75 extractive question-and-answer pairs built from Panchanan Maheshwari, published by ncert.nic.in. This document is a chapter from a biology textbook authored by Panchanan Maheshwari, focusing on plant reproduction. It covers the structures and events involved in pre-fertilisation, fertilisation, and post-fertilisation processes. Key topics include the stamen, pistil, microsporangium, megasporangium, pollination, double fertilisation, endosperm, embryo, seed development, apomixis, and polyembryony. The chapter concludes with a summary and exercises for students to test their understanding. Every answer is a verbatim span of text the source prints, and each row carries the passage it sits in, its offset in that passage, the source quote, the page and the location in the document, so any row can be checked against the original. 50 of the 75 pairs (66.7%) are explanatory questions and 25 restate a figure. 100.00% of rows pass the corpus quality gate.
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# One-time install: pip install desidata
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import desidata
df = desidata.load("panchanan-maheshwari-question-and-answer-dataset")
df.head()First 10 of 75 rows
| question | answer | context | answer_start | question_type | knowledge_quality_score | source_quote | source_page | source_location | confidence | validation_status |
|---|---|---|---|---|---|---|---|---|---|---|
| What is each cell of the sporogenous tissue capable of becoming? | a potential pollen or microspore mother cell | As each cell of the sporogenous tissue is capable of giving rise to a microspore tetrad. Each one is a potential pollen or microspore mother cell. The process of formation of microspores from a pollen mother cell (PMC) through meiosis is called microsporogenesis. | 101 | definition | 1.000 | Each one is a potential pollen or microspore mother cell. | 6 | page=6,block=2 | 0.850 | valid |
| What is the tissue where the archesporium differentiates? | the nucellus in which the archesporium differentiates | The ovules have a stalk called funicle, protective integument(s), and an opening called micropyle. The central tissue is the nucellus in which the archesporium differentiates. A cell of the archesporium, the megaspore mother cell divides meiotically and one of the megaspores forms the embryo sac (the female gametophyte). | 121 | definition | 1.000 | The central tissue is the nucellus in which the archesporium differentiates. | 23 | page=23,block=3 | 0.850 | valid |
| What function does the stigma serve in the female reproductive part of a flower? | serves as a landing platform for pollen grains | The gynoecium represents the female reproductive part of the flower. The gynoecium may consist of a single pistil (monocarpellary) or may have more than one pistil (multicarpellary). When there are more than one, the pistils may be fused together (syncarpous) (Figure 1.7b) or may be free (apocarpous) (Figure 1.7c). Each pistil has three parts (Figure 1.7a), the stigma, style and ovary. The stigma serves as a landing platform for pollen grains. The style is the elongated slender part beneath the stigma. The basal bulged part of the pistil is the ovary. Inside the ovary is the ovarian cavity ( ( ( ( (locule). The placenta is located inside the ovarian cavity. Recall the definition and types of placentation that you studied in | 400 | definition | 1.000 | The stigma serves as a landing platform for pollen grains. | 8 | page=8,block=4 | 0.700 | valid |
| What term describes the production of multiple embryos in a single seed in angiosperms? | Some angiosperms produce more than one embryo in their seed. This phenomenon is called polyembryony. | Zygote develops into the embryo and the primary endosperm cell forms the endosperm tissue. Formation of endosperm always precedes development of the embryo. The developing embryo passes through different stages such as the proembryo, globular and heart-shaped stages before maturation. Mature dicotyledonous embryo has two cotyledons and an embryonal axis with epicotyl and hypocotyl. Embryos of monocotyledons have a single cotyledon. After fertilisation, ovary develops into fruit and ovules develop into seeds. A phenomenon called apomixis is found in some angiosperms, particularly in grasses. It results in the formation of seeds without fertilisation. Apomicts have several advantages in horticulture and agriculture. Some angiosperms produce more than one embryo in their seed. This phenomenon is called polyembryony. | 724 | definition | 1.000 | Apomicts have several advantages in horticulture and agriculture. Some angiosperms produce more than one embryo in their seed. This phenomenon is called polyembryony. | 24 | page=24,block=3 | 0.700 | |
| What is the structure of an anther? | a four-sided (tetragonal) structure consisting of four microsporangia located at the corners, two in each lobe | The bilobed nature of an anther is very distinct in the transverse section of the anther. The anther is a four-sided (tetragonal) structure consisting of four microsporangia located at the corners, two in each lobe. The microsporangia develop further and become pollen sacs. | 104 | definition | 0.980 | The anther is a four-sided (tetragonal) structure consisting of four microsporangia located at the corners, two in each lobe. | 5 | page=5,block=4 | 0.850 | valid |
