不同灌水方式对‘寒富’苹果叶片光合功能和抗氧化酶活性的影响

Effects of different irrigation modes on the photosynthetic function and antioxidant enzyme activities of 'Hanfu' apple leaves

以‘寒富’苹果为试材,研究半根交替灌水、半根灌水及干旱处理对苹果叶片光合功能和抗氧化酶活性的影响。结果表明:与对照(常规灌水)相比,3种亏缺灌水处理对叶片净光合速率(Pn)和气孔导度(Gs)的抑制作用表现为干旱处理>半根灌水处理>半根交替灌水处理。半根交替灌水、半根灌水和干旱处理的叶绿素含量均是先升高,在第9天出现峰值后明显降低,干旱处理的叶绿素含量一直是最低的。3个处理的叶片脯氨酸含量随着处理时间的延长持续升高,干旱处理的脯氨酸含量最高,半根交替灌水处理的最低。3个处理的抗氧化酶活性变化各异,干旱和半根灌水处理的SOD酶活性先显著升高,在第9天出现峰值后迅速降低,半根交替灌水处理提高了SOD酶活性且一直较稳定;半根灌水和半根交替灌水处理的POD和CAT酶活性变化趋势相似,均在第9天出现峰值后呈下降的趋势,干旱处理的POD和CAT酶活性则是先显著升高,在第9天后维持在较高水平;3个处理均提高了叶片电导率和MDA含量,其中干旱处理显著高于其他处理,半根交替灌水处理最低。总之,半根交替灌水方式产生的水分胁迫较轻,并在减少灌水量的同时能维持较高的光合效率,可实现果树的节水栽培。

Taking ‘Hanfu’ apple （Malus domestica Borkh.） as test material, this paper studied the effects of different irrigation modes, including regular irrigation （control）, alternate half root-zone irrigation, half root-zone irrigation, and drought, on the photosynthetic function and antioxidant enzymes activities of apple leaves. Compared with the control, the other three irrigation modes had inhibitory effects on the leaf net photosynthetic rate （Pn） and stomatal conductance （Gs）, with the effects decreased in the order of drought 〉 half root-zone irrigation 〉 alternate half root-zone irrigation. Alternate half root-zone irrigation, half root-zone irrigation, and drought all made the leaf chlorophyll content decreased obviously after an initial increase, with the peak on the 9th day, and the chlorophyll content was the lowest in drought treatment all along. Alternate half root-zone irrigation, half root-zone irrigation, and drought increased the leaf proline content throughout the experiment, with the highest proline content in drought treatment and the lowest one in alternate half root-zone irrigation treatment. Alternate half root-zone irrigation, half root-zone irrigation, and drought induced different changes in the leaf antioxidant enzymes activities. The SOD activity in drought treatment and half root-zone irrigation treatment increased markedly and reached a peak on the 9th day, and then decreased rapidly, while the SOD activity in alternate half rootzone irrigation treatment kept at a relatively higher level. In half root-zone irrigation and alternate half root-zone irrigation treatments, the POD and CAT activities showed a similar variation trend, i.e., increased to a peak on the 9th day, followed by a decline later. In contrast, the POD and CAT activities in drought treatment went up speedily first and remained relatively high after 9 days. All the treatments except the control increased the leaf electrical conductivity and MDA content, with the increments being the highest and reached the significant level in drought treatment, and the lowest in alternate half root-zone irrigation treatment. In short, alternate half root-zone irrigation could maintain relatively higher efficiency of photosynthesis on the basis of reduced irrigation amount, with lighter drought stress, which could realize the water-saving cultivation of fruit trees.