Effect of stem length to stem slender ratio of current-year twigs on the leaf display efficiency in evergreen and deciduous broadleaved trees

doi:10.17521/cjpe.2016.0376

Abstract

Abstract:

Aims Branches and leaves are the two main structural units of tree crown composition. Among the adaptive strategies of plants, the functional traits of branches and the relationships between branch traits and leaf traits determine the capacity of trees to access light and space. In this study, our objective is to test the hypothesis that leaf display efficiency is affected by the stem length to stem slender ratio within current-year twigs.Methods The stem length to stem slender ratios of current-year twigs were used as the proxy of stem structure traits. Leaf area ratio (total leaf area per stem mass), leaf density (leaf number per stem length) and leaf/stem mass ratio (total leaf mass per stem mass) were used as the proxies of leaf display efficiency. The relationship between stem structure traits and leaf display efficiency within current-year twigs were studied for 25 evergreen and 60 deciduous broadleaved woody species in Qingliang Mountain, Zhejiang, China. The standardized major axis estimation method was used to examine the scaling relationship between stem structural traits and leaf display efficiency within current-year twigs.Important findings The proxies of leaf display efficiency, measured by leaf area ratio, leaf density or leaf/stem mass ratio, were all significantly and negative correlated with stem length to stem slender ratio within current-year twigs in both evergreen and deciduous broadleaved woody species. This suggested that leaf display efficiency decreased with stem length to stem slender ratios within current-year twigs, which may reflect the role of mechanical safety and light within twigs. The slope of the relationship between leaf display efficiency and stem long-dimension structure traits in evergreen species was not significantly different from the one in deciduous species. In contrast, the y-intercept of the relationship between leaf density and stem long-dimension structure traits was significantly larger in evergreen species than in deciduous species, i.e. the leafing intensity of evergreen species was higher than that of deciduous species. Individual leaf area and specific leaf area were smaller in evergreen species than in deciduous species, which resulted in deciduous species have a larger leaf area per stem mass and leaf mass per stem mass at a given stem length to stem slender ratio compared to evergreen species. It may reflect the conservative adaptive strategy of high consumption and slow benefit in evergreen species. Our results demonstrated that leaf display efficiency could be affected by stem length, and would change with leaf life-span (deciduous versus evergreen).

http://jtp.cnki.net/bilingual/detail/html/ZWSB201706006

Key words: stem length, stem slender ratio, leaf display efficiency, evergreen species, deciduous species

Jun-Hui LI, Guo-Quan PENG, Dong-Mei YANG. Effect of stem length to stem slender ratio of current-year twigs on the leaf display efficiency in evergreen and deciduous broadleaved trees[J]. Chin J Plant Ecol, 2017, 41(6): 650-660.

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References 65

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指标 (y 轴-x 轴) Index (y axis-x axis)	功能组 Functional group	样本量 Sample size	决定系数 Coefficient of determination	斜率(95%置信区间) Slope (95% confidence interval)	截距 Intercept
叶数量-小枝茎长度 Leaf number-stem length	落叶 Deciduous	60	0.192	0.510 (0.404, 0.645)	0.238
叶数量-小枝茎长度 Leaf number-stem length	常绿 Evergreen	25	0.279	0.463 (0.323, 0.662)	0.415
叶面积比-小枝茎纤细率 Leaf area ratio-stem slender ratio	落叶 Deciduous	60	0.613	-0.867 (-1.021, -0.737)	4.525
叶面积比-小枝茎纤细率 Leaf area ratio-stem slender ratio	常绿 Evergreen	25	0.620	-0.791 (-1.028, -0.608)	4.175
叶密度-小枝茎纤细率 Density of leaf number-stem slender ratio	落叶 Deciduous	60	0.617	-0.804 (-0.945, -0.684)	1.115
叶密度-小枝茎纤细率 Density of leaf number-stem slender ratio	常绿 Evergreen	25	0.781	-0.717 (-0.876, -0.587)	1.106
叶茎质量比-小枝茎纤细率 Leaf/stem mass ratio-stem slender ratio	落叶 Deciduous	60	0.629	-0.869 (-1.019, -0.741)	2.231
叶茎质量比-小枝茎纤细率 Leaf/stem mass ratio-stem slender ratio	常绿 Evergreen	25	0.823	-0.613 (-0.734, -0.512)	1.859
叶面积比-小枝茎长度 Leaf area ratio-stem length	落叶 Deciduous	60	0.628	-0.973 (-1.141, -0.829)	3.955
叶面积比-小枝茎长度 Leaf area ratio-stem length	常绿 Evergreen	25	0.683	-0.939 (-1.195, -0.738)	3.679
叶密度-小枝茎长度 Density of leaf number-stem length	落叶 Deciduous	60	0.741	-0.902 (-1.030, -0.789)	0.587
叶密度-小枝茎长度 Density of leaf number-stem length	常绿 Evergreen	25	0.787	-0.852 (-1.038, -0.699)	0.657
叶茎质量比-小枝茎长度 Leaf/stem mass ratio-stem length	落叶 Deciduous	60	0.614	-0.974 (-1.146, -0.828)	1.660
叶茎质量比-小枝茎长度 Leaf/stem mass ratio-stem length	常绿 Evergreen	25	0.852	-0.729 (-0.859, -0.618)	1.474
总叶面积-茎干质量 Total leaf area-stem dry mass	落叶 Deciduous	60	0.437	0.815 (0.670, 0.991)	0.504
总叶面积-茎干质量 Total leaf area-stem dry mass	常绿 Evergreen	25	0.439	0.722 (0.526, 0.992)	0.502

