Effect of Drought Stress in Different Cultivars of Tomato

Abstract

Plants are frequently exposed to many environmental stresses such as drought, cold, salt, flood, heat, heavy metal toxicity etc while growing in natural conditions. Of the different environmental stresses, drought stress is the most important stress and the main cause of significant losses in growth and productivity of many plants. Drought induces significant alterations in plant physiology and biochemistry. Severe drought stress may result in functional damage and loss of plant parts. Tomato is an important, popular and nutritious vegetable crop. This piece of work was carried out to identify the effects of drought stress in different cultivars of tomato. Mannitol and NaCl were used to induce drought stress. For the selection of osmoticum the tomato seeds were germinated in different concentrations of mannitol and NaCl. Under controlled condition, 96% of seeds were germinated. The germination percentage was reduced upto 36 % and 57.33% in 4000 ppm of NaCl and mannitol. Further work was carried out using NaCl. Drought tolerant cultivar (NCL) and drought sensitive cultivar (BL) were selected by subjecting germination of tomato seeds in different concentration of NaCl and by the measuring different physiological attributes (RWC and ELWR). The selected cultivars were further grown and treated with four different concentrations of NaCl solutions after 30 days of germination. Shoot length, fresh weight, dry weight and chlorophyll content of the selected cultivars were measured after 60 days of germination. Shoot length, fresh weight and dry weight were found to be more in BL but chlorophyll content was found to be present in higher amount in NCL. The effects of induced stress were more pronounced in BL. Shoot length, fresh weight and dry weight were reduced upto 39.82%, 42.03% and 24.13% respectively in BL. In NCL shoot length, fresh weight and dry weight were reduced by 28.76%, 38.74% and 16.22% respectively. Chlorophyll a and Chlorophyll b were reduced upto 36.05% and 37.78% respectively in NCL and upto 27.08% and 22.86% respectively in BL.