干旱胁迫对玉米苗期植株生长和保护酶活性的影响

以2个不同抗旱性玉米品种云瑞47(抗旱性强)和云瑞88(抗旱性弱)为材料,采用盆栽控水试验,设置轻度干旱胁迫(LS)、中度干旱胁迫(MS)、重度干旱胁迫(SS)3个干旱处理和正常灌水(CK),研究了干旱胁迫对2个玉米品种苗期株高、叶面积、生物量、根冠比和保护酶活性的影响,以探讨干旱胁迫对玉米苗期生长发育及其生理过程的影响机制。结果表明:(1)干旱胁迫抑制2个玉米品种苗期植株生长,导致植株株高降低、叶面积减少、整株生物量显著下降,根冠比增加,且抗旱性弱的品种云瑞88对干旱胁迫的敏感性高于抗旱性强的品种云瑞47。(2)干旱胁迫下2个玉米品种叶片的超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性表现为先升高后降低趋势,在MS处理下达到最高。与CK相比,云瑞47叶片SOD、POD和CAT分别增加了27.04%、16.95%和19.13%;云瑞88叶片SOD、POD和CAT分别增加了22.55%、11.20%和12.64%;(3)干旱胁迫增加了2个品种叶片丙二醛(MDA)含量,随着干旱胁迫程度的加剧,云瑞47(耐旱性强)叶片MDA变化幅度小于云瑞88(耐旱性弱),尤其SS处理下云瑞88的MDA积累量是云瑞47的1.31倍。云瑞47的各生理参数比云瑞88受旱影响小,干旱胁迫下仍具有较强的保护酶活性和较低的MDA含量,是云瑞47适应干旱环境的主要生理原因。

Effect of drought stress on growth and activities of antioxidant enzymes of maize seedling

Two cultivars with contrasting drought resistance, Yunrui47 (drought resistant) and Yunrui88(drought sensitive) were grown in pots experiment with four treatments, including mild drought (LS), moderate drought (MS), severe drought (SS) and normal treatment (CK). The study aims to investigate the effect of drought stress on plant height, leaf area, total biomass, ratio of root to shoot and antioxidant enzyme activities during seedling stage. The results showed that drought stress inhibited growth of the two maize cultivars, resulting in the significant decline in plant height, leaf area and biomass, while the ratio of root to shoot were increased. The drought sensitivity of Yunrui88 was greater than that of Yunrui47. Compared to CK, the activities of superoxide dismutase (SOD), peroxidase ( POD), catalase (CAT) increased firstly then decreased rapidly, being the highest in MS treatment. SOD, POD and CAT contents of Yunrui47 increased by 27.04%, 16.95% and 19.13%, and the SOD, POD and CAT contents of Yunrui88 increased by 22.55%, 11.20% and 12.64%, respectively. Compared to CK, MDA in leaf of the two cultivars was increased under drought stress. With the increasing of drought stress, Yunrui88 showed larger increase in MDA than Yunrui47 did. In particular for SS treatment, the MDA of Yunrui 88 was 1.31 times than that of Yunrui47, suggesting the higher antioxidant enzymes and lower MDA contents in Yunrui47 were responsible for its strong resistance to drought stress.