1. Apomixis:
* Definition: Apomixis is a form of asexual reproduction in plants where seeds are produced without meiosis or fertilization.
* Mechanism: The embryo inside the seed develops directly from the maternal tissues (like the ovule or the nucellus) without the fusion of gametes.
* Types: Apomixis can occur in several ways, including:
* Diplospory: The embryo develops from the unreduced diploid egg cell.
* Apospory: The embryo develops from a diploid cell in the ovule that is not part of the egg cell.
* Adventitious embryony: The embryo develops from a cell in the nucellus or other surrounding tissues.
* Examples: Dandelions, some grasses, and some citrus fruits.
2. Parthenocarpy:
* Definition: Parthenocarpy is the development of fruits without fertilization. These fruits are seedless or have underdeveloped seeds.
* Mechanism: This process usually involves hormonal changes within the plant, leading to fruit development without the usual pollination and fertilization.
* Types:
* Genetic Parthenocarpy: Inherently seedless, due to a genetic mutation or specific gene expression.
* Environmental Parthenocarpy: Induced by environmental factors like temperature, light, or hormones.
* Examples: Bananas, pineapples, seedless grapes, and some cucumbers.
Key Differences:
* Apomixis: Results in seeds that are genetically identical to the mother plant.
* Parthenocarpy: Results in fruits without seeds or with underdeveloped seeds, but does not directly involve seed development.
Both apomixis and parthenocarpy allow plants to reproduce without relying on pollinators or fertilization, leading to unique reproductive strategies in the plant kingdom.
