海滨木槿耐盐机理的研究-园林植物与观赏园艺专业论文.docxVIP

II II 分别有贮藏细胞，内含大量单宁酸，在表皮中和栅栏组织中有表皮异细 胞存在；在叶片多个部位存在结晶体；在盐胁迫下，海滨木槿栅栏组织 厚度增加，叶片变得更紧密。另外在表皮上还发现有表皮非腺毛和盐腺 的存在，以利排出盐离子。 关键词：盐胁迫，海滨木槿， 生理特性，离子含量，显微结构 PAGE PAGE IV Study on the mechanisms of salt tolerance in Hibiscus hamabo Abstract Hibiscus hamabo, a deciduous shrub or small tree of Malvaceae, mainly distributes at the seawall of islands, and has high salt tolerance and can be used as a garden plant. In this thesis, the salt tolerance of H. hamabo was investigated, from physiological response, ions distribution and anatomy structure of leaves, using sand-cultured 3-year old seedlings treated with 1/2 Hoagland solution containing 0 mmol.L-1, 50 mmol.L-1, 100 mmol.L-1, 200 mmol.L-1 and 400 mmol.L-1 NaCl. Treated for 20 days, Hibiscus syriacus was seriously injured under 200mmol.L-1 NaCl, and almost dying under 400mmol.L-1 NaCl. While, H. hamabo kept growing under salt stress for more than two month, which demonstrated that H. hamabo had high salt tolerance. Under salt stress, the relative electrical conductivity of the two trees increased with NaCl concentration rising. But the relative electrical conductivity of H. hamabo was lower than that of H. syriacus, which indicated that the membrane of H. hamabo could keep intact under salt stress. Although, growth of H. hamabo was obviously inhibited by salt stress compared with the control, the chlorophyll content and soluble protein content had an increase trend with NaCl concentration rising. Furthermore, Fv/Fm of H. hamabo leaves was not impacted by salt stress. These results showed that H. hamabo leaves could keep its normal function under salt stress. Na+ content of H. hamabo leaves increased dramatically with NaCl concentration increasing and salt stress elongating, while K+ content decreased obviously. At the same time, Mg2+ and Ca2+ content had an increase trend under salt stress, which demonstrated that H. hamabo could selectively absorb benefit elements and accumulate in leaves. It was found that Na+ content in leav