| What role do flowers play in angiosperms? | the seat of sexual reproduction in angiosperms | Flowers are the seat of sexual reproduction in angiosperms. In the flower, androecium consisting of stamens represents the male reproductive organs and gynoecium consisting of pistils represents the female reproductive organs. | 12 | definition | 0.980 | Flowers are the seat of sexual reproduction in angiosperms. | 23 | page=23,block=3 | 0.850 | valid |
| What does geitonogamy involve in plants? | Transfer of pollen grains from the anther to the stigma of another flower of the same plant | (ii) Geitonogamy Geitonogamy Geitonogamy Geitonogamy Geitonogamy – Transfer of pollen grains from the anther to the stigma of another flower of the same plant. Although geitonogamy is functionally cross-pollination involving a pollinating agent, genetically it is similar to autogamy since the pollen grains come from the same plant. (iii) Xenogamy Xenogamy Xenogamy Xenogamy Xenogamy – Transfer of pollen grains from anther to the stigma of a different plant (Figure 1.9b). This is the only type of pollination which during pollination brings genetically different types of pollen grains to the stigma. Agents of Pollination : Plants use two abiotic (wind and water) and one biotic (animals) agents to achieve pollination. Majority of plants use biotic agents for pollination. Only a small proportion of plants use abiotic agents. | 67 | definition | 0.980 | (ii) Geitonogamy Geitonogamy Geitonogamy Geitonogamy Geitonogamy – Transfer of pollen grains from the anther to the stigma of another flower of the same plant. | 12 | page=12,block=2 | 0.700 | valid |
| What does emasculation involve in artificial hybridisation? | removal of anthers from the flower bud before the anther dehisces using a pair of forceps | A breeder is interested in crossing different species and often genera to combine desirable characters to produce commercially ‘superior’ varieties. Artificial hybridisation is one of the major approaches of crop improvement programme. In such crossing experiments it is important to make sure that only the desired pollen grains are used for pollination and the stigma is protected from contamination (from unwanted pollen). This is achieved by emasculation and bagging techniques. If the female parent bears bisexual flowers, removal of anthers from the flower bud before the anther dehisces using a pair of forceps is necessary. This step is referred to as emasculation. Emasculated flowers have to be covered with a bag of suitable size, generally made up of butter paper, to prevent contamination of its stigma with unwanted pollen. This process is called bagging. | 528 | definition | 0.980 | If the female parent bears bisexual flowers, removal of anthers from the flower bud before the anther dehisces using a pair of forceps is necessary. | 17 | page=17,block=1 | 0.700 | |
| What do hormonal and structural changes in a plant lead to? | the differentiation and further development of the floral primordium | Much before the actual flower is seen on a plant, the decision that the plant is going to flower has taken place. Several hormonal and structural changes are initiated which lead to the differentiation and further development of the floral primordium. Inflorescences are formed which bear the floral buds and then the flowers. | 182 | relationship | 0.970 | Several hormonal and structural changes are initiated which lead to the differentiation and further development of the floral primordium. | 4 | page=4,block=5 | 0.800 | valid |
| What is the main benefit of sexual reproduction for a species? | creation of new variants, so that survival advantage is enhanced | Biology in essence is the story of life on earth. While individual organisms die without fail, species continue to live through millions of years unless threatened by natural or anthropogenic extinction. Reproduction becomes a vital process without which species cannot survive for long. Each individual leaves its progeny by asexual or sexual means. Sexual mode of reproduction enables creation of new variants, so that survival advantage is enhanced. This unit explains the details of reproductive processes in flowering plants and humans as easy to relate representative examples. A related perspective on human reproductive health and how reproductive ill health can be avoided is also presented to complete our understanding of biology of reproduction. Chapter 1 Sexual Reproduction in flowering Plants Chapter 2 Human Reproduction Chapter 3 Reproductive Health Reprint 2026-27 | 387 | relationship | 0.970 | Sexual mode of reproduction enables creation of new variants, so that survival advantage is enhanced. | 1 | page=1,block=0 | 0.700 | valid |
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