Sex-related differences in leaf morphological and physiological responses in Hippophae rhamnoides along an altitudinal gradient
Sex-related differences in leaf morphological and physiological responses in Hippophae rhamnoides along an altitudinal gradient
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DOI：
10.1093/treephys/27.3.399
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发表时间：
2007-03-01
期刊：
影响因子：
4
通讯作者：
Berninger, Frank
中科院分区：
文献类型：
--
作者：
Li, Chunyang;Xu, Gang;Berninger, Frank
在大多数木本植物中，叶片的形态和生理特征在不同的环境梯度中变化很大，特别是在不同的海拔梯度上。沙棘（Hippophae rhamnoides L.）是一种雄雄异株落叶灌木，在卧龙自然保护区分布广泛。沿海拔梯度测定了沙棘雌雄个体的生长、性别比和叶片的形态生理特征。在海拔梯度上，雄性的茎高（FIT）、单位干质量叶片氮浓度（N…）和叶片碳同位素组成（δ C-13）均高于雌性，而雌性的比叶面积（SLA）、气孔长度（SL）和气孔指数（SI）（即单位叶面积总气孔长度）均高于雄性。除2800 m外，各海拔高度雌花的气孔密度（SD）均较高。除2800 m海拔高度外，其他海拔高度的男女比（MFR）均倾向于男性。FIT、MFR、SLA、SD、SL、SI、n -质量、n -面积和δ C-13沿海拔梯度呈非线性变化。2800 m以下，FIT、SLA、SD、SL和SI随海拔升高而升高，2800 m以上随海拔升高而降低。MFR、Nmass、Narea和δ C-13随海拔高度呈相反的变化规律。因此，我们证实了我们的假设：(1)压力环境在各种方面对女性的负面影响大于男性；(2)在最优生长条件下，性别比是均匀的，但随着资源的限制，性别比开始向男性倾斜；(3)卧龙自然保护区沙棘生长的最佳海拔范围在2800 m左右。
In most woody plants, leaf morphological and physiological characteristics are extremely variable across environmental gradients, particularly across altitudinal gradients. Hippophae rhamnoides L., a dioecious and deciduous shrub species, occupies a wide range of habitats in the Wolong Nature Reserve, southwest China. We measured growth, sex ratio and morphological and physiological characteristics of leaves in male and female H. rhamnoides individuals along an altitudinal gradient. Shoot height (FIT), leaf N concentration per unit dry mass leaf N concentration per unit area (N,,,) and leaf carbon isotope composition (delta C-13) were higher in males than in females, whereas females had higher specific leaf area (SLA), stomatal length (SL) and stomatal index (SI) (i.e., total stomatal length per unit leaf area) than males along the altitudinal gradient. Females also had higher values of stomatal density (SD) at all altitudes except 2800 m. The male:female ratio (MFR) was biased toward males at all altitudes except at 2800 m. Changes in FIT, MFR, SLA, SD, SL, SI, N-mass, N-area and delta C-13 along the altitudinal gradient were nonlinear. Below 2800 m, FIT, SLA, SD, SL and SI increased with increasing altitude, but above 2800 m they decreased with increasing altitude. In contrast, MFR, Nmass, Narea and delta C-13 Show- ed the opposite patterns with altitude. Consequently, we confirmed our hypotheses: (1) stressful environments have a more negative impact on females than on males in a variety of ways; (2) under optimal growth conditions the sex ratio is even, but becomes male-biased as resources become limited; and (3) there is an optimum altitudinal range at around 2800 m for the growth of H. rhamnoides in the Wolong Nature Reserve.