岳桦幼苗光合特性和非结构性碳水化合物积累对干旱胁迫的响应  

Response of photosynthetic characteristics and non-structural carbohydrate accumulation of Betula ermanii seedlings to drought stress

作　　者：马玥 苏宝玲 韩艳刚 吴星慧 周旺明[2] 王庆伟[2] 周莉[2] 于大炮[2] MA Yue;SU Bao-ling;HAN Yan-gang;WU Xing-hui;ZHOU Wang-ming;WANG Qing-wei;ZHOU Li;YU Da-pao(College of Life Science and Bioengineering,Shenyang University,Shenyang 110044,China;Key Laboratory of Forest Ecology and Management,Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,China)

机构地区：[1]沈阳大学生命科学与工程学院,沈阳110044 [2]中国科学院沈阳应用生态研究所森林生态与管理重点实验室,沈阳110016

出　　处：《应用生态学报》2021年第2期513-520,共8页Chinese Journal of Applied Ecology

基　　金：国家自然科学基金项目(41871105)资助。

摘　　要：以长白山林线树种岳桦为对象,利用生长控制试验进行干旱处理,研究干旱对岳桦幼苗光合特性及非结构性碳水化合物(NSC)积累的影响。结果表明:干旱显著降低了岳桦幼苗的净光合速率和气孔导度,提高了其水分利用效率;干旱显著增加了岳桦幼苗叶、皮、干和根中的可溶性糖和总NSC的含量,但显著降低了淀粉含量;随着干旱的持续,叶片的气孔导度、光合速率和瞬时水分利用效率迅速降低,而可溶性糖、淀粉和NSC则是先增后减;在试验末期,叶片90%发黄,岳桦幼苗干、皮和根中可溶性糖与淀粉含量的比值均显著高于对照。这表明岳桦在受到干旱胁迫时,迅速降低气孔导度以减少水分散失,提高水分利用效率,它属于避旱型植物;岳桦通过优先储存策略来提高组织器官中可溶性糖含量、增加淀粉与糖之间的转化率来应对水分亏缺的不利环境;在遭受持续干旱,幼苗面临死亡的时候,干旱胁迫可能超过了植物自我调节的阈值,但此时其组织器官中NSC含量并未降低,这说明岳桦最终的死亡可能不是碳饥饿导致的。We explored the effects of drought stress on photosynthetic characteristics and non-structural carbohydrate(NSC) accumulation of the timberline tree species Betula ermanii in Changbai Mountain with a drought control experiment. The results showed that drought significantly reduced the net photosynthetic rate and stomatal conductance, but increased water use efficiency(WUE) of B. ermanii seedlings. Drought dramatically improved the contents of soluble sugar and total NSC in leaves, barks, stems, and roots of B. ermanii seedlings, but significantly reduced their starch content. The stomatal conductance, photosynthetic rate and WUE decreased rapidly as the drought continued, whereas the contents of soluble sugar, starch and NSC increased and then declined. At the end of the experiment, 90% of the leaves turned yellow, and the ratios of soluble sugar to starch in the stems, barks and roots under the drought treatment were significantly higher than those in the control. These results demonstrated that B. ermanii might be a drought-avoidance species that could reduce water loss by rapidly reducing stomatal conductance and improving WUE under drought stress. B. ermanii might have evolved priority storage strategy to cope with water deficit through improving the content of soluble sugar in organs and increasing the transformation rate between starch and sugar. With the extension of drought stress, seedlings tended to die, since water stress might exceed the threshold of the plant self-regulation capacity. However, the content of NSC in organs did not decrease, suggesting that the death of B. ermanii under drought stress might not be caused by carbon starvation.

关 键 词：干旱 光合响应 碳平衡 储存策略 高山林线 岳桦 

分 类 号：S792.15[农业科学—林木遗传育种]