Unlike nonvascular plants, all vascular plants—including seedless vascular plants—have a dominant sporophyte generation. 9. So, the gametophytic stage is restricted and of a very short duration as compared to the sporophytic stage. Like the ferns, gymnosperms (as well as angiosperms) have a dominant sporophyte (2n) generation. The ecological role and way of life of this sole photosynthetic phase of the conifer life cycle varies with the size, form, and habitat of each species. There are no free-living sporophytes. In other plants, such as ferns, both the gametophyte and sporophyte plants are free-living; however, the sporophyte is much larger. Remember the key features: 1. In other species, the size and shape of the sporophyte and gametophyte is nearly indistinguishable. Why is a dominant sporophyte generation an advantage on land? Most ferns have pinnate leaves, exhibiting small leaflets on a frond, as shown in Figure 19. The alternation of generations is an important concept in the evolution of plants. This means the cells of the plant in this generation or phase have two sets of chromosomes in their cells. Alternation of generations (also known as metagenesis) is the type of life cycle that occurs in those plants and algae in the Archaeplastida and the Heterokontophyta that have distinct haploid sexual and diploid asexual stages. In liverworts the gametophyte is the dominant generation. The gametophytes are very small and cannot exist independent of the parent plant. The life cycle of seedless plants like ferns, horsetails, and mosses has alternating phases of sporophyte and gametophyte phases. The sexual generation in plants produces gametes, or sex cells and is called the gametophyte generation. Bryophytes (mosses, liverworts and hornworts) have a dominant gametophyte stage on which the adult sporophyte is dependent on the gametophyte for nutrition. The seedless vascular plants include club mosses, which are the most primitive; whisk ferns, which lost leaves and roots by reductive evolution; and horsetails and ferns. In ferns the sporophyte is prominant (the large green plant), but the gametophytes, although small, are free-living and independent of the sporophyte. All land plants have alternating generations where one generation (the gametophyte generation) has half the genetic material as the second generation (the sporophyte). Learn vocabulary, terms, and more with flashcards, games, and other study tools. How Is The Sporophytic Generation Dominant In The Life Cycle Of Adiantum? Ferns do not have seeds: they only have spores. 2. The asexual phase produces spores and is called the sporophyte generation. Here, only the reproductive cells undergo meiosis or gametogenesis to give rise to male and female gametes that are haploid. A major function of the gametophyte generation is to produce haploid gametes. Liverwort is a gametophytic plant. A mature sporophyte fern has the familiar leafy fronds. Compare and contrast moss and fern sporophytes. The zygote or fertilized cell is what conduces to form the sporophyte. The heart-shaped prothallia produce gametes that unite to form a zygote, which develops into a new sporophyte plant. All land plants have alternation of generations. Separate male and female gametophytes are common which develop in micro and megaspores respectively. The following figure gives you an idea of the dominant and reduced stages in the life cycle of different plants. In the life cycle of a fern, the sporophyte generation is dominant. In many lower plants, gametophytes are the dominant and free-living generation. In these groups, a multicellular haploid gametophyte with n chromosomes alternates with a multicellular diploid sporophyte with 2n chromosomes, made up of n pairs. This means that the sporophyte is smaller is size and shorter-lived than the gametophyte generation. Plants may look simple, but the way they preserve their species is anything but. They have a life span that ranges from a few decades to more than 5,000 years. 10. Therefore, different generations are dominant in different plants. Large sporophyte nurtures the tiny female gametophytes. Sporophyte:The diploid sporophyte produces, in summer, a number of structures, the sori (singular Sourus). Gymnosperms: Sporophyte is dominant and heterosporous. This phase in the life cycle of a plant is the asexual, spore-bearing generation of the plant, featuring diploid cells. The plant body of the Bryophyte is gametophyte and it represents the dominant phase in its life cycle. Click to see full answer Besides, which generation is dominant in Coniferophytes? They are the only plants with a life cycle in which the gametophyte generation is dominant. Does Virginia Have A Tier 4 Extension? Alternation of generations describes a plant's life cycle as it alternates between a sexual phase, or generation and an asexual phase. The fern Their gametophytes are dependent on the sporophyte. These fuse to produce a diploid zygote. Seedless vascular plants include clubmosses and ferns.Figure below shows a typical fern life cycle. The fossil history of ferns shows them to have been a dominant plant group during the Paleozoic Era. The sporophyte is the dominant generation in Gymnosperms & Angiosperms. In ferns, gametophytes are tiny and only live for a few days. Answer (1 of 2): Life cycle of Adiantum shows heteromorphic alternation of generations. Fern gametophytes are very small and heart-shaped. Conifer - Conifer - Sporophyte phase: The sporophytes of all conifers are trees or shrubs. The haplontic life cycle is generally exhibited by algae. Fusion of the egg cell with the sperm cell gives rise to the sporophyte, thereby completing the life cycle (Raven et al., 1992). In ferns, the opposite is true and the sporophyte is the larger, more dominant individual. They have a life cycle which involves alternation between a generation of one set of chromosomes and two sets of chromosomes in order to reproduce.While the term sporophyte is referred to as plants that produce spores, the real definition is more complicated and interesting. Sporophyte generation is dominant in higher plants such as angiosperms and gymnosperms as well as in pteridophytes. Sori:The sori occur on the surface of the margins of the fertile pinnules.The margin of each pinnule is bent over the sorus to form a false indusium.The sori are green, but when rip they become dark brown. In mosses and their relatives (Bryophytes), the haploid gametophyte is the dominant generation, and the diploid sporophytes are sporangium-bearing stalks growing from the gametophytes. The moss sporophyte, a stalk and capsule, is dependent on the gametophyte, which is the dominant generation.