【摘要】 对长汀水土流失区不同生态恢复程度生境马尾松(Pinus massoniana)与木荷(Schima superba)的叶片稳定碳同位素组成(δ13C)、比叶面积(specific leaf area,SLA)、叶N含量及C/N进行了分析,并以叶片δ13C值和C/N分别指示植物的水分利用效率(water use efficiency,WUE)和氮素利用效率(nitrogen use efficiency,NUE).研究发现:1)随着生境恢复程度的提高,马尾松与木荷的δ13C值均呈下降趋势,其中木荷对环境的响应比马尾松敏感.2)同一生境,马尾松的δ13C值高于木荷,植被恢复程度较高的生境两者差异更明显,δ13C值变幅为2.20‰.3)相同生境,马尾松的NUE高于木荷,SLA和叶N含量低于木荷,恢复程度较高的生境差异显著(P<0.05).4)树种间的NUE与WUE不存在权衡,SLA和叶N含量的变化趋势与WUE相反.研究结果表明:马尾松与木荷WUE对资源梯度变化的响应趋势相似,木荷的可塑性较强;在干旱贫瘠生境中,马尾松比木荷具有更保守的水分利用方式和氮素消费方式,适应能力更强,能起先锋树种作用,随着生态恢复程度的提高,木荷具有更强的资源竞争能力和生态适应性.更多还原

【Abstract】 Stable carbon isotope composition(δ13C),specific leaf area(SLA),nitrogen concentrations and C/N ratios of Pinus massoniana and Schima superba under habitats with different ecological restoration degree in the soil erosion area of Changting County were measured.The foliar δ13C values were used to denote the long-term water use efficiency(WUE)of plants whereas long-term nitrogen use efficiency(NUE)was estimated by the ratio of C to N. The results indicated that:1)The δ13C values of both two species tended to decrease with increasing restoration degree,with S.superba having a bigger decrease.2)For the same habitat,the δ13C value of P.massoniana was higher than that of S.superba,and the gap could increase to 2.2 ‰ with higher restoration degree.3)P.massoniana had higher NUE and lower SLA and nitrogen concentrations compared with S.superba,significantly in the higher restoration degree habitat(P<0.05).4)There was no trade-off between WUE and NUE for P.massoniana and S.superba,between which the change trends of SLA and nitrogen concentrations were opposite to WUE.From these results,we concluded that:1)P.massoniana and S.superba had similar response to the change of resource gradients,with S.superba showing more plasticity.2)P.massoniana could enhance WUE and NUE in response to water and nitrogen deficit respectively,which showed that the pioneer tree could succeed in dry and poor lands,whereas S.superba had a rapider growth increasing its competitive ability under the higher restoration degree habitat.更多还原