Senior Inter Botany – Mineral Nutrition Four Mark important questions
Botany Mineral Nutrition Important Four Mark Questions– Senior Intermediate BIE
Botany Senior Intermediate Important questions on Mineral Nutrition have been characterized to help students to score more marks and gets more flexibility to have complete knowledge on the subject. Students can go through these questions and answers as well to score complete marks on this segment as well.
Q: What will happen if a healthy plant is supplied with excess essential elements.
A: If excess of Nitrogen is supplied to a healthy plant, its Vegetative growth is more but reproductive growth is inhibited. It results in poor yield. Moderate increase in the concentration of micronutrients causes toxicity. Any mineral ion concentration in tissues that reduces dry weight of tissues by about 10% is considered toxic. Excess of one element may inhibit the uptake of another element. Excess of Manganese shows Brown spots in the leaf surrounded by chlorotic veins. Excess of Manganese competes with other micro elements (Fe, Ca and Mg) and inhibits their uptake. So symptoms of Mntoxicity also results in the deficiency symptoms of Fe, Ca and Mg.
Q: Explain the steps involved in the formation of rootnodule?
A: The following steps are observed in the formation of root nodule:
1) Bacteria are attracted by sugars, amino acids andflavonoids secreted by the roots of leguminous plants.
2) Legumes select compatible strains of Rhizobium by specific proteins called Lectins.
3) Bacteria multiply and secrete curling factor. Root hair shows curling which is called Shepherd’s crook.
4) Bacteria invade the root hair and produce cellulase, pectinase to digest the cell wall.
5) Bacteria breach the cell wall. Plasma membrane invagination forms infection thread and carries bacteria into cortical cell.
6) Cortical cells produce Auxins, multiply and root nodule is formed into which bacteria are released.
7) Bacteria also stimulate pericycle cells to divide.
8) The nodule develops vascular connection.
9) It consists Leghaemoglobin (Pink coloured), Nitrogenase. The bacterial cells in the nodule become spherical & called bacteroid.