Guttation
Plants have a physiological trait called guttation that allows them to get rid of extra water and keep the root pressure regular. For plants to grow properly physiologically and developmentally, water is necessary. Additionally, it serves as a barrier to plant growth. Water aids in maintaining turgor pressure in plant components, however when the body of the plant contains less or more water than usual, it can jeopardize the plant’s ability to function normally. In order to maintain a good balance between the nutrient and water content in the plant body, this characteristic of plants serves as a safety mechanism.
Water is released from the tips of plant leaves during this procedure. The guttation process involves the passage of soil-derived water. It absorbs vitamins, enzymes, and other substances (xylem sap), such as wheat, grass, barley, tomatoes, etc. Hydathodes are used for guttation. A unique type of tissue found in leaves called a hydathode is composed of several intercellular gaps between live, thin-walled parenchymatous cells.
Process of Guttation
Root pressure buildup is the cause of guttation. Water enters the roots when the soil’s moisture content is high. This is made possible by the fact that roots have a lower water potential than soil, and that when water enters the roots, root pressure is produced. Hydathodes, which are structures found on the edges of the leaves, are used by the root pressure to force the water to ooze out as drops.
Long Distance Transport Of Water
In plants, long-distance transport facilitates the movement of organic solutes between the xylem and phloem. This happens as a result of protracted exchange procedures. Mineral nutrition in plants depends heavily on the flow of nutrients between the xylem and phloem.
Active transport and diffusion are not the ideal methods for moving water and nutrients from the roots to the leaves and back again since diffusion is a slow process. Only short lengths, such as those from one cell to the next, or circumstances like this are allowed for the utilization of these procedures.
Long-distance transport systems had to be created in order to move substances at a faster and more effective rate. The xylem and phloem of vascular plants, therefore, evolved to facilitate and speed up material transport.
History: Theory of Transpiration Pull
Two botanists, Dixon and Joly, put out this notion in 1895. It was altered by Dixon in 1914. The most plausible idea for sap ascension in all plants, from the smallest herbs to the tallest trees, is this one. The cohesion-tension theory, as it is often known, is based on several fundamental laws of physical nature.
Long Distance Transportation in Plants
Plants have two primary tissues: the xylem and phloem, which are used to transfer food (nutrients) and water. The removal of harmful substances from the leaf tissues and nourishment of the shoots both depend on long-distance transport.
The gradient in hydrostatic pressure, also known as root pressure, and the gradient in water potential are both responsible for the long-distance transfer of water in the xylem. The sieve tube cells of phloem, which are live cells, are used for long-distance transport. Water and other inorganic and organic solutes are transported over great distances from the roots to the shoots, where the stems are essential. The rate of volume movement in the xylem affects the transfer of the xylem to the phloem, which occurs in the stem.