IMPROVING HEAT STRESS TOLERANCE IN POTATO (SOLANUM TUBEROSUM) L.

Abstract

eat stress is one of the major abiotic stresses affecting potato growth and productivity in semi-arid and growing zones. Using new biotechnology approaches and application of nanomaterials could improve the productivity and profitability of potato. Silicon nanoparticles (SiO2 NPs) responsible for improvements lead finally to the enhancement of plant growth and productivity under salinity, drought, and heavy metal stresses. In this study, the effectiveness of SiO2 NPs at 5, 10 and 20 ppm under different levels of heat of 25, 35 and 45°C on growth and biochemical parameters was in vitro studied, for four potato cultivars. Results referred to the superiority of Agria, which was positively and significantly affected by SiO2 NP treatments followed by Hermes, and Cara. On the other hand, there was no significant effect of SiO2 NPs on Diamond cv, under different heat levels. At 45°C, Agria cv. produced the highest value of microtubers weight and length at 0, 5, 10 and 20 ppm of SiO2 NPs, followed by Diamond with SiO2 NPs of 5 and 20 ppm. The heighest vegetative characteristics of Agria were 14.67 cm for shoot length, 7.00 cm for shoots/explant, 5 cm for root length, and 10.33 for roots number/ explant, at 35°C with 10 ppm SiO2 NPs. About harvesting, for the same cultivar, microtubers weight was 0.89, 0.79 and 0.93 g at 45°C, without significant differences among SiO2 NPs. Microtubers number was 5.33 by 5 ppm at 25°C. Microtubers length was 1.43 cm with 5 and10 ppm SiO2 NPs at 45°C. For microtubers diameter, there was no significant effect among SiO2 NPs at all heat levels. Also, glutathione higher value was obtained by 5 ppm at 45 o C. Concerning lipid peroxidation level, the lowest level of the toxic product malondialdehyde (MDA) was obtained by 0 ppm, increased in other treatments at 25 o C. At 35 o C, the minimum level of MDA H