钾肥类型对菜心(菜薹)生长、细胞保护酶和内源激素的影响

为探讨钾肥类型对菜心(Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee)的作用效应,研究了不同钾肥类型和水平对菜心生长、细胞保护酶和内源激素的影响。结果表明,氯化钾或硫酸钾处理可提高菜心叶片的POD 和CAT 活性、IAA 和GA₃ 含量,降低MDA 含量,提高菜薹产量。随着钾水平的提高,叶片IAA 和GA₃ 含量、POD 和CAT 活性以及菜薹质量明显提高,MDA 含量降低。当施钾90 kg hm^-2 时,叶片的GA₃ 和IAA 含量显著下降,而POD 活性和菜薹产量没有显著变化。在相同水平下,氯化钾与硫酸钾对植株生长、菜薹产量、叶片GA₃ 含量的影响不显著。当施钾0~90 kg hm^-2 时,氯化钾处理的叶片POD 活性显著高于硫酸钾处理;而施钾135~180 kg hm^-2 时,氯化钾处理的叶片POD 活性则显著低于硫酸钾处理。除了90 kg hm^-2 氯化钾处理的CAT 活性和45 kg hm^-2 氯化钾处理的MDA 含量低于硫酸钾处理以及90 kg hm^-2 和180 kg hm^-2 氯化钾处理的IAA 含量高于硫酸钾处理的外,相同水平氯化钾和硫酸钾处理的CAT 活性、MDA 含量和IAA 含量没有显著差异。可见,钾肥类型对菜心的活性氧代谢系统及内源激素含量有一定的影响,但氯化钾与硫酸钾对菜心的施用效果相当,生产上可采用氯化钾代替硫酸钾以节约肥料成本,K₂O 施用量以90 kg hm^-2 为宜。

Effect of different types of potassium fertilizer on growth, cell protective enzymes and endogenous hormones of Flowering Chinese Cabbage

In order to understand the effects of potassium fertilizer types on flowering Chinese cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee), its growth, cell protective enzymes and endogenous hormones were studied treated by different types and levels of potassium fertilizer. The results showed that both KCl and K₂SO₄ fertilizer could increase activities of POD and CAT, contents of IAA and GA₃, and the yield of flowering Chinese cabbage, but decreased MDA content. With increment of potassium levels from 0 to 90 kg hm^-2, the contents of IAA and GA₃, the activities of POD and CAT and flower stalk yield increased significantly, however, when the potassium levels increased continuously, the contents of IAA and GA₃ decreased quickly, and POD activities and flower stalk yield kept stable. Under the same potassium levels of two types of potassium fertilizer, the plant growth, flower stalk yield and GA₃ contents in leaves had no differences. At 0-90 kg hm^-2 potassium fertilizer, the POD activity in leaves fertilized by KCl were higher than those by K₂SO₄, but at levels of 135-180 kg hm^-2, the POD activity in leaves by K₂SO₄ were higher than those by KCl. CAT activity in leaves fertilized by 90 kg hm^-2 KCl and MDA contents in leaves by 45 kg hm^-2 KCl were lower than those by the same levels of K₂SO₄. In contrary, IAA contents treated with 90 kg hm^-2 and 180 kg hm^-2 KCl were higher than those by K₂SO₄. At other fertilizer levels, the effects of two types of potassium fertilizer on CAT activity, MDA and IAA contents had no difference. Therefore, although two potassium types had different influence on activate oxygen metabolism and endogenous hormones in flowering Chinese cabbage, they had no effects on growth and flower stalk yield at the same levels of potassium fertilizer. Thus, KCl fertilizer could instead of K₂SO₄ fertilizer to save the cost in production, and the suitable level of KCl fertilizer was 90 kg hm^-2.