Plant Transport and Physiology

Xylem and phloem make up the vascular system of plants, transporting water, nutrients, and food. In animals, the circulatory system performs a highly similar role by pumping blood to distribute oxygen, nutrients, and waste products.

Sunlight stimulates the guard cells to open the stomata, which allows carbon dioxide to enter the leaf for photosynthesis. Since stomata are open, water vapor can easily diffuse out of the leaf, thereby increasing the rate of transpiration.

Translocation is the movement of organic nutrients, such as sucrose, through the phloem from sources (where they are produced or stored) to sinks (where they are consumed or needed for growth). This movement can occur in any direction depending on where the sources and sinks are located.

Translocation is the process by which soluble organic compounds, such as sucrose, are transported through the phloem of a plant. Transpiration occurs mainly through the xylem and stomata, while photosynthesis takes place in chloroplast-containing cells.

Xylem vessels are specialized, hollow tubes made of dead cells that transport water and dissolved mineral ions upward from the roots to the leaves. Phloem is responsible for transporting organic food, while the epidermis and mesophyll are leaf tissue layers.

Transpiration is the loss of water vapor from plant leaves, which is heavily influenced by environmental conditions. Light causes stomata to open, humidity affects the concentration gradient of water vapor, and air movement sweeps away saturated air, meaning all of these factors affect the rate.

Stomata are microscopic pores located primarily on the epidermis of leaves that allow gases and water vapor to diffuse in and out of the plant. While xylem transports water to the leaf cells, the actual exit point into the atmosphere is through these stomatal pores.

Elaborated sap, which consists of water and synthesized organic nutrients like sucrose, is distributed throughout the plant via phloem vessels. Xylem vessels transport raw sap (water and minerals), while stomata are pores for gas exchange.

Raw sap, which consists of water and mineral salts, is absorbed by the roots and travels to the leaves. There, it combines with carbon dioxide absorbed from the air and, using sunlight, transforms into elaborated sap (the plant's food).

Photosynthesis is the chemical process by which green plants use sunlight to synthesize nutrients from carbon dioxide and water. During this process, raw sap is converted into nutrient-rich elaborated sap.

Raw sap is the term used for the inorganic solution of water and mineral salts absorbed by plant roots from the soil before it undergoes photosynthesis.