Bottle gourd is unisexual plant and only plant with female reproductive plant can bear fruits.

Keeping beehives in crop fields during flowering period increases pollination efficiency, it improves yield of crops and honey.

Quiescent seeds can germinate when soaked in water under suitable temperature and in presence of oxygen. Quiescent condition is due to unfavourable factors.
The dormancy of seed is the condition of seed when it fails to germinate even through environmental conditions usually considered favourable for active growth are present. Dormancy is inability of seed to germinate even if conditions are favourable. 

1. By Longitudinal introse.
2. By Longitudinal extrose.
3. By Apical pores.
4. Transverse.

In general, the hybrid characters segregate in every generation and are not maintained.
The production of hybrid seed is costly and is too expensive for the farmers.
If the hybrids are made into apomicts, there will be no segregation of characters and seeds can be collected from the plants generation after generation and used for raising the new plants.

Micropyle is the opening left by the integuments at the trip of the ovule; this remains as an opening on the seed coat.
It facilitates the entry of oxygen water during seed germination.

(i) Pollination by abiotic agents (like wind and water) is not precise.
(ii) Many pollen grains fail to reach the stigma of female/bisexual flowers.
(iii) To compensate for the wastage, a large number of pollen grains are produced.

1.Emasculation is necessary to prevent the self-pollen grains falling on the stigma.
2. Emasculation is not needed when the female parent chosen bears unisexual,  i.e. female flowers.

(i) In Vallisneria, the male flowers are released on the surface of water and female flowers reach the surface by the long stalk.
(ii) Pollen grains are protected from wetting by a mucilaginous covering.