Abstract: To understand the effects of different UV-B radiation intensity on the physiological metabolism and its regulatory pathways of flue-cured tobacco, twodimensional gel electrophoresis and mass spectrum technique was adopted to study the physiological traits and protein expression profiles of Nicotina tobaccumL.cv. “K326”, a flue-tobacco cultivar commonly planted in Yunnan Province, under the covering of different transparent films to reduce UV-B radiation. Two treatments were installed, i.e., covering with polyethylene (treatment I, 75.8% UV-B radiation intensity) and Mylar (treatment II, 37.5% UV-B radiation intensity). In the two treatments, ten protein spots expressed significantly different. As compared in treatment I, five protein spots were upregulated while the other five were down-regulated in treatment II. Among the ten protein spots, three were redox-related, three were photosynthesisrelated, one was a kinase involved in energy metabolism, one was RNA-binding, and the other two were to be further identified. A preliminary research was also made on the effects of different UV-B radiation intensity on the physiological metabolism of “K326” at proteome level. During the physiological mature period, transition period, and process mature period of “K326”, the net photosynthetic rate (P_n) was significantly higher in treatment II than in treatment I, which was in accordance with the result mentioned above (three up-regulated proteins related with photosynthesis in treatment II). Comparatively, the “K326” in treatment I grew faster, and most of the morphological parameters such as stem girth and specific leaf mass were higher.

Key words: orchard, vegetation coverage, biological-control factor, soil erosion.