The plumule is the part of a seed embryo that develops into the shoot bearing the first true leaves of a plant. In most seeds, for example the sunflower, the plumule is a small conical structure without any leaf structure. Growth of the plumule does not occur until the cotyledons have grown above ground. This is epigeal germination.
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However, in seeds such as the broad bean, a leaf structure is visible on the plumule in the seed. These seeds develop by the plumule growing up through the soil with the cotyledons remaining below the surface. This is known as hypogeal germination.
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The terminal growing bud of the axis is called the plumule or gemmule, and represents the ascending axis.
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The early development of a monocot seedling like cereals and other grasses is somewhat different. A structure called the coleoptile, essentially a part of the cotyledon, protects the young stem and plumule as growth pushes them up through the soil. A mesocotyl—that part of the young plant that lies between the seed (which remains buried) and the plumule—extends the shoot up to the soil surface, where secondary roots develop from just beneath the plumule. The primary root from the radicle may then fail to develop further.
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They will lose their viability if stored for 3 years or more; some seeds survive if stored for 2 years. Germination is hypogeal and cotyledons remain within the seed coat. Strictly speaking, hypogeal means the cotyledons stay in the soil, acting as a food store for the seedling until the plumule emerges from the soil on the epicotyl or true stem. However, pawpaw seeds have occasionally been observed to emerge from the ground and form the true stem and plumule above ground.
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If the radicle begins to decay, the seedling undergoes pre- emergence damping off. This disease appears on the radicle as darkened spots. Eventually, it causes death of the seedling. The plumule is the baby shoot.
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The scutellum is a tissue within the seed that is specialized to absorb stored food from the adjacent endosperm. The coleoptile is a protective cap that covers the plumule (precursor to the stem and leaves of the plant). Gymnosperm seedlings also have cotyledons, and these are often variable in number (multicotyledonous), with from 2 to 24 cotyledons forming a whorl at the top of the hypocotyl (the embryonic stem) surrounding the plumule. Within each species, there is often still some variation in cotyledon numbers, e.g.
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Seeds are dispersed by birds and bats that feed upon the fruit. Seed germination is adjacent ligular—during germination, as the cotyledon expands it only pushes a portion of the embryo out of the seed. As a result, the seedling develops adjacent to the seed. The embryo forms a ligule, and the plumule protrudes from this.
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Taralea is a genus of flowering plants in the legume family, Fabaceae. It belongs to the subfamily Faboideae. Taralea can be distinguished from other members of the Dipterygeae by: > a black and rugose petiolule; an elliptical, hairy ovary; a legume with > elastic dehiscence; a circular, oval, compressed seed with a basal hilum; > and an embryo that displays a cleft below the radical–hypocotyl axis and an > inconspicuous plumule.
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A number of plants have soil-level or above-ground rhizomes, including Iris species and many orchid species. > T. Holm (1929) restricted the term rhizome to a horizontal, usually > subterranean, stem that produces roots from its lower surface and green > leaves from its apex, developed directly from the plumule of the embryo. He > recognized stolons as axillary, subterranean branches that do not bear green > leaves but only membranaceous, scale-like ones.
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African Journal of Biotechnology, 10, 16577-16580. Certain traits of Agropyron desertorum, however, allow it to overcome the stress from salinity. For example, A. desertorum plants with greater root length, plumule length, seed length, and seed vigor have been found to germinate and tolerate salinity better during the seedling stage. Agropyron desertorum plants with these conditions can be selected for and grown within drier areas, to allow for better crop production of this crested wheatgrass.
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The opening of the cotyledons exposes the shoot apical meristem and the plumule consisting of the first true leaves of the young plant. The seedlings sense light through the light receptors phytochrome (red and far-red light) and cryptochrome (blue light). Mutations in these photo receptors and their signal transduction components lead to seedling development that is at odds with light conditions, for example seedlings that show photomorphogenesis when grown in the dark..
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Germinating sunflower seedlings Seed germination is a process by which a seed embryo develops into a seedling. It involves the reactivation of the metabolic pathways that lead to growth and the emergence of the radicle or seed root and plumule or shoot. The emergence of the seedling above the soil surface is the next phase of the plant's growth and is called seedling establishment. Three fundamental conditions must exist before germination can occur.
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About 20 days after germination, the cotyledon reaches a length of about and begins to swell. By the thirtieth day the lower are swollen, and about half the reserves in the seed have been mobilised. At about this point in time, the young root (the radicle) emerges. Sixty days after germination the transfer of reserved from the seed has been completed, but it is only after 80 or 90 days that the young shoot (the plumule) emerges from the cotyledon.
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As the plant embryo grows at germination, it sends out a shoot called a radicle that becomes the primary root, and then penetrates down into the soil. After emergence of the radicle, the hypocotyl emerges and lifts the growing tip (usually including the seed coat) above the ground, bearing the embryonic leaves (called cotyledons), and the plumule that gives rise to the first true leaves. The hypocotyl is the primary organ of extension of the young plant and develops into the stem.
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