摘要
墨兰（Cymbidium sinense（Andr.）Willd.）叶片外有较厚的角质和蜡质。气孔分布于叶背面,密度为100—130mm-2,气孔上覆有气孔盖。叶肉没有海绵组织与栅栏组织的分化,维管束鞘细胞中无叶绿体。叶片叶绿体基粒较发达,有较多的亲锇颗粒。功能叶最高量子产率为0.082左右。光合作用光补偿点约为5μE·m-1·s-1,光饱和点大约为200 μE·m-2·s-1。墨兰的光合速率很低,一般在2.0—2.6.μmol CO2·m-2·s-1,一年生叶片光合作用最适温度大约在25℃,而3年生叶片光合速率随温度的上升而下降。叶片叶绿素a/b值基本稳定在2.7左右。墨兰CO2补偿点在105—220ppm之间。实验结果说明、墨兰属于低光合速率,高CO2补偿点的典型阴生植物。所以,墨兰生长极其缓慢。
The leaf surface of Cymbidium sinense(Andr.) Willd was covered with cuticle and wax. The stomata were distributed in the dorsum of the leaf,the density being 100-130 mm^(-2). There was a stomatal cover on each stoma.The mesophyll was not differentiated into spongy tissue and palisade tissue.No chloroplast was observed in the vascular bundle sheath cells.The chloroplast in the mesophyll cells had well developed grana,with lightly stacked thylakoids and osmiophilic granules.The highest quantum yield of functional leaf was 0.082.The light compensation point of photosynthesis was about 5 μE·m^(-2)·s^(-2),the light saturation point was about 200 μE·m^(-2)·s^(-1).The photosynthetic rate of Cymbtdium sinense was very low,generally 2.0-2.6 μmol CO_2·m^(-2)·^(-1).The optimum temperature of photosynthesis of one-year-old leaf was 25℃.The photosynthetic rate of the three-year-old leaf declined with temperature rise. The ratio of chlorophyll a/b was abom 2.7.The CO_2 compensation point of photosynthesis was 105-220 ppm.All these data show that Cymbidium sinense belongs to the typical shade plants with low photosynthetic rate and high CO_2 compensation point that explains that the growth of Cymbtdium sinense is slow in nature.
关键词
墨兰
光合速率
叶片结构
光合作用
Cymbidium sinense(Andr.) Willd
Phorosynthetic rate, stama
Light compensation point
Light
saturation point
CO_2 compensation point
