Learn How Mosses Reproduce Bryophyta Life Cycle

today we're going to talk about reproduction and mosses or bryophyta but first let's define what Mosses are Mosses are non-vascular plants that don't produce flowers and seeds but instead reproduce with spores even though some mosses have tissues that transport nutrients within moss body these Transport Systems don't contain lignin and are structurally different from True vascular tissue in the vascular plants true mosses belong to the phylum bryophyta but you might have come across the more general term bryophytes before bryophytes include three different phyla liverworts or mercantiophyta hornworts or anthocerotophyta and finally our mosses bryophyta be careful about these terms sometimes you might see these terms bryophyta versus bryophytes used incorrectly while all bryophytes share many characteristics and look quite similar we will be focusing only on true mosses the bryophyta you've probably seen mosses growing in Shady moist environments where most of them Thrive but these are not the only types of places where you can find them they grow anywhere from the Arctic tundra through sand dunes to Tropical regions foreign Roots as vascular plants do but have short rhizoids to help them attach to surface or substrate you might see this when you try to peel the Moss from the surface it's growing on it usually comes off very easily having these rhizoids can be quite advantageous since it means that mosses don't necessarily need soil and can grow on different types of substrates including hard surfaces like walls roofs rocks or bark or on top of solid frozen soil in Arctic regions as we mentioned before this also means they can inhabit areas where vascular plants can't survive because of their lack of vascular system in the majority of species nutrients and water are absorbed from the atmosphere and rainwater directly through the surface of the Moss body as opposed to being sucked up from the soil and transported by conducting systems into the rest of the plant as in the vascular plants not having lignified vascular tissue restricts mosses in another way the ability to reach grade height that's why you mostly see them growing in low Mounds or creeping along surfaces now that we know that mosses don't have flowers or seeds how does their reproduction work mosses can reproduce both asexually and sexually asexual reproduction Works via fragmentation where pieces of vegetative tissue simply break off and regrow into new plant genetically identical to the parent plant on the other hand sexual reproduction results in plant with an equal combination of genetic material from two parent plants mosses sometimes take advantage of both sexual and asexual reproduction during their lives however sexual reproduction is more frequent let's start with the Moss life stage that we observe most commonly those round green Mounds are spreading mats with short leafy shoots here we're looking at the longest lived and the most conspicuous stage of the Moss life cycle the gametophyte so what's the difference between gametophyte and sporophyte you might have heard these terms in connection with the concept of alternation of generations in plant's life cycle this type of plant life cycle consists of both the gametophyte stage in which plant cells have only one set of chromosomes we call this haploid or 1n and the sporophyte phase in which their cells have two sets of chromosomes one set from each parent we call this diploid or 2N however different plant groups spend different amounts of time in each stage vascular plants the dominant life phase is the sporophyte and the gametophyte is severely reduced this is remarkable difference between the bryophytes and the vascular plants which are also called higher plants let's get back to our Moss gametophyte most Moss species produce only male or only female sexual organs on one individual which means that there are separate male and female plants we call these species diocas however mosses can also be monochus meaning that one individual produces both male and female sexual organs in this case on separate stalks whether the mass is diocus or monochus is dependent on the species hamas's sexual organs develop at the tip of chute or stem usually hidden by rosette of leaves called pericardium and are not easily observable without microscope both male and female sexual structures produce sexual cells which we call gametes via cell division the male sexual structure is called an antheridium and it produces many male gametes called sperm female sexual structure is called an archegonium and each archegonium produces one egg both male and female gametes sperm and eggs are haploid just like gametophyte since they were created by type of cell division called mitosis in which parent cell divides into two identical daughter cells with the same number of chromosomes so now that there are sperm and eggs we need suitable conditions for these two reproductive cells to meet in bryophytes their meeting requires water Mosses are characterized by their flagellic sperm that need water in order to swim to the egg and how does tiny sperm actually make it from its antheridium all the way to the archegonium where the egg is waiting one of the most commonly discussed methods is transportation of sperm to egg via raindrop that lands on the antheridium splashing the sperm out it then lands in an archegonium as you can imagine such raindrop usually doesn't take the sperm very far and that's why some mosses have evolved Splash cups which are modified structures around antheridia making the splash of the Raindrop reach much further with water droplets loaded with sperm might have different means of transportation by little creatures living in mosses most commonly springtails who can passively carry droplets on their bodies as they roam between Moss stems and in doing so accidentally spread the sperm to an archegonium once the sperm gets to the egg the sperm and egg combine into one cell forming zygote this zygote then divides and grows into an embryo via mitosis note that the zygote and the daughter cells resulting from this mitosis carry genetic information from both parents this is the beginning of the diploid or sporophyte phase of the Moss life cycle sporophyte part of the Moss stays attached to the gametophyte so we get moss plant in which the bottom portion is gametophyte and the top asporophyte the sporophyte consists of aceta which looks like stem with bulge on the top that bulge is Spore capsule however in some species the Sedum might be missing the Spore capsule is often covered by detachable calyptra sort of hat or beak for the structure that provides the maturing capsule protection from dehydration the capsule is covered by an operculum which functions as lid and is often easily visible as differently colored tip of the capsule inside the Spore capsule spores are created by meiosis during meiosis the number of chromosomes is reduced by half while at the same time the genetic material is recombined resulting in numerous cells Each of which has unique combination of its parents genetic material this gets us back to the haploid part of the Moss life cycle this point you can already see how brief the diploid portion of the Moss life cycle was when spores inside the capsule mature the caliptra is shed the operculum opens up and the spores are released the rim of the capsule is frequently lined by triangular teeth collectively called the peristome peristome teeth move Inward and outward in response to humidity aiding the release of the spores if Spore lands in place with suitable moist conditions it starts to germinate and develops into protonema which is the juvenile form of the gametophyte protonema is filamentous and looks similar to green algae as it continues with its development the protonema creates buds that eventually grow into the leafy moss form we're familiar with the gametophyte cycle starts over again foreign