Transport in plants

• Flowering plants


  In simple terms Xylem and Phloem are something like our veins and arteries. Xylem are the larger, more sturdy transport system for water and Phloem the system for nutrients.
• Xylem


  Xylem are the vessels that deliver most of the water and minerals to the leaf. They form a continuous transport system

  
• Phloem


  The phloem transport the products of photosynthesis and distributes them to the rest of the plant as required

  
• Transpiration

  Transpiration is the loss of water from plant leaves via diffusion. In hot, dry and windy conditions the rate of transpiration will increase. This will create a shortage of water in the leaf
• Transpiration rate is affected by 4 main elements

  Light intensity. The more intense the light, the greater the rate of transpiration. This is because during hours of darkness, the stomata are closed. This is because photosynthesis cannot happen in the dark. The additional photosynthesis, caused by greater light intensity, causes stomata to open which also increases loss of water by transpiration.Temperature. Transpiration increases with temperature. This is because the higher the temperature, the more energy the water molecules have, making it more likely that they will evaporate. Also, higher temperatures cause the stomata to open.Air movement. In high wind, transpiration occurs faster. This is because if air is moving, the air above the leaf will not become saturated with water molecules. Instead these water molecules will blow away.Relative humidity. The more humid the atmosphere, the slower transpiration will take place because the concentration of water molecules in the air is very high in humid conditions. This, in turn means, that the concentration gradient between the inside of the leaf and the atmosphere is low, thus retarding diffusion
• Root hairs

  These root hairs are fine, single cells, with a thin cell membrane easing the passage of substances in and out of the plant. Water moves into the roots by osmosis and mineral ions move into the root by diffusion. At times of higher concentration of mineral ions within the plant, mineral ions will be moved by active transport