Effects Of Simulated Warming On Photosynthetic Characteristics Of Dominant Species Under The Background Of Deyeuxia Angustifolia Invading Changbai Mountain Tundra

In this paper,the research object is the invasive plant Deyeuxia angustifolia on the west slope of the Changbai Mountain and the native plant Rhododendron aureum.Using an open-top temperature-increasing chamber(OTC),a three-year uninterrupted field simulated temperature increase experiment was conducted to study the effect of simulated temperature increase on the photosynthetic characteristics of dominant species under the background of Deyeuxia angustifolia invading Changbai Mountain tundra,and the following conclusions were obtained:(1)Simulated temperature increase leads to increase in soil temperature and humidity,and herb invasion leads to decrease in soil humidity,but for soil temperature,mild herb invasion can increase it.Moreover,there is a difference in the changing trend of temperature and humidity between the growing season and the non-growing season.(2)Simulated temperature increase significantly increased the photosynthetic rate,leaf length,chlorophyll and height of Rhododendron aureum and Deyeuxia angustifolia,and did not directly lead to the invasion of Deyeuxia angustifolia in the dominant position in terms of photosynthetic rate and leaf traits.(3)The Deyeuxia angustifolia of the invasive plant in the herbaceous invasive community has obvious advantages in photosynthetic rate and leaf traits.Herbal invasion significantly increased the net photosynthetic rate,height,coverage and number of plants of Deyeuxia angustifolia.but had no significant effect on the net photosynthetic rate of Rhododendron aureum,but significantly reduced its leaf thickness,chlorophyll,height,cover and number of plants.(4)The superposition of simulated warming and herb invasion will accelerate the settlement,distribution and expansion of invasive plant Deyeuxia angustifolia.The interaction of these two factors significantly improved the net photosynthesis of Deyeuxia angustifolia,and significantly reduced the photosynthetic rate of Rhododendron aureum.The effects on the leaf area,chlorophyll and leaf thickness,and the number of plants of the two plants reached a significant level.In summary,global warming is unstoppable.It may bring about changes in the ecological environment,and plants may have a series of responses to it.But despite this,global warming will not directly cause alien species invasion,but once there is already alocal invasion,global warming will make the invasive alien species quickly expand in the local area or be in a dominant position to strengthen the invasion effect.