Tag: botany

Guttation is the loss of water through water stomata (hydathodes) in the form of the dilute solution of mineral salts. When the absorption of water exceeds transpiration i.e., when plants are absorbing water actively, a positive root pressure is built up under the influence of which excess water simply oozes out through the dead ends of xylem tracheids and vessels. This usually happens during early morning hours when transpiration is low.

The exudation of xylem sap at the edges or tips of the leaves of some vascular plants, like grasses is called guttation. Unlike transpiration, it takes place only in certain conditions like cool and highly humid atmosphere. It is because plants can absorb up a limited amount of water. The excess water is secreted from the roots through the xylem and out through the hydathodes or water glands.

When the plant absorbs water by their own, it is called active absorption. It takes place when transpiration is low and amount of water in the soil is high. In this case root hairs play the major role in the absorption of water. Root pressure is the positive pressure that develops in the roots of plants by the active absorption of nutrients from the soil. It causes sap to rise through a plant stem to the leaves. Guttation is the exudation of xylem sap on the tips or edges of leaves of some vascular plant. According to the passive absorption, root hairs do not play any role in absorption. It takes place only when transpiration rate is high. So, the correct option is D.

The process of exudation of sap on the tips or edges of leaves in plant is called guttation. It takes place only under certain conditions like cold and high relative humidity in the atmosphere. It occurs through the specialized structures called hydathodes. They are generally restricted to the apex or the edges of the margins of leaves. Structurally, hydathodes consist of a simple pore in the epidermal layer found at the tip.

Guttation is the excretion of drops of xylem sap on the tips or edges of leaves of some vascular plants, such as grasses. It is the loss of water in liquid form through hydathodes.

The soil rich in moisture content, water floods a plant root system. Leaves can retain only a finite amount of water. Excess water i.e xylem sap is given out from the roots through pores or edge of leaves and this process is called guttation. Thus the correct answer is option B.

Transpiration is the process in which water vapors are released from the stomata. Guttation is the process of release of water droplets from the hydathodes.

Guttation is the loss of water in liquid form as a dilute solution from uninjured leaf tips. The uninjured leaf tips have hydathodes or water stomata. Under conditions of low transpiration dilute solution of minerals oozes out through them under the influence of increased root pressure.

Root pressure is osmotic pressure within the cells of a root system. Root pressure is generated by active uptake of minerals by roots, which lowers water potential of root cells and water flows inside the cells along its concentration gradient. Thus, on the cutting of shoot, excretion of watery substance from cut side occurs.

All plants do not show guttation. It is restricted to about 345 genera of herbaceous and some woody plants.
e.g., Garden Nasturtium, Oat Balsum, Tomato etc