University:
Central Michigan University
Course:
BIO 525 | Plant Ecology
Academic year:

2022
Views:

205

Pages:

2
Author:

Carissa Thomas

Moss Life Cycle The moss life cycle is our example for the bryophytes. This is your first plant life cycle to learn, and it is an excellent example of Alternation of Generations. Make sure you familiarize yourself with the template for Alternation of Generations before you start on applying it to this one. A. Spore Germination and Gametophyte Development When the haploid spores are released by the diploid sporophyte and are introduced into a suitable area with moist soil, they will germinate into the first of two gametophyte stages. Haploid protonema will emerge from the spores and resemble filamentous green algae. These protonema are unique to the bryophytes and are not seen in any other plant group ǁĞŝŶǀĞƐƚŝŐĂƚĞƚƐŽŵĞƉŽŝŶƚƐŵĂůůďƵĚƐǁŝůůĨŽƌŵ on t ema, and those buds will eventually develop by mito is into the haploid l hyte, which is the second gametophyte stage. Mosses are dioecious, meaning they have separate male and female plants. Each have their own specific gametangia. The male gametophytes have antheridia and the female gametophytes have archegonia. B. Gamete Formation and Fertilization Spermatogenous tissue within the a ia of the the male gametophyte will produce flagellated sperm itosis. The a a are surrounded by several sterile hairs called p yses, which are designed to trap water for keeping the antheridia moist. Like the male gametophyte ridia, the female gametophyte will have several archegonia. Archegonia have a swollen base, called the venter, that contains a single egg. Above the venter is the neck, with a hollow center called the neck canal, which provides a pathway for the flagellated sperm to reach the egg. Like the antheridia, the archegonia are also surrounded by several paraphyses. The sperm are transported to the archegonia by water splashing the sperm from the antheridia to the archegonia. Once the sperm reach the egg, fertilization occurs to produce a diploid zygote. C. Sporophyte Development and Spore Production The diploid zy will under several mitotic divisions to produc ryo and that e o will continue to d de by mitosis l it is a y te. The sp e stage is d n the ga yte for energy and cannot survive on its own. The sporo yte will con nue ng until the it tes into a long stalk called the a that will support the capsule, which is a sporangium. Within the sporangium is sporogenous tissue that will undergo meiosis to produce the haploid spores. On the tip of the capsule is a protective cap called the operculum, and it will remain in place until the spores are ready to be released. Under the operculum is a structure called the peristome. When the operculum detaches, the peristome will flex with changes in humidity and that is the mechanism that releases the spores. When the spores are released, they will germinate when conditions are optimal, thus starting the life cycle again.

Moss Life Cycle Guide

Related Documents

Recommended Documents

Description

Related Documents

Almost There!

Free up your schedule!

Take 5 seconds to unlock