Abstract:

To explore the effects of air temperature rise(ATR)on photosynthesis and growth in the native xeric tree species,Salix matsudana in semi-arid Mu Us sandland,the temperature gradient was set up through using small solar dome to increase air temperature.ATR had no significant effects on initial fluorescence,maximum quantum yield,and the ratio of maximum fluorescence to initial fluorescence of the leaves of this species,but had significant influence on their variable fluorescence,photosynthesis rate,transpiration rate,water use efficiency,and the ratio of substomatal CO₂ to atmospheric CO₂.ATR affected plant biomass,plant height,leaf weight ratio,root weight ratio,specific leaf area,and leaf area ratio significantly,while had no significant effects on specific root length.Moderate ATR may be beneficial to accelerate the species' growth during growing season.

Key words: Salix matsudana, Air temperature rise(ATR), Fluorescence feature, Gas exchange, Growth and allocation, Morphology