| 1. | They delay senescence, thus, due to their application the fruits can be left on the tree so as to extend the market period |
| 2. | GA3 is used to speed up the malting process in brewing industry |
| 3. | Spraying sugarcane crop with GA increases the length of stem, thus increasing the yield by as much as 20 tonnes per acre |
| 4. | Spraying juvenile conifers with GA slows down the maturity period thus leading to delayed seed production |
| (i) | GA causes increase in length of grape stalks and causes apples to elongate and improve its shape |
| (ii) | GA causes bolting in beet, cabbage and many plants with rosette habit |
| (iii) | Kinetin is a modified cytosine |
| (iv) | Cytokinins are abundant in root apices, developing shoot buds and young fruits |
| (v) | Cytokinins cause lateral shoot growth and adventitious shoot formation |
| (i) | Causes horizontal growth of seedlings. |
| (ii) | It is highly effective in causing fruit ripening. |
| (iii) | Is responsible for respiratory climatic in fruits which is the enhanced respiration rate during fruit ripening. |
| (iv) | Ethylene breaks seed and bud dormancy, initiates germination in peanut seeds, and causes the sprouting of potatoes. |
| (v) | It is used to initiate flowering and for synchronising fruit set in pineapples. |
| 1. | Ethylene induces flowering in mango tree |
| 2. | Ethylene promotes senescence of plant organs especially of leaves and flowers |
| 3. | Ethylene promotes rapid internode/petiole elongation in deep water rice plants |
| 4. | Ethylene is the least used PGR in agriculture and horticulture |
| 1. | Hastens fruit ripening in tomatoes and apples, accelerates abscission in flowers and fruits |
| 2. | Promotes female flowers in cucumbers thereby increasing the yield |
| 3. | In aqueous solution is readily absorbed and transported within the plant and releases ethylene slowly |
| 4. | All of the above |
| 1. | Inhibits seed germination |
| 2. | Stimulates stomatal opening |
| 3. | Decreases the tolerance of plants to various kinds of stresses |
| 4. | In most situation acts synergistically with GA |
| (i) | The role of PGR is of only one kind of intrinsic control |
| (ii) | Along with genomic control and extrinsic factors, they play an important role in plant growth and development |
| (iii) | Many of the intrinsic factors such as temperature and light, control the plant growth and development via PGR like vernalisation, flowering, dormancy , seed germination and plant movements |
| (iv) | Gibberellins promote senescence in plants |
| (v) | Both light and temperature has a role on initiation of flowering |
| Options | A | B | C |
| 1. | SDP | DNP | LDP |
| 2. | SDP | LDP | SDP |
| 3. | DNP | LDP | SDP |
| 4. | SDP | LDP | DNP |