银叶树幼苗生长和化学计量特征对干旱胁迫的响应

Responses of the Growth and Stoichiometric Characteristics of Heritiera littoralis Seedlings to Drought Stress

选取2年生银叶树Heritiera littoralis 幼苗,分别按照田间持水量的75%~80%、55%~60%、35%~40%、15%~20%设置干旱胁迫处理,研究干旱胁迫对银叶树幼苗生物量的分配和不同器官化学计量特征的影响。结果表明:与适宜水分相比,随着干旱胁迫程度的加剧,叶、茎、根的生物量均显著降低,但根冠比显著增加。随着干旱程度的加剧,叶N浓度、根N浓度、叶C:P和N:P显著增加,叶P浓度、叶C:N、根C:N、根C:P显著降低。干旱胁迫环境下,根、茎、叶之间的N或P浓度正显著相关(P<0.05),各器官的N与P浓度间均无明显相关性(P>0.05)。综上,干旱胁迫显著影响了银叶树幼苗的生长和生物量分配格局,影响了叶和根的养分浓度及其化学计量比。银叶树幼苗不同器官间的N、P在环境胁迫下仍存在较强的协变性。

To understand the effects of drought stress on the growth and stoichiometric characteristics of Heritiera littoralis seedlings,two-year-old seedlings were grown under suitable water level,mild,moderate and serious water stress treatments,i.e.,75%-80%,55%-60%,35%-40%,15%-20% of field capacity,with water controlling method in pots.The results showed that compared with the suitable water level treatment,with the increase of drought stress degree,the biomass of leaf,stem,root significantly decreased,but the root:shoot ratio significantly increased.With increasing drought stress degree,leaf N concentration,root N concentration,leaf C:P and N:P significantly increased,leaf P concentration,leaf C:N,root C:N,root C:P significantly decreased.There were significantly correlations among leaves,stems,and roots in N or P content (P<0.05),while N content was not correlated with P content in all organs (P>0.05).In conclusion,drought stress significantly effects on the biomass and its allocation,significantly effects on the nutrient concentration,and its stoichiometric characteristics of leaves and roots.The N concentration,or P concentration,in different organs have strong convariation under environment stress.