Effects of Water and Nitrogen Addition on Leaf Functional Traits of Populus tomentosa under Different Thinning Intensities

doi:10.7525/j.issn.1673-5102.2026.04.010

Abstract

Abstract:

To systematically reveal the synergistic regulatory mechanisms of thinning intensity and water-nitrogen addition on leaf functional traits in plantations， this study conducted a split-plot experiment with Populus tomentosa plantations in the Yellow River Flood Plain. Two thinning intensities（50% and 75%） and three water-nitrogen treatments（water-nitrogen addition， single water addition， and control） were established. The response characteristics and coupling relationships were analyzed from three dimensions： leaf water status， structural construction， and nutrient stoichiometry. The results indicate that：（1）Leaf relative water content remained generally stable， whereas leaf dry mass water content exhibited high sensitivity to thinning and its interaction with water-nitrogen treatments， showing a significant increase of 43.05% under 75% thinning with water-nitrogen addition. （2）Structural traits showed no significant overall changes， with low variation in leaf dry matter content and high variation in specific leaf mass， demonstrating potential plasticity. （3）Among nutrient traits， leaf carbon content remained relatively stable， whereas leaf nitrogen and phosphorus contents as well as their stoichiometric ratios responded significantly to the treatments. The leaf N∶P ratio（mass ratio）ranged from 11.06 to 18.46， with an average value of 13.94， indicating that the P.tomentosa plantations in the study area were generally under nitrogen limitation. （4）Multivariate analysis revealed significant coupling relationships among leaf water content， structural traits， and nutrient allocation， with leaf dry mass water content and specific leaf mass identified as key traits driving nutrient partitioning. （5）Principal component analysis revealed that the first two principal components cumulatively explained 66.4% of the variation. Thinning at 75% promoted leaf adjustment towards high resource-use efficiency， while 50% thinning maintained a conservative strategy. Different water and nitrogen treatments primarily diverged along the nutrient structure dimension， with the single water addition treatment showing strong association with nutrient ratio traits. Overall， thinning and water-nitrogen regulation drive coordinated changes in leaf functional traits by altering resource availability， thereby influencing plant resource utilization strategies.

Key words: Populus tomentosa, thinning intensity, water and nitrogen addition, leaf functional traits, stoichiometric characteristics, resource-use strategy

CLC Number:

S714.7

Yafei WANG, Xiaofei DING, Liming JIA. Effects of Water and Nitrogen Addition on Leaf Functional Traits of Populus tomentosa under Different Thinning Intensities[J]. Bulletin of Botanical Research, 2026, 46(4): 688-699.

