铜胁迫对嫁接和自根黄瓜幼苗光合作用及营养元素吸收的影响

Effect of Cu stress on photosynthesis and nutrient absorption of grafted and ungrafted cucumber seedling

以"新泰密刺"黄瓜/黑籽南瓜嫁接苗和"新泰密刺"自根苗为材料,采用日光温室水培的方法研究了铜胁迫下嫁接对黄瓜幼苗光合作用和营养元素吸收的影响。结果表明,铜(Cu2+)胁迫6d后,嫁接和自根黄瓜幼苗叶片叶绿素含量和类胡萝卜素含量显著降低;净光合速率和气孔导度显著下降,胞间CO2浓度随Cu2+离子浓度的增加而降低,但各浓度处理间差异并不显著;电解质渗漏率明显升高,细胞膜透性发生改变;根系和叶片中的营养元素(N、K、Ca、Mg)含量明显降低。嫁接黄瓜幼苗叶片叶绿素和类胡萝卜素含量、净光合速率、营养元素含量显著高于自根黄瓜,电解质渗漏率显著低于自根黄瓜。嫁接黄瓜幼苗叶片中Cu2+含量显著低于自根黄瓜,表明嫁接能够明显减少Cu2+向叶片的运输,缓解Cu2+毒害作用。

Under water culture, this paper researched into the effect of copper stress on photosynthesis and nutrient absorption of grafted （Cucumis sativus L. ＂Xintaimici＂ / Cucurbita ficifolia） and ungrated cucumber. Under 6 days of copper stress, there is significant depression in the contents of chlorophyll, carotenoid, nutrient（N, K, Ca, and Mg）, and in net photosynthetic rate and stomatal conductance in both grafted and ungrafted cucumber seedling leaves. An obvious increase in electrolyte leakage is also observed. Though intercellular CO2 concentration depresses with increase in Cu concentration, there exists no significant correlation among the treatments. The contents of chlorophyll, carotenoid and nutrient （N, K, Ca, and Mg） and the net photosynthetic rate of grafted cucumber seedling leaves are significantly higher than those in ungrafted cucumber plants. On the other hand, percent electrolyte leakage is significantly lower in grafted than that in ungrafted cucumber plants. Copper content in grafted cucumber seedling leaves is significantly lower than that in ungrafted seedling leaves. This implies that grafted cucumber plants have the strong capacity for inhibiting Cu^2＋ accumulation in leaves which alleviates copper poison.