维管植物的运输

•H+ •H+
•– •– •H+ •–
•+
•+ •H+
•+
•H+
•H+
•細胞外液
•高濃度H+ •低濃度NO3-
•Cell accumulates •anions (•NO3– , for •example) by •coupling their transport to the inward diffusion
– Contribute to a voltage known as a membrane potential (膜電位), also a kind of potential energy
•細胞質•CYTOPLASM
•EXTRACELLULAR FLUID •細胞外液
•–
•+
•ATP
•–
•–
•+ •H+
•！？
•！？
•！？
•報告完畢 •敬請指教
•！？
•！？
维管植物的运输
Effects of Differences in Water Potential 水勢差的效應
• To survive plants must balance water uptake and loss
• Differences in water potential drive water transport in plant cells (水勢差驅動植物細胞中的 水份運輸)
•細胞質
•低濃度H+ •高濃度su•Sgar
•–
•H+ •–
•H+
•–
•+
•H+
•H+
•+
•+
•H+
•H+
•細胞外液
•Plant cells can •also accumulate a •neutral solute, •such as sucrose
•H+
•cotransporter •H–+
•H+ •( •S ), by •cotransporting
• Vascular tissue transports nutrients throughout a plant; such transport may occur over long distances (長途運輸)
•Figure 36.1
维管植物的运输
Key Concepts
• Concept 36.1: Physical forces drive the transport of materials in plants over a range of distances
• Concept 36.5: Organic nutrients are translocated through the phloem (韌皮部)
维管植物的运输
• Concept 36.1: Physical forces drive the transport of materials in plants over a range of distances
维管植物的运输
2020/12/13
维管植物的运输
• 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)
维管植物的运输
• 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)
••4 Through stomata, leaves
take in CO2 and expel O2.
•of •H+ through a
•cotransporter.
•共同運輸蛋白
•(b) Cotransport of anions (陰離子的共同運輸)
•Figure 36.4b
维管植物的运输
• The “coattail” effect of cotransport (共同運輸)
– Is also responsible for the uptake of the sugar sucrose (neutral solute) by plant cells
– To drive the transport of many different solutes
•細胞質•CYTOPLASM •–
•+
•EXTRACELLULAR FLUID •細胞外液
•K+ •K+
•K+ •K+
•K+
•–
•+
•–
•+
•K+
•transporter
•K+
•–
•+
•Cations ( •K+ , for •example) are driven into the cell by the membrane potential.
– A transport protein (cotransporter) couples the passage of one solute to the passage of another
•細胞質 •H+
•低濃度H+ •高濃度NO3-
•H+ •H+
•–
•+
•H+
•–
•+
•–
•+ •H+
•H+
•cotransporter
维管植物的运输
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
• Osmosis (滲透作用)
– Determines the net uptake or water loss by a cell
– Is affected by solute concentration and pressure
维管植物的运输
• Osmotic pressure (滲透壓) in animal cells
维管植物的运输
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)
• 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)
•Light
•(韌皮液)
••6 Sugars are transported as •phloem sap to roots and other •parts of the plant.
•O2 •CO2
•Figure 36.2
••7 Roots exchange gases •with the air spaces of soil, •taking in O2 and discharging •CO2. In cellular respiration, •O2 supports the breakdown •of sugars.
low osmotic pressure=low [solute]=high [water]
high osmotic pressure=high [solute]=low [water]
• Direction of moving water
low osmotic pressure=low [solute]=high [water]
– 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)
•(木質液)
•CO2
••1 Roots absorb water •and dissolved minerals •from the soil.
•H2O •Minerals
•O2 •Sugar
••5 Sugars are produced by •photosynthesis in the leaves.
• 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)
• 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)
•H+
•+ •H+
•Proton pump generates
•H+
•Proton pump
•H+
•membrane potential •and H+ gradient.
•H+ •Figure 36.3
•–
•+ •H+
•–
•H+ •+
维管植物的运输
• Plant cells use energy stored in the proton gradient (氫離子梯度) and membrane potential (膜電位), both of which are potential energy
•stomata), creates a force within
•leaves that pulls xylem sap
upward.
•(木質液)
•2• Water and minerals are •transported upward from •roots to shoots as xylem sap.
•高濃度H+
••H+ down the •低濃度sugar
•–
•+ •H+
•–
•+
•steep proton •gradient.
•H+
•S
•H+
•+ •–
•(c) Cotransport of a neutral solute (中性溶質的共同運輸)
•Figure 36.4c
维管植物的运输
•！？
The CO2 provides carbon for
•photosynthesis. Some O2
produced by photosynthesis is used in cellular respiration.
•H2O
•(蒸散作用)
•ຫໍສະໝຸດ Baidu •Transpiration, the loss of water •from leaves (mostly through
•–
•+ •Transport protein
•(transportor)
•(a) Membrane potential and cation uptake (陽離子的吸收)
•Figure 36.4a
维管植物的运输
• In the mechanism called cotransport (共同運輸)