Reproduction in Plants

Plants reproduce in two ways. In asexual reproduction, new plants arise without seeds. In vegetative propagation, new plants grow from roots, stems, leaves or buds: a rose from a stem cutting, potato from the eyes of its tuber, ginger from its rhizome and Bryophyllum from buds on its leaf margins. Yeast reproduces by budding, the alga Spirogyra by fragmentation, and fungi, mosses and ferns by spores, which have a hard protective coat. In sexual reproduction, the flower is the reproductive part. The stamen (anther and filament) is the male part, producing pollen grains, and the pistil (stigma, style and ovary with ovules) is the female part. Flowers with both are bisexual, like mustard and rose, while unisexual flowers, as in corn, papaya and cucumber, have only one. Pollination by wind, water or insects transfers pollen to the stigma. Male and female gametes then fuse in fertilisation, forming a zygote that develops into an embryo. The ovary becomes the fruit and the ovules become seeds, which are dispersed by wind, water, animals or by explosion of the fruit.

Detailed Worksheet: Reproduction in Plants Section A - Definitions (10 marks) 1. Define asexual and sexual reproduction in plants. (2 marks) 2. What is vegetative propagation? Give two examples. (2 marks) 3. Define pollination. Distinguish between self-pollination and cross-pollination. (2 marks) 4. What is fertilisation? What is a zygote? (2 marks) 5. What are spores? How do they help fungi survive? (2 marks) Section B - Calculations and Applications (15 marks) 6. Name the method of asexual reproduction in (i) yeast (ii) Spirogyra (iii) bread mould (iv) potato (v) Bryophyllum (vi) fern. (3 marks) 7. Classify as unisexual or bisexual flowers: mustard, corn, papaya, rose, cucumber, petunia. (3 marks) 8. Name the agent of seed dispersal for each: (i) drumstick (ii) coconut (iii) Xanthium (iv) castor (v) madar (aak) (vi) lotus. Give the feature that helps in each case. (3 marks) 9. State three advantages of vegetative propagation and one disadvantage. (3 marks) 10. Why is seed dispersal important? What would happen if all seeds fell under the parent plant? (3 marks) Section C - Diagrams (10 marks) 11. Draw a labelled diagram of the longitudinal section of a flower showing the sepals, petals, stamen (anther, filament) and pistil (stigma, style, ovary, ovules). (4 marks) 12. Draw labelled diagrams showing budding in yeast. (3 marks) 13. Draw a labelled diagram of a Bryophyllum leaf with buds and of a potato with eyes. (3 marks) Section D - Analysis and Higher-order Thinking (15 marks) 14. A potato kept in a dark corner sprouted after some weeks. (i) What are the points from which the shoots grew called? (ii) What type of reproduction is this? (iii) How can farmers use this? (iv) Will the new plants be identical to the parent? Why? (5 marks) 15. Bees visit flowers for nectar. (i) How do bees help in pollination? (ii) What features of flowers attract insects? (iii) Which type of pollination is mostly done by insects? (iv) What would happen to crop production if bees disappeared? (5 marks) 16. Trace the events from the formation of pollen to the formation of a seed. (i) Where is pollen formed? (ii) How does it reach the ovule? (iii) What does the zygote become? (iv) Which part forms the fruit and which forms the seed? (5 marks) Instructions: Time allowed 2 hours. Attempt all sections. Draw diagrams with a sharp pencil and label all parts.