Search results
Results from the WOW.Com Content Network
Germination of seedlings raised from seeds of eucalyptus after three days of sowing. In agriculture and gardening, the germination rate describes how many seeds of a particular plant species, variety or seedlot are likely to germinate over a given period. It is a measure of germination time course and is usually expressed as a percentage, e.g ...
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 (seed coat) more permeable to water and gases is known as scarification.
Moisture stress is a form of abiotic stress that occurs when the moisture of plant tissues is reduced to suboptimal levels. Water stress occurs in response to atmospheric and soil water availability when the transpiration rate exceeds the rate of water uptake by the roots and cells lose turgor pressure .
True dormancy or inherent (or innate) dormancy is caused by conditions within the seed that prevent germination even if the conditions are favorable. [7] Imposed dormancy is caused by the external conditions that remain unsuitable for germination [8] Seed dormancy can be divided into two major categories based on what part of the seed produces dormancy: exogenous and endogenous. [9]
Soil moisture has an effect on the thermal properties of a soil profile, including conductance and heat capacity. [4] The association of soil moisture and soil thermal properties has a significant effect on temperature-related biological triggers, including seed germination, flowering, and faunal activity.
The radicle is the first part of a seedling (a growing plant embryo) to emerge from the seed during the process of germination. [4] The radicle is the embryonic root of the plant, and grows downward in the soil (the shoot emerges from the plumule) where it absorbs more water.
Functionally, the hilar valve allows water vapor to enter or exit to ensure viability, while blocking liquid water. If however, humidity levels gradually rise to a high enough level, the hilar valve remains open, allowing liquid water passage for germination. [17] Physiologically, the inner and outer epidermides have independent hilar valve ...
Seeds can withstand high soil temperatures, and the primary limit to germination is inadequate moisture. Germination is best in the dark or in diffuse light. They germinate most quickly when covered with soil, but do not need to be in contact with bare soil. Some leaf litter cover will generally improve germination and establishment of seedlings.