Test: Pollination

1. In Vallisneria pollination occurs outside water called epihydrophily.
2. Salvia is insect pollinated and is an example of entomophily.
3. Anemophily is the pollination by wind. Anemophilous plants are characterized by small flowers, pollens present in large number which are small, dry and light in weight, number of ovules generally reduced in ovary, feathery or brushy stigma to recieve the pollen. All these features are shown by coconut flower.
4. Callistemon (Bottle brush) is pollinated by birds and is an example of ornithophily.

• Homogamy refers to the maturation of male and female reproductive organs at the same time.
• Also known as simultaneous or synchronous hermaphroditism and is the antonym of dichogamy.

In self-pollinating plants, there is less dependence on the external factors to cause pollination. These plants depend on wind or other smaller insects that visit the flower regularly. In self- pollinating flowers, the anthers, and stigma are of similar lengths to facilitate the transfer of pollen.

Self -pollination can be further divided into two types:
1. Autogamy– In this type of self-pollination, the pollen is transferred from the anthers of one flower to the stigma of the same flower.
2. Geitonogamy– In this type of self- pollination, the anthers are transferred from the anthers of one flower to the stigma of another flower but on the same plant.

Self Pollination:

• Cleistogamy is autogamous pollination.
• Cleistogamous flowers are those that stay close together to avoid cross pollination and have adaptations to assist self pollination.
• Self-pollination OR Autogamy:
  
  Fig: Cleistogamous Flowers (inside unopened buds)

• Most pollen walls are composed of two major distinct layers:
  (i) the exine, accumulated primarily by sporopollenin.
  (ii) the intine, mainly composed of pectin and cellulose.
• In addition, different protein and lipid-rich materials form a pollen coat (tryphine) anchor on the exine.

Fig: Layers of Pollen Grain (Exine & Intine)

• Bat pollination is called Chiropterophily.
• Bat-pollinated flowers tend to be large and showy, white or light coloured, open at night and have strong musty odours.
• They are often large and bell-shaped or a ball of stamens. Flowers are typically borne away from the trunk or other obstructions.

Fig: Pollination by Bats

• Allogamy- The fertilization of a flower by pollen from another flower, especially one on a different plant.
• Porogamy- entry of pollen tube from micropylar end.
• Mesogamy - entry of pollen tube from middle(integuments).
• Chalazogamy - entry of pollen tube from chalazal end.

Hence, only allogamy is related to fertilisation, all other are related to entry of pollen tube.

1. Geitonogamy is a type of self pollination in which pollen is transferred from the anther of one flower to the stigma of another flower of the same plant.

2. Xenogamy is the cross-pollination between the flowers of different plants. It produces hererozygosity because two genetically different parents are involved.
Cross-pollination is the transfer of pollen grains from anther to stigma of different flower

3. Chasmogamy is the condition in which bisexual flowers have exposed anthers and stigma. Both self-pollination and cross pollination can occur in these flowers.

4. Autogamy is a type of self-pollination in which pollen is transferred from the anther to the stigma of the same flower.
Thus, it's xenogamy that can bring genetically different pollen grains to the stigma of a plant.

So, the correct answer is B.

• In Cleistogamy and Homogamy, the male and female are present in the same plant and ripens at the same time so self-pollination is the most possible.
• But in Dichogamy, the male and female organs are present in the same plant but the ripening of male and female parts happens at a different time, and self-pollination is prevented. So, cross-pollination is the only way for pollination.

• Wind pollination is common in grasses.
• Grasses produce large amount of pollen which by the help of wind reach to the stigma for reproduction.