figure 365d water potential (水势).ppt

(3) Chapter 36 Transport in Vascular Plants 維管植物的運輸 Overview: Pathways for Survival of vascular plant (維管植物存活途徑) For vascular plants, the evolutionary journey (演化之旅) onto land involved the differentiation of the plant body into roots and shoots (植物體分化為根與枝條) Vascular tissue transports nutrients throughout a plant; such transport may occur over long distances (長途運輸) Key Concepts Concept 36.1: Physical forces drive the transport of materials in plants over a range of distances Concept 36.2: Roots absorb water and minerals from the soil Concept 36.3: Water and minerals ascend from roots to shoots through xylem (木質部) Concept 36.4: Stomata help regulate the rate of transpiration (蒸散作用) Concept 36.5: Organic nutrients are translocated through the phloem (韌皮部) Concept 36.1: Physical forces drive the transport of materials in plants over a range of distances Transport in vascular plants occurs on three scales (三種尺度/三種層次) Transport of water and solutes by individual cells, such as root hairs (個別細胞水與溶質的運輸) Short-distance transport of substances from cell to cell at the levels of tissues and organs (組織與器官內細胞間物質的短距離運輸) Long-distance transport within xylem and phloem at the level of the whole plant (整株植物木質部與韌皮部的長距離運輸) A variety of physical processes (物理過程) are involved in the different types of transport (眾 多物理過程介入或參與不同型式的運輸) Selective Permeability of Membranes: A Review膜的選擇通透性----各種膜系統 The selective permeability (選擇通透性) of a plant cell’s plasma membrane (細胞膜) Controls the movement of solutes into and out of the cell Specific transport proteins/transportor (專一性輸送蛋白) Enable plant cells to maintain an internal environment different from their surroundings Solutes in cell: cation (陽離子), anion (陰離子), neutral solute (中性溶質) The Central Role of Proton Pumps (質子唧筒) Proton pumps (質子唧筒) in plant cells Create a hydrogen ion gradient (氫離子梯度) that is a form of potential energy (潛能) that can be harnessed (=used) to do work (作功) Contribute to a voltage known as a membrane potential (膜電位), a