10/23/2020 The Fern Gametophyte Is Typically
Best Answer: The gametophyte is the generation that grows from a fern spore. It is a tiny heart-shaped plant that produces both eggs and sperms (gametes). When the eggs are fertilized, the resulting zygote grows into the sporophyte generation which is the plant that we recognize as a. The sexual form, called the gametophyte or prothallium, is a tiny kidney-shaped haploid (N) plant that is difficult to find in the wild. The asexual form, or sporophyte form, is represented by the fern plant as it is commonly known and is diploid (2N). Sporophytes can reproduce either by vegetative cloning via their rhizomes or through spore.
•••ale_ssandra/iStock/GettyImages
By J. Dianne Dotson
In all plants and some algae, an alteration of generations exists in which the species have diploid and haploid phases. Sexual reproduction results in gametes that combine two cells from different individuals. Meiosis also produces gametes. Haploids contain one set of chromosomes in each of their cells. Diploids cells contain two chromosome sets. For plants, haploid and diploid cells divide via mitosis. The plants’ haploid phase is called the gametophyte, and the diploid phase is called the sporophyte. Offspring alternate from diploid sporophytes to haploid gametophytes and back again in generations. This means plants generate two different kinds of plants with the same genetic material.
TL;DR (Too Long; Didn't Read)
Plants exist in alternation generations called sporophytes and gametophytes. Sporophytes represent the diploid phase of plants. Gametophytes represent the haploid phase of plants.
Characteristics of Sporophytes
Sporophytes are diploid plants that use meiosis to produce spores. These spores are haploid cells that grow into haploid gametophytes. Megaspores grow into female gametophytes, and microspores grow into male gametophytes. Meiosis occurs in the sporangium of a sporophyte and results in haploid spores. These spores contain one cell that can become another new plant without mating. Sporophytes have evolved in vascular plants to become larger, more dominant and longer-lived compared to gametophytes.
Characteristics of Gametophytes
Gametophytes are haploid plants that use mitosis to make haploid gametes. These gametes are female in the form of an ovum (egg) or male in the form of sperm. Gametophytes contain the archegonium, or female sex organ, or they contain the antheridium, or male sex organ. The sperm and egg unite in the archegonium to produce a diploid zygote cell. That zygote becomes a sporophyte. https://alarmven.weebly.com/blog/boot-camp-vm-for-mac. Vascular plant gametophytes tend to be much smaller than sporophytes, sometimes even only a few cells in size. A pollen grain represents an example of a male gametophyte in vascular plants.
Non-vascular vs. Vascular Plants
Vascular and non-vascular plants display interesting differences between their sporophytes and gametophytes. Vascular plants do not require as much water to thrive, and they display their large, long-lived sporophyte phase as the actual plant. Gymnosperms such as conifers contain a bit of female gametophyte tissue in their cones, such as pine nuts. Those nuts contain the embryonic diploid sporophyte. The male conifer gametophyte exists as pollen, which is wind-dispersed. For flowering plants such as fruit trees and flowers, female gametophytes contain a few cells and reside inside the ovary of the flower; the male exists as pollen. The small gametophytes of vascular plants only live for a season. Vascular plants that make two kinds of spores and gametophytes are called heterosporic.
Non-vascular plants such as bryophytes (which include mosses, liverworts and hornworts) display different characteristics for their gametophytes and sporophytes. Bryophytes comprise the oldest land plants on the planet, having existed for over 400 million years. They require wetter locales for their reproductive success. Their sporophytes are not visibly dominant. However, their gametophyte generation is the noticeable, photosynthetic part of the plant (like green moss) that attaches to substrates via rhizoids rather than the diploid sporophyte. In fact, their sporophytes are not as long-lived as in vascular plants. The sporophyte forms from a fertilized egg inside the flask-like archegonium and attaches to the gametophyte via a penetrating foot. The sporophyte receives nourishment from the gametophyte. The sporophyte forms a very small stalk called a seta and a single sporangium. A protective covering called a calyptra surrounds this embryonic sporophyte. Single-celled spores travel via wind and germinate only in a moist area; water is required for fertilization. Then they form a new gametophyte plant, which creates more spores in the sporophyte cycle. Because they make just one type of spore and gametophyte, these non-vascular plants are called homosporic.
Genetic Controls of Generation Processes
Scientists continue to learn more alternating generations in plants. Genetic studies of mosses reveal that a group of proteins called KNOX help drive development of sporophytes. https://gainentrancement.weebly.com/blog/mugen-characters-download-game-walkers. In the angiosperm Arabidopsis thaliana, the PKL gene is needed for maternal sporophytes to promote male and female gametophyte development. Continued research yields even more fascinating aspects of the complex nature of sporophyte and gametophyte generation processes. Bayapadathe rabbit mac song download.
A gametophyte represents the sexual phase of the plant life. This cycle is named alternation of generations and organisms alternate between a sexual phase, or gametophyte generation and an asexual phase, or sporophyte generation. The term gametophyte may refer to the gametophyte phase of the plant life cycle or to the particular plant body or organ that produces gametes.
