What are Clay and humus?
Clay is an inorganic material. It consists of aluminium and silicon oxides. Humus consists of carbonaceous residue. It is derived from lignin of cell walls.
What is free space or apperent free space?
The tenn free space is used for the part of the plant cell and tissue where ions can freely move by diffusion. It is also called apparent free space (AFS).
What is ion exchange?
The exchange of anions 07 cations of the cells with the ions of the same and equivalem charge of outer solution is called ion exchange.
What is contact exchl nge theory?
According to this theory, ions are not dissolved in water. Theroots are present near the clay particles in the soil. Cations are adsorbed on surface of the clay colloids. The roots releases ion. These Fr ion are directly exchanged by the cations of clay particles.
- What is carbonic exchange theory?
Ans: According this theory, ions first dissolve in the soil solution.
Carbon dioxide released during the respiration in roots. It dissolves in soil water and form carbonic acid (H2C01). Carbonic acid is a weak acid. It dissociates into H ions ad HCO3– ions. H’ ion ions reach the clay particles. They are exchanged with cation like K present in the soil.
- What is Donn equilibrium?
Ans: The equilibrium of ions between root cells and soil solution in the presence of fixed ions in the root cells is called Dolman equilibrium.
- How does proton pump works?
Ans: Proton pump is present in the membrane of the root cells. It is an
electrogenic pump. It uses ATP. Proton pump actively transport hydrogen ion of the cell. It also creates membrane potential in the cells. It set proton gradient across the membrane of cell. This gradient enforces the minerals inside.
- What is contransport?
Ans: The transport by which a substance indirectly drives the active
transport of several other solutes is called con-transport.
- Differentiate between antiport and symport.
Ans: Antiprot: In this case, the two transported molecules moves in
Symport: In this case, two molecules move in the same direction
- What is meant by essential elements? Give their number
Ans: The elements which are needed by the plants for normal and healthy life are called essential elements. Only 16 elements are essential elements.
- What are macronutrients?
Ans: These elements are required by the plants in large quantity. The major elements are C, F, 0, N, S. P. Ca, K and Mg.
- What are trace elements?
B, Cu, Zn, Mo and Cl.
- Give two physiological roles of nitrogen.
Ans: Nitrogen is an essential component of proteins and nucleic acids. It is also an important component of chlorophyll.
- Give two deficiency symptoms of nitrogen.
Ans: The lateral buds remain dormant. Flower formation is delayed or suppressed. If flowers are formed, the fruits and seeds remain small and weak.
- Give two physiological roles of calcium.
Ans: Calcium is deposited in the cell wall in the form of calcium pectate. Calcium pectate forms middle lamella. Cell wall remains weak without this compound. Calcium concentrates around the chromosomes. It plays role in binding of nucleic acid to protein.
- Give two deficiency symptoms of calcium.
Ans: Chlorotic patches appear mar the leaf margin in young leaves. Calcium deficiency causes rapid disintegration of the grow ing tips of roots and shoots in many plants.
- Give two physiological roles of potassium.
Ans: It provides the necessary ionic balance. This ionic balance is
necessary for the survival of plant. It plays an important role in the plant metabolism. It acts as an activator of many plant enzymes.
- Give two deficiency symptoms of phosphorus.
Ans: Growth is retarded and leaf colour becomes dark-green. Sometimes dead patches appear on leaves, petioles and fruits and the leaves fall early.