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以八角金盘、夹竹桃、阔叶十大功劳、樟叶槭4种常绿植物为试材,测定人工模拟低温条件下离体叶片可溶性糖、可溶性蛋白、游离脯氨酸、过氧化物酶活性、叶绿素含量和相对电导率的变化,结合自然越冬过程中叶片叶绿素指数(SPAD)、叶表面特征及解剖组织结构的变化,综合评价这4种常绿树种的抗寒能力.结果表明:在人工低温胁迫过程中,4种常绿植物叶片叶绿素含量呈下降趋势,可溶性蛋白含量在-20℃出现高峰值,可溶性糖、游离脯氨酸、过氧化物酶活性和相对电导率整体呈上升趋势.八角金盘、夹竹桃、阔叶十大功劳和樟叶槭的低温半致死温度分别为-8.0、-13.4、-19.4和-14.8℃.自然越冬期间,4种植物叶片SPAD值变化幅度较大,显示出植物叶片中叶绿素相对含量变化对低温的适应性;同时,叶片厚度、角质层厚度、栅栏组织厚度和紧密度均有增加,并先后出现质壁分离,叶肉细胞中淀粉粒、草酸钙簇晶含量呈增高的趋势.夹竹桃叶片特有的气孔窝和窝内密被的非腺毛,阔叶十大功劳叶中的厚壁组织等在一定程度上提高了其抗寒性.叶片表面蜡质层破损、表皮毛断裂、栅栏组织形变、胞间空隙增大等现象的出现表明植物遭到了一定程度的低温伤害.
Four kinds of evergreen plants such as octagonal gold plate, oleander, broadleaf leaves and camphor leaf maple were used as materials to measure soluble sugar, soluble protein, free proline and peroxide in detached leaves under artificial simulated low temperature Enzyme activity, chlorophyll content and relative conductivity of the four evergreen species were analyzed in combination with changes of leaf chlorophyll index (SPAD), leaf surface characteristics and anatomical structure during the natural overwintering process.The results showed that: In the process of artificial low temperature stress, the chlorophyll content of four evergreen leaves showed a decreasing trend. The soluble protein content peaked at -20 ℃. The soluble sugar, free proline, peroxidase activity and relative electrical conductivity increased as a whole The semi-lethal temperatures at the low temperature were-8.0, -13.4, -19.4 and -14.8 ℃, respectively.The changes of SPAD value of four plant leaves during natural wintering period The amplitude of chlorophyll content in plant leaves showed low temperature adaptability. At the same time, leaf thickness, cuticle thickness, palisade tissue thickness and tightness increased, , The starch granules in mesophyll cells and the calcium oxalate cluster showed a tendency of increasing.Non-glandular foraminifera and intraparenchymal non-glandular trichomes in the leaves of Nerium indicum, And the cold resistance of the plants was increased.The emergence of the waxy layer on the surface of the leaves, the rupture of the epidermis, the deformation of the palisade and the increase of the intercellular space showed that the plants had some degree of hypothermia.