Photosynthesis under stressful environments: An overview

Abstract

Stressful environments such as salinity, drought, and high temperature (heat) cause alterations in a wide range of physiological, biochemical, and molecular processes in plants. Photosynthesis, the most fundamental and intricate physiological process in all green plants, is also severely affected in all its phases by such stresses. Since the mechanism of photosynthesis involves various components, including photosynthetic pigments and photosystems, the electron transport system, and CO 2 reduction pathways, any damage at any level caused by a stress may reduce the overall photosynthetic capacity of a green plant. Details of the stress-induced damage and adverse effects on different types of pigments, photosystems, components of electron transport system, alterations in the activities of enzymes involved in the mechanism of photosynthesis, and changes in various gas exchange characteristics, particularly of agricultural plants, are considered in this review. In addition, we discussed also progress made during the last two decades in producing transgenic lines of different C 3 crops with enhanced photosynthetic performance, which was reached by either the overexpression of C 3 enzymes or transcription factors or the incorporation of genes encoding C 4 enzymes into C 3 plants. We also discussed critically a current, worldwide effort to identify signaling components, such as transcription factors and protein kinases, particularly mitogen-activated protein kinases (MAPKs) involved in stress adaptation in agricultural plants.

Finding out Relationships Among Some Morpho-Biochemical Parameters of Christ's Thorn (Ziziphus spina-christi) under Drought and Salinity Stresses

“…Chlorophyll a and chlorophyll b content had a positive relationship with each other, and similar results were reported by (Ashraf et al, 2013). On the other hand, all morphological traits and RWC had a highly positive relationship with one another.…”

Gas exchange and photosynthetic pigments in bell pepper irrigated with saline water

“…This reduction may also be associated with the decrease in the biosynthesis of chlorophyll a and with the increment in the activity of the chlorophyllase enzyme, and with the instability of the protein complexes caused by the effects of the salt stress (Houimili et al, 2010). The lower reduction in the content of carotenoids may be related to its activity as antioxidant, mitigating the oxidative effects and resulting in more constant contents, even with the increase in salinity (Ziaf et al, 2009;Ashraf & Harris, 2013).…”

Connection of the Photochemical Reflectance Index (PRI) with the Photosystem II Quantum Yield and Nonphotochemical Quenching Can Be Dependent on Variations of Photosynthetic Parameters among Investigated Plants: A Meta-Analysis

“…[124]. It is very probable that even a crude guess of the range of photosynthetic parameters can allow one to estimate the efficiency of the PRI in an accurate analysis of photosynthetic stress in plants.…”

“…Detailed models of PRI, which include a description of the geometry and discontinuity of canopy and different depth penetrations of light into the canopy, are developed on the basis of these models [109,137,138]. Also, linear and nonlinear regressions are widely used to describe the connection between PRI and photosynthetic parameters [62,76,124,137,139]. Development of mechanistic models of PRI and photosynthetic processes is another important method of PRI simulation [109].…”