Question 1

Q1: Name the parts of an angiosperm flower in which development of male and female gametophyte take place.

Accepted Answer

In an angiosperm flower, the development of gametophytes takes place in the following parts: 1.  Male Gametophyte: The development of the male gametophyte (pollen grain) occurs in the anther, which is a part of the stamen (the male reproductive organ). Specifically, it develops inside the microspora...

Question 2

Q10: What is bagging technique? How is it useful in a plant breeding programme?

Accepted Answer

Bagging Technique: Bagging is a technique used in artificial hybridization where the emasculated flowers are covered with a bag of a suitable size, usually made of butter paper. This bag prevents the contamination of the stigma with unwanted pollen from other sources. Usefulness in Plant Breeding Pr...

Question 3

Q11: What is triple fusion? Where and how does it take place? Name the nuclei involved in triple fusion.

Accepted Answer

Triple Fusion: Triple fusion is one of the two fertilization events that occur in the embryo sac of an angiosperm. It is the fusion of one male gamete with the two polar nuclei present in the central cell of the embryo sac.    Where it takes place: Triple fusion occurs inside the central cell of the...

Question 4

Q12: Why do you think the zygote is dormant for sometime in a fertilised ovule?

Accepted Answer

The zygote remains dormant for some time after fertilization because it waits for the endosperm to develop. This is an evolutionary adaptation to ensure that the developing embryo receives adequate nutrition. The primary endosperm cell (PEC), formed after triple fusion, divides repeatedly to form th...

Question 5

Q13: Differentiate between: (a) hypocotyl and epicotyl; (b) coleoptile and coleorrhiza; (c) integument and testa; (d) perisperm and pericarp.

Accepted Answer

Question 6

Q14: Why is apple called a false fruit? Which part(s) of the flower forms the fruit?

Accepted Answer

Apple is called a false fruit (or pseudocarp) because the main edible, fleshy part of the fruit does not develop from the ovary. Instead, it develops from another floral part, the thalamus (receptacle), which grows and surrounds the ovary. In a true fruit, the fruit develops exclusively from the ova...

Question 7

Q15: What is meant by emasculation? When and why does a plant breeder employ this technique?

Accepted Answer

Emasculation is the process of removing the anthers from a bisexual flower bud before they dehisce (release pollen). This is typically done using a pair of forceps.    When it is employed: A plant breeder employs this technique during artificial hybridization experiments, specifically when the chose...

Question 8

Q16: If one can induce parthenocarpy through the application of growth substances, which fruits would you select to induce parthenocarpy and why?

Accepted Answer

If parthenocarpy (development of fruit without fertilization) can be induced, I would select fruits where the seeds are numerous or are considered an inconvenience to the consumer. The goal would be to enhance the fruit's economic value and edibility. Examples of fruits to select:    Grapes: Seedles...

Question 9

Q17: Explain the role of tapetum in the formation of pollen-grain wall.

Accepted Answer

The tapetum is the innermost nutritive layer of the microsporangium (anther wall). It plays a crucial role in the development and formation of pollen grains, especially their wall. The roles of the tapetum in pollen-grain wall formation are: 1.  Providing Nutrition: The primary function of the tapet...

Question 10

Q18: What is apomixis and what is its importance?

Accepted Answer

Apomixis: Apomixis is a form of asexual reproduction that mimics sexual reproduction by producing seeds without fertilization. In this process, an embryo develops directly from a diploid cell of the ovule (such as a diploid egg cell or a nucellar cell) without undergoing meiosis and syngamy. The res...

Question 11

Q2: Differentiate between microsporogenesis and megasporogenesis. Which type of cell division occurs during these events? Name the structures formed at th...

Accepted Answer

Question 12

Q3: Arrange the following terms in the correct developmental sequence: Pollen grain, sporogenous tissue, microspore tetrad, pollen mother cell, male gamet...

Accepted Answer

The correct developmental sequence is as follows: 1.  Sporogenous tissue: A mass of homogenous cells in a young anther. 2.  Pollen mother cell (PMC): Each cell of the sporogenous tissue differentiates into a PMC. 3.  Microspore tetrad: The PMC undergoes meiosis to form a cluster of four haploid micr...

Question 13

Q4: With a neat, labelled diagram, describe the parts of a typical angiosperm ovule.

Accepted Answer

A typical anatropous ovule of an angiosperm consists of the following parts (as shown in Figure 1.7d of the textbook):    Funicle: The stalk that attaches the ovule to the placenta.    Hilum: The region where the body of the ovule fuses with the funicle. It represents the junction between the funicl...

Question 14

Q5: What is meant by monosporic development of female gametophyte?

Accepted Answer

Monosporic development of the female gametophyte refers to the method of embryo sac formation where the embryo sac develops from a single functional megaspore.  In most flowering plants, the megaspore mother cell (MMC) undergoes meiosis to produce four haploid megaspores. Out of these four megaspore...

Question 15

Q6: With a neat diagram explain the 7-celled, 8-nucleate nature of the female gametophyte.

Accepted Answer

The mature female gametophyte or embryo sac in most angiosperms is a 7-celled, 8-nucleate structure (as shown in Figure 1.8c of the textbook). The formation and organization are as follows: The functional megaspore nucleus divides mitotically three times, resulting in eight nuclei within a single cy...

Question 16

Q7: What are chasmogamous flowers? Can cross-pollination occur in cleistogamous flowers? Give reasons for your answer.

Accepted Answer

Chasmogamous Flowers: Chasmogamous flowers are flowers that open at maturity, exposing their stamens (anthers) and pistil (stigma) to pollinating agents. They are similar to the flowers of most species and can undergo both self-pollination (autogamy) and cross-pollination (geitonogamy and xenogamy)....

Question 17

Q8: Mention two strategies evolved to prevent self-pollination in flowers.

Accepted Answer

Flowering plants have evolved many strategies (outbreeding devices) to prevent self-pollination and encourage cross-pollination. Two such strategies are: 1.  Dichogamy (Non-synchronization): In some species, the pollen release and stigma receptivity are not synchronized. This means the anther mature...

Question 18

Q9: What is self-incompatibility? Why does self-pollination not lead to seed formation in self-incompatible species?

Accepted Answer

Self-incompatibility is a genetic mechanism that prevents self-pollination from being effective. It is a form of pre-fertilization barrier that inhibits the fusion of gametes from the same individual plant, thus promoting outbreeding. Self-pollination does not lead to seed formation in self-incompat...

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