Figures/Tables 9

Table 1

Table 2

Fig.1

Table 3

Fig.2

Fig.3

Fig.4

Table 4

Fig.5

References 41

[1]	Westoby M， Wright I J.Land-plant ecology on the basis of functional traits［J］.Trends in Ecology & Evolution，2006，21（5）：261-268.
[2]	Wright I J， Reich P B， Westoby M，et al.The worldwide leaf economics spectrum［J］.Nature，2004，428（6985）：821-827.
[3]	Xu T Y， Niu X， Wang B，et al.Variations in leaf functional traits and photosynthetic parameters of Cunninghamia lanceolata provenances［J］.Forests，2023，14（9）：1708.
[4]	何念鹏，刘聪聪，张佳慧，等.植物性状研究的机遇与挑战：从器官到群落［J］.生态学报，2018，38（19）：6787-6796.
	He Nianpeng， Liu Congcong， Zhang Jiahui，et al.Perspectives and challenges in plant traits：from organs to communities［J］.Acta Ecologica Sinica，2018，38（19）：6787-6796.
[5]	李跃，毕舒贻，万修福，等.紫花苜蓿幼苗生长及其叶片形态对水分胁迫的响应［J］.草地学报，2017，25（6）：1232-1238.
	Li Yue， Bi Shuyi， Wan Xiufu，et al.Responses of the growth and leaf morphology of alfalfa seedlings to water stress［J］.Acta Agrestia Sinica，2017，25（6）：1232-1238.
[6]	刘明秀，梁国鲁.植物比叶质量研究进展［J］.植物生态学报，2016，40（8）：847-860.
	Liu Mingxiu， Liang Guolu.Research progress on leaf mass per area［J］.Chinese Journal of Plant Ecology，2016，40（8）：847-860.
[7]	田地，严正兵，方精云.植物生态化学计量特征及其主要假说［J］.植物生态学报，2021，45（7）：682-713.
	Tian Di， Yan Zhengbing， Fang Jingyun.Review on characteristics and main hypotheses of plant ecological stoichiometry［J］.Chinese Journal of Plant Ecology，2021，45（7）：682-713.
[8]	Reich P B.The world-wide ‘fast-slow’ plant economics spectrum：a traits manifesto［J］.Journal of Ecology，2014，102（2）：275-301.
[9]	何芸雨，郭水良，王喆.植物功能性状权衡关系的研究进展［J］.植物生态学报，2019，43（12）：1021-1035.
	He Yunyu， Guo Shuiliang， Wang Zhe.Research progress of trade-off relationships of plant functional traits［J］.Chinese Journal of Plant Ecology，2019，43（12）：1021-1035.
[10]	Chaves M M， Flexas J， Pinheiro C.Photosynthesis under drought and salt stress：regulation mechanisms from whole plant to cell［J］.Annals of Botany，2009，103（4）：551-560.
[11]	Poorter H， Niinemets Ü， Poorter L，et al.Causes and consequences of variation in leaf mass per area （LMA）：a meta-analysis［J］.New Phytologist，2009，182（3）：565-588.
[12]	杨雨薇，何宝辉，韩学娇，等.林龄对毛白杨功能性状和林下土壤理化性质的影响及其耦合关系［J］.植物研究，2023，43（6）：857-867.
	Yang Yuwei， He Baohui， Han Xuejiao，et al.Effects of stand age on functional traits and understory soil physicochemical properties of Populus tomentosa and their coupling relationships［J］.Bulletin of Botanical Research，2023，43（6）：857-867.
[13]	杨乐梅，张宝刚，陈有超，等.毛竹林林下植物叶片功能性状的模拟氮沉降响应［J］.林业科学，2025，61（12）：61-71.
	Yang Lemei， Zhang Baogang， Chen Youchao，et al.Leaf functional traits of understory plants in a moso bamboo forests in response to simulated nitrogen deposition［J］.Scientia Silvae Sinicae，2025，61（12）：61-71.
[14]	刘旻霞，李俐蓉，车应弟，等.高寒草甸不同演替阶段植物叶片功能性状研究［J］.植物研究，2019，39（5）：760-769.
	Liu Minxia， Li Lirong， Che Yingdi，et al.Functional traits of plant leaves at different succession stages in alpine meadow［J］.Bulletin of Botanical Research，2019，39（5）：760-769.
[15]	Benedetti-Ruiz S， Loewe-Muñoz V， Del Río R，et al.Effect of thinning on growth and shape of Castanea sativa adult tree plantations for timber production in Chile［J］.Forest Ecology and Management，2023，530：120762.
[16]	Forrester D I， Collopy J J， Beadle C L，et al.Effect of thinning，pruning and nitrogen fertiliser application on transpiration，photosynthesis and water-use efficiency in a young Eucalyptus nitens plantation［J］.Forest Ecology and Management，2012，266：286-300.
[17]	Forrester D I， Collopy J J， Beadle C L，et al.Interactive effects of simultaneously applied thinning，pruning and fertiliser application treatments on growth，biomass production and crown architecture in a young Eucalyptus nitens plantation［J］.Forest Ecology and Management，2012，267：104-116.
[18]	Xi B Y， Clothier B， Coleman M，et al.Irrigation management in poplar （Populus spp.） plantations：a review［J］.Forest Ecology and Management，2021，494：119330.
[19]	Mo Q F， Zou B， Li Y W，et al.Response of plant nutrient stoichiometry to fertilization varied with plant tissues in a tropical forest［J］.Scientific Reports，2015，5：14605.
[20]	李素新，张芸香，郭晋平.氮添加对华北落叶松叶片化学计量与养分重吸收效率的影响［J］.水土保持学报，2021，35（5）：249-254，263.
	Li Suxin， Zhang Yunxiang， Guo Jinping.Effects of nitrogen addition on leaf stoichiometry and nutrients reabsorption efficiency of Larix principis-rupprechtii ［J］.Journal of Soil and Water Conservation，2021，35（5）：249-254，263.
