青杨扦插苗生物量积累与分配对土壤水-氮有效性的短期响应及动态调整  

Response of biomass accumulation and allocation in Populus cathayana cuttings to soil water and nitrogen availabilities and its dynamic adjustment

作　　者：郑东辉[1,2] 马伟伟 谢路路 王丽霞 刘庆 尹春英[1] ZHENG Donghui;MA Weiwei;XIE Lulu;WANG Lixia;LIU Qing;YIN Chunying(CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization&Ecological Restoration Biodiversity Conservation Key Laboratory of Sichuan Province,Chengdu Institute of Biology,Chinese Academy of Sciences,Chengdu 610041,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院成都生物研究所,中国科学院山地生态恢复与生物资源利用重点实验室,生态恢复与生物多样性保育四川省重点实验室,成都610041 [2]中国科学院大学,北京100049

出　　处：《应用与环境生物学报》2022年第4期1002-1011,共10页Chinese Journal of Applied and Environmental Biology

基　　金：国家自然科学基金项目(31370495,31770658)资助。

摘　　要：大气氮沉降是全球气候变化的主要特征之一,近年来关于树木对土壤水、氮有效性响应的研究很多,但树木如何在生物量积累与分配方面动态调整以适应水、氮供应仍不清楚.以青杨(Populus cathayana)扦插苗为材料,通过盆栽控制试验,采用两因素(水分×施氮)随机区组设计,设置3个水分(W1、W2、W3,分别为最大田间持水量的40%、60%、80%)和3个施氮梯度(N0、N1、N2,分别为0、4和8 g m^(-2) a^(-1)),并于施氮处理后1、7、14、31和62 d测定青杨生物量的积累与分配、叶片及根系性状,进而探究其对水、氮有效性的动态响应过程.结果表明:(1)土壤水分的增加和施氮显著地促进了青杨根、茎、叶和总生物量的积累,在W3处理下最大;施氮效应随时间延长更加明显,N2的促进效应明显高于N1.水氮交互作用对其影响不显著.(2)生物量的分配主要受杨树生长节律(时间)的控制,茎重比和根重比随处理时间延长显著增加,而叶重比显著降低.土壤水分有效性的提高显著提高了茎重比,降低了根重比,而对叶重比影响不显著.氮素及水氮交互作用对根重比、茎重比和叶重比均无显著影响.(3)施氮对比叶重的影响随时间变化而不同.到试验后期,施氮在土壤水分不足处理提高了比叶重;在水分充足处理降低了比叶重.(4)土壤水分有效性的提高显著促进了杨树细根的比根长和比表面积,施氮效应随处理时间逐渐变化.试验后期,土壤水分较好条件下(W3)施氮均促进根系增长;在干旱胁迫(W1)下氮添加抑制了根系生长.总体而言,施氮先促进叶生物量积累,随后根、茎生物量作出响应,最终形成有利于植株生长的分配格局;土壤水分有效性的提高显著提高了杨树扦插苗细根的比根长和比表面积,施氮效应因土壤水分而异;本研究结果可加深对树木响应气候变化机制的理解.(图5表3参63)Atmospheric nitrogen deposition is one of the main features of global climate change. In recent years, many studies have been conducted to explore the effects of water and nutrient availability on tree growth.However, how trees dynamically adjust to water and nitrogen supply in terms of biomass accumulation and distribution remains unclear. Thus, Populus cathayana was selected as the model species in our study for a pot experiment to explore the response of biomass accumulation and allocation to water and nitrogen availability. A two-factor(water and nitrogen) randomized block experiment, including three water regimes [field water holding capacity(FC) of 40%, 60%, and 80%, as W1, W2, and W3, respectively] and three nitrogen levels( NHNOcontents of 0, 4, and 8 gN/m^(2)/yr, as N0, N1, and N2, respectively), was designed. Samples were taken at 1, 7, 14,31, and 62 days after nitrogen application to determine the biomass accumulation and distribution of P. cathayana and then to explore its dynamic response to water and nitrogen availability. The results showed that:(1) Increased soil water and nitrogen availability significantly promoted the biomass accumulation of roots, stems, leaves, as well as total biomass of P. cathayana, which reached a maximum under the W3 treatment, and the effect of nitrogen application became more obvious with time. The promotive effect of N2 was significantly greater than that of N1.The interaction between water and nitrogen had no effect on biomass accumulation.(2) Biomass allocation of P.cathayana was mainly controlled by growth rhythm(time). Specifically, the stem and root weight ratios increased,while the leaf weight ratio decreased with plant growth and treatment time extension. Increasing water availability significantly increased the stem weight ratio and deceased the root weight ratio, but had no significant effect on the leaf weight ratio. Nitrogen and water-nitrogen interactions had no significant effect on the root weight ratio,stem weight ratio, or leaf weight ratio.(3) Effect

关 键 词：生物量 根重比 水氮有效性 比叶重 比根长 

分 类 号：S792.113[农业科学—林木遗传育种]