A dicotyledonous plant bears flowers but never produces fruits and seeds. The most probable cause for the above situation is:
1. | Plant is dioecious and bears only pistillate flowers. |
2. | Plant is dioecious and bears both pistillate and staminate flowers. |
3. | Plant is monoecious. |
4. | Plant is dioecious and bears only staminate flowers. |
The outermost and innermost wall layers of microsporangium in an anther are respectively:
1. Endothecium and tapetum
2. Epidermis and endodermis
3. Epidermis and middle layer
4. Epidermis and tapetum
Autogamy can occur in a chasmogamous flower if:
1. Pollen matures before the maturity of ovule.
2. Ovules mature before the maturity of pollen.
3. Both pollen and ovules mature simultaneously.
4. Both anther and stigma are of equal lengths.
A particular species of the plant produces light, non-sticky pollen in large numbers and its stigmas are long and feathery. These
modifications facilitate pollination by:
1. | Insects | 2. | Water |
3. | Wind | 4. | Animals |
In an embryo sac, the cells that degenerate after fertilisation are:
1. Synergids and primary endosperm cell
2. Synergids and antipodals
3. Antipodals and primary endosperm cell
4. Egg and antipodals
In the embryos of a typical dicot and a grass, true homologous structures are:
1. | Coleorhiza and coleoptile | 2. | Coleoptile and scutellum |
3. | Cotyledons and scutellum | 4. | Hypocotyl and radical |
The phenomenon observed in some plants wherein parts of the sexual apparatus are used for forming embryos without fertilisation is called
1. | Parthenocarpy | 2. | Apomixis |
3. | Vegetative propagation | 4. | Sexual reproduction |
In a type of apomixis known as adventive embryony, embryos develop directly from:
1. Nucellus or integument
2. Zygote
3. Synergids of antipodals of embryo sac
4. Accessory embryo sac in the ovule
Parthenocarpic fruits are produced by:
1. | Treating plants with phenyl Mercuric acetate. |
2. | Treating plants with low concentrations of gibberellic acid and auxin. |
3. | Removing androecium of flowers before releasing pollen grains. |
4. | Raising plants from vernalised seeds. |
An organic substance that can withstand environmental extremes and cannot be degraded by any enzyme is:
1. | Cuticle | 2. | Sporopollenin |
3. | Lignin | 4. | Cellulose |