%A LI Chang-Ning,Manoj Kumar SRIVASTAVA,NONG Qian,LI Yang-Rui %T Mechanism of Tolerance to Drought in Sugarcane Plant Enhanced by Foliage Dressing of Abscisic Acid under Water Stress %0 Journal Article %D 2010 %J Acta Agronomica Sinica %R 10.3724/SP.J.1006.2010.00863 %P 863-870 %V 36 %N 05 %U {https://zwxb.chinacrops.org/CN/abstract/article_4537.shtml} %8 2010-05-12 %X
Drought is a major limiting factor for sugarcane growth. Abscisic acid (ABA) regulates much important plant physiological and biochemical processes, and induces tolerance to different stresses including drought. Understanding the mechanism of tolerance to drought in sugarcane plant with foliage dressing of ABA under water stress would facilitate breeding and field management for improving drought resistance. Thus, an experiment was set up to investigate the interrelationship between drought induced ABA biosynthesis and antioxidative defense system, and to confer the farther role of foliar application of ABA in imparting drought tolerance to the sugarcane plant. The treatments were: T1 (drought), T2 (drought + foliar application of 15 µmol L–1 ABA) and C (control, normal irrigation) using a drought tolerant cultivar ROC22. The results showed that drought treatment (T1) enhanced the ABA concentration in leaf that was significantly higher in combined treatment (T2), suggesting the ABA biosynthesis was triggered in leaf by the ABA application. Both T1 and T2 resulted in an increase in proline, H2O2 and MDA contents while the exogenous ABA alleviated the increase in MDA content. ABA application decreased the degradation of chlorophyll, and counteracted, at least in part, the decrease in maximal PSII efficiency (Fv/Fm) and quantum efficiency of PSII (ΦPSII). Overproduction of H2O2 in T1 was followed by increasing activities of CAT, GPX, GR, and APX, which was further improved by the ABA treatment (T2). A decrease in H2O2 level with increasing stress in T2 showed that ABA highly induced antioxidative defense system which was found to be vanished progressively in T1. The results clearly suggest that the tolerant cultivar showed an enhanced protective system against drought conditions, and the foliar application of ABA further improved its tolerance by triggering the over expression of antioxidative defense system.