互花米草幼苗在不同浓度NaCl溶液中的生长和溶质的积累

THE GROWTH AND SOLUTE ACCUMULATION OF SPARTINA ALTERNIFLORA SEEDLINGS IN NaCI SOLUTION OF DIFFERENT CONCENTRATION

互花米草在NaCl营养液中能够大量积累Na^+和Cl^-,并对K^+、可溶性糖和游离脯氨酸的积累也有一定的促进作用,同时抑制了Ca^(2+)、Mg^(2+)和Pi的吸收。幼苗积累Na^+和Cl^-作为主要渗透剂。Na^+/K^+比值随着培养基NaCl浓度增大而提高。根部无机离子的总量明显高于地上部。NaCl明显降低幼苗地上部的渗透势,其变化随培养基渗透势的下降而降低。在NaCl营养液中培养的幼苗鲜重和含水置下降,但对于重影响不大,鲜重/干重比值随培养基NaCl浓度增大而降低。

The seedlings of Spartina alterniflora were grown in sand culture with different concentration Hoagland solution of NaCl, ranging from 50 to 400mmol/L. The amount of growth in 14th day was measured, and samples were collected. The samples were assayed for osmotic potential, inorganic ions, soluble sugar and free proline, The purpoes was to determinevhether any correlation existed between seedling growth and solute accumulation under salt-stress.The results showed that a large amount of Na^+ and CI^- were accumulated in seedlings in the solution containing NaCI, and the accumulation of soluble sugar and proline were accelerated. The contents of Na^+ and CI^- increased with enhanced concentration of external NaCI. The content of K^+ slightly decreased in 50 mmol/L and incraesed in 100—400 mmol/L NaCI nutrient solution. Therefore the ratio of Na^+ to K^+ increased with enhanced concentration of external NaCI. Seedlings of Spartina alterniflora utilize Na^+ and CI^- as principial osmotiea. Inorganic ions (?)pproximately account for 78—85% of the osmotic substanees, the soluble sugar and proline account for about 12—15% and 2—4.6%. The total content of accumulated inorganic ions in roots were higher than in shoots. Due to accumulation of solutes, the osmotic potential of pressed juice in shoots reduced with increased concentration of external NaCI.The fresh weight of seedlings was inhibited by external NaCI solution. Their dry weight was not markedly affeeted. The ratio of fresh weight/dry weight decreased with increased concentration of external NaCI.