AEBI 210 Lecture Notes - Turgor Pressure, Root Pressure, Capillary Action
8 Jan 2013
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Document Summary
Root hairs take in water from the soil to the plant xylem. Water moves up the stem by capillary action in the xylem. Leaf veins transport water to pallisade cells for photosynthesis. Stomata allow 90% of the water to be released, while 10% is lost through the cuticle. Capillary action pushes water upwards because of cohesion and adhesion. Air bubbles prevent water from passing to the next element. Co2 enters the membrane in solution, so leaf surfaces must be kept wet. Water is always evaporating, so transpiration must occur. Temperature rise increases the rate of transpiration and photosynthesis. Open or close according to temperature, humidity, [co2] and light. Water follows k+, causing the guard cells to swell and stomata to open. Tend to open during the day and close at night. Hormones(abscisic acid- aba) can control the stomata according to water status. Water can enter the intercellular space of the cortex by capillary action.
