Temperature stress and redox homeostasis in agricultural crops

Abstract

Plants are exposed to a wide range of environmental conditions and one of the major forces that shape the structure and function of plants are temperature stresses, which include low and high temperature stresses and considered as major abiotic stresses for crop plants. Due to global climate change, temperature stress is becoming the major area of concern for the researchers worldwide. The reactions of plants to these stresses are complex and have devastating effects on plant metabolism, disrupting cellular homeostasis and uncoupling major physiological and biochemical processes. Temperature stresses disrupt photosynthesis and increase photorespiration thereby altering the normal homeostasis of plant cells. The constancy of temperature, among different metabolic equilibria present in plant cells, depends to a certain extent on a homeostatically regulated ratio of redox components, which are present virtually in all plant cells. Several pathways, which are present in plant cells, enable correct equilibrium of the plant cellular redox state and balance fluctuations in plant cells caused by changes in environment due to stressful conditions. In temperature stresses, high temperature stress is considered to be one of the major abiotic stresses for restricting crop production worldwide. The responses of plants to heat stress vary with extent of temperature increase, its duration and the type of plant. On other hand, low temperature as major environmental factor often affects plant growth and crop productivity and leads to substantial crop loses. A direct result of stress-induced cellular changes is overproduction of reactive oxygen species (ROS) in plants which are produced in such a way that they are confined to a small area and also in specific pattern in biological responses. ROS (superoxide; O − 2 , hydroxyl radicals; OH − , alkoxyl radicals and non-radicals like hydrogen peroxide; H 2 O 2 and singlet oxygen; 1 O 2) are highly reactive and toxic and cause damage to proteins, lipids, carbohydrates which ultimately results in oxidative stress. ROS may also serve as signaling molecules in mediating important signal transduction pathways that coordinate an astonishing range of diverse plant processes under temperature stress. To counter temperature induced oxidative stress, plants upregulate a variety of enzymatic and non-enzymatic antioxidants which are also information-rich redox buffers and important components of redox signaling that interact with biomembrane-related compartments. They provide essential information on cellular redox state, and regulate gene expression associated with stress responses to optimize defense and survival, stress acclimation and tolerance. The work done by various researchers has explored a direct link between ROS scavenging and plant tolerance under temperature extremes in various crops which include legumes, cereals, oil crops and vegetables. There is ample need to develop temperature tolerance in crop plants by exploring suitable strategies to manage oxidative stress and maintain cel...

Cadmium treatment effects on the growth and antioxidant system in barley plants under optimal and low temperatures

“…It is known that an agreed increase of the antioxidant enzymes activity is essential for maintaining the balance between the generation and neutralization of ROS (Gechev et al, 2003;Avasthi et al, 2015). Hence, the enhanced SOD activity alone, without an increase in the activity of CAT and/or PRX, as was observed in our experiments, leads to a build up of the hydrogen peroxide concentration in cells, and, accordingly, to an acceleration of oxidative processes.…”

“…In small amounts, ROS are formed during metabolic processes and normally they are inactivated due to the components of antioxidant system. Under unfavorable conditions, the formation of ROS sharply increases, leading to oxidative stress, resulting in damage to proteins and nucleic acids, lipid oxidation and cell membrane damage, and eventually causing inhibition of plant growth and development, and sometimes their death (Avasthi et al, 2015). The same reaction is observed in plants exposed to cadmium.…”

Effective diffusion rates and cross-correlation analysis of “acid growth” data

“…Temperature is one of the main factors that affects their growth and development; however, its effect on plants is difficult to examine in detail because virtually every biological process has an inherent optimum temperature at which it occurs most effectively. This optimum value not only depends on the species, organs and tissues but also depends on the stage of the development of the organism (Awasthi et al 2015). Both supra-and sub-optimal temperature stresses are the factors that may cause structural damage, interfere with metabolism and consequently weaken growth and reduce plant vigour or lead to cell death (Hasanuzzaman et al 2013;Awasthi et al 2015).…”

“…This optimum value not only depends on the species, organs and tissues but also depends on the stage of the development of the organism (Awasthi et al 2015). Both supra-and sub-optimal temperature stresses are the factors that may cause structural damage, interfere with metabolism and consequently weaken growth and reduce plant vigour or lead to cell death (Hasanuzzaman et al 2013;Awasthi et al 2015). Different plant species developed mechanisms which allow them to survive at extreme temperatures (Hasanuzzaman et al 2013) and to be able to conduct photosynthesis and maintain their development, though in limited degree.…”

“…These mechanisms in the case of cold shock for crop plants include: reorganising the membrane structure by increasing the proportion of polyunsaturated fatty acids and maintaining large reservoir of ATP and NADPH, which allows them to preserve or even stimulate the synthesis of more reduced compounds playing a role in osmoregulation (Guy 1999). The ability to tolerate high temperatures, in turn, can be achieved by reducing the absorption of solar radiation, owing to special forms on the cuticle surface which reflect light, hairs on the leaves, a greater thermal stability of enzymes, elevated transpiration, as well as increased content of saturated fatty acids in the lipid membrane or through the biosynthesis of heat-shock proteins-HSPs (Iba 2002;Hasanuzzaman et al 2013;Awasthi et al 2015). Most plants have a high capacity to adapt to a particular temperature range and can change the optimum temperature to conduct photosynthesis.…”