Abstract: The grassland ecosystem accounts for 50.9% of the Qinghai-Tibet Plateau,which is a sensitive area of climate change and an ecologically fragile zone. It is an ideal place to study the response mechanism of grassland ecosystems to climate change. The sexual reproduction stage of plants is very sensitive to the small variation in environmental conditions. The response mechanism of alpine plant growth and reproduction strategies to global warming is still unrevealed. In order to explore reproduction strategies of alpine plants to adapt to global warming and guide the prediction of the trend of alpine vegetation communities,in this study,a simulated warming experiment was set up using the Open-Top Chambers (OTCs)-type device to explore the effect of warming on the sexual reproduction characteristics of apline representative plants:Kobresia humilis, Carex moorcroftii, and Elymus nutans. The results showed that:1) The numbers of reproductive shoots and the reproductive efficiency of Kobresia humilis significantly decreased (P<0.01);The effective spikelets length of Carex moorcroftii increased significantly (P<0.05),and the length of Elymus nutans spikelets increased significantly under the warming (P<0.01). 2) Simulated warming caused a significant decrease in seed production capacity of Kobresia humilis (P<0.01)and Elymus nutans (P<0.05),and there was no significant difference in seed yield of Carex moorcroftii (P>0.05). 3) The germination potential of three plants significantly decreased under the increase of temperature (P<0.05),but the germination rate did not change significantly (P>0.05). 4) According to the heatmap analysis,under the influence of temperature increase,each index of Kobresia humilis had highly negative responses to the warming effect. It is expected that the grassland with Kobresia humilis as the dominant vegetation would have the highest inhibitory degree of sexual reproduction under the effect of warming. In summary,under the climate warming,different plants showed different adaptation strategies. The sexual reproduction of Kobresia humilis was inhibited,and the response to warming was the most sensitive.

Key words: Alpine meadow, Long-term warming, Alpine plants, Sexual reproduction characteristics

摘要： 近年来，全球气候变化影响植物群落已经成为研究热点，植物有性繁殖对环境条件微小变化的响应十分敏感。为探究高寒植物采取何种生长繁殖策略以适应全球气候变暖，从而预测高寒植被群落变化趋势，本研究利用开顶式生长室（Open-Top Chambers，OTCs）装置模拟增温，探究增温对高寒植物中常见的矮生嵩草（Kobresia humilis）、青藏苔草（Carex moorcroftii），和垂穗披碱草（Elymus nutans）有性繁殖特征的影响。结果表明：1）增温下矮嵩草繁殖枝数量、有性繁殖效力极显著降低（P<0.01），青藏苔草小穗长度显著增加（P<0.05），垂穗披碱草小穗长度在增温下极显著增加（P<0.01）；2）增温导致矮嵩草和垂穗披碱草种子生产能力显著降低（P<0.05），青藏苔草种子产量变化不明显（P<0.05）；3）3种植物发芽势在增温下呈现显著降低的趋势（P<0.05），但发芽率无显著变化（P<0.05）；4）经热图（heatmap）分析，高寒植物有性繁殖对增温响应不一致，且增温严重抑制矮嵩草有性繁殖。综上，在气候变暖下，不同植物可能表现出不同的适应策略，矮嵩草有性繁殖受到增温的抑制，且最为敏感。

关键词: 高寒草甸, 长期增温, 高寒植物, 有性繁殖