Differences in leaf traits and trait correlation networks between karst and non-karst forest tree species

doi:10.17521/cjpe.2022.0469

Abstract

Abstract:

Aims This study aims to clarify the differences in ecological strategies between karst and non-karst forest tree species, in terms of leaf morphology and anatomy, hydraulics, and mechanical resistance.

Methods A total of 101 tree species were selected from typical karst and non-karst forests in tropical-subtropical regions. We measured: (1) leaf morphological and anatomical traits including leaf thickness (LT), leaf density (LD), vein density and leaf mass per area (LMA); (2) leaf mechanical traits including force to punch and force to tear (F_t); and (3) leaf hydraulic traits including maximum hydraulic conductance (K_{leaf_max}), cavitation resistance (P50_leaf), turgor loss point (Ψ_tlp), and stomatal safety margin (HSM_tlp). We compared the differences in leaf traits between karst and non-karst forest tree species, and analyzed their traits correlation networks.

Important findings (1) Compared to non-karst forest tree species, on average the karst tree species had greater F_t, higher K_{leaf_max}, lower (more negative) Ψ_tlp and HSM_tlp. (2) Leaf trait network of karst forest tree species showed shorter average path length and diameter and lower edge density than non-karst forest tree species, indicating that traits combinations were closer in karst forests. (3) Mechanical traits and LMA showed high connectedness in the trait networks of karst forest tree species, LT and LD showed high connectedness in those of non-karst tree species. In karst forest tree species, LMA was positively correlated with F_t and negatively correlated with Ψ_tlp, indicating that increasing leaf carbon investment can simultaneously enhance meachnical resistance and drought tolerance. However, no such correlations were found in non-karst forest tree species. (4) Across karst forests tree species, we found a significant tradeoff between K_{leaf_max} and P50_leaf, both of which were not related with leaf mechanical resistance, and morphological and anatomical traits. By contrast, there was no hydraulic tradeoff in non-karst forest tree species, and K_{leaf_max} was significantly correlated with LT and LD. This study further reveals that compared to non-karst forest tree species, karst forest tree species tend to exhibit isohydraulic strategy and show closer coordination among leaf traits.

Key words: morphology, anatomy, hydraulics, mechanical resistance, tropical-subtropical forest, karst

WAN Chun-Yan, YU Jun-Rui, ZHU Shi-Dan. Differences in leaf traits and trait correlation networks between karst and non-karst forest tree species[J]. Chin J Plant Ecol, 2023, 47(10): 1386-1397.

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URL: https://www.plant-ecology.com/EN/10.17521/cjpe.2022.0469

https://www.plant-ecology.com/EN/Y2023/V47/I10/1386

Figures/Tables 4

References 58

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类别 Type	性状 Trait	缩写 Code	单位 Unit	定义 Definition
形态解剖 Morphology & anatomy	比叶质量 Leaf mass per area	LMA	g·m^-2	叶面积与干质量的比值, 经济学核心性状, 与碳投资成本有关(Wright et al., 2004) Defined as leaf dry mass per unit area. A central leaf economic trait that related to carbon investment (Wright et al., 2004)
	叶片密度 Leaf density	LD	mg·cm^-3	叶干质量与体积的比值, 反映叶组织的致密程度, 与碳投资成本有关(Lamont et al., 2015) Defined as the ratio of dry mass to volume. It reflects the density of leaf tissue, a central leaf economic trait that related to carbon investment (Lamont et al., 2015)
	叶脉密度 Vein density	VD	mm·mm^-2	单位面积三级叶脉以上的叶脉长度之和, 与水分运输有关(Lamont et al., 2015) Defined as the sum of the vein length per unit leaf area. It relates to water transport capacity (Lamont et al., 2015)
	叶片厚度 Leaf thickness	LT	μm	叶各组织厚度之和, 与抗性和光合能力以及碳投资成本相关(Lamont et al., 2015) Defined as the sum of the thicknesses of leaf tissues. It relates to resistance, photosynthetic capacity, and carbon investment cost (Lamont et al., 2015)
机械抗性 Biomechanics	穿刺力 Leaf force to punch	F_p	kN·m^-1	穿透单位周长的叶片所需要的力, 反映机械抗性(Onoda et al., 2011) Defined as the force to penetrate a leaf. It reflects mechanical resistance (Onoda et al., 2011)
机械抗性 Biomechanics	撕裂力 Leaf force to tear	F_t	kN·m^-1	撕裂单位宽度的叶片所需要的力, 反映机械抗性(Onoda et al., 2011) Defined as the force to tear a leaf. It reflects mechanical resistance (Onoda et al., 2011)
水力学 Hydraulics	抗栓塞能力 Leaf cavitation resistance	P50_leaf	MPa	叶片导水率损失50%时的水势值, 反映叶栓塞抗性和水力失败的阈值(Sack & Frole, 2006) Defined as the water potential inducing 50% loss of leaf hydraulic conductance. It reflects embolic resistance and the threshold of hydraulic failure (Sack & Frole, 2006)
	叶片最大导水率 Maximum leaf hydraulic conductance	K_{leaf_max}	mmol·m^-2·s^-1· MPa^-1	反映叶水分运输能力, 与气体交换参数相关(Sack & Frole, 2006) It reflects the water transport capacity of leaves and relates to gas exchange (Sack & Frole, 2006)
	膨压丧失点 Leaf water potential at turgor loss point	Ψ_tlp	MPa	膨压为0时的水势, 反映耐失水能力, 与气孔关闭有关(Bartlett et al., 2012) Defined as leaf water potential at which turgor pressure is zero. It estimates to desiccation resistance and relates to stomatal closure (Bartlett et al., 2012)
	气孔安全边界 Stomatal safety margin	HSM_tlp	MPa	Ψ_tlp与P50_leaf的差值, 反映气孔调节策略(Powers et al., 2020) Defined as the difference between Ψ_tlp and P50_leaf. It reflects the stomatal regulation strategy (Powers et al., 2020)

