盐生植物长叶红砂泌盐特性的研究

Study on Characters of Ions Secretion from Reaumuria trigyna

长叶红砂(Reaumuria trigynaMaxim.)为东阿拉善-西鄂尔多斯种,属我国特有,是古地中海残遗珍稀植物。通过对长叶红砂野外生存环境、泌盐结构以及泌盐特点的研究,结果显示:长叶红砂是一种具有多细胞盐腺的向外泌盐的泌盐盐生植物;长叶红砂植物体内、盐腺分泌物中盐分离子组分与生存土壤的离子组分一致,均含有Na+、K+、Ca2+、Mg2+、SO42-和Cl-等离子,但含量差异较大,其中土壤中阳离子以Na+或以Na+和Ca2+为主,阴离子以Cl-或SO42-为主;植物的根、茎、叶中阳离子却以K+为主,且6种离子含量的基本趋势均是:根<茎<叶;分泌物中Na+、Cl-的含量最高,其次是SO42-;盐腺的分泌速率表现为:上午的分泌量高于下午,白昼高于夜间,这些结果说明盐腺的分泌选择性与其保持植物体内适当的盐分和养分浓度以适应野生生境有关。

Reaumuria trigyna Maxim, a rare remnant derived from the Mediterranean Sea, is peculiarly endemic to Alax-Erdos Desert of China. The structure of salt gland and secretion characteristics of salt excretion from Reaumur.ia trigyna, and their relationship with salt distribution in the soil of field environment were studied.＇ The halophyte Reaumuria trigyna, with salt-gland-ferous multi-cells, can secrete salt. The ion composition in Reaumuria trigyna plant and its secretion is consistent to that in habitat soil, all have ions of Na^＋ , K^＋ , Ca^2＋ , Mg^2＋ , SO4^2- and Cl, but different in ion content. Cations as Na^＋ or Na^＋ and Ca^2＋ , and anions as Cl or SO4^2- are dominant in soil solutions; K^＋ is dominant in the roots, stems and leaves of plant, the contents of the six ions follow the order： roots〈stems〈leaves. In the secretion of Reaumuria trigyna the content of Na^＋ and Cl^- is the highest, followed by SO4^2-. The excreting rate of salt gland was higher in the morning than that in the afternoon and higher in daytime than that at night. Such high selectivity of salt gland secreting salt is the self-adjustment mechanism of Reaumuria trigyna to adapt to the wild habitat, maintaining the proper salt and nutrient contents.