半红树植物玉蕊对淹水-盐度胁迫的生长及生理响应

Growth and physiological responses of semi-mangrove plant Barringtonia racemosa to waterlogging and salinity stress

关键词:  玉蕊, 半红树植物, 淹水-盐度胁迫, 濒危植物, 适生条件

Key words:  Barringtonia racemosa, semi-mangrove plants, waterlogging and salinity stress, endangered plants, suitable conditions

摘要:

玉蕊(Barringtonia racemosa)是典型的半红树植物,具有重要的药用及观赏价值,目前已被列为濒危植物,亟需保护。为探明不同淹水水位、淹水时长以及水体盐度对玉蕊生长的影响,筛选出适合玉蕊生存的最佳环境组合,该文以二年生玉蕊实生苗为试验材料,模拟全日潮,采用L₉(3⁴)正交试验设计,对其生长及生理指标进行分析。结果表明:(1)第1组(淹水水位为地径高、淹水时长为4 h、水体盐度为4‰)、第4组(淹水水位为枝下高、淹水时长为4 h、水体盐度为8‰)、第6组(淹水水位为枝下高、淹水时长为12 h、水体盐度为4‰)最适合玉蕊生长。(2)第5组(淹水水位为枝下高、淹水时长为8 h、水体盐度为12‰)的植株叶片MDA含量最大,POD、CAT活性及可溶性糖含量也达到最大值,表明其通过启动保护酶系统及调节渗透物质有效抵抗逆境。(3)第7组至第9组(淹水水位为植株高)均出现死亡株,死亡率分别为33.33%、8.33%、25%,其中第9组在株高、地径、叶片数的增长量均为最小值。综上结果发现,玉蕊在淹水水位≤枝下高、淹水时长≤12 h、水体盐度≤12‰的环境组合中均表现出积极的形态适应及较强的抗性,能在一定深度、淹长时长及盐度的潮汐水淹环境下生长,而淹水水位和水体盐度对玉蕊生长影响显著,淹水时长对植株整体影响不大。

Abstract:

Barringtonia racemosa is a typical semi-mangrove plant with important medicinal and ornamental values, but it has been listed as an endangered plant and needs urgent protection. In order to explore the effects of different flooding levels, flooding durations, and water salinity on the growth of B. racemosa, the best environmental combination suitable for the survival of B. racemosa was screened out. In this study, two-year-old B. racemosa seedlings were used as experimental materials to simulate all-day tides. The L₉(3⁴)orthogonal test design was used to analyze its growth and physiological indicators. The results were as follows:(1)The first group(the flooded water level was ground height, the flooded time was 4 h, and the water salinity was 4‰), the fourth group(the flooded water level was height under branch, the flooded time was 4 h, the water salinity was 8‰), and the sixth group(the flooded water level was height under branch, the flooded time was 12 h, and the water salinity was 4‰)were most suitable for the growth of B. racemosa.(2)The MDA content in the leaves of plants in the fifth group(the flooded water level was height under branch, the flooded time was 8 h, and the water salinity was 12‰)was the highest, while the POD, CAT activities and soluble sugar content also reached the highest, indicating that it could effectively resist adversity by activating the protective enzyme system and regulating osmotic substances.(3)The 7th-9th groups(the flooded water level was plant height)all showed dead plants, and the mortality rate was 33.33%, 8.33% and 25% respectively. Among them, the 9th group increased in plant height, ground diameter and number of leaves both were the least. All the above results indicate that B. racemosa exhibits better morphological adaptation and stronger resistance in environmental combinations where the flooded water level was less than height under branch, the flooded time was less than 12 h, and the water salinity was less than 12‰. It grows under tidal water flooded environment with salinity, while the flooded water level and water salinity have a significant effect on the growth of B. racemosa, and the flooded time has no significant effect on the overall plant.