[21]	王亚飞，杨红青，周欧，等.水氮耦合下高密度毛白杨纸浆林树木各器官化学计量特征［J］.北京林业大学学报，2023，45（12）：68-79.
	Wang Yafei， Yang Hongqing， Zhou Ou，et al.Chemical stoichiometry characteristics of various organs of trees in high-density Populus tomentosa pulp forests under water-nitrogen coupling［J］.Journal of Beijing Forestry University，2023，45（12）：68-79.
[22]	Liu J Q， Li D D， Fernández J E，et al.Variations in water-balance components and carbon stocks in poplar plantations with differing water inputs over a whole rotation：implications for sustainable forest management under climate change［J］.Agricultural and Forest Meteorology，2022，320：108958.
[23]	He Y L， Xi B Y， Li G D，et al.Influence of drip irrigation，nitrogen fertigation，and precipitation on soil water and nitrogen distribution，tree seasonal growth and nitrogen uptake in young triploid poplar （Populus tomentosa） plantations［J］.Agricultural Water Management，2021，243：106460.
[24]	Xi B Y， Bloomberg M， Watt M S，et al.Modeling growth response to soil water availability simulated by HYDRUS for a mature triploid Populus tomentosa plantation located on the North China Plain［J］.Agricultural Water Management，2016，176：243-254.
[25]	Wang Y， Xi B Y， Bloomberg M，et al.Response of diameter growth，biomass allocation and N uptake to N fertigation in a triploid Populus tomentosa plantation in the North China Plain：ontogenetic shift does not exclude plasticity［J］.European Journal of Forest Research，2015，134（5）：889-898.
[26]	Chaves M M， Maroco J P， Pereira J S.Understanding plant responses to drought： from genes to the whole plant［J］.Functional Plant Biology，2003，30（3）：239-264.
[27]	Liu Y， Li Y， Gao G Y，et al.Effects of thinning on soil water content and water use characteristics of artificial forest in the Loess Plateau of China［J］.Catena，2025，254：108997.
[28]	Hipps N A， Davies M J， Dunn J M，et al.Effects of two contrasting canopy manipulations on growth and water use of London plane（Platanus×acerifolia） trees［J］.Plant and Soil，2014，382（1）：61-74.
[29]	Poorter H， Niklas K J， Reich P B，et al.Biomass allocation to leaves，stems and roots：meta-analyses of interspecific variation and environmental control［J］.The New Phytologist，2012，193（1）：30-50.
[30]	赵航，贾彦龙，王秋凤.中国地带性森林和农田生态系统C-N-P化学计量统计特征［J］.第四纪研究，2014， 34（4）：803-814.
	Zhao Hang， Jia Yanlong， Wang Qiufeng.Statistical characteristics of C-N-P stoichiometry in Chinese zonal forest and farmland ecosystems［J］.Quaternary Sciences，2014，34（4）：803-814.
[31]	Schreeg L A， Santiago L S， Wright S J，et al.Stem，root，and older leaf N∶P ratios are more responsive indicators of soil nutrient availability than new foliage［J］.Ecology，2014，95（8）：2062-2068.
[32]	Yuan Z Y， Chen H Y H， Reich P B.Global-scale latitudinal patterns of plant fine-root nitrogen and phosphorus［J］.Nature Communications，2011，2：344.
[33]	马玉珠，钟全林，靳冰洁，等.中国植物细根碳、氮、磷化学计量学的空间变化及其影响因子［J］.植物生态学报，2015，39（2）：159-166.
	Ma Yuzhu， Zhong Quanlin， Jin Bingjie，et al.Spatial changes and influencing factors of fine root carbon，nitrogen and phosphorus stoichiometry of plants in China［J］.Chinese Journal of Plant Ecology，2015，39（2）：159-166.
[34]	Elser J J， Fagan W F， Denno R F，et al.Nutritional constraints in terrestrial and freshwater food webs［J］.Nature，2000，408（6812）：578-580.
[35]	Han W X， Fang J Y， Guo D L，et al.Leaf nitrogen and phosphorus stoichiometry across 753 terrestrial plant species in China［J］.New Phytologist，2005，168（2）：377-385.
[36]	任书杰，于贵瑞，陶波，等.中国东部南北样带654种植物叶片氮和磷的化学计量学特征研究［J］.环境科学，2007，28（12）：2665-2673.
	Ren Shujie， Yu Guirui， Tao Bo，et al.Leaf nitrogen and phosphorus stoichiometry across 654 terrestrial plant species in NSTEC［J］.Environmental Science，2007，28（12）：2665-2673.
[37]	Elser J J， Dobberfuhl D R， MacKay N A，et al.Organism size，life history，and N：P stoichiometry［J］.BioScience，1996，46（9）：674-684.
[38]	Güsewell S.N∶P ratios in terrestrial plants：variation and functional significance［J］.New Phytologist，2004，164（2）：243-266.
[39]	He J S， Wang L， Flynn D F B，et al.Leaf nitrogen∶phosphorus stoichiometry across Chinese grassland biomes［J］.Oecologia，2008，155（2）：301-310.
[40]	Qiu X C， Wang H B， Peng D L，et al.Thinning drives C∶N∶P stoichiometry and nutrient resorption in Larix principis-rupprechtii plantations in North China［J］.Forest Ecology and Management，2020，462：117984.
[41]	Osnas J L D， Lichstein J W， Reich P B，et al.Global leaf trait relationships：mass，area，and the leaf economics spectrum［J］.Science，2013，340（6133）：741-744.

