Spermatophyta : Definition, Example, Image, Type, Characteristics, Classification
Posted: Dec 01, 2019
[/ul]Spermatophyta body structure as follows:
[/ol]Seedlings can be either woody or watery stems. Stems in seed plants can be modified into stolons, rhizomes, and tubers. Stem cells differentiate into epidermis, cortex, and central cylinder (there are xylem and phloem).
[/ul]In its life cycle there are several stages, including:
Gametogenesis, namely the formation of gametes (sex cells). Occur in the flower section.
Pollination (Pollination), ie the fall / adherence of pollen to the pistil's head (to Angiosperms) or adhering to pollen on the ovaries (Gymnosperms).
Type of Pollination:
Based on pollen origin
Feature: flowers that are not able to pollinate themselves. This is because the stamens or pistils do not mature together. Protandri, i.e. if the stamens cook earlier than the pistil. Protogeny, i.e. if the pistil cooks before the stamens.
Fertilization (fertilization), which is the process of fusion of male gametes (sperm) with female gametes (ovums).
After pollination, sperm move towards the egg through the pollen reed, then the fusion of the egg nucleus and sperm nucleus occurs in the ovule. Ovula is a sporophyte structure containing female megasporangium and gametophyte. Fertilization between male and female gametes will produce embryos (institutions).
Based on that event, seed plants are also called embryophyta siphonogama, which are plants that have embryos and their mating takes place through the formation of a feather. Embryos in seed plants are bipolar (dwipolar), because at one pole they will grow and develop to form stems and leaves, while other poles form a root system.
There are 2 types of fertilization in seed plants:
Single fertilization (fertilization that occurs once fertilization), namely the fusion of male gametes and female gametes that produce embryos. Occurs in Gymnosperms.
Dual fertilization (fertilization that occurs twice fertilization), namely:
fusion of sperm nucleus> embryo.
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