title: Responses in the morphology, physiology and biochemistry of Taxus chinensis var. mairei grown under supplementary UV-B radiation.
abstract: The effects of supplemental UV-B radiation on Taxus chinensis var. mairei were studied. Leaf traits, gas exchange parameters and the concentrations of photosynthetic pigments, cellular defense system products, secondary metabolites and ultrastructure were determined. UV-B radiation significantly decreased leaf area (p<0.05). Leaf number, secondary branch number, leaf weight per plant and leaf moisture all increased dramatically (p<0.05). Neither the leaf weight nor the specific leaf weight (SLW) exhibited significant differences between ambient and enhanced UV-B radiation. Gas exchange parameters were all dramatically reduced by enhanced UV-B radiation (p<0.05). The contents of chlorophyll and the chlorophyll a/b ratio were not distinctly affected by UV-B radiation, while carotenoids content significantly decreased (p<0.05). Supplemental UV-B treatment induced significant flavonoid accumulation (p<0.05), which was able to protect plant from radiation damage. Meanwhile, the appendage content, abaxial stomatal density, papilla density and particulate matter content in substomatic chambers increased noticeably by supplemental UV-B radiation, whereas the aperture size of single stomata was diminished. The number and area of plastoglobuli were apparently reduced by UV-B radiation, but stroma and grana lamellae were not destroyed. Our results demonstrated that T. chinensis var. mairei can activate several defense mechanisms against oxidative stress injury caused by supplemental UV-B radiation.
authors.affiliation: Key Laboratory of Forest Plant Ecology, Ministry of Education, Northeast Forestry University, Harbin 150040, China. zygorl@vip.hl.cn
authors.forename: Yuan-gang
authors.initials: YG
authors.lastname: Zu
authors.forename: Hai-He
authors.initials: HH
authors.lastname: Pang
authors.forename: Jing-Hua
authors.initials: JH
authors.lastname: Yu
authors.forename: De-Wen
authors.initials: DW
authors.lastname: Li
authors.forename: Xiao-Xue
authors.initials: XX
authors.lastname: Wei
authors.forename: Yin-Xiang
authors.initials: YX
authors.lastname: Gao
authors.forename: Lu
authors.initials: L
authors.lastname: Tong
mesh_terms: D060387:Ascorbate Peroxidases; D002374:Catalase / Q000378:metabolism; D005419:Flavonoids / Q000032:analysis; D017239:Paclitaxel / Q000032:analysis; D010544:Peroxidases / Q000378:metabolism; D018515:Plant Leaves / Q000737:chemistry / Q000528:radiation effects / Q000648:ultrastructure; D018526:Plant Transpiration; D013482:Superoxide Dismutase / Q000378:metabolism; D020946:Taxus / Q000737:chemistry / Q000201:enzymology / Q000528:radiation effects*; D014466:Ultraviolet Rays
chemical_list: D005419:Flavonoids; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D017239:Paclitaxel