不同生境下广西红鳞蒲桃幼苗的生态适应性

Ecological adaptation of Syzygium hancei seedlings in Guangxi in different habitats

关键词:  红鳞蒲桃, 抗氧化酶, 渗透调节, 光合色素, 适应性

Key words:  Syzygium hancei, antioxidant enzymes, osmoregulation, photosynthetic pigments, adaptability

摘要:

为了解在天然更新条件下3种不同生境的红鳞蒲桃幼苗对环境因子的适应性,该文以广西滨海地区天然更新的当年生红鳞蒲桃幼苗为研究对象,对其叶片和根系的抗氧化酶活性、可溶性糖(SS)含量、丙二醛(MDA)含量以及叶片的光合色素进行测定。结果表明:(1)对环境因子进行方差分析(ANOVA)表明,3种不同生境间的光照强度差异极显著,地表温度和土壤含水率差异不显著。(2)不同生境下幼苗叶片与根系的生理特征随着光照强度而变化。随着光照强度的增加,生境B中幼苗叶片的超氧化物歧化酶(SOD)活性、SS含量、MDA含量、叶绿素a/b含量以及根系的过氧化物酶(POD)活性显著高于生境A; 而生境A中叶片的POD活性、叶绿素a含量、叶绿素b含量、总叶绿素含量以及根系的SOD活性、SS含量、MDA含量显著高于生境B。(3)随着光照强度的降低,生境B中幼苗叶片的SOD活性、MDA含量以及根系的POD活性显著高于生境A; 而生境A中叶片的POD活性、SS含量显著高于生境B; 叶绿素a含量、叶绿素b含量、总叶绿素含量以及根系的SS含量、MDA含量,先是生境A显著高于生境B,随后变为生境B显著高于生境A; 叶绿素a/b含量以及根系的SOD活性,先是生境B显著高于生境A,随后变为生境A显著高于生境B。综合分析表明,由于3种生境的生理生化特征均表现出不同的适应性,其中郁闭度最小的生境B发生了光抑制现象,因此需要人工调整郁闭度来创造适宜的光照环境,为幼苗的天然更新提供条件。

Abstract:

In order to understand the adaptation ability of Syzygium hancei seedlings to environmental factors in three different habitats under natural regeneration conditions, the current year's S. hancei seedlings were collected as experimental materials that regenerated in naturally coastal environments of Guangxi, and then antioxidant enzyme activities, soluble sugar(SS)content, malondialdehyde content and photosynthetic pigments in leaves and roots were measured. The results were as follows:(1)Variance analysis(ANOVA)was conducted on multiple environmental factors, which indicated that light intensitIES had highly significant differences, soil surface temperature and water content had not significant differences between the three sample plots.(2)Various light densities resulted in the changes of physiological characteristics of seedling leaves and roots in different habitats. With the light density increasing, superoxide dismutase(SOD)activity, SS content, MDA content, and chlorophyll a/b contents in leaves, and peroxidase(POD)activity in roots of seedlings were significantly higher in Habitat B than those in Habitat A; while POD activity, chlorophyll a, chlorophyll b and total chlorophyll contents in leaves, and SOD activity, SS and MDA contents in roots were higher in Habitat A than those in Habitat B.(3)With light intensity decreasing, seedlings that regenerated in Habitat B represented significantly higher SOD activity and MDA content in leaves, and POD activity in roots than those regenerated in Habitat A; however, these seedlings that regenerated in Habitat A represented significantly higher POD activity and SS content in leaves compared with those regenerated in Habitat B; chlorophyll a, chlorophyll b, total chlorophyll, and SS and MDA contents in roots were significantly higher in Habitat A than those in Habitat B firstly, and then changed to Habitat B being significantly higher than Habitat A; chlorophyll a/b content and SOD activity in roots were significantly higher in Habitat B than those in Habitat A firstly and then changed to Habitat A being significantly higher than Habitat B. Comprehensive analyses show that the physiological and biochemical characteristics of all the three habitats showing different adaptation abilities, in the meanwhile, photoinhibition occurrs in Habitat B with the lowest canopy density, hence, some manual adjusting practices are needed to create a moderate light environment, and to provide a suitable condition for promoting the natural regeneration of seedlings.