity to OsHsfC1b with typical DNA binding domain, hydrophobic oligomerization domain, and a nucleus localization signal. Transient expression with FaHsfC1b-eGFP in protoplasts of Arabidopsis leaves indicated its nucleus localization. qRT-PCR analysis showed that FaHsfC1b responded to heat, osmotic, salt, and cold stress in leaves and roots during 48-h treatment. Physiological analysis showed that FaHsfC1b overexpression enhanced plant survival rate, chlorophyll content, and photochemical efficiency, while it resulted in decreases in electrolyte leakage, H2O2 and O2− content under heat stress. qRT-PCR showed that endogenous HsfC1 was induced in transgenic plants and the expression levels of heat protection protein genes, including several HSPs, AtGalSyn1, AtRof1, and AtHSA32, as well as ABA-synthesizing gene (NCED3) were significantly upregulated in transgenic plants overexpressing FaHsfC1b under heat stress. Our results first demonstrate that HsfC1b plays positive roles in plant tolerance to heat stress in association with the induction and upregulation of heat-protective genes. HsfC1b may be used as a candidate gene for genetic modification of cool-season plant species for improving heat tolerance.

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Effects of different stressors on the PSII photochemical efficiency and application to sporeling transportation in cultured young sporophytes of Undaria pinnatifida

Journal of Applied Phycology ◽

10.1007/s10811-021-02616-8 ◽

2021 ◽

Author(s):

Yoichi Sato ◽

Daisuke Saito ◽

Gregory N. Nishihara ◽

Ryuta Terada

Keyword(s):

Undaria Pinnatifida ◽

Photochemical Efficiency ◽

Psii Photochemical Efficiency ◽

Young Sporophytes

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Traits in Spring Wheat Cultivars Associated with Yield Loss Caused by a Heat Stress Episode after Anthesis

Journal of Agronomy and Crop Science ◽

10.1111/jac.12085 ◽

2014 ◽

Vol 201 (1) ◽

pp. 32-48 ◽

Cited By ~ 25

Author(s):

M. Vignjevic ◽

X. Wang ◽

J. E. Olesen ◽

B. Wollenweber

Keyword(s):

Heat Stress ◽

Spring Wheat ◽

Yield Loss ◽

Wheat Cultivars

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Effect of two‐week heat stress during grain filling on stem reserves, senescence, and grain yield of European winter wheat cultivars

Journal of Agronomy and Crop Science ◽

10.1111/jac.12410 ◽

2020 ◽

Vol 206 (6) ◽

pp. 722-733 ◽

Cited By ~ 5

Author(s):

Siegfried Schittenhelm ◽

Tina Langkamp‐Wedde ◽

Martin Kraft ◽

Lorenz Kottmann ◽

Katja Matschiner

Keyword(s):

Heat Stress ◽

Winter Wheat ◽

Grain Yield ◽

Grain Filling ◽

Wheat Cultivars ◽

Winter Wheat Cultivars ◽

European Winter Wheat ◽

Stem Reserves

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Lipid Peroxidation and Chlorophyll Fluorescence of Photosystem II Performance during Drought and Heat Stress is Associated with the Antioxidant Capacities of C3 Sunflower and C4 Maize Varieties

International Journal of Molecular Sciences ◽

10.3390/ijms21144846 ◽

2020 ◽

Vol 21 (14) ◽

pp. 4846

Author(s):

Dilek Killi ◽

Antonio Raschi ◽

Filippo Bussotti

Keyword(s):

Lipid Peroxidation ◽

Antioxidant Activity ◽

Heat Stress ◽

Chlorophyll Fluorescence ◽

Photosystem Ii ◽

Membrane Damage ◽

Drought Tolerant ◽

Maize Varieties ◽

Catalase Peroxidase ◽

Drought And Heat Stress

Agricultural production is predicted to be adversely affected by an increase in drought and heatwaves. Drought and heat damage cellular membranes, such as the thylakoid membranes where photosystem II occurs (PSII). We investigated the chlorophyll fluorescence (ChlF) of PSII, photosynthetic pigments, membrane damage, and the activity of protective antioxidants in drought-tolerant and -sensitive varieties of C3 sunflower and C4 maize grown at 20/25 and 30/35 °C. Drought-tolerant varieties retained PSII electron transport at lower levels of water availability at both temperatures. Drought and heat stress, in combination and isolation, had a more pronounced effect on the ChlF of the C3 species. For phenotyping, the maximum fluorescence was the most effective ChlF measure in characterizing varietal variation in the response of both species to drought and heat. The drought-tolerant sunflower and maize showed lower lipid peroxidation under drought and heat stress. The greater retention of PSII function in the drought-tolerant sunflower and maize at higher temperatures was associated with an increase in the activities of antioxidants (glutathione reductase, superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase), whereas antioxidant activity declined in the drought-sensitive varieties. Antioxidant activity should play a key role in the development of drought- and heat-tolerant crops for future food security.

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