Plant Pathology - Study Mode
[#536] Which one explains ascent of sap
Correct Answer
(A) Cohesion-tension theory of Dixon and Jolly
Explanation
Solution: Cohesion-tension theory of Dixon and Jolly explains the ascent of sap. The ascent of sap in the xylem tissue of plants is the upward movement of water and minerals from the root to the aerial parts of the plant. The work was published by Dixon in book form with a great wealth of experimental details in 1914. The theory states that transpiration pull or tension, cohesion property of water, and hydration of the cell walls are collectively responsible for the ascent of sap.
[#537] What is the source of Agar Agar
Correct Answer
(D) Algae
Explanation
Solution: Algae is the source of Agar Agar. Agar or agar-agar, is a jelly-like substance consisting of polysaccharides obtained from the cell walls of some species of red algae. Agar was first subjected to chemical analysis in 1859 by the French chemist Anselme Payen, who had obtained agar from the marine algae Gelidium corneum. It forms the supporting structure in the cell walls of certain species of algae and is released on boiling. These algae are known as agarophytes, belonging to the Rhodophyta (red algae) phylum.
[#538] Rate of water absorption is slow near freezing point because
Correct Answer
(A) Cell membranes become more viscous
Explanation
Solution: The rate of water absorption is slow near the freezing point because Cell membranes become more viscous. Membrane fluidity refers to the viscosity of the lipid bilayer of a cell membrane or a synthetic lipid membrane. As the temperature lowers, the water or moisture in the atmosphere starts freezing that ultimately lowering the rate of absorption.
[#539] Steamed bone meal contains
Correct Answer
(D) 30 - 35% P 2 O 5
Explanation
Solution: Steamed bone meal contains 30 - 35% P 2 O 5 . Bone meal is a mixture of finely and coarsely ground animal bones and slaughter-house waste products. It is used as a dietary supplement to supply calcium (Ca) and phosphorus (P) to monogastric livestock in the form of a hydroxiapathite. The N-P-K rating of bone meal is typically 3-15-0 along with a calcium content of around 12% (18% CaO equiv.) and 30 - 35% P 2 O 5 . It is used as an organic fertilizer for plants and as a nutritional supplement for animals. As a slow-release fertilizer, bone meal is primarily used as a source of phosphorus and protein.
[#540] The C : N ratio of farmyard manure is
Correct Answer
(D) 40 : 1
Explanation
Solution: The C : N ratio of farmyard manure is 40 : 1. C : N ratio is the ratio of the mass of carbon to the mass of nitrogen in a substance. FYM (Farmyard manure) is an important organic resource for agricultural production in live-stock-based farming systems in the semi-arid tropics of India. The C : N ratio of farmyard manure is 40 : 1.