模拟氮沉降对夏蜡梅幼苗生长及非结构性碳水化合物的影响

Effects of Simulated Nitrogen Deposition on the Growth and the Content of Non-structure Carbohydrate of Sinocalycanthus chinensis Seedlings

以一年生夏蜡梅(Sinocalycanthus chinensis)幼苗为研究对象,设置4种氮水平:对照(CK,0 gN·m-2·a-1)、[JP]低氮(N1,2 gN·m-2·a-1)、中氮(N2,8 gN·m-2·a-1)、高氮(N3,32 gN·m-2·a-1),处理1年后,测定不同氮沉降水平下夏蜡梅幼苗生长指标、生物量分配以及非结构性碳水化合物的差异,探讨夏蜡梅幼苗对氮沉降的响应机制。结果表明:随着氮浓度的增大,夏蜡梅幼苗的株高、基径呈现先升高后降低的趋势,它们均以中氮处理最高。随着氮浓度的升高,夏蜡梅幼苗的叶、冠层生物量呈现出逐渐升高的趋势,而茎、根、总生物量、根生物量比和根冠比则表现出先升高后降低的趋势。叶生物量比随着氮浓度的升高呈现先降低后升高的趋势。叶平均周长、叶平均长度、叶平均面积均以中氮处理最大;叶宽长比以高氮处理最高;中氮、高氮处理的比叶面积明显低于对照。叶中的淀粉、非结构性碳水化合物(NSC)含量均以中氮处理最高;茎中的淀粉、NSC含量以高氮处理最低。总之,不同浓度氮沉降均促进了夏蜡梅的生长,中氮处理促进作用最明显,对其他生长和生理指标也产生了一定的影响。

With the seedlings of Sinocalycanthus chinensis,four simulated nitrogen deposition levels,including control(CK,0 g·m-2·a-1),[JP2]lower nitrogen(N1,2 g·m-2·a-1),medium nitrogen(N2,8 g·m-2·a-1),[JP]and high nitrogen(N3,32 g·m-2·a-1).After 1 year,the growth,biomass allocation and the content of the non-structure carbohydrate of S.chinensis seedlings among the different treatments were measured.The results showed that:the plant height and base diameter of the seedling showed a trend of increasing first and then decreasing,with medium nitrogen treatment being the highest.The leaf and shoot biomass of the seedlings showed a trend of gradual increase,while the stem,root,total biomass of the seedlings,and root biomass ratio and root shoot ratio showed a trend of increasing first and then decreasing.The leaf biomass ratio showed a trend of decreasing first and then increasing with the increase of nitrogen concentration.The mean perimeter of the maximum leaf,the mean length and area of the leaf was the highest in the treatment of N2.The width/length ratio of the maximum leaf was the highest in the treatment of N3.The specific leaf area in the treatments of N2 and N3 were significantly lower than that in treatment CK.The contents of starch and non-structural carbohydrates in the leaves were highest in the treatment of N2,while those in the stem were the lowest in the treatment of N3.In conclusion,nitrogen deposition showed negative effects on the growth and physiological traits of S.chinensis seedlings and the most significant effect were found in the treatment of N2.