皖南亚热带常绿阔叶林林下灌木层主要树种叶片养分特征

对皖南亚热带常绿阔叶林林下灌木层主要树种草珊瑚〔Sarcandra glabra(Thunb.)Nakai〕、乌药〔Lindera aggregata(Sims)Kosterm.〕、香桂(Cinnamomum subavenium Miq.)、红楠(Machilus thunbergii Sieb.et Zucc.)、连蕊茶〔Camellia cuspidata(Kochs)H.J.Veitch〕、甜槠〔Castanopsis eyrei(Champ.ex Benth.)Tutch.〕、矩叶鼠刺(Itea oblonga Hand.-Mazz.)、红淡比(Cleyera japonica Thunb.)和小叶蚊母树〔Distylium buxifolium(Hance)Merr.〕叶片养分(包括C、N、P、K、Ca和Mg)含量、单位叶面积养分含量和比叶面积进行了测定,并分析了比叶面积与养分含量和单位叶面积养分含量的相关性。结果表明:9种树种叶片的C、N、P、K、Ca和Mg含量分别为438.09~492.31、9.79~15.60、0.33~2.06、11.39~32.52、3.84~13.34和2.85~14.05 g·kg-1,单位叶面积C、N、P、K、Ca和Mg含量分别为24.48~47.38、0.66~1.03、0.02~0.21、0.73~1.82、0.22~1.35和0.20~1.05 g·m-2,C/N比、C/P比和N/P比分别为31.40~47.88、227.76~1 495.66和5.26~32.90。9种树种叶片的比叶面积平均值为14.5 m2·kg-1,其中草珊瑚的比叶面积最大(17.90 m2·kg-1)、小叶蚊母树的比叶面积最小(9.89 m2·kg-1)。相关性分析结果表明:供试树种叶片的C/P比与N/P比间呈极显著正相关;比叶面积与叶片N含量呈显著正相关,与单位叶面积C、N和Ca含量分别呈极显著和显著负相关,与其他指标的相关性均不显著。综合分析结果表明:皖南亚热带常绿阔叶林下灌木层主要树种叶片的养分含量及比叶面积差异明显,其中,乌药、草珊瑚、矩叶鼠刺和香桂叶片的养分含量较高,而小叶蚊母树、红淡比和红楠的单位叶面积养分含量较高。

Foliar nutrient characteristics of main tree species in shrub layer under subtropical evergreen broad-leaved forest in Southern Anhui

Nutrient （ including C, N, P, K, Ca and Mg） content in leaf, nutrient content per unit leaf area and specific leaf area （ SLA ） of main tree species Sarcandra glabra （ Thunb.） Nakai, Lindera aggregata （ Sims ） Kosterm., Cinnamomum subavenium Miq., Machilus thunbergii Sieb. et Zucc., Camellia cuspidata （ Kochs） H. J. Veitch, Castanopsis eyrei （ Champ. ex Benth.） Tutch., Itea oblonga Hand.-Mazz., Cleyera japonica Thunb. and Distylium buxifolium （ Hance） Merr. in shrub layer under subtropical evergreen broad-leaved forest in Southern Anhui were determined, and correlations of SLA with nutrient content and nutrient content per unit leaf area were analyzed. The results show that contents of C, N, P, K, Ca and Mg in leaf of nine tree species are 438. 09-492. 31, 9. 79-15. 60, 0. 33-2. 06, 11. 39-32. 52, 3. 84-13. 34 and 2. 85-14. 05 g·kg^-1 , respectively; contents of C, N, P, K, Ca and Mg per unit leaf area are 24 . 48-47 . 38 , 0 . 66-1 . 03 , 0 . 02-0 . 21 , 0 . 73-1 . 82 , 0 . 22-1 . 35 and 0 . 20-1. 05 g·m-2 , respectively;and ratios of C/N, C/P and N/P are 31. 40-47. 88, 227. 76-1 495. 66 and 5. 26-32. 90, respectively. Average SLA of nine tree species is 14. 5 m2 ·kg^-1, in which, SLA of Sarcandra glabra is the largest （17. 90 m2·kg^-1）, that of Distylium buxifolium is the smallest （9. 89 m2 ·kg^-1 ）. Correlation analysis result shows that there is extremely significantly positive correlation between C/ P ratio and N/ P ratio of leaf of tree species tested, significantly positive correlation between SLA and N content in leaf, and extremely significantly or significantly negative correlations of SLA with C, N and Ca contents per unit leaf area, respectively, while, correlations between SLA and other indexes are not significant. Comprehensive analysis result indicates that there are obvious differences in foliar nutrient content and SLA of main tree species in shrub layer under subtropical evergreen broad-leaved forest in Southern Anhui, in which, nutrient content in leaf of Lindera aggregate, Sarcandra glabra, Itea oblonga and Cinnamomum subavenium are higher, while nutrient content per unit leaf area in leaf of Distylium buxifolium, Cleyera japonica and Machilus thunbergii are higher.