Mitigation of Heat Stress Effects on Snake Cucumber Plants by Silicon Additions and Rice Straw Soil Cover

Abstract

ABSTRACT A two-year experiment (2018 and 2019) was conducted to investigate the conjoint effect of applying rice straw as a soil mulch and treating snake cucumber (Cucumis melo var. flexuosus) plants by potassium silicate solution (4 mM) either by soaking seeds or by foliar applications for different periods, on soil fertility, vegetative growth and yield traits, antioxidant activities in plant, nutrient uptake, and total yield under heat stress conditions. The experiment was conducted during summer season (the maximum weekly temperature ranged from 35.8 to 40.6°C) on a clay soil at Dokki field under greenhouse conditions, Giza governorate, Egypt. The treatment of T5 (soaking seeds for 24 h in potassium silicate solution) combined with covering soil with rice straw gave superior effects on enhancing soil fertility and nutrient uptake, increasing chlorophyll content, increasing antioxidant enzymes activity, decreasing proline and other free amino acids (FAA), total soluble salts (TSS), and vitamin C content, and these were probably the reasons that increased the plant tolerance to face the stress. Total yield increased by 13.4 and 8.19% under rice straw soil cover. Also, its highest values were achieved by the treatment of T5 (173 and 200%), during the two tested seasons, respectively. Results of this study suggest that the conjoint effect of using rice straw as a soil cover and treating plants with potassium silicate solution (4 mM) by soaking their seeds for 24 h is beneficial for improving soil fertility, nutrient uptake as well as for crop production under heat stress conditions.