European Journal of Sustainable Agroecosystems

Lentil (Lens culinaris Medik.) is a key cool-season pulse crop that suffers from the joint attack of heat and water deficiency aggravated by temperature rise and shifting rainfall patterns worldwide. As joint stress does not simply lead to an increase in physiological stress caused by either heat or water deficit, there is a need for adequate assessment of the effects of heat and drought to be able to develop appropriate crop varieties. The study presents the results of assessing the physiological and biochemical response of lentil variety to the selected treatment comprising four variations: control (applied adequate water), heat stress, drought, and combined heat and drought stress. Growth, leaf water relations, chlorophyll stability, gas exchange parameters, osmolytes accumulation, antioxidant enzyme activity, oxidative stress markers, and yield components were the parameters evaluated throughout the treatment period. Compared to the control, the combined stress caused the greatest reductions in relative water content, chlorophyll concentration, net photosynthetic rate, and stomatal conductance as well as their total effect for some traits. Stress resulted in the highest accumulations of proline and soluble sugars and the greatest activities of enzymes such as catalase, superoxide dismutase, peroxidase, ascorbate peroxidase, and glutathione reductase, which did not allow sufficiently to balance the high plant stress. The most significant reduction of yield parameters including pods per plant, number of seeds per plant, seed yield, and harvest index was found for combined stress. Analysis of correlation and principal components suggested that membrane stability, osmotic adjustment, and antioxidant enzyme capability were correlated with productivity under stress. Thus, results obtained help to reveal the physiological importance of combined heat and drought stresses in lentil as well as note the importance of membrane stability, osmobuffer accumulation, and synchronisation of antioxidant defense as major physiological markers for breeding climate-resilient lentils for hotter and drier production areas.