Submitted by
Sonia Hassan
Samreen Mehmood
Irum Shaheen
*
*
Some time the growth is suspended because of
the lack of favorable conditions in the
environment.
Such seeds will germinate if they are supplied
with water and suitable temperature.
In many other cases, even if they are not
provided with water etc.
This failure of seeds to germinate even under
favorable conditions is termed as Dormancy.
*
*The seed is called dormant and the phenomenon
is called dormancy.
*In majority of the cases, true dormancy helps the
seed to survive through an unfavorable season
e.g, very cold winter or a very hot summer
*
*Seed dormancy can be defined as the state or a
condition in which seeds are prevented from
germinating even under the favorable environmental
conditions.
*DORMANT:Not active
*
There are two types of seed dormancy.
*Seed coat(physical)Dormancy.
*Internal Dormancy.
*The dormancy of the seeds is regulated by
hormones or by temperature and restricted
oxygen uptake by hard seed-coat.
*
*Seed coats impermeable to water. ...
*Seeds coats impermeable to oxygen. ...
*Immaturity of the Embryo. ...
*Germination Inhibitors. ...
*Chilling or low temperature requirement. ...
*Light sensitive seeds.
*High temperature
*
*Dormancy helps seeds to remain alive in the soil for
several years and provides a continuous source of
new plants, even when all the mature plants of the
area have died down due to natural disasters.
*
* Exogenous Dormancy
Exogenous dormancy Exogenous dormancy is caused
by conditions outside the embryo.
*Endogenous Dormancy
Endogenous dormancy is caused by conditions within
the embryo itself
These are methods to overcome seed dormancy.
Artificial overcoming seed dormancy.
Treatment with hot water.
Hydraulic pressure of upto 2000kg for 5-20
mint.
*
Weakening of seed coat by mechanical abrasion or
injury.
Action of digestive enzymes present in alimentary
canals of birds and other animals which happens to
feed on their fruits.
Leaching of inhibitors present in seed coa.
Inactivation or oxidation of inhibitors by heat, cold
and light
*
*Hard seed coat.
*Mechanical resistance.
*Gas imperability.
*Dormancy due to specific light requirements.
*Dormancy due to germination inhibitors.
*

seed dormaancy

  • 1.
    Submitted by Sonia Hassan SamreenMehmood Irum Shaheen *
  • 2.
    * Some time thegrowth is suspended because of the lack of favorable conditions in the environment. Such seeds will germinate if they are supplied with water and suitable temperature. In many other cases, even if they are not provided with water etc. This failure of seeds to germinate even under favorable conditions is termed as Dormancy.
  • 3.
    * *The seed iscalled dormant and the phenomenon is called dormancy. *In majority of the cases, true dormancy helps the seed to survive through an unfavorable season e.g, very cold winter or a very hot summer
  • 4.
    * *Seed dormancy canbe defined as the state or a condition in which seeds are prevented from germinating even under the favorable environmental conditions. *DORMANT:Not active
  • 5.
    * There are twotypes of seed dormancy. *Seed coat(physical)Dormancy. *Internal Dormancy.
  • 6.
    *The dormancy ofthe seeds is regulated by hormones or by temperature and restricted oxygen uptake by hard seed-coat.
  • 7.
    * *Seed coats impermeableto water. ... *Seeds coats impermeable to oxygen. ... *Immaturity of the Embryo. ... *Germination Inhibitors. ... *Chilling or low temperature requirement. ... *Light sensitive seeds. *High temperature
  • 8.
    * *Dormancy helps seedsto remain alive in the soil for several years and provides a continuous source of new plants, even when all the mature plants of the area have died down due to natural disasters.
  • 9.
    * * Exogenous Dormancy Exogenousdormancy Exogenous dormancy is caused by conditions outside the embryo. *Endogenous Dormancy Endogenous dormancy is caused by conditions within the embryo itself
  • 10.
    These are methodsto overcome seed dormancy. Artificial overcoming seed dormancy. Treatment with hot water. Hydraulic pressure of upto 2000kg for 5-20 mint.
  • 11.
    * Weakening of seedcoat by mechanical abrasion or injury. Action of digestive enzymes present in alimentary canals of birds and other animals which happens to feed on their fruits. Leaching of inhibitors present in seed coa. Inactivation or oxidation of inhibitors by heat, cold and light
  • 12.
    * *Hard seed coat. *Mechanicalresistance. *Gas imperability. *Dormancy due to specific light requirements. *Dormancy due to germination inhibitors.
  • 14.