Sexual Reproduction In Flowering Plants

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

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The correct option is (B) : Downward

The body of the ovule is rotated by 180 degrees in an anatropous ovule.The ovule and micropyle's bodies are parallel to the funicle. The micropyle is located at the side of the hilum or in close proximity to it, making it an inverted ovule. At the top, the chalazal end is visible. Two polar nuclei in the core of the ovule fuse, resulting in the formation of a seven-celled stage.

Answer:

Explanation:

• In most angiosperms, the development of the female gametophyte (embryo sac) begins when the megaspore mother cell (MMC) undergoes meiosis (reduction division).
• This meiosis results in the formation of four haploid megaspores, out of which usually only one is functional and develops into the embryo sac.
• This is a characteristic process of sexual reproduction in flowering plants (angiosperms).

Why the other options are incorrect:

• Option 1: The synergids, not the egg cell, possess a filiform apparatus.
• Option 2: Typically, there are only three antipodal cells in the embryo sac of angiosperms.
• Option 4: The central cell is large, not small, and contains two polar nuclei.

Explanation:
In monocot plants like maize:

• There is only one cotyledon.
• This single cotyledon is specially modified and is called the scutellum.
• The scutellum is a thin, shield-like structure that helps in the absorption of nutrients from the endosperm during germination.

Other terms:

• Coleorhiza – protective sheath covering the root.
• Coleoptile – protective sheath covering the shoot (plumule).
• Plumule – part of the embryo that develops into the shoot.

So, the correct answer is: Scutellum

Option 1: "Insects that consume pollen or nectar without bringing about pollination are called pollen/nectar robbers."
This statement is correct. Insects that visit flowers to consume pollen or nectar but do not contribute to the pollination process (i.e., they do not transfer pollen from one flower to another) are called "pollen robbers" or "nectar robbers." They take resources from the plant without aiding in its reproductive process.

Option 2: "Pollen germination and pollen tube growth are regulated by chemical components of pollen interacting with those of the pistil."
This statement is correct. The process of pollen germination and the growth of the pollen tube is regulated by chemical signals. These signals come from the pistil (the female part of the flower). Chemical components in the pistil attract the pollen tube, which grows through the style to reach the ovary for fertilization to occur.

Option 3: "Pollen grains of many species can germinate on the stigma of a flower, but only one pollen tube of the same species grows into the style."
This statement is correct. When pollen grains land on the stigma of a flower, they begin to germinate. However, only one pollen tube (from the same species) will grow down the style to reach the ovary. This ensures that the right pollen from the correct species fertilizes the ovules.

Option 4: "Some reptiles have also been reported as pollinators in some plant species."
This statement is incorrect. While some reptiles have been observed interacting with plants, they are not typical pollinators. Reptiles like lizards or iguanas may occasionally visit flowers, but their role in pollination is minimal compared to insects (such as bees) or birds (such as hummingbirds), which are the primary pollinators for many plants. The primary pollinators of most plant species are insects, birds, and sometimes mammals.

Conclusion: The incorrect statement is Option 3. While reptiles may occasionally interact with flowers, they are not considered important or common pollinators. Pollination is mainly carried out by insects, birds, and sometimes mammals. Thus, Option 3 is the answer that is not correct.

Winged pollen grains are present in Pinus. In Pinus, the outer exine is extended on two lateral sides to form the wings of pollen. Pollen grains are the male gametophyte present in the anther of flowering plants.

For cycas and pinus, wind is the pollinating agent but the pollens of cycas are dry, light and round-shaped. The pollens of mango and mustard are sticky and heavy. In these plants, pollination is carried out by insects.

Therefore, option A is the correct answer.

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