TRANSPORT IN PLANTS

ADHESION

* The tendency of unlike molecules to stick together

* Adhesion is the tendency of dissimilar particles or surfaces to cling to one another 

TRANSPORT IN PLANTS

COHESION

* The tendency of like molecules to stick together

* The sticking together of particles of the same substance

TRANSPORT IN PLANTS

CAPILLARY ACTION

* The movement of a liquid along the surface of a solid

*Is the movement of liquid along a surface of a solid caused by the attraction of molecules of the liquid to the molecules of the solid. Plants use capillary action to bring water up the roots and stems to the rest of the plant.

TRANSPORT IN PLANTS

PLASMOLYSIS

*The shrinking of the cytoplasm & the cell membrane away from the ell wall due to the outflow of water from the cell

* Contraction of the protoplast of a plant cell as a result of loss of water from the cell

TRANSPORT IN PLANTS

PRESSURE-FLOW THEORY

* An explanation of how plant nutrients are transported from leaves to other parts of the plant, driven by pressure built up by hypertonic solutions in the phloem

*The pressure flow hypothesis, is the best-supported theory to explain the movement of sap through the phloem. ... This creates turgor pressure, also known as hydrostatic pressure, in the phloem. Movement of phloem sap occurs by bulk flow from sugar sources to sugar sinks

TRANSPORT IN PLANTS

ROOT PRESSURE

* Pressure exerted on water in the roots by osmosis

* Is the transverse osmotic pressure within the cells of a root system that causes sap to rise through a plant stem to the leaves. Root pressure occurs in the xylem of some vascular plants when the soil moisture level is high either at night or when transpiration is low during the day

TRANSPORT IN PLANTS

SINK

* A place in a plant where products of photosynthesis are stored

*Sinks are areas in need of nutrients, such as growing tissues. When they are low in supply, storage areas such as the roots and stems cane function as sinks. The contents of the phloem tubes flow from the sources to these sinks, where the sugar molecules are taken out of the phloem by active transport

TRANSPORT IN PLANTS

SOURCE

* A place in a plant where products of photosynthesis are manufactured

* The nutrient-rich regions that supply sugars for the rest of the plant are called the sources. Sources include the leaves, where sugar is generated through photosynthesis. When they are high in supplies, the nutrient storage areas, such as the roots and stems, can also function as sources

TRANSPORT IN PLANTS

TONICITY

* A term that relates the concentration of solute particles in solutions separated by a semi-permeable membrane

* Is a measure of the relative concentration of solute particles on either side of a semi-permeable membrane (e.g. inside a cell versus outside the cell). Only solutes that cannot cross the membrane contribute to tonicity. It determines the direction and extent to which water moves by osmosis

TRANSPORT IN PLANTS

TRANSPIRATION PULL

* A pull on water molecules in xylem due to the evaporation of water through stomata & lenticels

* Is the force which aids in drawing the water upward from roots to leaves. In leaves, some amount of water is used for photosynthesis and excess water is released into atmosphere through openings called as stomata