Seed hibernation
Encyclopedia
Seed hibernation is different from seed dormancy
. While seed dormancy can be defined as "a seed not germinating when conditions, e.g. light, water/nutrient availability or the presence of activating substances like smoke, are favourable", hibernation is the ability of a seed
to remain in hibernation
when there is a lack of things essential to its development (water, sunlight, nutrient
s, etc.) or in harsh conditions (extreme cold, extreme heat, hard ground, etc.). There is no specific time limit in which a seed may hibernate; Seeds found in the Canadian arctic and thought to be 10000 years old and still viable were finally shown to be approximately 10 years old by radio carbon dating (Zazula et al., 2009 New Phytologist). The oldest seeds that have been found to be viable are of the Date Palm (Phoenix dactylifera): several seeds found in the Israeli fortress of Masada were radiocarbon dated to be 2000 years old. One seed was still able to germinate (Sallon et al., 2008 Science). When conditions are right for the particular type of seed, they can come out of hibernation
and grow.
Seeds display hibernation for very short periods of time every year. In autumn, seeds produced in summer may have a chance to grow while the soil
is still warm, but instead do not grow until spring. The seeds have chemicals encoded into them that will not allow them to germinate until the soil warms up again, a sign of spring. This is called after ripening.
Seeds may also go into hibernation for other causes. Many pines have adapted to forest fires that destroy trees by creating pine cones that open in extreme heat (fire) and release seeds coated with a material that will break down only in extreme heat. The seeds hibernate until this happens.
Seeds of the Canna Lily
, and other plants, have a hard coating that must be broken down by contact with rough rock
, soil
, etc. before they begin to grow. Until the shell is broken and water reaches the seed, the seed remains dormant.
When released, some seeds (especially those in a desert environment
) must wait for rain before the seed is triggered out of hibernation and begins to grow.
There are many other causes of dormancy
. It is an unclear phenomenon; the limits of seed hibernation are still unknown, and many triggers have yet to be discovered.
Seed dormancy
Seed dormancy is a condition of plant seeds that prevents germination when the seeds are under optimal environmental conditions for germination. Living, non dormant seeds germinate when soil temperatures and moisture conditions are suited for cellular processes and division; dormant seeds do...
. While seed dormancy can be defined as "a seed not germinating when conditions, e.g. light, water/nutrient availability or the presence of activating substances like smoke, are favourable", hibernation is the ability of a seed
Seed
A seed is a small embryonic plant enclosed in a covering called the seed coat, usually with some stored food. It is the product of the ripened ovule of gymnosperm and angiosperm plants which occurs after fertilization and some growth within the mother plant...
to remain in hibernation
Hibernation
Hibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food supplies are limited, tapping energy reserves, body fat, at a slow rate...
when there is a lack of things essential to its development (water, sunlight, nutrient
Nutrient
A nutrient is a chemical that an organism needs to live and grow or a substance used in an organism's metabolism which must be taken in from its environment. They are used to build and repair tissues, regulate body processes and are converted to and used as energy...
s, etc.) or in harsh conditions (extreme cold, extreme heat, hard ground, etc.). There is no specific time limit in which a seed may hibernate; Seeds found in the Canadian arctic and thought to be 10000 years old and still viable were finally shown to be approximately 10 years old by radio carbon dating (Zazula et al., 2009 New Phytologist). The oldest seeds that have been found to be viable are of the Date Palm (Phoenix dactylifera): several seeds found in the Israeli fortress of Masada were radiocarbon dated to be 2000 years old. One seed was still able to germinate (Sallon et al., 2008 Science). When conditions are right for the particular type of seed, they can come out of hibernation
Hibernation
Hibernation is a state of inactivity and metabolic depression in animals, characterized by lower body temperature, slower breathing, and lower metabolic rate. Hibernating animals conserve food, especially during winter when food supplies are limited, tapping energy reserves, body fat, at a slow rate...
and grow.
Seeds display hibernation for very short periods of time every year. In autumn, seeds produced in summer may have a chance to grow while the soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
is still warm, but instead do not grow until spring. The seeds have chemicals encoded into them that will not allow them to germinate until the soil warms up again, a sign of spring. This is called after ripening.
Seeds may also go into hibernation for other causes. Many pines have adapted to forest fires that destroy trees by creating pine cones that open in extreme heat (fire) and release seeds coated with a material that will break down only in extreme heat. The seeds hibernate until this happens.
Seeds of the Canna Lily
Canna (plant)
Canna is a genus of nineteen species of flowering plants. The closest living relations to cannas are the other plant families of the order Zingiberales, that is the gingers, bananas, marantas, heliconias, strelitzias, etc.Canna is the only genus in the family Cannaceae...
, and other plants, have a hard coating that must be broken down by contact with rough rock
Rock (geology)
In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...
, soil
Soil
Soil is a natural body consisting of layers of mineral constituents of variable thicknesses, which differ from the parent materials in their morphological, physical, chemical, and mineralogical characteristics...
, etc. before they begin to grow. Until the shell is broken and water reaches the seed, the seed remains dormant.
When released, some seeds (especially those in a desert environment
Desert
A desert is a landscape or region that receives an extremely low amount of precipitation, less than enough to support growth of most plants. Most deserts have an average annual precipitation of less than...
) must wait for rain before the seed is triggered out of hibernation and begins to grow.
There are many other causes of dormancy
Dormancy
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...
. It is an unclear phenomenon; the limits of seed hibernation are still unknown, and many triggers have yet to be discovered.