Reproduction in Plants Flashcards
What are the advantages of asexual reproduction?
Only one parent is required, and there is no fusion of gametes. All the beneficial qualities are passed on to the offspring. Asexual reproduction is a faster method of producing offspring compared to sexual reproduction.
What are the advantages of sexual reproduction?
The offspring may inherit beneficial qualities from both parents. There is also greater genetic variation in the offspring, leading to species that are better adapted to changes in the environment.
What are the parts of a stamen and their functions?
The anther contains two pollen sacs that helps with pollination. The filament holds the anther in a suitable position to disperse pollen.
What are the parts of a pistil and their functions?
The stigma receives pollen grains and stimulates them to germinate. The style holds the stigma in a suitable position to trap pollen grains. The ovary develops into a fruit after fertilisation.
What is pollination?
Pollination is the transfer of pollen grains from the anther to the stigma.
What are the features of a self-pollinating plant?
The flowers are bisexual with anthers and stigmas maturing at the same time. The stigma is situated directly below the anther.
What are the advantages of self-pollination?
Only one parent plant is required, and the offspring inherits its genes from the parent plant. Beneficial qualities are more likely to be passed down to the offspring. It does not depend on external factors like wind or insects. There is a higher probability that pollination will occur, and less pollen and energy will be wasted compared to cross-pollination.
What are the advantages of cross-pollination?
Offspring produced may inherit beneficial qualities from both parents. There will be more genetic variation. The likelihood of harmful recessive alleles being expressed will be lower.
What are the features of insect-pollinated flowers?
Flowers are large, fragrant and brightly-coloured. Nectar and nectar guide is present. Stigmas are usually small, compact and do not protrude out of the flower. Stamens are not pendulous and do not usually protrude out of the flower.
What are the features of wind-pollinated flowers?
Flowers are usually small, dull-coloured and odourless. Stigmas are large, feathery and usually protrude out of the flower to provide a large surface area to trap pollen. Stamens have long, pendulous filaments and protruding anthers.
How does fertilisation take place?
After pollination, the pollen grains germinate due to the sugary fluid secreted by the stigma. A pollen tube grows out from each pollen grain and secretes enzymes to digest surrounding tissue of the stigma and style. The pollen tube enters the ovule through the micropyle and releases the two male gametes. The nucleus of one male gamete fuses with that of the ovum to form the zygote.
