seed dormancy

(noun)

a seed with the ability to delay germination and propagation of the species until suitable conditions are found

Related Terms

  • dispersal
  • mechanisms

Examples of seed dormancy in the following topics:

  • Fruit and Seed Dispersal

    • The fruit has a single purpose: seed dispersal.
    • Modifications in seed structure, composition, and size aid in dispersal.
    • Humans also play a major role in dispersing seeds when they carry fruits to new places, throwing away the inedible part that contains the seeds.
    • Seed dormancy allows plants to disperse their progeny through time: something animals cannot do.
    • Summarize the ways in which fruits and seeds may be dispersed
  • Development of the Seed

    • Monocot and dicot seeds develop in differing ways, but both contain seeds with a seed coat, cotyledons, endosperm, and a single embryo.
    • The seed, along with the ovule, is protected by a seed coat that is formed from the integuments of the ovule sac.
    • In monocot seeds, the testa and tegmen of the seed coat are fused.
    • However, many mature seeds enter a period of dormancy marked by inactivity or extremely-low metabolic activity.
    • Dormancy helps keep seeds viable during unfavorable conditions.
  • Abscisic Acid, Ethylene, and Nontraditional Hormones

    • ABA inhibits stem elongation and induces dormancy in lateral buds.
    • ABA induces dormancy in seeds by blocking germination and promoting the synthesis of storage proteins.
    • Plants adapted to temperate climates require a long period of cold temperature before seeds germinate.
    • As the hormone gradually breaks down over winter, the seed is released from dormancy and germinates when conditions are favorable in spring.
    • Apical dominance, seed germination, gravitropism, and resistance to freezing are all positively influenced by hormones.
  • The Evolution of Seed Plants and Adaptations for Land

    • The evolution of seeds allowed plants to reproduce independently of water; pollen allows them to disperse their gametes great distances.
    • Seed plants, such as palms, have broken free from the need to rely on water for their reproductive needs.
    • Storage tissue to sustain growth and a protective coat give seeds their superior evolutionary advantage.
    • Furthermore, seeds remain in a state of dormancy induced by desiccation and the hormone abscisic acid until conditions for growth become favorable.
    • Seed plants dominate the landscape and play an integral role in human societies.
  • Subtropical Deserts and Chaparral

    • Seed plants in the desert produce seeds that can remain in dormancy for extended periods between rains.
    • The chaparral vegetation is dominated by shrubs and is adapted to periodic fires, with some plants producing seeds that only germinate after a hot fire .
    • Some plants produce seeds that only germinate after a hot fire.
  • Auxins, Cytokinins, and Gibberellins

    • Gibberellins (GAs) are a group of about 125 closely-related plant hormones that stimulate shoot elongation, seed germination, and fruit and flower maturation.
    • GAs are synthesized in the root and stem apical meristems, young leaves, and seed embryos.
    • GAs break dormancy (a state of inhibited growth and development) in the seeds of plants that require exposure to cold or light to germinate.
    • Seedless grapes are obtained through standard breeding methods; they contain inconspicuous seeds that fail to develop.
    • Because GAs are produced by the seeds and because fruit development and stem elongation are under GA control, these varieties of grapes would normally produce small fruit in compact clusters.
  • Angsiosperm Fruit

    • A fertilized, fully grown, and ripened ovary containing a seed forms what we know as fruit, important seed dispersal agents for plants.
    • As the seed develops, the walls of the ovary in which it forms thicken and form the fruit, enlarging as the seeds grow.
    • Regardless of how they are formed, fruits are an agent of seed dispersal.
    • Once eaten, tough, undigested seeds are dispersed through the herbivore's feces.
    • The winged shape of Alsomitra macrocarpa's seeds allow them to use wind for dispersal.
  • Agricultural Diversity

    • Sometimes, however, seed banks are lost through accidents; there is no way to replace them.
    • In 2008, the Svalbard Global Seed Vault began storing seeds from around the world as a backup system to the regional seed banks .
    • If a regional seed bank stores varieties in Svalbard, losses can be replaced from those stored here.
    • The seed vault is located deep into the rock of an arctic island.
    • The Svalbard Global Seed Vault is a protected storage facility in the arctic for seeds of earth's diverse crops.
  • Evolution of Gymnosperms

    • Seed ferns gave rise to the gymnosperms during the Devonian Period, allowing them to adapt to dry conditions.
    • The fossil plant Elkinsia polymorpha, a "seed fern" from the Devonian period (about 400 million years ago) is considered the earliest seed plant known to date.
    • Seed ferns produced their seeds along their branches without specialized structures .
    • What makes them the first true seed plants is that they developed structures called cupules to enclose and protect the ovule (the female gametophyte and associated tissues) which develops into a seed upon fertilization.
    • This gave a reproductive edge to seed plants, which are better adapted to survive dry spells.
  • The Major Divisions of Land Plants

    • Land plants, or embryophytes, are classified by the presence or absence of vascular tissue and how they reproduce (with or without seeds).
    • Lycophytes and pterophytes are both referred to as seedless vascular plants because they do not produce any seeds.
    • The seed producing plants, or spermatophytes, form the largest group of all existing plants, dominating the landscape.
    • Seed-producing plants include gymnosperms, most notably conifers, which produce "naked seeds," and the most successful of all modern-day plants, angiosperms, which are the flowering plants.
    • Land plants are categorized by presence or absence of vascular tissue and their reproduction with or without the use of seeds.
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