In horticulture, stratification is a process of treating seeds to simulate natural conditions that the seeds must experience before germination can occur. Many seed species have an embryonic dormancy phase and generally will not sprout until this dormancy is broken. [1]
The term stratification can be traced back to at least 1664 in John Evelyn's Sylva, or A Discourse of Forest-Trees and the Propagation of Timber , [2] where seeds were layered (stratified) between layers of moist soil and the strata were exposed to winter conditions. Thus, stratification became the process by which seeds were artificially exposed to conditions to encourage germination.
Cold stratification is the process of subjecting seeds to both cold and moist conditions. Seeds of many trees, shrubs and perennials require these conditions before germination will ensue. [3]
In the wild, seed dormancy is usually overcome by the seed spending time in the ground through a winter period and having its hard seed coat softened by frost and weathering action. By doing so the seed is undergoing a natural form of "cold stratification" or pretreatment. This cold moist period triggers the seed's embryo; its growth and subsequent expansion eventually break through the softened seed coat in its search for sun and nutrients.[ citation needed ]
Cold stratification simulates the natural process by subjecting seed to a cool (ideally +1 to +3 °C [34 to 37 degrees Fahrenheit]) moist environment for a period one to three months. Seeds are placed in a medium such as vermiculite, peat, or sand and refrigerated in a plastic bag or sealed container. [1] Soaking the seeds in cold water for 6–12 hours before placing them in cold stratification can cut down on the amount of time needed for stratification, as the seed needs to absorb some moisture to enable the chemical changes that take place.[ citation needed ]
Use of a fungicide to moisten the stratifying vermiculite will help prevent fungal diseases. Chinosol (8-quinolyl potassium sulfate [4] ) is one such fungicide used to inhibit Botrytis cinerea infections. [5]
Any seeds that are indicated as needing a period of warm stratification followed by cold stratification should be subjected to the same measures, but the seeds should additionally be stratified in a warm area first, followed by the cold period in a refrigerator later. Warm stratification requires temperatures of 15–20 °C (59–68 °F). In many instances, warm stratification followed by cold stratification requirements can also be met by planting the seeds in summer in a mulched bed for expected germination the following spring. Some seeds may not germinate until the second spring.[ citation needed ]
In botany, a seed is a plant embryo and nutrient reserve enclosed in a seed coat, a protective outer covering called a testa. More generally, the term "seed" means anything that can be sown, which may include seed and husk or tuber. Seeds are the product of the ripened ovule, after the embryo sac is fertilized by sperm from pollen, forming a zygote. The embryo within a seed develops from the zygote and grows within the mother plant to a certain size before growth is halted.
Stratification may refer to:
Germination is the process by which an organism grows from a seed or spore. The term is applied to the sprouting of a seedling from a seed of an angiosperm or gymnosperm, the growth of a sporeling from a spore, such as the spores of fungi, ferns, bacteria, and the growth of the pollen tube from the pollen grain of a seed plant.
Dormancy is a period in an organism's life cycle when growth, development, and physical activity are temporarily stopped. This minimizes metabolic activity and therefore helps an organism to conserve energy. Dormancy tends to be closely associated with environmental conditions. Organisms can synchronize entry to a dormant phase with their environment through predictive or consequential means. Predictive dormancy occurs when an organism enters a dormant phase before the onset of adverse conditions. For example, photoperiod and decreasing temperature are used by many plants to predict the onset of winter. Consequential dormancy occurs when organisms enter a dormant phase after adverse conditions have arisen. This is commonly found in areas with an unpredictable climate. While very sudden changes in conditions may lead to a high mortality rate among animals relying on consequential dormancy, its use can be advantageous, as organisms remain active longer and are therefore able to make greater use of available resources.
Plant propagation is the process by which new plants grow from various sources, including seeds, cuttings, and other plant parts. Plant propagation can refer to both man-made and natural processes.
Silviculture is the practice of controlling the growth, composition/structure, as well as quality of forests to meet values and needs, specifically timber production.
Asclepias incarnata, the swamp milkweed, rose milkweed, rose milkflower, swamp silkweed, or white Indian hemp, is a herbaceous perennial plant species native to North America. It grows in damp through wet soils and also is cultivated as a garden plant for its flowers, which attract butterflies and other pollinators with nectar. Like most other milkweeds, it has latex containing toxic chemicals, a characteristic that repels insects and other herbivorous animals.
