NaCl胁迫下温室内两个砧木的生理响应机制

Physiological response mechanism of different salt-resistant rootstocks under NaCl stress in greenhouse

为了探明NaCl胁迫下不同砧木耐盐性差异的生理机制,采用水培,研究了温室栽培条件下2个耐盐性不同的砧木(黑籽南瓜和超丰8848瓠瓜)在盐胁迫下的生长量、根系活力、离子含量和酶活性的变化。结果表明,盐胁迫下,2个砧木的地上部和根干质量、根系活力、Ca2+和Mg2+的含量及K+/Na+比值均显著降低,叶片中Na+的含量虽然显著增加,但叶中Na+的含量显著低于根茎;超丰8848瓠瓜的SOD、POD活性、MDA含量均无显著变化,而黑籽南瓜的SOD、POD活性显著增强,MDA含量显著增加。低盐胁迫下Na+主要集中在根茎部,高盐胁迫下Na+主要集中在茎部。通过根茎阻止Na+向叶片运输,是2个砧木耐盐的主要生理机制。超丰8848瓠瓜较黑籽南瓜耐盐性强的生理机制在于其在盐胁迫下具有更高的根系活力。

The growth, root activity, ion content and enzyme activity of two salt-resistant rootstock seedlings（Cucurbit ficifolia cv. ‘Heizinangua＇, Lagenaria siceraria Standl. var. clavata Makino cv.‘＇Chaofeng 8848＇） were investigated to reveal physiological mechanism of different rootstocks with different salt-resistant under salt stress by using water culture in the greenhouse. The results show that under salt stress, the dry weights of shoot and root, root activity, the contents of Ca^2＋ and Mg^2＋ and the ratio ofK^＋ to Na^＋ in leaves decrease significant under salt stress. The content ofNa^＋ in leaves decrease hut is significantly lower than that in stem and root. The activities of superoxide dismutase（SOD） and peroxidase（POD）, and the content of malondlaldehyde（MDA） in ‘Chaofeng 8848＇ white-flowered gourd have no obvious change, whereas those of ‘Heizinangua＇ increase under salt stress. The Na^＋ pooled mostly in the root and stem under lower salinity（50 mmol/L NaCl）, but in the stem under higher salinity（100 and 150 mmol/L NaCl）. Limiting the translocation of Na^＋ from root and stem to leaf is the key physiological mechanism of salt resistance for two rootstocks. ‘Chaofeng 8848＇ white-flowered gourd exhibits a better salt resistance by maintaining higher root activity than ‘Heizinangua＇.