THE EFFECT OF WATER STRESS ON ABSCISIC ACID, JASMONIC ACID AND PHYSIOLOGICAL CHARACTERISTIC OF CITRUS

Seasonal drought is the main environmental stress that affected yield and quality of Citrus fruits in China. The effects of water deficit stress on abscisic acid (ABA), jasmonic acid (JA) and physiological characteristic were examined for 2 years old potted Newhall Orange [C. sinensis (L) Osbeck] and Yamasitaka [C. unshin Marc] mandarin seedlings on Poncirus trifoliate (L) rootstocks. The result showed: ABA and JA content was significantly affected by water stress in Yamasitaka and Newhall orange. Compared with CK, the content of ABA under 7% soil water treatment was over 2-fold. The content of ABA in Yamasitaka showed no significant different among CK, 21% and 14% water treatments, however, the ABA content upgrade to 10.42 ng/g under 7% water treatment. The content of JA under 7% soil water treatment in Newhall orange was approximate 300% more than that of CK. There was a similar trend of JA content in Yamasitaka, the content of JA under well water condition was only 63.2% of that under 7% soil water treatment. Regardless of treatment, the content of JA in Yamasitaka is much less than that in Newhall orange. Water stress could induce proline and reductive sugar accumulation in both two cultivars, the content of proline and reductive sugar reach its maximum value under 7% soil water treatment.