盐胁迫对空心莲子草生长和光合作用的影响

Effects of Salt Stress on the Growth and the Photosynthesis in Alternanthera philoxeroides(Amaranthaceae)

用NaCl浓度为0(对照)、50、100、150、200、250、300、350mmol/L处理空心莲子草[Alternantheraphiloxeroides(Mart.)Griseb]。结果表明:盐胁迫下,植株鲜重、干重和根冠比都下降,含水量和肉质化程度先略高于对照,而后逐渐下降;根、茎和叶中Na+含量呈上升趋势,而K+含量呈下降趋势,且在同一浓度的盐处理下,叶的Na+和K+含量最高,茎的次之,根的最低;游离氨基酸(free amino acid,FAA)逐渐减少,脯氨酸(proline,Pro)含量先略低于对照,而后则急剧上升,可溶性糖含量(soluble sugar,SS)的变化正相反;净光合速率(net photosynthetic rate,Pn)、气孔导度(stomatal conductance,Gs)和蒸腾速率(transpirationrate,Tr)呈下降趋势,胞间CO2浓度(intercellular CO2concentration,Ci)呈上升趋势;膜稳定性呈下降趋势。因此,空心莲子草是一种盐生植物,且最适盐浓度较低;Na+主要积累在地上部的茎和叶中。推测它有可能向盐渍土壤蔓延。

Alternanthera philoxeroides was treated with NaCl of different concentrations(0,50,100,150,200,250,300 and 350 mmol/L).The results showed:(1)Under NaCl treatment,the fresh weight,the dry weight and the root/shoot ratio decreased.(2)Water content and the succulency degree of whole plant appeared to increase first and then gradually decline as salinity increased.(3)Na+ contents increased and K+ contents decreased in root,stem and leaf.Na+ and K+ contents in leaf were the highest under the same salinity,those ...