ABIOTIC STRESSES AND THEIR EFFECTS ON PLANT GROWTH, YIELD AND NUTRITIONAL QUALITY OF AGRICULTURAL PRODUCE
Plants are considered to be under stress when environmental conditions are not ideal for growth. How adverse environments affects plant growth is not only a fundamental scientific question but is also of vital importance for agriculture and food security. adverse environments were estimated to cause an overall yield loss of 70 percent in key agricultural crops.
Abiotic stress caused by deficiencies or excesses in environmental factors including water, salt, light, heavy metals, temperature, and nutrients can substantially reduce plant growth, when plants are under stress, growth and development of a plant are accomplished through enlargement division and differentiation of cell and involves ecological, genetical, physiological and morphological events. Cell growth is considered is one of the most stress sensitive physiological process because of the reduction in turgor pressure. Under serve drought, cell elongation in higher plants get repressed due to the disruption of water movements from xylem to the surrounding elongating cell. Under abiotic stress the compromised mitotic cell division, cell elongation and expansion result in decreased plant height, leaf area, biomass production and reduction in root biomass.
Abiotic stresses also effect the productivity and yield of crops, due to studies on different plant species have indicated that heat stress is more harmful at the reproductive stage of crop growth. Heat stress significantly disrupts the anatomy at the tissue, cellular and sub-cellular level. The major disruptions include deformation of the chloroplast, swelling of stomatal lamellae etc. yield reduction due to drought stress have been reported in many crops, water plays an important role in the mineral nutrition of plants since most of the nutrients from the soil are mobilized with the movement of water. The biological yield of crops under unfavorable environmental condition is affected due to inefficient physiological and biochemical activities.
Global climate changes are expected to further worsen climatic conditions which will not only affects the productivity of the crops but the quality of the produces also.an increased in protein content at the grain formation stage has been reported due to abiotic stresses.in wheat decreased quality of gluten, glutenin contents, grain hardness has been reported in wheat under salt and drought stresses. Studies on three wheat cultivars under heat, drought, and the combined effects of heat and drought were found to cause decreased glucan contents in grain, drought stress reduced the uptake of Iron, Zinc, and Copper from the soil.
Reduction in biomass production by crops plants is the most apparently and widely recognized effects of abiotic stresses which is result in quantitative and qualitative losses. However, a multi-disciplinary research effort would be required to integrate, genotypic, phenotypic, proteomic, transcriptomic, epigenetic this would help in devising better strategies to design climatic-resilient crop plants to cope with the effects of climate change.