Responses of leaf trait networks to extreme drought in typical steppe plants of Inner Mongolia

doi:10.11686/cyxb2025118

Abstract

Abstract:

With the intensification of global climate change， extreme drought events are occurring with increasing frequency， posing severe threats to plant survival and ecosystem functioning. Leaf trait networks， which integrate multiple functional traits and their interactions， provide a comprehensive framework for understanding plant responses to environmental stress. Although previous studies have examined the effects of extreme drought on individual or a few leaf traits， the response of the overall trait network structure and its key traits under extreme drought remains unclear. This study was conducted in the typical steppe of Inner Mongolia， where two types of extreme drought were simulated： a 66% reduction in precipitation from May to August each year （CHR）， and a 100% reduction in precipitation during June and July each year （INT）. We systematically measured 20 leaf traits and employed a trait network analysis approach to assess the impacts of extreme drought on trait variation and network properties. It was found that extreme drought significantly reduced leaf water potential and increased magnesium concentration， while weakening network connectivity and complexity， as indicated by decreases in the number of edges， edge density， and average clustering coefficient. Furthermore， by classifying the selected traits into hydraulic， compositional， and morphological categories， we found that hydraulic traits consistently exhibited the highest degree， closeness， and betweenness under both drought treatments. This highlights their central regulatory role in the network， suggesting that they play a dominant role in coordinating the responses of other functional traits to drought stress. This study provides novel insights into the integrated regulatory mechanisms of plant adaptation to extreme drought from a trait network perspective. Our findings enhance the understanding of plant drought resistance strategies and ecological adaptability， and offer a theoretical foundation for predicting plant ecological responses under future climate change scenarios.

Key words: typical grassland, leaf trait network, extreme drought, hydraulic behavior

Ya-nan QIAO, Hong-qiang WANG, Ying LI, Qiang YU. Responses of leaf trait networks to extreme drought in typical steppe plants of Inner Mongolia[J]. Acta Prataculturae Sinica, 2026, 35(2): 107-119.

Figures/Tables 6

References 50

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分类 Sort	性状 Traits	单位 Unit	缩写 Abbreviation
叶片水力学性状 Leaf hydraulic traits	叶片含水量Leaf water concentration	%	LWC
	气孔器长Stomatal length	μm	SL
	气孔器宽Stomatal width	μm	SW
	气孔长Stomatal pore length	μm	PL
	气孔面积Stomatal area	μm²	SA
	气孔密度Stomatal density	pores·mm^-2	SD
	气孔面积指数Stomatal area fraction	%	SAF
	叶片水势Leaf water potential	Mpa	LWP
叶片组成性状 Leaf composition traits	叶片钙含量Leaf calcium concentration	mg·g^-1	Ca
	叶片铁含量Leaf iron concentration	mg·g^-1	Fe
	叶片钾含量Leaf potassium concentration	mg·g^-1	K
	叶片镁含量Leaf magnesium concentration	mg·g^-1	Mg
	叶片磷含量Leaf phosphorus concentration	mg·g^-1	P
	叶片硫含量Leaf sulfur concentration	mg·g^-1	S
	叶片锌含量Leaf zinc concentration	mg·g^-1	Zn
	叶绿素含量Chlorophyll concentration	-	SPAD
叶片形态学性状 Leaf morphological traits	叶片厚度Leaf thickness	mm	LT
	叶片面积Leaf area	cm2	LA
	比叶面积Specific leaf area	mm²·mg^-1	SLA
	叶片干物质含量Leaf dry matter concentration	%	LDMC

分类 Sort	性状 Traits	单位 Unit	缩写 Abbreviation
叶片水力学性状 Leaf hydraulic traits	叶片含水量Leaf water concentration	%	LWC
	气孔器长Stomatal length	μm	SL
	气孔器宽Stomatal width	μm	SW
	气孔长Stomatal pore length	μm	PL
	气孔面积Stomatal area	μm²	SA
	气孔密度Stomatal density	pores·mm^-2	SD
	气孔面积指数Stomatal area fraction	%	SAF
	叶片水势Leaf water potential	Mpa	LWP
叶片组成性状 Leaf composition traits	叶片钙含量Leaf calcium concentration	mg·g^-1	Ca
	叶片铁含量Leaf iron concentration	mg·g^-1	Fe
	叶片钾含量Leaf potassium concentration	mg·g^-1	K
	叶片镁含量Leaf magnesium concentration	mg·g^-1	Mg
	叶片磷含量Leaf phosphorus concentration	mg·g^-1	P
	叶片硫含量Leaf sulfur concentration	mg·g^-1	S
	叶片锌含量Leaf zinc concentration	mg·g^-1	Zn
	叶绿素含量Chlorophyll concentration	-	SPAD
叶片形态学性状 Leaf morphological traits	叶片厚度Leaf thickness	mm	LT
	叶片面积Leaf area	cm2	LA
	比叶面积Specific leaf area	mm²·mg^-1	SLA
	叶片干物质含量Leaf dry matter concentration	%	LDMC

