盐度和温度对北美海蓬子在厦门海区引种以及生长特性的影响

Effects of Salinity and Temperature on Introduction and Cultivation of the Euhalophyte Salicornia bigelovii Torr. in the Xiamen Ambient Sea

研究了厦门海区盐度和温度对北美海蓬子(Salicornia bigelovii)种子萌发和幼苗生长的影响。结果显示,海蓬子种子对温度变化反应非常敏感,在15°C时发芽率最高(94%),但萌发指数最低,而在20°C时萌发指数最大;在盐度5g.L-1时种子具有最高的发芽率和萌发指数,在盐度50g.L-1时仍有13.3%的发芽率,并且各种盐度处理下逐日萌发指数均能在2天内达到最大。盐度10-20g.L-1最适宜幼苗生长,高盐(>30g.L-1)具有一定的抑制作用,主要表现为生长缓慢,含水量和根系活力下降,并且根的盐敏感程度大于茎。在不同盐度处理下,北美海蓬子适应一种新的耐盐机制,在无盐(0g.L-1)和高盐(40g.L-1)胁迫下,过氧化氢酶(catalase,CAT)和过氧化物酶(peroxide,POD)这2种酶蛋白对盐离子效应敏感,起主要的抗氧化作用;相反,生长在适宜盐度范围(10-30g.L-1)内,超氧化物歧化酶(superoxide dismutase,SOD)维持较高活性。研究结果表明,北美海蓬子适宜在沿海滩涂环境条件下生长,有望作为一种抗盐耐海水蔬菜加以开发和利用,并进一步在污染海水净化修复中发挥可能的生态功能。

To introduce and cultivate euhalophyte Salicornia bigeloviiT, in the Xiamen ambient sea, we studied the effects of salinity and temperature on seed germination and seedling growth. The fastest rate of germination occurred with fewer than 15℃ seeds germinated with a minimal germination index, which was maximal under 20℃. The germination of seeds was sensitive to salinity, and decreases in salinity resulted in progressive increments of the germination rate, which reached the peak level （94.0%） at salinity of 5 g·L^-1 and was still 13.3% at 50 gg·L^-1salinity; as well, the maximal daily germination index was reached within 2 days under all treatments. Also, high salinity （〉30 g·L^-1） reduced the growth of seedlings, tissue water content and root vigor, although adequate salinity （10-20 g·L^-1） promoted these features. The salt tolerance ability of the plant is associated with the original function of internal antioxidant enzymes, including superoxide dismutase （SOD）, catalase （CAT） and peroxidase （POD）, with SOD showing high activity at optimal salinity, 10-30 g·L^-1, and POD and CAT showing high activity at polar salinity of 0 and 40 g·L^-1, with the activity of POD 5-10 times higher than that of CAT. On the basis of its adaptation to salinity and temperature, S. bigelovii is suitable for cultivation in the Xiamen ambient sea and can be applied for phytoremediation in the sea.