海水胁迫下4种苗木的生长与生理特性

Seawater Stress on Vegetative and Physiological Characteristics of Four Tree Species

采用盆栽的方式,以无柄小叶榕(Ficus concinna var.subsessilis)、台湾相思(Acacia confusa)、巨桉(Eucalyptu grandis)和木麻黄(Casuarina equisetifolia)的两年生实生苗为试验材料,设海水体积分数为0(CK)、乍浦30%、乍浦50%、乍浦70%、乍浦100%和三甲河100%等6个处理。随后分别在第4、8、12、16、20和24天采样进行分析,研究不同体积分数海水处理下4种2a生幼苗形态、存活率、SOD活性、MDA质量摩尔浓度及离子吸收分布的影响情况。结果表明,4种苗木均在海水体积分数高于乍浦50%(pH 8.15)时形态发生变化,并在三甲河100%处理24d后,巨桉出现死亡;随着海水体积分数的增加与胁迫时间的延长,4种苗木叶片中超SOD均呈先升高后降低的趋势,在三甲河100%处理时,巨桉叶片中MDA质量摩尔浓度的累积量最高;随着海水体积分数的增加,4种苗木植株体内Na+质量分数均增加,且叶片中Na+质量分数的增幅依次为巨桉>台湾相思>无柄小叶榕>木麻黄。此外,4种苗木叶片中K+质量分数均呈先增加后减少的趋势。经比较得出,在海水胁迫下,苗木的耐盐性高低为无柄小叶榕>台湾相思>木麻黄>巨桉,并且4种苗木均能适应pH 8.50以上的环境,都属于碱土植物。

To study the effects of different seawater volume fraction on growth, osmotic accumulation of antioxidant enzymes, and ion distribution with Casuarina equisetifolia, Acacia confusa , Ficus concinna var. subsessilis and Eucalyptu grandis, pot experiments were conducted. A randomized complete design with six treatments consisting of 0 （a control）, Zapu 30%, Zapu 50%, Zapu 70%, Zapu 100%, Sanjia river 100% seawater and eight replications was used. Plants were harvested on 4, 8, 12, 16, 20, 24 d after treatment and analyzed with multiple comparison. Results showed that, （i） when seawater volume fraction was more than Zapu 50% （pH 8.15） for four seedlings, the configura- tion changed, moreover, E. grandis died after 24 d treatment under Sanjia river 100%. Also, （ii） compared with control plants, superoxide dismutase （SOD） activity was significantly greater in leaves of seawater-stressed seedlings, and increased at the beginning and then decreased with increasing sea water volume fractions and accumulation of time. Under the treatment of Sanjia river 100% Malondi aldehyde （MDA） molality in leaves of E. grandis was the highest. Finally, （iii）with increasing seawater volume fraction , Na＋ mass fraction of the four seedlings increased, and in the order of E. grandis〉A. confusa〉F, concinna〉C, equisetifolia; in addition, K＋ mass fraction in the leaves of four seedlings increased at the beginning and then decreased. Thus, from the results of the present experiment, it was concluded that the salt tolerance of the four tree species was in the order of F. concinna〉 A. confusa〉C, equisetifolia〉E, grandis; however, because all were alkali-soil plants, they could adapt to appropriate volume fraction s of seawater stress.