Understanding down‐regulation of photosynthesis under water stress: future prospects and searching for physiological tools for irrigation management

Abstract

Photosynthetic down-regulation and/or inhibition under water stress conditions are determinants for plant growth, survival and yield in drought-prone areas. Current knowledge about the sequence of metabolic events that leads to complete inhibition of photosynthesis under severe water stress is reviewed. An analysis of published data reveals that a key regulatory role for Rubisco in photosynthesis is improbable under water stress conditions. By contrast, the little data available for other Calvin cycle enzymes suggest the possibility of a key regulatory role for some enzymes involved in the regeneration of RuBP. There are insufficient data to determine the role of photophosphorylation.Several important gaps in our knowledge of this field are highlighted. The most important is the remarkable scarcity of data about the regulation/inhibition of photosynthetic enzymes other than Rubisco under water stress. Consequently, new experiments are urgently needed to improve our current understanding of photosynthetic down-regulation under water stress. A second gap is the lack of knowledge of photosynthetic recovery after irrigation of plants which have been subjected to different stages of water stress. This knowledge is necessary in order to match physiological down-regulation by water stress with controlled irrigation programmes.

Analysis of biochemical variations and microRNA expression in wild (Ipomoea campanulata) and cultivated (Jacquemontia pentantha) species exposed to in vivo water stress

“…Decreased chlorophyll is recognized to directly affect photosynthesis which plays a vital role in plant growth and development (Chaves et al 2009;Flexas et al 2004;Lawlor and Tezara 2009). Larger fall in the chlorophyll content of J. pentantha may depict its susceptibility to water deficit.…”

Discriminating Irrigated and Rainfed Maize with Diurnal Fluorescence and Canopy Temperature Airborne Maps

“…These mechanisms consist in the dissipation of excess excitation energy as chlorophyll fluorescence and/or heat. Since these two occur in competition with photosynthesis, variations of the yield of chlorophyll fluorescence and heat dissipation have been exploited to detect stress-induced variations in photosystem II efficiency [9]. Both sun-induced chlorophyll fluorescence (F760) and heat dissipation can in principle be retrieved using hyperspectral optical data.…”

Comparative Proteomics Analysis of Differentially Expressed Proteins in Chickpea Extracellular Matrix during Dehydration Stress

“…Among the unfavorable environmental conditions, water deficit or dehydration is the most significant factor that adversely affects plant growth, development, and productivity. In recent years, the physiological and molecular basis for plant responses to dehydration tolerance has been the subject of intense research (3,4). It is now well established that plants, being sessile, have evolved many adaptations to counteract dehydration.…”