锌对玉米光合特性及抗氧化体系的影响

在玉米拔节期每隔7 d叶片喷施一次0(CK)、2、4、6、8 g/L共5个处理浓度的锌(Zn)叶面肥,连续喷施3次,研究大喇叭口期、抽雄吐丝期及灌浆期微量元素Zn对玉米光合特性及抗氧化系统的影响。试验结果表明,Zn处理有利于提高玉米叶片SPAD值、净光合速率(Pn)、气孔导度(Gs)及蒸腾速率(Tr),降低胞间CO2浓度(Ci),提高叶片固定CO2的能力,从而增强光合作用,促进干物质积累;同时,提高了超氧化物歧化酶(SOD)、过氧化物酶(POD)及过氧化氢酶(CAT)活性,有效降低了丙二醛(MDA)含量,缓解了MDA带来的膜质过氧化伤害。其中在抽雄吐丝期喷施8 g/L锌叶面肥处理,与CK比,Pn、Gs、Tr分别提高25.37%、14.05%、21.72%,Ci降低8.12%;SOD、POD和CAT活性分别提高30.90%、25.65%、20.42%;MDA降低21.18%;SPAD值增加23.34%,干物质积累增加22.33%。综合来看,Zn处理以最高喷施量8 g/L处理效果最好。

Effects of Zinc on Photosynthetic Characteristics and Antioxidant System of Maize(Zea mays L.)

The effects of microelement zinc(Zn)on photosynthetic characteristics and antioxidant system of maize at bellmouth stage,tasseling stage and filling stage were studied by spraying 0(CK),2,4,6 and 8 g/L Zn leaf fertilizer every 7 days for 3 times at jointing stage.The results showed that Zn treatment was beneficial to increase SPAD value,net photosynthetic rate(Pn),stomatal conductivity(Gs)and transpiration rate(Tr)of maize leaves,decreased intracellular CO2 concentration(Ci),increased CO2 fixation ability of leaves,thus enhanced photosynthesis and promoted dry matter accumulation.At the same time,the activities of superoxide dismutase(SOD),peroxide(POD)and catalase(CAT)were increased,the content of malondialdehyde(MDA)was effectively decreased,and the damage of membrane peroxidation caused by MDA was alleviated.Compared with CK,Pn,Gs,Tr increased by 25.37%,14.05%and 21.72%,Ci decreased by 8.12%,and the activities of SOD,POD and CAT increased by 30.90%,25.65%and 20.42%,respectively.MDA decreased by 21.18%,SPAD value increased by 23.34%,and the accumulation of dry matter increased by 22.33%.In general,the optimal spraying concentration was dose of 8 g/L.