It is in the haploid gametophyte structure that gametes are formed. These male and female sex cells, also known as eggs and sperm, unite during fertilization to form a diploid zygote. The zygote develops into a diploid sporophyte, which represents the asexual phase of the cycle. Sporophytes produce the haploid spores from which haploid gametophytes develop. Depending on the type of plant, most of its life cycle may be spent in either the gametophyte generation or sporophyte generation. Other organisms, such as some algae and fungi, may spend most of their life cycles in the gametophyte phase.
Gametophyte Development
Gametophytes develop from the germination of spores. Spores are reproductive cells that can give rise to new organisms asexually (without fertilization). They are haploid cells that are produced by meiosis in sporophytes. Upon germination, the haploid spores undergo mitosis to form a multicellular gametophyte structure. The mature haploid gametophyte then produces gametes by mitosis.
This process differs from what is seen in animal organisms. In animal cells, haploid cells (gametes) are only produced by meiosis and only diploid cells undergo mitosis. In plants, the gametophyte phase ends with the formation of a diploid zygote by sexual reproduction. Adobe acrobat xi downloads. The zygote represents the sporophyte phase, which consists of the plant generation with diploid cells. The cycle begins anew when the diploid sporophyte cells undergo meiosis to produce haploid spores.
Gametophyte Generation in Non-vascular Plants
The gametophyte phase is the primary phase in non-vascular plants, such as mosses and liverworts. Most plants are heteromorphic, meaning that they produce two different types of gametophytes. One gametophyte produces eggs, while the other produces sperm. Mosses and liverworts are also heterosporous, meaning that they produce two different types of spores. These spores develop into two distinct types of gametophytes; one type produces sperm and the other produces eggs. The male gametophyte develops reproductive organs called antheridia (produce sperm) and the female gametophyte develops archegonia (produce eggs).
What Is A Gametophyte Apex
Non-vascular plants must live in moist habitats and rely on water to bring the male and female gametes together. Upon fertilization, the resulting zygote matures and develops into a sporophyte, which remains attached to the gametophyte. The sporophyte structure is dependent upon the gametophyte of nourishment because only the gametophyte is capable of photosynthesis. The gametophyte generation in these organisms consists of the green, leafy or moss-like vegetation located at the base of the plant. Eyelink data viewer download mac. The sporophyte generation is represented by the elongated stalks with spore-containing structures at the tip.
Gametophyte Generation in Vascular Plants
In plants with vascular tissue systems, the sporophyte phase is the primary phase of the life cycle. Unlike in non-vascular plants, the gametophyte and sporophyte phases in non-seed producing vascular plants are independent. Both the gametophyte and the sporophyte generations are capable of photosynthesis. Ferns are examples of these types of plants. Many ferns and other vascular plants are homosporous, meaning that they produce one type of spore. Best mac app for adding text to photos. The diploid sporophyte produces haploid spores (by meiosis) in specialized sacs called sporangia.
Sporangia are found on the underside of the fern leaves and release spores into the environment. When a haploid spore germinates, it divides by mitosis forming a haploid gametophyte plant called a prothallium. The prothallium produces both male and female reproductive organs, which form sperm and eggs respectively. Water is needed for fertilization to take place as sperm swim toward the female reproductive organs (archegonia) and unite with the eggs. After fertilization, the diploid zygote develops into a mature sporophyte plant that arises from the gametophyte. https://conceptsite942.weebly.com/blog/sony-vaio-touchpad-scroll-driver-windows-7. In ferns, the sporophyte phase consists of the leafy fronds, sporangia, roots, and vascular tissue. The gametophyte phase consists of the small, heart-shaped plants or prothallia.
Gametophyte Generation in Seed Producing Plants
Rosetta stone full free download. In seed producing plants, such as angiosperms and gymnosperms, the microscopic gametophyte generation is totally dependent upon the sporophyte generation. In flowering plants, the sporophyte generation produces both male and female spores. Male microspores (sperm) form in microsporangia (pollen sacs) in the flower stamen. Female megaspores (eggs) form in megasporangium in the flower ovary. Many angiosperms have flowers that contain both microsporangium and megasporangium.
The fertilization process occurs when pollen is transfered by wind, insects, or other plant pollinators to the female portion of the flower (carpel). The pollen grain germinates forming a pollen tube that extends downward to penetrate the ovary and allow a sperm cell to fertilize the egg. The fertilized egg develops into a seed, which is the beginning of a new sporophyte generation. The female gametophyte generation consists of the megaspores with embryo sac. The male gametophyte generation consists of microspores and pollen. The sporophyte generation consists of the plant body and seeds.
The Fern Gametophyte Is Typically OneGametophyte Key TakeawaysThe Fern Gametophyte Is Typically
SourcesFern Gametophyte Sporophyte
Comments are closed.
|
AuthorWrite something about yourself. No need to be fancy, just an overview. Archives
December 2020
Categories |