嫁接对盐胁迫下西瓜植株体内Na^+和K^+含量及其分布的影响

Effects of Grafting on K^+,Na^+ Contents and Distribution of Watermelon (Citrullus vulgaris Schrad.) Seedlings Under NaCl Stress

采用营养液栽培,进行NaCl盐胁迫处理,以耐盐性较强的葫芦为砧木嫁接西瓜,研究嫁接对盐胁迫下嫁接苗根部和地上部、根组织各部位Na+和K+含量的影响。结果表明,嫁接苗地下部比地上部截留了较多的Na+,而地上部的K+含量明显高于地下部;嫁接苗对Na+的根部截流和K+的地上部吸收能力强于自根苗。说明西瓜嫁接苗可阻隔根系内皮层对Na+向中柱导管中的运输以及限制Na+向中柱导管中的装载,进而将Na+较多地截流在根部,阻止其向地上部分运输;同时将K+较多地运输到地上部分,使地上部保持较高的[K+]/[Na+]比值,从而保持西瓜嫁接苗较强的耐盐性。

With nutrient solution culture, our experiments were conducted to investigate the the content of K ^＋ , Na^＋ in roots and shoots of grafted watermelon （ Citrullus vulgaris Schrad. , siceraria Standl. is rootstock） under salt stress. The findings show that, compared with own-root effects on Lagenaria seedlings the salt tolerant grafted seedlings accumulated Na ^＋ mainly in the roots, and maintained higher level of K ^＋ in the shoots, which indicated that grafted seedlings could absorb more K ^＋ in the shoots and also maintain more Na^＋ in the roots. X-ray microanalysis of root transverse section in watermelon seedlings shows that roots endodermis of grafted watermelon could retain the transport of Na ^＋ to stellar parenchyma vessels maintaining much Na ^＋ in the roots whereas promote the flow of K ^＋ to the shoots thus to keep higher [ K ^＋ ] / [ Na ^＋ ] resulting grafted waterrnelon＇s ability of salt resistance.