
A pollen tube, produced from the pollen grain, contains........... male gametes.
A) One
B) Two
C) Seven
D) Eight
Answer
561.6k+ views
Hint:Within the pollen grains that are produced from the anthers while flowering, male gametes are found. These gametes are produced by cells of generative origin. Germ cell division may appear before or after pollination.
Complete answer
To answer this question, we should know about the pollen grains. By meiosis, the pollen grain is formed and extracted from the anthers of the stamens in the flower. The stigma sits on the pollen grain and the pollen tube is formed. The cells divide inequitably within the pollen grain and build two cells: a generative cell and a vegetative cell.
The reproductive cell, particularly a cell of an angiosperm pollen grain that divides mitotically to make complete male gamete nuclei, is a generative cell. The tube cells that form the pollen tube while germination, from which these two male gamete nuclei move to the ovule, develop rapidly via the sporophytic tissues of the style and inside the ovule into the embryo sac (female gametophyte).
The vegetative cell contains nutrition and inevitably leads to the pollen tube, a tubular protrusion from the pollen grain inside its cytoplasm that holds the sperm cells.
Hence, the correct answer is option (B) .
Note:Four microsporangia include a typical anther, which forms pollen sacs. These experience meiosis to create haploid spores that differentiate and then divide mitotically after meiosis to create an immature microgametophyte. Angiosperm pollen should land on the stigma, the sensitive surface of the carpel, of an acceptable flower, in order to be successfully pollinated. Immature (pollen grain) microgametophytes probably complete their growth period after arriving to the stigma.
Complete answer
To answer this question, we should know about the pollen grains. By meiosis, the pollen grain is formed and extracted from the anthers of the stamens in the flower. The stigma sits on the pollen grain and the pollen tube is formed. The cells divide inequitably within the pollen grain and build two cells: a generative cell and a vegetative cell.
The reproductive cell, particularly a cell of an angiosperm pollen grain that divides mitotically to make complete male gamete nuclei, is a generative cell. The tube cells that form the pollen tube while germination, from which these two male gamete nuclei move to the ovule, develop rapidly via the sporophytic tissues of the style and inside the ovule into the embryo sac (female gametophyte).
The vegetative cell contains nutrition and inevitably leads to the pollen tube, a tubular protrusion from the pollen grain inside its cytoplasm that holds the sperm cells.
Hence, the correct answer is option (B) .
Note:Four microsporangia include a typical anther, which forms pollen sacs. These experience meiosis to create haploid spores that differentiate and then divide mitotically after meiosis to create an immature microgametophyte. Angiosperm pollen should land on the stigma, the sensitive surface of the carpel, of an acceptable flower, in order to be successfully pollinated. Immature (pollen grain) microgametophytes probably complete their growth period after arriving to the stigma.
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