Polyembryony in Gymnosperms
Polyembryony in Gymnosperms includes conifers, cycads, ginkgoes, and genitals, and can manifest in several distinct types. Here are some of the different types of polyembryony observed in gymnosperms:
Polyembryony in Cycadales
- Cycadales, commonly known as cycads, are ancient gymnosperms characterized by their palm-like appearance.
- In Cycadales, polyembryony typically involves the formation of multiple embryos from a single fertilized egg cell.
- The additional embryos may arise through the process of cleavage or the division of the zygote into several cells, each of which can develop into an embryo.
- Polyembryony in Cycadales contributes to the production of multiple seedlings from a single seed, potentially increasing the chances of survival and dispersal for the species.
Polyembryony in Coniferales
- Coniferales, also known as conifers, include familiar trees such as pines, spruces, firs, and cedars.
- In Coniferales, polyembryony can occur through various mechanisms. One common mechanism involves the formation of multiple embryos from several fertilized egg cells within the same seed.
- Polyembryony in conifers can also result from the development of adventitious embryos from tissues other than the fertilized egg, such as the nucellus or integuments.
- Like in Cycadales, polyembryony in Coniferales contributes to the production of multiple seedlings from a single seed, potentially enhancing reproductive success and genetic diversity.
Polyembryony in Taxales
- Taxales, represented by the single extant genus Taxus (yews), are another group of gymnosperms.
- Polyembryony in Taxales is less common compared to some other gymnosperm groups, but it still occurs.
- In Taxales, polyembryony typically involves the formation of multiple embryos from a single fertilized egg cell or multiple fertilized egg cells within the same seed.
- As with other gymnosperms, polyembryony in Taxales can lead to the production of multiple seedlings from a single seed, potentially increasing the chances of successful seedling establishment.
Polyembryony in Gnetales
- Gnetales is a small group of gymnosperms that includes three genera: Gnetum, Ephedra, and Welwitschia.
- Polyembryony in Gnetales is relatively rare compared to other gymnosperm groups.
- In Gnetales, polyembryony can occur through the formation of multiple embryos from a single fertilized egg cell or from multiple fertilized egg cells within the same seed.
- While less common, polyembryony in Gnetales still contributes to the production of multiple seedlings from a single seed, which may enhance reproductive success and dispersal in these plants.
Polyembryony – Types, Causes, and Importance
Polyembryony refers to the occurrence of multiple embryos developing within a single ovule, seed, or fertilized ovum, and it is observed in both animals and plants. Polyembryony can be influenced by environmental conditions and genetic factors. Environmental factors such as temperature, light, and nutrient availability can cause polyembryony in certain plant species. Polyembryony examples are seen in mango, citrus, and in gymnosperms.
Genetic factors, including specific gene mutations or variations, may also play a role in regulating polyembryony. In this article, we will look into the meaning, causes, types, examples, and significance of polyembryony.
Table of Content
- What is Polyembryony in Plants?
- Causes of Polyembryony
- Types of Polyembryony
- Polyembryony in Mango
- Polyembryony in Gymnosperms
- Examples of Polyembryony
- Difference Between Apomixis and Polyembryony
- Importance of Polyembryony in Plants