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研究报告目录 |
模拟氮沉降对南亚热带两种乔木幼苗生物量及其分配的影响 |
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| 出 版 社：植物生态学报 |
| 发表时间：2005 |
| 台 站：
鼎湖山森林生态系统定位研究站
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| 作 者：李德军 莫江明 方运霆 李志安 |
| 点 击 率：5561 |
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| 关 键 字：南亚热带 氮沉降 树苗 生物量 分配 |
| 摘 要：探讨了南亚热带季风常绿阔叶林两种优势树种荷木(Schima superba)和黄果厚壳桂(Cryptocarya concinna)幼苗的生物量及其分配对氮沉降增加的响应。实验分为对照(CK)、T5、T10、T15和T30 5 个处理,每个处理设置3 次重复。所施氮肥为NH4NO3,以溶液方式喷施,5 个处理浓度分别为0、0.12、0.24、0.36、0.72 mol N•L-1。每月喷施2次,5个样方1年喷施的总氮量分别相当于氮沉降率0、5、10、15、30 g N•m-2•a-1。经过11个月的施氮处理,两种幼苗对氮沉降的响应存在差异,其中黄果厚壳桂幼苗的基径、株高、全株生物量和相对生长速率除最高处理T30外,均高于对照,但荷木幼苗的基径、全株生物量和相对生长速率除T10外,均小于对照。氮处理也对生物量的分配产生了明显的影响,两种幼苗的叶重比以T30最低,表明高氮处理不利于幼苗叶片的生长;枝重比均以T30最高,反映了高氮处理的幼苗生物量分配到枝干的比例最高;根重比和根冠比均以对照样方幼苗的最高,表明氮处理抑制根的生长,分配到根部分的生物量下降。总的来看,经过11个月的处理,除最高处理T30外,氮处理仍对黄果厚壳桂幼苗的生长有促进作用,而对荷木幼苗的生长则趋向于一定程度的抑制效应,表明黄果厚壳桂幼苗更能耐受高氮条件。 |
| 关 键 字(英文)：Subtropics Nitrogen deposition Tree seedlings Biomass production Allocation |
| 摘 要(英文)：To better understand the effects of elevated nitrogen deposition on biomass production and allocation in seedlings of Schima superba and Cryptocarya concinna , the dominant species in subtropical monsoon evergreen broadleaved forests in China , a simulated nitrogen deposition field experiment was conducted. S. superba and C. concinna seedlings were exposed to five nitrogen treatments using NH4NO3 solutions of 0 , 0. 12 ,0. 24 , 0. 36 and 0. 72 mol N·L - 1 . Solutions were applied twice a month from January through November ,2003 , equivalent to nitrogen deposition rates of 0 , 5 , 10 , 15 and 30 g N·m- 2·a - 1 . Each treatment was divided into three subplots and 40 seedlings of each of the two species were transplanted into each subplot . The two species responded differently to the different rates of nitrogen deposition. The stem base diameter , height ,whole-plant biomass and relative growth rate of C. concinna seedlings grown in 5 , 10 , 15 g N·m- 2·a - 1
treatments were all higher than those in the control plot ; however , the stem base diameter , height , whole-plant
biomass and relative growth rate of treated S . superba seedlings were lower than those in the control plot with the exception of the 10. 0 treatment . The leaf-weight ratio of seedlings of the two species was the lowest in the highest treatment , implying that the high N deposition was harmful to the foliage. The branch-and- stem weight ratio of seedlings of both species was the highest in the highest treatment indicating that the biomass allocated to branches and stems increased under high N deposition. The rootweight ratio and the root to shoot ratio of seedlings in the control plots were the highest , demonstrating that the ratio of biomass allocated to roots decreased under the conditions of elevated nitrogen deposition. Overall , except for the highest N treatment , nitrogen additions enhanced the growth of C. concinna but had the opposite effect on S . superba individuals ,indicating that C. concinna seedlings were more resistant to high nitrogen loads. |
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 模拟氮沉降对南亚热带两种乔木幼苗生物量及其分配的影响.PDF |
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