NaCl胁迫对两种南瓜幼苗离子含量的影响

Effects of NaCl Stress on Cation Contents in Seedlings of Two Pumpkin Varieties

NaCl胁迫7d明显抑制了两种南瓜——黑籽南瓜(CucurbitaficifoliaBouche.)和白籽南瓜(CucurbitamoschataDuch.)幼苗地上部和根系的生长,使地上部相对含水量明显下降。随NaCl胁迫浓度(150、300和500mmol/L)的提高,两种南瓜幼苗根、茎和叶片中Na+含量明显增加,K+含量明显下降。Na+和K+含量在两个南瓜品种各器官中的分布规律分别是:根>茎>叶片和茎>叶片>根。NaCl胁迫后黑籽南瓜根、茎和叶片Na+含量远低于白籽南瓜,而叶片游离脯氨酸含量、可溶性糖含量和地上部相对含水量明显高于白籽南瓜。表明两者在渗透调节方式、离子的吸收和运输能力上有差异,黑籽南瓜耐盐性较强。

Effects of different concentration NaCl stress on cation contents of pumpkin cultivars （ Cucurbita ficifolia and Cucurbita moschata） usually used as rootstocks of cucumber was studied. The results showed that, in both cultivars treated with 150, 300 and 500 mmol/L NaCl for 7 d, increasing salinity caused in increasing retardation of shoot and root growth, and reduction of shoot relative water content （Table 1）. With increasing NaCl concentration, Na^＋ content increased while K^＋ content decreased distinctly in roots, stems and leaves of both cultivars. And Na^＋ and K^＋ contents in different organs were in the orders roots〉stems〉leaves and stems〉leaves〉roots respectively （Fig.3）. There were less Na^＋ in root, stem and leaf （Fig.3）, more free proline and soluble sugar in leaves （Figs. 1,2）, and higher shoot relative water content （Table 1） in C. ficifolia than in C. moschata. So there are differences between C. ficifolia and C. moschata in osmotic adjustment mechanisms and selective absorption and transportation of different cations, and the salt tolerance of C. ficifolia is higher than C. moschata.