摘要:植物生物量分配特征的变化反映了不同环境条件下植物的适应策略，全球气候变暖正在改变青藏高原高寒生态系统植被动态和生物量分配格局。然而，到目前为止，有关青藏高原高寒灌丛生物量分配特征对气候变暖的响应研究较少。为了探究气候变暖对高寒灌丛生物量分配的影响，以青藏高原东部典型的窄叶鲜卑花高寒灌丛为研究对象，分析了高寒灌丛灌木层、草本层和群落水平生物量分配特征对开顶式生长室（OTC）模拟增温的响应。研究结果表明：整个生长季节，模拟增温使空气温度和表层土壤温度分别升高0.6℃和1.2℃，使表层土壤水分含量下降2.7%。模拟增温使草本层和群落地上生物量显著增加57.8%和7.2%，使灌木层、草本层和群落根系生物量显著增加42.5%、105.6%和45.6%。然而，模拟增温没有显著影响灌木层地上生物量。同时，模拟增温使灌木层、草本层和群落总生物量显著增加25.6%、85.7%和28.4%，使灌木层、草本层和群落根冠比显著增加33.2%、30.4%和36.0%。由此可见，模拟增温在促进高寒灌丛生物量生产的同时将显著提高向地下根系部分的分配比例。Pearson相关分析表明，高寒灌丛生物量分配与空气温度、土壤温度和土壤硝态氮含量呈显著正相关关系；多元线性回归分析结果也表明，空气温度、土壤温度和土壤硝态氮含量解释了高寒灌丛生物量分配变异的50.8%以上。这些结果表明，青藏高原东部高寒灌丛植被能够通过调节生物量分配模式应对未来气候变暖。



Abstract:The changes of plant biomass allocation patterns reflect the adaptation strategies of plants under different environmental conditions. Under the future climate warming, plant production and biomass allocation will change significantly in the alpine ecosystems of the Qinghai-Tibet Plateau. However, up to date, little information has been available on the plant biomass allocation and its responses to climate warming in the alpine scrubland on the eastern Qinghai-Tibet Plateau. In order to investigate the effects of climate warming on plant biomass allocation patterns of the alpine scrubland, open top chambers (OTC) were employed to simulate warming in this study. We examined the effects of the simulated warming on the plant biomass allocation patterns of shrub, herbaceous layer and community level of the typical Sibiraea angustata alpine scrubland on the eastern Qinghai-Tibet Plateau. The results showed that the simulated warming increased the air temperature and soil surface temperature by 0.6 ℃ and 1.2 ℃, respectively, but decreased soil surface water contents by 2.7% throughout the whole growing season. Simulated warming significantly increased the aboveground biomass of herbaceous layer and community level by 57.8% and 7.2%, respectively, as well as significantly increased the root biomass of shrub, herbaceous layer and community level by 42.5%, 105.6% and 45.6%, respectively. However, the simulated warming did not significantly affect the aboveground biomass of shrub layer. Simultaneously, the simulated warming not only significantly increased the total biomass of shrub, herbaceous layer and community level by 25.6%, 85.7% and 28.4%, respectively, but also significantly increased the root:shoot ratios of those by 33.2%, 30.4% and 36.0%, respectively. The results implied that the simulated warming promoted plant biomass production, and also significantly increased the proportion of plant biomass allocation to belowground roots in these alpine scrub ecosystems. Moreover, Pearson correlation analysis revealed that plant biomass allocation of alpine scrubland was significantly and positively correlated with air temperatures, soil temperatures and soil nitrite nitrogen contents. Multiple linear regression analysis also showed that air temperatures, soil temperatures, and soil nitrate nitrogen contents explained more than 50.8% of the variation of plant biomass allocation in the alpine scrubland. The results indicated that plants in these alpine scrubland could adapt to future climate warming by modulating their biomass allocation patterns on the eastern Qinghai-Tibet Plateau.





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