What do you mean by ascent of sap? Describe the vital and root pressure theories of ascent of sap.
ASCENT OF SAP The water is absorbed from the soil by the roots and moved upward to all the parts of the stem through xylem. Inside the …
Category: Biology
Describe the physical theories of ascent of sap.
PHYSICAL THEORIES Physical theories which consider the involvement of physical pressure exerted inside the dead cells of the plant during the ascent of sap are known as physical …
Define transpiration. What are the different types of transpiration? Mention the different types of stomata and differentiate between evaporation and transpiration.
TRANSPIRATION The loss of water in the form of vapours from the living tissue of the aerial part of plants is called transpiration. Less than 3% of total water …
Explain the role of K+ in stomatal movement. Describe the potassium ion pump theory.
POTASSIUM ION PUMP THEORY OR PROTON TRANSPORT HYPOTHESIS ROLE OF K+ IN STOMATAL MOVEMENT: Imamura and M. Fujino (1959) found a direct correlation between stomatal movement and …
Mention the factors affecting stomatal movements. What is guttation? Differentiate between transpiration and guttation.
The opening and closing of stomata is affected by the following factors: Light: In most of the plants, stomata open in the presence of light and closes in darkness. …
What is the significance of transpiration? Compare between the opening and closing of stomata in light and dark. Differentiate between stomata and hydathodes.
SIGNIFICANCE OF TRANSPIRATION Transpiration is regarded as a “necessary evil” Curtis (1926) or unavoidable evil (Steward 1959) because it cannot be avoided though potentially harmful. The stomata remain …
What are the factors affecting mineral salt absorption? Differentiate between active and passive salt absorption.
FACTORS AFFECTING MINERAL SALT ABSORPTION Absorption of mineral salts by plants is influenced by some external and internal factors. These factors include mainly temperature, light, H+ ion concentration, …
What is nitrogen fixation? Explain asymbiotic and symbiotic nitrogen fixation.
NITROGEN FIXATION About 78% of nitrogen is present in the atmosphere. Nitrogen is not directly absorbed by the plants. Nitrates, nitrites, ammonium salt, and organic nitrogenous compounds act …
What do you mean by asexual reproduction in plants? Describe the methods of natural vegetative propagation.
ASEXUAL REPRODUCTION Reproduction is the process of formation of new individuals of a species from the preexisting ones. Plants show two types of reproduction, asexual and sexual. Asexual …
DESCRIBE THE VARIOUS METHODS OF ARTIFICIAL VEGETATIVE PROPAGATION AND MENTION ITS SIGNIFICANCE.
METHODS OF ARTIFICIAL VEGETATIVE PROPAGATION: The artificial method of vegetative propagation includes cuttings, layering, grafting and micropropagation. Cuttings: Stem cuttings are generally used to obtain new plants. At times, …