Seed dormancy is an evolutionary adaptation that prevents seeds from germinating during unsuitable ecological conditions that would typically lead to a low probability of seedling survival. Dormant seeds do not germinate in a specified period of time under a combination of environmental factors that are normally conducive to the germination of non-dormant seeds.
Lilies seed germination is classified as either epigeal or hypogeal. These classifications may be further refined as immediate or delayed. Whether a lily is epigeal or hypogeal may be related to survival strategies developed according to the climate where the lily originated. Epigeal lilies evolved in moderate climates. Hypogeal lilies evolved in harsher habitats where it would be advantageous to store food in a bulb, and later send up leaves in the spring.
Gibberella zeae, also known by the name of its anamorph Fusarium graminearum, is a fungal plant pathogen which causes fusarium head blight (FHB), a devastating disease on wheat and barley. The pathogen is responsible for billions of dollars in economic losses worldwide each year. Infection causes shifts in the amino acid composition of wheat, resulting in shriveled kernels and contaminating the remaining grain with mycotoxins, mainly deoxynivalenol (DON), which inhibits protein biosynthesis; and zearalenone, an estrogenic mycotoxin. These toxins cause vomiting, liver damage, and reproductive defects in livestock, and are harmful to humans through contaminated food. Despite great efforts to find resistance genes against F. graminearum, no completely resistant variety is currently available. Research on the biology of F. graminearum is directed towards gaining insight into more details about the infection process and reveal weak spots in the life cycle of this pathogen to develop fungicides that can protect wheat from scab infection.
Asclepias speciosa is a milky-sapped perennial plant in the dogbane family (Apocynaceae), known commonly as the showy milkweed and is found in the western half of North America.
Chaerophyllum bulbosum is a species of flowering plant from the carrot family and known by several common names, including turnip-rooted chervil, tuberous-rooted chervil, bulbous chervil, and parsnip chervil. It is native to Europe and Western Asia. It was a popular vegetable in the 19th century.
Winter rest is a state of reduced activity of plants and warm-blooded animals living in extratropical regions of the world during the more hostile environmental conditions of winter. In this state, they save energy during cold weather while they have limited access to food sources.
Sylva, or A Discourse of Forest-Trees and the Propagation of Timber in His Majesty's Dominions by the English writer John Evelyn was first presented in 1662 as a paper to the Royal Society. It was published as a book two years later in 1664, and is recognised as one of the most influential texts on forestry ever published.
Liriope muscari is a species of flowering plant from East Asia. Common names in English include big blue lilyturf, lilyturf, border grass, and monkey grass. This small herbaceous perennial has grass-like evergreen foliage and lilac-purple flowers which produce single-seeded berries on a spike in the fall. It is invasive to North America and considered a threat to native wildlife.
Scarification in botany involves weakening, opening, or otherwise altering the coat of a seed to encourage germination. Scarification is often done mechanically, thermally, and chemically. The seeds of many plant species are often impervious to water and gases, thus preventing or delaying germination. Any process designed to make the testa more permeable to water and gases is known as scarification.
The Propagation of Christmas trees is the series of procedures carried out to grow new Christmas trees.
Asclepias viridis is a species of milkweed, a plant in the dogbane family known by the common names green milkweed, green antelopehorn and spider milkweed. The Latin word viridis means green. The plant is native to the midwestern, south central and southeastern United States, as well as to the southeastern portion of the western United States.
Celtis koraiensis, commonly known as the Korean hackberry is a deciduous tree in the genus Celtis. The species is endemic to the Korean Peninsula and the north of China. It is typically found in altitudes of 100 to 1,500 metres.
In plants, vivipary occurs when seeds or embryos begin to develop before they detach from the parent. Plants such as some Iridaceae and Agavoideae grow cormlets in the axils of their inflorescences. These fall and in favourable circumstances they have effectively a whole season's start over fallen seeds. Similarly, some Crassulaceae, such as Bryophyllum, develop and drop plantlets from notches in their leaves, ready to grow. Such production of embryos from somatic tissues is asexual vegetative reproduction that amounts to cloning.