性状 Traits	对照 Control	5-8月降水量减少66% The precipitation decreased by 66% from May to August	6-7月降水量减少100% The precipitation in June and July decreased by 100%
叶片厚度 Leaf thickness （mm）	0.245±0.016a	0.225±0.017a	0.231±0.033a
叶片面积 Leaf area （cm²）	7.905±2.221a	7.706±1.831a	8.149±0.238a
叶片含水量 Leaf water content （%）	0.661±0.058a	0.734±0.046a	0.743±0.061a
比叶面积 Specific leaf area （mm²·mg^-1）	54.420±17.597a	51.927±6.112a	57.729±6.550a
叶片干物质含量 Leaf dry matter content （%）	0.598±0.041a	0.648±0.007a	0.620±0.025a
叶片水势 Leaf water potential （MPa）	12.825±1.402a	8.305±1.026b	9.428±0.282ab
叶绿素含量 Chlorophyll concentration	25.287±6.395a	35.097±0.608a	31.326±3.697a
气孔密度 Stomatal density （pores·mm^-2）	1187.711±254.074a	615.443±53.889a	511.659±200.541a
气孔器长 Stomatal length （μm）	0.020±0.004a	0.022±0.002a	0.024±0.001a
气孔器宽 Stomatal width （μm）	0.015±0.003a	0.014±0.002a	0.015±0.001a
气孔长 Stomatal pore length （μm）	0.013±0.002a	0.013±0.002a	0.015±0.001a
气孔面积 Stomatal area （μm²）	214.365±78.887a	200.715±40.244a	216.898±21.307a
气孔面积指数 Stomatal area fraction （%）	0.112±0.007a	0.063±0.021a	0.065±0.024a
叶片钙含量 Leaf calcium concentration （mg·g?1）	64.993±9.344a	81.673±11.979a	90.204±12.828a
叶片铁含量 Leaf iron concentration （mg·g?1）	1.484±0.072a	2.977±0.895a	2.008±0.286a
叶片钾含量 Leaf potassium concentration （mg·g?1）	147.292±16.118a	170.308±21.986a	180.783±38.755a
叶片镁含量 Leaf magnesium concentration （mg·g?1）	11.728±1.476b	17.276±1.531a	19.460±1.773a
叶片磷含量 Leaf phosphorus concentration （mg·g?1）	11.004±0.331a	15.368±2.723a	16.454±1.176a
叶片硫含量 Leaf sulfur concentration （mg·g?1）	18.695±4.075a	23.280±3.084a	24.832±1.907a
叶片锌含量 Leaf zinc concentration （mg g^-1）	0.265±0.009a	0.365±0.053a	0.328±0.011a

性状 Traits	对照 Control	5-8月降水量减少66% The precipitation decreased by 66% from May to August	6-7月降水量减少100% The precipitation in June and July decreased by 100%
叶片厚度 Leaf thickness （mm）	0.245±0.016a	0.225±0.017a	0.231±0.033a
叶片面积 Leaf area （cm²）	7.905±2.221a	7.706±1.831a	8.149±0.238a
叶片含水量 Leaf water content （%）	0.661±0.058a	0.734±0.046a	0.743±0.061a
比叶面积 Specific leaf area （mm²·mg^-1）	54.420±17.597a	51.927±6.112a	57.729±6.550a
叶片干物质含量 Leaf dry matter content （%）	0.598±0.041a	0.648±0.007a	0.620±0.025a
叶片水势 Leaf water potential （MPa）	12.825±1.402a	8.305±1.026b	9.428±0.282ab
叶绿素含量 Chlorophyll concentration	25.287±6.395a	35.097±0.608a	31.326±3.697a
气孔密度 Stomatal density （pores·mm^-2）	1187.711±254.074a	615.443±53.889a	511.659±200.541a
气孔器长 Stomatal length （μm）	0.020±0.004a	0.022±0.002a	0.024±0.001a
气孔器宽 Stomatal width （μm）	0.015±0.003a	0.014±0.002a	0.015±0.001a
气孔长 Stomatal pore length （μm）	0.013±0.002a	0.013±0.002a	0.015±0.001a
气孔面积 Stomatal area （μm²）	214.365±78.887a	200.715±40.244a	216.898±21.307a
气孔面积指数 Stomatal area fraction （%）	0.112±0.007a	0.063±0.021a	0.065±0.024a
叶片钙含量 Leaf calcium concentration （mg·g?1）	64.993±9.344a	81.673±11.979a	90.204±12.828a
叶片铁含量 Leaf iron concentration （mg·g?1）	1.484±0.072a	2.977±0.895a	2.008±0.286a
叶片钾含量 Leaf potassium concentration （mg·g?1）	147.292±16.118a	170.308±21.986a	180.783±38.755a
叶片镁含量 Leaf magnesium concentration （mg·g?1）	11.728±1.476b	17.276±1.531a	19.460±1.773a
叶片磷含量 Leaf phosphorus concentration （mg·g?1）	11.004±0.331a	15.368±2.723a	16.454±1.176a
叶片硫含量 Leaf sulfur concentration （mg·g?1）	18.695±4.075a	23.280±3.084a	24.832±1.907a
叶片锌含量 Leaf zinc concentration （mg g^-1）	0.265±0.009a	0.365±0.053a	0.328±0.011a