Determination of Hydraulic and Osmotic Properties of Soybean Root Systems

摘要: An analytical technique which allows the experimental determination of soybean (Glycine max L.) root properties is presented. Two major problems hamper interpretation data. These are: (a) influence a possible boundary layer raises effective value pi degrees above that bulk solution; and (b) difficulty obtaining an adequate measure internal osmotic pressure except at high values volume flow rate due primarily to exchanges solutes between xylem adjacent tissues. Consideration these two leads previous models reconcilable with criticisms Newman (Plant Physiology 1975 57: 738-739).In experiments, estimates hydraulic conductivity reflection coefficient are based on data where effects minimized. Because difficulties attached evaluation pi(i), low moderate rates, any for evaluating parameters depends knowledge when difference (in bars) zero will be subject large errors, least until both metioned have been adequately resolved.An additional problem must dealt in terminal segments effect standing gradient. It thought this not serious complex system.Transpiration rates calculated basis leaf surface areas experimentally determined flow. shown necessary sustain transpiration shoots easily accommodated by model levels applied difference.