丝瓜作砧木对黄瓜幼苗耐热性的影响

Effect of towel gourd as rootstock on thermal tolerance of cucumber seedlings

采用水培方式,以五叶香丝瓜为砧木,春秋王2号黄瓜为接穗,研究了嫁接苗在根际高温、高气温、及二者互作(整体高温)下,幼苗叶片的相对叶绿素含量(SPAD值)、叶绿素荧光参数及气体交换参数,叶片和根系中丙二醛(MDA)、脯氨酸、可溶性蛋白及总糖含量的变化。结果表明:黄瓜自根嫁接苗在3种高温处理下,其SPAD值、PSⅡ的光能捕获效率(Fv'/Fm')、PSⅡ的实际光化学效率(ΦPSⅡ)及净光合速率(Pn)、蒸腾速率(Tr)、光化学猝灭系数(q P)较丝瓜嫁接苗相应处理下均有所降低,其中单独根际高温处理下降严重;丝瓜嫁接苗叶片和根系中的MDA含量显著小于黄瓜自根嫁接苗,而根系中脯氨酸含量显著大于自根嫁接苗,不同高温处理叶片和根系中的可溶性蛋白和总糖含量因不同砧木也发生了变化。嫁接换根可缓解高温对黄瓜幼苗造成的伤害,为丝瓜作砧木提高黄瓜耐高温研究提供了相应的理论依据。

Under hydroponic culture,effects of high root-zone temperature,high air temperature and the above temperature interaction（overall high temperature） on relative chlorophyll content（SPAD value）,chlorophyll fluorescence and photosynthesis parameters in leaf,the content of malondiadehyde（MDA）,proline,soluble protein and total sugar of＂Wuyexiang＂towel gourd rootstock grafted seedlings and self-rooted cucumber seedlings in leaf and root were studied. Towel gourd rootstock grafted seedlings showed higher SPAD values,excitation energy capture efficiency of photosystem（PSⅡ） reaction center（Fv＇ / Fm＇）,actual photochemical efficiency of PSⅡ（ΦPSⅡ）,leaf net photosynthetic rate（Pn）,transpiration rate（Tr） and photochemical fluorescence quenching coefficient（q P） than self-rooted seedlings. And the former ones in roots had lower MDA content and higher proline content than the latter ones. The contents of soluble protein and total sugar in leaf and root also changed under the above three treatments with different rootstocks. The results indicated that grafting could relieve the heat stress of cucumber in some extent by changing the content of some substances in roots and leaves under different heat treatments.