摘要
植物叶片碳氮磷化学计量和非结构性碳水化合物(NSCs)及其组分含量对于理解植物体的养分利用效率和生态策略具有重要作用。树木个体的生长发育状况和保护防御能力受资源可利用性的影响,与林分密度密切相关。林地施肥能够改变林分的养分状况,然而施肥对植物叶片化学计量和NSCs含量以及碳利用策略的影响仍不清楚。本研究选取3年氮添加的蒙古栎(Quercus mongolica)中龄林为对象,设置2种林分密度(D_(1):1300株·hm^(-2)和D_(2):1700株·hm^(-2))和3个氮添加水平[0(CK)、100 g N·tree^(-1)·a^(-1)(N_(1))和200 g N·tree^(-1)·a^(-1)(N_(2))],测定了叶片C、N、P和NSCs含量以及土壤养分含量的变化。结果表明:随着N添加水平增加,叶片N含量显著升高,C∶N降低。低密度林分(D_(1))随施N量增加叶片P含量缓慢升高,C∶P降低,N∶P先上升后下降;高密度林分(D_(2))随施N水平增加叶片P含量先降低后升高,C∶P和N∶P先上升后下降。N添加升高了D_(1)林分叶片NSCs和可溶性糖(SS)含量,降低了淀粉(ST)含量,而D_(2)林分叶片的NSCs、SS和ST含量均先上升后下降。叶片P含量与SS含量在D_(1)林分具正相关关系,在D_(2)林分具负相关关系。本研究表明,蒙古栎林生长受到林分密度和氮磷元素的多重限制,N添加加剧了高密度蒙古栎林分P限制,碳利用策略由生长转为防御保护。
The ecological stoichiometry of foliar carbon(C),nitrogen(N),and phosphorus(P)can reflect nutrient use efficiency and ecological strategy of plants.The concentrations of the nonstructural carbohydrates(NSCs)and their components of leaves provide important information for understanding plant growth,development,and defense strategies,which are related to nutrient availability and dependent on stand density.Nitrogen addition can improve soil nutrient status.However,carbon utilization strategies and growth or defense mechanisms in relation to changes in soil N availability remain unclear.In this study,the concentrations of C,N,P,and NSCs and their ratios in the leaves of Mongolian oak(Quercus mongolica)and soil nutrients were examined with a three-year N addition experiment.Leaf samples of Mongolian oaks were collected from two blocks with different stand densities(D_(1):1300 trees·hm^(-2)and D_(2):1700 trees·hm^(-2))and each stand density with one of three N addition levels(0 g N·tree^(-1)·a^(-1),CK;100 g N·tree^(-1)·a^(-1),N_(1);200 g N·tree^(-1)·a^(-1),N_(2)).The results showed that N addition significantly increased leaf N concentration and decreased leaf C∶N ratio.Leaf P concentration increased slowly,C∶P decreased,and N∶P increased first and then decreased with N application in D_(1),whereas leaf P concentration decreased first and then increased,C∶P and N∶P increased first and then decreased in D_(2).Additionally,N addition elevated the concentrations of NSCs and soluble sugar(SS)and reduced the concentrations of leaf starch(ST)in D_(1).On the contrary,the concentrations of leaf NSCs,SS and ST first increased and then decreased with N addition in D_(2).Furthermore,the relationship between leaf P and SS concentrations was significantly positive in D_(1) but negative in D_(2)(P<0.05).Overall,our results indicated that the development of Mongolian oak stands may be controlled by N and P limitations,as well as by stand density.Nitrogen addition would aggravate P limitation in higher stand density and result in a shift of carbon use strategies from growth to defensive processes.
作者
王睿照
毛沂新
云丽丽
尤文忠
张慧东
WANG Rui-zhao;MAO Yi-xin;YUN Li-li;YOU Wen-zhong;ZHANG Hui-dong(Liaoning Academy of Forestry,Shenyang 110032,China;Liaoning Bingla Mountain Forest Ecological Station,Xifeng 112400,Liaoning,China;Liaoning Institute of Economic Forest,Dalian 116030,Liaoning,China)
出处
《生态学杂志》
CAS
CSCD
北大核心
2022年第7期1369-1377,共9页
Chinese Journal of Ecology
基金
国家重点研发计划项目(2017YFD0601103-02)
沈阳市中青年科技创新人才支持项目(RC210294)
辽宁省“兴辽英才计划”项目(XLYC1902015)
辽宁省农业科学院基本科研业务费计划项目(2021HQ1910)资助。
关键词
蒙古栎
氮添加
林分密度
可溶性糖
淀粉
碳利用策略
Quercus mongolica
nitrogen addition
stand density
soluble sugar
starch
carbon use strategy
