Effects of Spraying Exogenous Nitric Oxide under High Temperature Stress on Physiological Characteristics of Phaseolus vulgaris L. in Recovery Growth Period

PurposeTo mitigate the damage of high temperature stress to Phaseolus vulgaris L.

MethodsDifferent concentrations of exogenous nitric oxide donor sodium nitroprusside (SNP) were sprayed to the test material ‘Yellow Seed Bean’ seedlings, a local kidney bean variety in west Fujian, under high temperature stress. The growth changes of the seedlings were observed and determined, and the changes of the relevant physiological indicators were determined to study the effects of SNP on the physiological characteristics of the seedlings in the recovery growth period.

ResultsHigh temperature stress obviously inhibited the growth of P. vulgaris, resulting in leaf burns, wilting and curling, with the plant height, stem diameter, fresh weight and dry weight significantly lower than normal temperature control. Treatment with appropriate concentrations of SNP (0.5-1.0 mmol/L) could effectively improve the phenotype and the growth of plant height and stem diameter of P. vulgaris under stress conditions, and the effects of treatment with 0.7 mmol/L SNP were the best. The growth recovery test results showed that: compared with those under normal temperature control, the contents of chlorophyll, soluble sugar, soluble protein, proline and endogenous NO, and the activities of SOD and CAT in the leaves of P. vulgaris were significantly reduced, and the MDA content and POD activity were significantly increased after high temperature stress; the contents of chlorophyll, osmoregulation substances and endogenous NO in the leaves of P. vulgaris in the recovery stage were significantly increased, the antioxidant enzyme activities were promoted and the MDA contents were reduced by spraying exogenous nitric oxide under high temperature stress. The indicators were the best under the treatment with 0.7 mmol/L SNP, and were close to those of the P. vulgaris growing at normal temperature after recovery 48-72 hours.

ConclusionSpraying a certain concentration of SNP under high temperature stress can effectively protect the growth of P. vulgaris and promote its growth recovery.