指标 (y 轴-x 轴) Index (y axis-x axis)	功能组 Functional group	样本量 Sample size	决定系数 Coefficient of determination	斜率(95%置信区间) Slope (95% confidence interval)	截距 Intercept
叶数量-小枝茎长度 Leaf number-stem length	落叶 Deciduous	60	0.192	0.510 (0.404, 0.645)	0.238
叶数量-小枝茎长度 Leaf number-stem length	常绿 Evergreen	25	0.279	0.463 (0.323, 0.662)	0.415
叶面积比-小枝茎纤细率 Leaf area ratio-stem slender ratio	落叶 Deciduous	60	0.613	-0.867 (-1.021, -0.737)	4.525
叶面积比-小枝茎纤细率 Leaf area ratio-stem slender ratio	常绿 Evergreen	25	0.620	-0.791 (-1.028, -0.608)	4.175
叶密度-小枝茎纤细率 Density of leaf number-stem slender ratio	落叶 Deciduous	60	0.617	-0.804 (-0.945, -0.684)	1.115
叶密度-小枝茎纤细率 Density of leaf number-stem slender ratio	常绿 Evergreen	25	0.781	-0.717 (-0.876, -0.587)	1.106
叶茎质量比-小枝茎纤细率 Leaf/stem mass ratio-stem slender ratio	落叶 Deciduous	60	0.629	-0.869 (-1.019, -0.741)	2.231
叶茎质量比-小枝茎纤细率 Leaf/stem mass ratio-stem slender ratio	常绿 Evergreen	25	0.823	-0.613 (-0.734, -0.512)	1.859
叶面积比-小枝茎长度 Leaf area ratio-stem length	落叶 Deciduous	60	0.628	-0.973 (-1.141, -0.829)	3.955
叶面积比-小枝茎长度 Leaf area ratio-stem length	常绿 Evergreen	25	0.683	-0.939 (-1.195, -0.738)	3.679
叶密度-小枝茎长度 Density of leaf number-stem length	落叶 Deciduous	60	0.741	-0.902 (-1.030, -0.789)	0.587
叶密度-小枝茎长度 Density of leaf number-stem length	常绿 Evergreen	25	0.787	-0.852 (-1.038, -0.699)	0.657
叶茎质量比-小枝茎长度 Leaf/stem mass ratio-stem length	落叶 Deciduous	60	0.614	-0.974 (-1.146, -0.828)	1.660
叶茎质量比-小枝茎长度 Leaf/stem mass ratio-stem length	常绿 Evergreen	25	0.852	-0.729 (-0.859, -0.618)	1.474
总叶面积-茎干质量 Total leaf area-stem dry mass	落叶 Deciduous	60	0.437	0.815 (0.670, 0.991)	0.504
总叶面积-茎干质量 Total leaf area-stem dry mass	常绿 Evergreen	25	0.439	0.722 (0.526, 0.992)	0.502

性状 Trait	常绿 Evergreen	落叶 Deciduous	显著水平 Significant value, p
茎纤细率 Stem slender ratio (cm·cm^-1)	41.80 ± 3.98	46.87 ± 2.80	0.318
茎直径 Stem diameter (cm)	0.18 ± 0.01	0.18 ± 0.01	0.887
茎长度 Stem length (cm)	6.77 ± 0.62	8.01 ± 0.50	0.158
茎干质量 Stem mass (mg)	112.03 ± 11.72	132.50 ± 13.22	0.352
总叶干质量 Total leaf mass (mg)	853.32 ± 74.69	840.87 ± 62.55	0.909
叶密度指数 Leaf density index (No.·cm^-1)	1.20 ± 0.20	0.76 ± 0.06	0.007
叶面积比 Leaf area ratio (cm²·g^-1)	1β081.71 ± 146.01	1β573.41 ± 130.10	0.030
单叶面积 Individual leaf area (cm²)	16.21 ± 1.97	34.66 ± 2.34	<0.001
总叶面积 Total leaf area (cm²)	95.19 ± 10.34	163.68 ± 11.69	0.001
比叶面积 Specific leaf area (cm²·g^-1)	114.31 ± 6.89	200.76 ± 4.42	<0.001
叶茎质量比 Leaf/stem mass ratio (mg·mg^-1)	9.14 ± 0.99	7.96 ± 0.66	0.335

性状 Trait	常绿 Evergreen	落叶 Deciduous	显著水平 Significant value, p
茎纤细率 Stem slender ratio (cm·cm^-1)	41.80 ± 3.98	46.87 ± 2.80	0.318
茎直径 Stem diameter (cm)	0.18 ± 0.01	0.18 ± 0.01	0.887
茎长度 Stem length (cm)	6.77 ± 0.62	8.01 ± 0.50	0.158
茎干质量 Stem mass (mg)	112.03 ± 11.72	132.50 ± 13.22	0.352
总叶干质量 Total leaf mass (mg)	853.32 ± 74.69	840.87 ± 62.55	0.909
叶密度指数 Leaf density index (No.·cm^-1)	1.20 ± 0.20	0.76 ± 0.06	0.007
叶面积比 Leaf area ratio (cm²·g^-1)	1β081.71 ± 146.01	1β573.41 ± 130.10	0.030
单叶面积 Individual leaf area (cm²)	16.21 ± 1.97	34.66 ± 2.34	<0.001
总叶面积 Total leaf area (cm²)	95.19 ± 10.34	163.68 ± 11.69	0.001
比叶面积 Specific leaf area (cm²·g^-1)	114.31 ± 6.89	200.76 ± 4.42	<0.001
叶茎质量比 Leaf/stem mass ratio (mg·mg^-1)	9.14 ± 0.99	7.96 ± 0.66	0.335