PJB-2011-182
MODULATION OF PLANT GROWTH, WATER STATUS AND ANTIOXIDANTIVE SYSTEM OF TWO MAIZE (ZEA MAY L.) CULTIVARS INDUCED BY EXOGENOUS GLYCINEBETAINE UNDER LONG TERM MILD DROUGHT STRESS
ZHANG LI XIN1*, GAO MEI1, LI SHIQING2, LI SHENGXIU2 AND LIANG ZONGSUO1
Abstract
Modulation of lipid per-oxidation, antioxidant enzyme activity, water status and plant growth induced by glycinebetaine (GB) applied foliarly was investigated in the plants of two maize (Zea mays L.) cultivar i.e. drought-tolerant Shaandan 9 (S9) and -sensitive Shaandan 911 (S911) under long-term mild drought stress (LMDS). Long-term mild drought stress was found to decrease dry matter (DM), grain yield (GY) and leaf relative water content (RWC), but to increase malondialdehyde (MDA) accumulationin in leaves of both cultivars. The patterns of rises initially and declines afterward in activities of superoxide dismutase (SOD: EC 1.15.1.1), peroxidase (POD: EC 1.11.1.7), and catalase (CAT: EC 1.11.1.6) were closely dependant on cultivar and growth stage. Dry matter, GR, RWC and these antioxidative enzymes activities were greater but MDA concentration was lower for S9 than those for S911 under LMDS. Additionally, exogenous GB application increased DM, GR, RWC and antioxidant enzymes activities measured, but reduced MDA accumulation in both cultivars under LMDS unlike well-watered control, which exhibited no such obvious effect with GB. The modulation induced by GB applying was more pronounced in S911 than that in S9 under LMDS. The greatest positive role of GB seemed to be found in the plants subjected to the largest MDA accumulation at mature stage. It is, therefore, concluded that GB may protect cells against oxidative damage and alleviate the negative effect of DS on water status and plant growth, particularly in this drought sensitive cultivar and imposed to more serious damage from DS environment.
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