Phloem is a type of vascular tissue that is responsible for the transport of organic nutrients, such as sugars, from the leaves to other parts of the plant.
Phloem carries organic nutrients, such as sugars, amino acids, and hormones, from the leaves to other parts of the plant, such as the roots and flowers.
Sieve tubes are specialized cells that make up the phloem tissue. They are associated with companion cells, which help to regulate the movement of materials into and out of the sieve tubes. The function of sieve tubes is to transport organic nutrients, such as sugars, from the leaves to other parts of the plant. The companion cells provide energy and other resources to the sieve tubes to help them carry out this function.
Translocation is the process by which organic nutrients, such as sugars, are transported through the phloem tissue from the leaves to other parts of the plant.
Pressure and water potential aid translocation by creating a pressure gradient that drives the movement of materials through the phloem tissue. The pressure gradient is created by the accumulation of sugars in the sieve tubes, which draws water into the tubes and increases the pressure inside them. This pressure gradient helps to move the organic nutrients through the phloem tissue.
Aphid stylets can be used to measure phloem transport rates because they are specialized mouthparts that aphids use to feed on the sap that flows through the phloem tissue. By measuring the rate at which aphids feed on the sap, researchers can estimate the rate at which organic nutrients are being transported through the phloem tissue.
Radioactively-labelled CO2 can be used to measure phloem transport rates by exposing a leaf to a small amount of radioactive CO2 and then tracking the movement of the radioactive material through the plant. By measuring the rate at which the radioactive material moves through the plant, researchers can estimate the rate at which organic nutrients are being transported through the phloem tissue.
Meristems are regions of actively dividing cells in plants that are responsible for growth and development.
Apical meristems are regions of actively dividing cells located at the tips of stems and roots. These regions are important because they are responsible for the growth of new plant tissue, which allows the plant to get larger and develop new organs, such as leaves and flowers.
The process that causes the growth of new plant tissue is cell division, which is controlled by the meristems.
Tropism refers to the growth or movement of a plant in response to an external stimulus