萌发中食松幼苗贮藏物质的利用和变化

采用电镜技术观察了黑暗中萌发中食松子叶和提供营养的雌配子体中脂肪体和与脂肪利用有关的乙醛酸循环体的变化,测量比较了子叶、下胚轴、根的长度、干重、淀粉含量,以及果糖1,6二磷酸酶的活性变化,对贮藏物质脂类、淀粉的利用及与生长的关系进行了分析.雌配子体中脂肪的利用快于子叶,淀粉作为临时贮藏物质在子叶和下胚轴中大量积累,根中极少,淀粉/干重比表明,子叶中淀粉比重大于下胚轴,这个由上向下的顺序变化与雌配子体由下向上,最后在子叶尖端脱离幼苗的变化暗示了贮藏物质通过接触从雌配子体传递到幼苗.在子叶中细胞质和质体果糖1,6二磷酸酶的活性都明显高于下胚轴,根和未萌发胚中细胞质和质体果糖1,6二磷酸酶的活性极低,表明子叶和下胚轴进行活跃的蔗糖和淀粉合成活动.

Usage and Changes of Storage Material in Post-Germinating Pinus edulis Engelm. Seedlings

Efficient usage of the main storage material in megagametophyte before it falls off from seedling is important for seed germination of Pinus edulis Engelm.(pinyon).We examined and compared lipid usage in both megagametophyte and cotyledon with electromicroscopic technique,the length,dry weight,starch content and FBPase activities of each part of the seedling were measured and compared.FBPase activities in both cytosol and plastid are much higher in cotyledon than in hypocotyls.However,the slightly higher ratio of starch to dry weight in hypocotyls than that in cotyledon indicates that in cotyledon more types of synthetic activities happened.The results show that lipid in megagametophyte is preferentially used during germination than lipid from embryo or seedlings and starch accumulation in cotyledon and hypocotyl functioned as temperate storage material.