Responses of physiochemical attributes of kinnow budded on Jatti Khatti to triazole treatment under salinity

Abstract

The response given by the photosynthetic pigments, antioxidant enzyme activity and nutrient accumulation of kinnow (Citrus nobilis×C. deliciosa) budded onCitrus jambhiriLush rootstocks (var. Jatti Khatti) to triazole compounds was studied under NaCl stress. Eighteen-month-old budded kinnow plants were irrigated with 0 or 50 mM NaCl with or without triazole compounds. Paclobutrazol (PBZ) at 100 mg 1−1and triazole (TRZ), triadimefon (TDM) and hexaconazole (HEX) at 20 mg l−1were applied by drenching the soil one week prior to NaCl application. PBZ, TRZ and TDM were equally effective in preventing chlorophyll degradation under NaCl stress. The improvement in catalase (CAT) activity was greater in TRZ- and TDM-treated plants under stress, while for superoxide dismutase (SOD) activity, TRZ, PBZ and TDM were found to be equally effective. The peroxidase (POX) activity increased more in TDM-treated plants. The application of TDM and HEX had a more pronounced effect on the upregulation of proline content under stress. Furthermore, triazole compounds increased the accumulation of K+and Ca2+ions and inhibited that of Na+and Cl−, resulting in an improvement in the K+/Na+and K+/Cl−ratios. For PBZ-treated plants, the K+/Na+and K+/Cl−ratios in leaf tissues increased 2.4- and 2.1-fold compared to plants treated with NaCl alone, while HEX had a more striking effect on Ca2+upregulation and significantly (1.5-fold) increased leaf Ca2+under stress.