3种盐胁迫对玉米幼苗生长及叶片抗氧化酶和离子累积的影响

Effects of three-salt stress on the growth of maize seedlings and the accumulation of antioxidant enzymes and ions in leaves

选取2个玉米品种(金玉819和金单999),探讨了3种盐胁迫(NaCl、Na2SO4和NaNO3)对玉米幼苗生长、抗氧化酶活性以及叶片中K^+、Na^+、Ca^2+累积的影响。结果表明:3种不同类型的盐胁迫均会导致玉米幼苗鲜重下降,地上部鲜重金玉819下降超过28.6%,金单999下降超过18%;盐胁迫下金玉819叶片SOD酶活上升2.1倍以上,POD酶活性最高上升4.5倍,APX最高上升2.1倍,CAT最高上升2.2倍;金单999叶片SOD酶活最高上升2.1倍,APX最高上升1.6倍,CAT最高上升1.9倍。2个基因型玉米胁迫下叶片内Na^+含量上升4.5~6.3倍;NaCl和NaNO3处理下,K^+/Na^+比对照降低90%~93%,而Na2SO4处理下K^+/Na^+下降78%~82%,金玉819和金单999的Ca^2+/Na^+比对照分别降低了85%~90%和92%~94%。综合分析表明NO-3引起的次生盐害对玉米生产危害较大。与金单999相比,金玉819对盐胁迫更加敏感,相同Na^+浓度处理下,金玉819的鲜重和SOD酶活性下降显著且拥有较低的K^+/Na^+和Ca^2+/Na^+值。

In this study,two maize cultivars,Jinyu 819 and Jindan 999,were used.The effects of different salinities(NaCl,Na2SO4,and NaNO3)on the growth,biochemical and mineral contents(K^+,Na^+,and Ca^2+)accumulation in maize seedlings were investigated.The results showed that three different types of Na^+stress led to the decrease of fresh weight of maize seedlings.The decrease in fresh weight was more than 28.6%for Jinyu 819 and more than 18%for Jindan 999.The SOD activity increased more than 2.1 times and the POD activity increased up to 4.5 times.The APX increased 2.1 times and the CAT increased 2.2 times.With Jindan 999 under the stress,the SOD activity increased up to 2.1 times,APX 1.6 times,and CAT 1.9 times.With both genotypes under the stress,Na^+content in leaves increased 4.5~6.3 times,K^+/Na^+decreased 90%~93%compared with that of the control,while K^+/Na^+decreased 78%~82%under the treatment of Na2SO4,and Ca^2+/Na^+of Jinyu 819 and Jin-dan 999 decreased 85%~90%and 92%~94%,respectively,compared with the control.The comprehensive analysis showed that the secondary salt damage caused by NO-3 was harmful to maize production.And it was clear that Jinyu 819 was more sensitive than Jindan 999 to the salt stress.When treated with the same Na^+concentration,the fresh weight and SOD activity of Jinyu 819 significantly decreased and the ratio of K^+/Na^+and Ca^2+/Na^+were decreased.