EFFECTS OF SALT STRESS ON NUTRITIONAL QUALITY OF ORANGE-HEADING CHINESE CABBAGE SEEDLINGS

To study the effects of NaCl on nutritional quality in Chinese cabbage is of great significance to clarify the mechanism of salt stress on the formation of fruit and vegetable quality, orange-heading Chinese cabbage was treated with 0, 50, 100, 150 and 200 mmol/L NaCl, the effects of NaCl on the carotenoids, vitamin C, soluble sugar and crude fiber in leaves were studied, to study the gene expressions of key enzymes in carotenoid metabolism pathway, total RNA was extracted and the first strand of cDNA was synthesized by reverse transcription. The results showed carotenoids in orange-heading Chinese cabbage treated with 100 mmol/L NaCl was higher than that of the control, and the difference was significant (p<0.05). The vitamin C increased first and then decreased, vitamin C in orange-heading Chinese cabbage treated with 150 mmol/L NaCl was higher than that of the control. The soluble sugar increased with the NaCl increase, and the difference was significant between the control and NaCl treatments. The crude fiber decreased first and then increased, and there was not much differences among different NaCl treatments. The genes expression of carotenoids synthesis enzymes PDS, ZDS and LYCE increased, and reached the highest under 100 mmol/L NaCl, then decreased under 150 mmol/L NaCl, while increased under 200 mmol/L NaCl. The results indicated NaCl stress might have effects on the carotenoid, vitamin C, soluble sugar and crude fiber in orange-heading Chinese cabbage. Especially the changes between the carotenoid contents and the genes expression of carotenoids synthesis enzymes were similar, therefore salt stress had a positive effect on the production of orange-heading Chinese cabbage carotenoids and it is likely influencing the quality of orange-heading Chinese cabbage.