类别 Type	性状 Trait	缩写 Code	单位 Unit	定义 Definition
形态解剖 Morphology & anatomy	比叶质量 Leaf mass per area	LMA	g·m^-2	叶面积与干质量的比值, 经济学核心性状, 与碳投资成本有关(Wright et al., 2004) Defined as leaf dry mass per unit area. A central leaf economic trait that related to carbon investment (Wright et al., 2004)
	叶片密度 Leaf density	LD	mg·cm^-3	叶干质量与体积的比值, 反映叶组织的致密程度, 与碳投资成本有关(Lamont et al., 2015) Defined as the ratio of dry mass to volume. It reflects the density of leaf tissue, a central leaf economic trait that related to carbon investment (Lamont et al., 2015)
	叶脉密度 Vein density	VD	mm·mm^-2	单位面积三级叶脉以上的叶脉长度之和, 与水分运输有关(Lamont et al., 2015) Defined as the sum of the vein length per unit leaf area. It relates to water transport capacity (Lamont et al., 2015)
	叶片厚度 Leaf thickness	LT	μm	叶各组织厚度之和, 与抗性和光合能力以及碳投资成本相关(Lamont et al., 2015) Defined as the sum of the thicknesses of leaf tissues. It relates to resistance, photosynthetic capacity, and carbon investment cost (Lamont et al., 2015)
机械抗性 Biomechanics	穿刺力 Leaf force to punch	F_p	kN·m^-1	穿透单位周长的叶片所需要的力, 反映机械抗性(Onoda et al., 2011) Defined as the force to penetrate a leaf. It reflects mechanical resistance (Onoda et al., 2011)
机械抗性 Biomechanics	撕裂力 Leaf force to tear	F_t	kN·m^-1	撕裂单位宽度的叶片所需要的力, 反映机械抗性(Onoda et al., 2011) Defined as the force to tear a leaf. It reflects mechanical resistance (Onoda et al., 2011)
水力学 Hydraulics	抗栓塞能力 Leaf cavitation resistance	P50_leaf	MPa	叶片导水率损失50%时的水势值, 反映叶栓塞抗性和水力失败的阈值(Sack & Frole, 2006) Defined as the water potential inducing 50% loss of leaf hydraulic conductance. It reflects embolic resistance and the threshold of hydraulic failure (Sack & Frole, 2006)
	叶片最大导水率 Maximum leaf hydraulic conductance	K_{leaf_max}	mmol·m^-2·s^-1· MPa^-1	反映叶水分运输能力, 与气体交换参数相关(Sack & Frole, 2006) It reflects the water transport capacity of leaves and relates to gas exchange (Sack & Frole, 2006)
	膨压丧失点 Leaf water potential at turgor loss point	Ψ_tlp	MPa	膨压为0时的水势, 反映耐失水能力, 与气孔关闭有关(Bartlett et al., 2012) Defined as leaf water potential at which turgor pressure is zero. It estimates to desiccation resistance and relates to stomatal closure (Bartlett et al., 2012)
	气孔安全边界 Stomatal safety margin	HSM_tlp	MPa	Ψ_tlp与P50_leaf的差值, 反映气孔调节策略(Powers et al., 2020) Defined as the difference between Ψ_tlp and P50_leaf. It reflects the stomatal regulation strategy (Powers et al., 2020)