Describe how the parts of an ovule (integument. megaspore, megasporangium) correspond to the parts of a seed
To describe: The way in which the parts of an ovule such as integument, megaspore, and megasporangium develop into the corresponding parts of a seed.
Introduction: The ovule in the female plant contains a single or a double layer of the diploid integument (2n). The megaspore cell is haploid (n) inside the ovule. The tissue megasporangium (2n) is present inside the ovule. The fertilization of the ovule by the sperm leads to the formation of the diploid zygote. It forms the seed ahead.
Explanation of Solution
The integument is the outer layer of the ovule in the female, which is diploid (2n). The megaspore cell is haploid inside the ovule. The tissue megasporangium inside the ovule is diploid (2n). The haploid (n) sperm cell enters the ovule through the pollen tube and fertilizes it. This leads to the formation of the fertilized diploid zygote in the plants like angiosperms and the gymnosperms. The other two haploid cells are fertilized by the other sperm to form the triploid (3n) cell containing the endosperm. This leads to the formation of the complete seed. The seed contains the fertilized ovule inside. The development of the seed takes place to form the seed coat, spore wall, and the inner tissue that supplies the food and nutrition.
The fertilization of the female ovule (n) takes place by the help of the male haploid (n) sperm. This leads to the formation of the diploid fertilized zygote (2n). The zygote then grows to form the seed containing the nutritious tissue, which provides the food and water. The other two haploid cells inside the ovule get fertilized by the sperm cell to form the triploid cell inside the ovule. This forms the complete seed in the plants.
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Chapter 30 Solutions
Campbell Biology (11th Edition)