NaCl胁迫对黄瓜幼苗体内K+、Na+和Cl-分布的影响

he effects of different NaCl levels on distribution and absorbing and transporting selectivity of K+, Na+ and Cl- in organs of two cucumber (Cucumis sativus L.) cultivar seedlings with different levels of tolerance to salinity in hydroponics were investigated. The results showed that K+ content decreased, companied with an increase of Na+ and Cl- contents in salt-treated cucumber seedlings, and the ranging magnitudes increased with increasing salinity. Determinations on the ion contents in different organs indicated that the contents of Na+ and Cl- were higher in stem and were lower in upper leaves than in other organs, and that the difference in K+ content in upper leaves was less than in other organs. For the salt-resistant cv. ‘Changchun Mici’, the transporting selectivity of K+ to Na+ from root to stem was higher and retained more Na+ in root, and the transporting selectivity of K+ to Na+ and Cl- to Na+ from stem to upper leaves was higher than for the salt-susceptible cv. ‘Jinchun No.2’. As the result, leaves of ‘Changchun Mici’ accumulated more K+ and less Na+, and the ratios of K/Na and Cl/Na were higher than the other cultivar. So the biomass of ‘Changchun Mici’ was more than that of ‘Jinchun No.2’ under same salinity. It is suggested that the main reasons for the salt-tolerance in ‘Changchun Mici’ were the higher accumulation of Na+ in roots and the lower transporting selectivity of Na+ from stem to upper leaves.