海马齿对不同比例淡海水组培的生长和生理响应

Growth and Physiological Responses of Sesuvium portulacastrum to Hydroponics of Different Combinations of Fresh and Sea Water

以红树林伴生植物海马齿为研究对象,通过水培试验系统考察了海马齿植株在不同淡海水组合培养条件下的生长和生理变化,以探讨海马齿植株盐环境的适应性和耐盐机制.结果显示,随着培养液中海水比例增加,海马齿植株生长速度变慢,节间变短,叶片肉质化程度加重,但都能健康生长并完成其固有的生长周期.随着培养液中海水比例的增加,海马齿植株叶片叶绿素含量、蛋白质含量以及节间长度均呈下降趋势,可溶性糖、脯氨酸含量和茎周长却逐渐增加,叶片水分含量和根系活力先升高后降低,而叶片干物质和丙二醛含量则呈先降低后升高趋势.2∶1淡/海水组合培养液中海马齿植株的长势最好,根系活力最强.研究结果表明,海马齿植株最适宜在一定比例的淡/海水培养液中或一定盐浓度环境下生长,其具有很强的耐盐碱特性,渗透调节是其适应外界盐胁迫的机制之一.

In the condition of hydroponics of different combinations of fresh and sea water, the growth and physiological responses of Sesuvium portulacastrum, a mangrove associated plant species,were systematically examined,and its salt adaptability and salt-tolerant mechanism were primarily investigated. The resuits showed that with the increase of seawater proportion the growth rate of Sesuvium portulacastrum plants slew down, the internode became shorter and the leaves more fleshy, but all S. portulacastrum plants were healthy and could complete their life cycles in various combinations of fresh and sea water. With the increase o{ seawater proportion the contents of chlorophyll and protein in leaves and length of internode gradually decreased,but the contents of soluble sugar and proline and stem girth increased. The moisture content of leaves and roots activity first increased then decreased, while leaf dry matter and content of malondialdehyde （MDA） first reduced,and then increased. All the S. portulacastrum plants in 2 ： 1 fresh/sea water mix displayed the strongest root activity,and grew better than others. All data suggest that a certain seawater proportion or salt-concentration is more conducive to the growth of S. portulacastrum plants compared to full fresh or sea water,and the S. portulacastrum plants have high salt-tolerance,in which osmotic adjustment is one of the mechanisms of adaption to the outside salt stress.