处理 Treatment	2023年生长季前 Beginning of the 2023 growing season		2023年生长季末 End of the 2023 growing season
处理 Treatment	胸径D_BH/cm	树高H/m	胸径D_BH/cm	树高H/m
T₅₀CK	14.56±1.94	15.21±0.68	15.83±1.86^ab	17.36±1.17
T₅₀W	14.23±0.24	15.38±1.76	15.64±0.32^ab	16.69±1.50
T₅₀WN	14.54±1.88	16.59±0.36	16.00±1.79^a	17.55±2.12
T₇₅CK	13.63±1.40	14.49±0.44	15.17±1.47^b	16.94±0.44
T₇₅W	13.04±0.50	14.62±0.67	14.59±1.11^b	16.73±0.69
T₇₅WN	13.61±0.99	15.15±0.44	15.73±0.98^ab	16.88±0.17

指标 Indexes	变异来源 Source of variation
	间伐强度 Thinning intensity（T）		水氮添加处理 Water and nitrogen addition treatment（WNT）		间伐强度×水氮添加处理 T×WNT
	F	P	F	P	F	P
叶片相对含水量R_WC	4.445	0.057	0.203	0.819	3.907	0.049
叶片干质量含水量D_WWC	6.117	0.029	0.620	0.554	16.204	<0.001
叶片干物质含量L_DMC	0.027	0.872	0.172	0.844	2.527	0.121
比叶质量L_MA	0.738	0.407	2.836	0.098	0.171	0.845
叶片有机碳ω（LC）	3.711	0.078	0.238	0.792	2.626	0.113
叶片全氮ω（LN）	3.519	0.085	2.860	0.096	6.706	0.011
叶片全磷ω（LP）	11.554	0.005	32.806	<0.001	4.778	0.030
C∶N	8.145	0.015	2.224	0.151	11.813	0.001
C∶P	40.740	<0.001	57.731	<0.001	13.373	<0.001
N∶P	2.058	0.177	32.741	<0.001	0.741	0.497

叶片性状 Leaf traits	变异系数 Coefficient of variation/%
叶片性状 Leaf traits	T₅₀CK	T₅₀W	T₅₀WN	T₇₅CK	T₇₅W	T₇₅WN
叶片相对含水量R_WC	9.34	3.37	14.74	2.85	12.70	13.32
叶片干质量含水量D_WWC	7.60	5.23	4.97	3.53	7.40	9.83
叶片干物质含量L_DMC	1.67	3.67	8.54	1.04	2.60	3.08
比叶质量L_MA	3.07	32.26	29.11	3.39	20.61	35.42
叶片有机碳ω（LC）	6.70	3.69	3.96	6.03	2.45	6.94
叶片全氮ω（LN）	6.39	7.65	3.21	2.47	11.61	5.20
叶片全磷ω（LP）	9.89	7.67	6.82	4.79	8.02	2.38
C∶N	4.79	10.58	4.97	8.03	9.12	8.61
C∶P	5.21	3.90	3.35	9.15	5.89	6.08
N∶P	3.71	14.62	8.34	5.93	7.80	3.31

叶片养分 Leaf nutrient	叶片水分/结构性状 Leaf moisture/structural traits	直接通径系数 Direct path coefficient	间接通径系数 Indirect path coefficient
叶片养分 Leaf nutrient	叶片水分/结构性状 Leaf moisture/structural traits	直接通径系数 Direct path coefficient	D_WWC	L_DMC	L_MA
ω（LC）	D_WWC	-0.406		-0.036	0.060
	L_DMC	0.083	0.177		0.047
	L_MA	0.218	-0.111	0.018
ω（LN）	D_WWC	0.196		0.188	0.121
	L_DMC	-0.431	-0.086		0.095
	L_MA	0.445	0.054	-0.092
ω（LP）	D_WWC	0.611		-0.107	-0.130
	L_DMC	0.245	-0.267		-0.102
	L_MA	-0.477	0.167	0.052