| Climate change alone, and in combination with other global environmental changes, will inevitably have considerable impact on existing ecosystems. Many recent papers have emphasized the unfortunate impacts of global climate change on plant migration. Global warming has been predicted to occur most rapidly at high altitude. In montane environment, climate and vegetation can change dramatically in short distances along an altitudinal gradient. Altitude is one of the most important factors determining microsite conditions that affect plant physiology and growth. Consequently, the physiological and ecological traits of subalpine and alpine plants are highly correlated with elevation along altitudinal gradients.Dwarf bamboo as a common kind of understory sympodial vegetation in mountain regions, which is distributed widely over underwood in forests and become the single dominant plant species, together with the dominant tree species:arbores (e.g. fir tree and pine tree) who have the trait of secondary growth form the alpine/subalpine plant ecological community. Many studies investigated the secondary growth and physiological responses of trees to altitude. However, the eco-physiological responses of plants without secondary growth (e.g. bamboos) to elevation have not been reported.This research studied dwarf bamboo in subalpine forest in Wolong Nature Reserve ecotone on western Sichuan. Select two species:Fargesia angustissima and Fargesia nitida, the major types of the dwarf bamboos, we chose samples from Dayingou, Gengda to Zhenghegou and Sichuan Wolong subalpine dark coniferous forest ecosystem located station (102°58'21"E,30°51'41"N, altitude 2750～2760 m) to Beimuping Balang mountain, which distributed from 1200 to 1810m and 2480 to 3170m respectively. Investigated some physiological indexes, include SLA, N, NSC, and trace element, by using the theory and methods about plant bionomy, physiology and biochemistry. Study the altitudinal changes in physiological indexes of treeline trees at different environment and different season and intent to understand the relationship between such difference and subalpine change, and how global warming affects eco-physiological characteristics of dwarf bamboos.The main results of the study are as follows:1. By researching the morphological traits, the SLA of F. angustissima with increasing elevation tend to not linear both in April and October as well as F. nitida in April while F. nitida tend to decline in October. With increasing altitudes of F. angustissima show a "high-low-high" trend as well as F. nitida in April, the difference is the minimum not in the same elevation. Besides, the discrepancy in elevations of F. nitida is higher than that of F. angustissima.2. Leaf NSC content and Narea in F. angustissima did not respond to altitude, whereas all other parameters studied changed non-linearly with increasing elevation. Leaf N-mass and NSC-mass of F. angustissima with increasing elevation showed a concave curve with a turning point at～1620 m a.s.l.3. Changes in tissue NSC concentrations of F. nitida with increasing elevation showed a "low-high-low-high" trend in April, but they were a convex curve in October, peaked at～2800 m a.s.l.4. Differences in responses of growth and ecophysiology of F. angustissim and F. nitida to altitude reflected the differences in their biological adaptation to environmental conditions, and their growth and survival strategy in a changing global climate.5. This result may reflect both the species-specific ecophysiology and the species-specific sensitivity to temperature. The high-altitude species (F. nitida) may be more sensitive to global warming than the low-altitude species (F. angustissima).
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