Abstract:

In order to study the germination ability of snap bean seeds under high temperature stress, and to explore the alleviating effect of salicylic acid (SA) on heat stress of snap bean seeds during germination, the snap bean variety ‘A18’ was used as experimental material, the normal temperature control (CK1) and high temperature control (CK2) were set respectively, four SA concentration treatments were set up at high temperature: T1 (0.005 mmol/L), T2 (0.01 mmol/L), T3 (0.05 mmol/L) and T4 (0.1 mmol/L), and germination test and physiological test were carried out after soaking the seeds for 6 hours. The germination rate, germination index, seed vigor index and physiological indexes of seeds under different treatments were determined. The results showed that the germination rate and seed vigor index of normal temperature control (CK1) were as high as (97.61 ±2.09)% and 861.13 ±81.30. The germination rate and seed vigor index of high temperature control (CK2) were (56.67±3.33)% and 306.50 ±62.33, which were decreased by 41.94% and 62.13% compared with those of CK1. Under high temperature, with the increase of SA concentration, the germination rate and seed vigor index of snap bean seeds increased at first and then decreased, and T2 performed the best. Compared with those of CK2, the germination rate, germination index and seed vigor index of T2 were increased by 41.18%, 25.33% and 67.04%, respectively, SOD activity was improved, the content of soluble protein was increased, and the content of O₂^-. and MDA were decreased. The SA treatment of 0.01 mmol/L can alleviate the adverse effects of high temperature and improve the heat tolerance of snap bean seeds.

Key words: snap bean, high temperature, salicylic acid, seed, germination