施锌对石灰性褐土上小白菜光合作用及保护酶活性的影响

通过田间试验的方法,采用30(低锌)、75(中锌)和120kg/hm2ZnSO4(高锌)3个施锌水平,研究施锌对山西省石灰性褐土上小白菜叶片叶绿素含量、净光合速率、硝酸还原酶(NR)活性、抗氧化酶活性及丙二醛(MDA)含量的影响.结果表明:随着施锌量的提高,小白菜叶片各叶绿素组分含量、总叶绿素含量、净光合速率和NR活性均呈先升后降的变化趋势,并均以中锌处理最大,且中、高锌处理显著高于对照(不施锌);小白菜叶片过氧化物酶(POD)和过氧化氢酶(CAT)活性也呈先升后降的趋势,而超氧化物歧化酶(SOD)活性持续增加,CAT、POD和SOD活性分别在低锌、中锌和高锌处理时达到最大值,所有施锌处理的3种保护酶活性均显著高于缺锌对照;各处理小白菜叶片MDA含量随着施锌量增大而逐渐降低,且所有施锌处理均显著低于缺锌对照.研究发现,施锌能有效增强石灰性褐土上小白菜叶片光合能力和氮同化能力,显著提高其抗氧化酶系活性,并以75kg/hm2ZnSO4效果最佳.

Effects of Zinc on Photosynthesis and the Activities of Protective Enzymes of Chinese Cabbage in Calcareous Cinnamon Soil

By field experimental method,we applied 30(low Zn) and 75(medium Zn) and 120 kg/hm2 ZnSO4(high Zn) treatments so as to study the effects of zinc on contents of chlorophyll,net photosynthetic rate,activities of nitrate reductase(NR),antioxidative enzymes and contents of malondialdehyde(MDA),in the leaves of Chinese cabbage(Brassica campestris ssp.chinensis),on calcareous cinnamon soil of Shanxi Province.The results showed that under the experimental condition,with the increase of the application of zinc fertilizer,the chlorophyll contents,net photosynthetic rate and activities of NR all tended to decline after rose and reached peak under the medium Zn,and medium and high Zn treatments apparently higher than the treatment without Zn;The peroxidase(POD) and catalase(CAT) in the leaves of Chinese cabbage also tended to decline after rose,while the superoxide dismutase(SOD) activity increased persistingly,the activities of CAT,POD and SOD reached the peak in the low Zn,medium Zn and high Zn treatment respectively,and the activities of CAT,POD and SOD significantly higher than the treatment without Zn;the MDA content in the leaves of Chinese cabbage declined gradually with the increase of the zinc sulfate,and in all the treatment of adding zinc sulfate,the MDA contents were lower than that the treatment lacking of zinc sulfate.It was shown that,adding zinc sulfate could significantly increase the abilities of photosynthetic and nitrogen assimilation in the leaves of Chinese cabbage growing on calcareous cinnamon soil,and improved the activities of protective enzymes,and meanwhile the optimum applied amount was:zinc sulfate 75 kg/hm2.