Question

State the type of exogenous and endogenous dormancy.

Answer 1

In this question, as we know that there are four sorts of endogenous dormancy and three sorts of exogenous dormancy. Exogenous dormancy is of 3 varieties that are physical, mechanical, and chemical dormancy.

Complete answer:
Physiological and morphophysiological square measure the two major styles of endogenous dormancy found in tree species. Morphological dormancy could also be a 3rd style of endogenous dormancy however it's most often seen in nonwoody plants. Seeds with physiological dormancy need a amount of dampish, chilling to satisfy dormancy.

Double dormancy, in some species, seeds have dormancy due to arduous seed coats and dormant embryos. Such seeds need 2 years for breaking dormancy in nature. Among the primary spring, the microorganisms create it weak and soft then embryo dormancy is broken by chilling temperature among the winter next year.

Secondary dormancy is due to germination conditions. It's an additional adaptation to prevent germination of Associate in Nursing imbibed seed if different environmental conditions are not favorable.

Exogenous dormancy is of 3 varieties.
a) Physical dormancy : reproductive structure or seed covering might become arduous, fibrous or viscous throughout dehydration and ripening as a result they become impermeable to water and gases, that prevents the physiological processes initiating germination this type of dormancy is extraordinarily common in stone fruit fruits.
b) Mechanical dormancy: In some fruits seed covering restricts body structure growth, resulting in dormancy of seeds. Some seed covering structures, like shells of walnut, pits of stone fruits and stones of olive square measure are too robust to allow the dormant embryo to expand throughout germination.
c) Chemical dormancy: In seeds of some fruits chemicals that accumulate in fruit and seed covering tissues throughout development and stay with the seed when harvested. it's quite common in fleshy fruits or fruits whose seeds stay in juice as in citrus, cucurbits, stone fruits, pear, grapes and tomatoes.

Note: Exogenous dormancy is caused due to the conditions outside of the seed's embryo. As an Associate in Nursing example, exogenous dormancy is once the reproductive structure is simply too sturdy for wet to infiltrate, effectively preventing germination. Endogenous dormancy happens thanks to the chemical changes among the seed's embryo.