Apomixis & Parthenocarpy | Biology Class 12 - NEET PDF Download

Apomixis

• The term ‘Apomixis’ was introduced by Winkler(1908). ‘Apomixis is the substitution of sexual reproduction, which does not involve meiosis and syngamy.’
• Apoximis refers to the formation of the plant from a seed without fertilization or normal sexual reproduction. This mechanism produces clones, hence can be considered as a form of asexual reproduction.

It is of two types:

(i) Vegetative Reproduction: It is a type of asexual reproduction, mostly in plants when a plant part is detached and produces new progeny.Apomixis: Vegetative Propagation

(ii) Agamospermy: Process which involves sex cells but takes place without fertilisation or meiosis.

(a) 
(b) Adventitive Embryony: The nucellar or integumentary cells produce a diploid embryo.
(c) Apospory: Cell, outside the embryo sac produces aposporic embryo sac.

Parthenocarpy

It is the process of producing fruits without fertilisation.

On the basis of its causes, it is of three types:
(i) Genetic Parthenocarpy: Parthenocarpic fruits are produced because of hybridisation or mutation.
(ii) Environmental Parthenocarpy: The environmental condition like fog, frost, high temperature and freezing led to the non-functioning of the reproductive organ and results in parthenocarpy.
(iii) Chemical Induced Parthenocarpy: The artificial application of IAA, α-NAA, gibberellin leads to the production of parthenocarpic fruits.