Leaf Structure in Relation to Solute Transport and Phloem Loading

拟议的研究涉及对发展和 选择的C3和C4植物的叶的结构，利用 明场、相位和电子显微镜。 的发展和 结构研究由实验研究补充， 决定：1）途径随后的光合同化物在未成熟 （库）和成熟（源）叶; 2）韧皮部卸载的网站， 库叶和源叶韧皮部负载的途径 随后水和溶质进入叶质外体， 不同发育阶段叶片的蒸腾流。 的 实验研究包括：旨在确定 叶片各细胞的溶质浓度; 显微放射自显影研究旨在确定 叶中的.1.4C.蔗糖和.1.4C.同化物; ATP酶定位 旨在确定活性韧皮部卸载位点的研究， 加载; free.space旨在确定途径的标记物研究 随后水和溶质进入叶质外体， 蒸腾流;和全叶放射自显影研究， 遵循汇-源转换和水运动的模式， 发育中的叶子 这些研究将使人们更好地了解 与库源有关的叶发育结构变化 叶的过渡，以及生产物质的方式 将叶片装入叶脉的导粮细胞中， 从工厂出口。

The proposed research involves studies on the development and structure of leaves of selected C3 and C4 plants, utilizing bright.field, phase and electron microscopy. The developmental and structural studies are complemented by experimental studies aimed at determining: 1) the pathways followed by photoassimilates in immature (sink) and mature (source) leaves; 2) the sites of phloem unloading in sink leaves and of phloem loading in source leaves; and 3) the pathways followed by water and solutes entering the leaf apoplast in the transpiration stream in leaves at different stages of development. The experimental studies include: plasmolytic studies aimed at determining the solute concentrations of various cells of the leaf; microautoradiographic studies aimed at determining pathways followed by .1.4C.sucrose and .1.4C.assimi lates in leaves; ATPase localization studies aimed at determining the sites of active phloem unloading or loading; free.space marker studies aimed at determining the pathways followed by water and solutes entering the leaf apoplast in the transpiration stream; and whole leaf autoradiographic studies aimed at following patterns of sink.to.source conversion and water movement in developing leaves. These studies will provide a greater understanding of the structural changes of leaf development related to sink.to.source transition in leaves, and of the way in which substances manufactured in the leaf are loaded into the food conducting cells of the leaf veins for export from the plant.