关键词: 云锦杜鹃, 水分胁迫, 光合生理特性, 光响应, 温度响应

Abstract: The effects of soilwater stress on some photosynthetic physiological characteristics in leaves of
Rhododendron fortunei and their response to light and temperature were investigated by using 5-year-old pot-cultured seedlings as experimentalmaterials and exposing them to different levels of water stress. Twelve pots
of p lant seedlingswith a similar growth were divided into 4 groups: no stress ( control) , light stress, moderate
stress and heavy stress. Net photosynthesis rate ( Pn) declined underwater stress conditions. According to the
criteria suggested by Farquhar and Sharkey, the dep ression of photosynthesismay be attributed to stomatal limitation under light water stress conditions, while thatmay be linked to non-stomatal limitation undermoderate
and heavy stress conditions. In comparison with the control group, light compensation point (LCP) and stomatal resistance ( r_s ) increased, light saturation point (LSP) , apparent quantum yield (AQY) , maximal Pn
( Pm) , Fv/Fm and transp iration rate ( Tr) in the other group s declined along the water stress gradients. Besides, the dark resp iration rate (Rd) increased under light and moderate stress, but decreased under heavy
stress. The intercellular CO₂ concentration (Ci) disp layed adverse trend compared with that of Rd. High temperature aggravated the stress effect of water on photosynthesis.

Key words: Rhododendron fortunei, Water stress, Photosynthetic physiological characteristics, Responseto light, Response to temperature