High temperature reduces photosynthesis in maize leaves by damaging chloroplast ultrastructure and photosystem II

Abstract

Global warming has increased the frequency and duration of high temperature (HT) stress. Photosynthesis determines yield in maize and is extremely HT sensitive. The effects of HT on photosynthesis in maize leaves have been strongly examined under controlled conditions. Here, to explore the mechanism and primary inhibitory sites of HT to photosynthesis, the HT sensitivity of photosynthesis in XY335 and ZD958 maize hybrids was systematically studied in field by multiple methods. HT decreased leaf area and photosynthetic rate of unit leaf area and hence limited growth. HT disrupted chloroplast and mitochondrial membrane structure, possibly delaying photosynthetic recovery after HT. These changes were greater in XY335 than ZD958. Stomatal conductance decreased significantly under HT, and this did not restrict CO2 fixation but may weaken the heat dissipation through transpiration. HT caused photoinhibition of PSII but not PSI. HT damaged both the oxygen‐evolving complex, located at donor side of PSII, and electron transfer from QA to QB, located at acceptor side of PSII. Interference of electron transfer from QA to QB caused by degradation of QB‐binding (D1) protein was the primary site of PSII inhibition by HT in maize leaves. The different stomatal behaviour and photoinhibition sites under HT between maize and wheat were discussed.

Effects of repeated drought stress on the physiological characteristics and lipid metabolism of Bombax ceiba L. during subsequent drought and heat stresses

“…The sharp reduction of qP, Y(II) and rETR confirm that heat stress severely decreased the photosynthetic activity. In this way, the absorbed excessive energy may have led to the accumulation of reactive oxygen species, which might have further disrupted the membrane structure and damaged some heat-sensitive components of the photosynthetic apparatus such as the oxygen-evolving complex and D1 protein [34,35].…”

Application of Optimal Combined Microfertilizers of Boron, Molybdenum, and Copper Improves Root Tuber Yield Trait and Photosynthetic Response Characteristics in Pseudostellaria heterophylla

“…The optimal combination of microfertilizers improved PSII photochemical activity and alleviated photoinhibition. PSII is the primary and main part of photoinhibition when plants are exposed to high temperatures, strong light, and other environmental stresses (Yu et al, 2020). In the light reaction system, PSII is affected more easily by the internal and external environment than photosystem I.…”

Variability and selection among mutant families of wheat for biomass allocation, yield and yield‐related traits under drought‐stressed and non‐stressed conditions

“…The number of tillers and leaf characteristics such as chlorophyll content and leaf area directly influences photosynthetic capacity (Aditya & Bhartiya, 2013; Zhang et al., 2009). The accumulation of large shoot biomass could potentially lead to a large canopy to prevent direct moisture loss from the soil and thus promote water utilization for high grain yield production in wheat (Amani et al., 2008; Botwright et al., 2002; Li et al., 2020). The large canopy would provide an advantage where transpirational losses are minimized during drought stress.…”