Part 2 Long-Distance Transport o 2.1 Overview of diffusive and convective transport in plants o 2. 1. 1 Diffusion and convection are the basis for solute transport o Diffusion: An independent movement of molecules driven by a concentration gradient Convective transport: Bulk flow of solution driven by a pressure gradient
Part 2 Long-Distance Transport ⚫ 2.1 Overview of diffusive and convective transport in plants ⚫ 2.1.1 Diffusion and convection are the basis for solute transport. ⚫ Diffusion: An independent movement of molecules driven by a concentration gradient. ⚫ Convective transport: Bulk flow of solution driven by a pressure gradient
2.1.2 Water and solutes can move from cell to cell along either of two parallel aqueous pathways Cytosol Plasmodesmata Vacuole Cell wall Intercellular space
2.1.2 Water and solutes can move from cell to cell along either of two parallel aqueous pathways
2.1.3 The concept of water potential provides a thermodynamic basis for the study of water movement Equation 2. 1.3 ●V=Vb+。+vg+V ● w water potentia ppressure potential o Vs: solute(osmotic) potential Vg: gravitational potential Vm: matrix potential
2.1.3 The concept of water potential provides a thermodynamic basis for the study of water movement. ⚫ Equation 2.1.3 ⚫ ψw=ψp+ψs+ψg+ψm ⚫ ψw :water potential ⚫ Ψp : pressure potential ⚫ ψs : solute (osmotic) potential ⚫ ψg : gravitational potential ⚫ ψm: matrix potential
o 2. 1. 4 Concentration gradients over short distances tend to drive both diffusion and osmotically generated pressure flow(OGPF)
⚫ 2.1.4 Concentration gradients over short distances tend to drive both diffusion and osmotically generated pressure flow (OGPF)
A)Hydraulically C)Conducting cells olated cell 兀P asi ng P? 兀,P ecreasll 吗g从 (B)Hydraulically linked cells 兀,P termediate 兀P high 兀 intermediate 兀 lo 兀,P Solutes low Water