Reproduction in Plants PDF - Class 7 Notes

REPRODUCTION IN PLANTS 1. Define reproduction Ans- Production of offspring from the parents is called reproduction. 2. Differentiate between asexual and sexual mode of reproduction. +-----------------------------------+-----------------------------------+ | Asexual mode...

REPRODUCTION IN PLANTS 1. Define reproduction Ans- Production of offspring from the parents is called reproduction. 2. Differentiate between asexual and sexual mode of reproduction. +-----------------------------------+-----------------------------------+ | Asexual mode | Sexual mode | +===================================+===================================+ | a. Involves only one parent | Involves two parent organism or | | organism | gametes. | +-----------------------------------+-----------------------------------+ | b. Offsprings are identical to | Offsprings are similar to the | | the parent and known as clone | parents but not identical. | +-----------------------------------+-----------------------------------+ | c. Variations are rarely | Variations are commonly observed. | | observed | | +-----------------------------------+-----------------------------------+ 3. Explain the process of fragmentation. Ans- a. Algae on maturation, fragments or divides into multiple parts b\. Each fragment grows into a new individual. c\. e.g- Spirogyra. 4. Explain budding with the help of well labelled diagram. Ans- Budding is an asexual method of reproduction. It involves following steps- a. Under favourable conditions, an outgrowth is produced on the body of parent organism. It is called bud. b. The bud gradually grows and eventually detaches from parent organism. c. In yeast, the bud might remain attached and form chain of buds. Budding in Yeast 5. What is vegetative propagation? Give some examples of natural vegetative propagation. Ans- Method of asexual reproduction which takes place with the help of vegetative parts (leaf, stem and roots) only is called vegetative propagation. Natural vegetative propagation- a. Leaf- e.g notches in bryophyllum gives rise to new buds. b. Roots- e.g- sweet potato, carrot, radish c. Underground stems- i. Tuber- cylindrical stem. Each eye (scar) gives rise to new buds. E.g- potato ii. Bulb- short and upright structure. E.g onions iii. Corm- short and upright structure with concentrically arranged nodes. E.g- colocasia iv. Rhizome- horizontal stem. E,g- ginger Sub aerial stem propagation- i. Runner- spreads horizontally all over the ground. E,g- grass, oxalis ii. Stolon- a short branch arises upwards and bends down, touch the ground and form roots. E.g- mint, strawberry iii. Sucker- it grows underground and then grows upwards obliquely. E.g- banana 6. List three common methods of artificial propagation. Ans- Cutting- In this small stem is cut from parent plant. The lower part is buried in the soil. After few days, the cutting develops roots. E.g- rose, grapes, sugarcane Grafting is also a method of vegetative reproduction in stems, where new plants of desired qualities is developed from two different plants. The part that has shoot part is called scion and part having root is called stock. Scion is attached to the stock which provides support and basic requirement for the development of plant, e.g. apple, mango, rose, etc. In layering, a mature branch of parent plant is bent down and covered with soil. The tip of the plant is kept above the ground. The root develops from the branches and grows into a new plant. Layering method is usually done in the plants that have long and slender branches, e.g. jasmine. 7. Explain the process of spore formation. Ans- a. Fungi like bread mould reproduce asexually by spore formation. b\. Fungi develops bulb like structure called sporangium during unfavourable conditions. c\. with the onset of favourable conditions, the sporangium bursts releasing spores which germinate to form new plants.  8. Draw a well labelled diagram of a flower. KNP Rare Plants Database: Glossary 9. Differentiate between a. Complete flower and incomplete flower b. Unisexual and bisexual flower +-----------------------------------+-----------------------------------+ | Complete flower | Incomplete flower | +===================================+===================================+ | a. Flower which contains all the | a. Flower lacking any of the | | four whorls are present i.e | four whorls are called | | pistil, stamen, calyx and | incomplete flowers. | | corolla. | | +-----------------------------------+-----------------------------------+ | b. E.g- pea, mustard, hibiscus | E.g- date palm, mulberry, maize | | and gulmohar | | +-----------------------------------+-----------------------------------+ +-----------------------------------+-----------------------------------+ | Unisexual flower | Bisexual flower | +===================================+===================================+ | a. Flower containing either | Flower containing both pistil and | | pistil or stamen | stamen | +-----------------------------------+-----------------------------------+ | b. Only cross pollination takes | Both self and cross pollination | | place in such flowers. | can take place. | +-----------------------------------+-----------------------------------+ | c. E.g- papaya, water melon | e.g- hibiscus, rose | +-----------------------------------+-----------------------------------+ 10. What is pollination? Differentiate between cross pollination and self-pollination. Ans- The transfer of pollen grains from the anther of a stamen to the stigma of a pistil is called pollination. +-----------------------------------+-----------------------------------+ | Self-pollination | Cross pollination | +===================================+===================================+ | a. Transfer of pollen from | Transfer of pollen from anther of | | anther to stigma within the | one flower to stigma of another | | same fllower. | flower. | +-----------------------------------+-----------------------------------+ | b. It happens only in bisexual | It happens in both unisexual and | | flowers | bisexual flowers. | +-----------------------------------+-----------------------------------+ | c. It does not require | It requires pollinationg agents. | | pollinating agents | | +-----------------------------------+-----------------------------------+ 11. Classify the agents of pollination. Biotic- bees, birds, mammals Abiotic- wind, water 12. Differentiate between anemophily, hydrophily and entomophily. ANEMOPHILY HYDROPHILY ENTOMOPHILY --------------------------------- ---------------------------------- -------------------------------- Pollination by wind Pollination by water Pollination by insects Clourless and odourless flowers Colourless and odourless flowers Colourful and fragrant flowers Pollen is light and non sticky Pollen is light, ribbon like Pollen is sticky e.g- grasses Hydrilla, vallisneria Rose, hibiscus