Apomixes in Plants: Definition, Examples, Types Diplospory, Apospory, Apogamy, Parthenogenesis, Adventive Embryony I Free Notes I LetsBloomStudyMaterial I Plant Anatomy #biology #pgtbiology #kvs #nvs #emrs

Introduction

Reproduction is the process of producing new individuals or Offspring from parents.

There are two major ways for reproduction:

1. Sexual Reproduction

2. Asexual Reproduction

In Sexual reproduction there is fusion of male and female gametes to form a diploid zygote that develops into diploid embryo inside a seed, this embryo can develop into new organism.

In Asexual Reproduction there is no such fusion of gametes, but the parent plant can produce a new organism from a part of itself.

But there is a kind of Asexual Reproduction in which there is no fusion of gametes, but Embryo is formed, but how? this occurs by a process named Apomixes.

What is Apomixes?

Production of seed without fertilization.

The process of formation of embryo without fusion or mixing of gametes.

In apomixes embryo is formed from female gametophyte or sporophyte tissue, hence new offspring produced from them are identical to female parent.

Apomixes can also be defined as Such asexual seeds that produces progeny identical to female parent are called as Apomictic seeds and this phenomenon is called as Apomixes.

Apomixis can also be defined as Asexual reproduction without involvement of meiosis and syngamy.

EXAMPLES: In Grasses, Citrus fruits and Mango.

TYPES OF APOMIXES

1) PARTHENOGENESIS

When embryo develops from unfertilized egg cell (haploid) of embryo sac this is called as Haploid Parthenogenesis.

Gametophytic cell---> Haploid Embryo sac ----> Haploid Embryo

2) APOGAMY

When embryo develops from other cells of embryo sac this type of apomixes is called as Apogamy.

Gametophytic cell---> Haploid Embryo sac ----> Haploid Embryo

3)DIPLOSPORY

When embryo develops from unreduced Megaspore Mother Cell that fails to form Embryo sac this type is called as Diplospory

Diploid MMC---> Diploid Embryo Sac ----> Diploid embryo

4) APOSPORY

When embryo sac develops from a somatic cell that act as diploid spore this is called as Apospory.

Formation of gametophyte from sporophyte tissue is called as Apospory

Diploid Simatic Tissue---> Diploid Spore---> Diploid embryo

5) ADVENTIVE EMBRYONY

When embryo formation takes place from somatic cells within ovule this is called as Adventive embryony.

The somatic cell can be of nucellus or integument.

In this condition more than two embryo formed in a seed.

Example: In Mango and Citrus fruits.

QUESTION PRACTICE TIME

When embryo develops from a cell of an embryo sac other than egg cell then this condition of development is known as:

Apospory

Parthenogenesis

Parthenocarpy 

Apogamy

Explanation:

In Apospory embryo develops from a diploid spore

In Parthenogenesis embryo develops from unfertilized egg cell

In Parthenocarpy seedless fruits were formed

In Apogamy embryo develops from cell of embryo sac other than egg cell

Special mechanism in grasses to produce seeds without fertilization is known as: (NVS Exam)

Emasculation

Parthenogenesis

Parthenocarpy 

Apomixes

The development of diploid gametophyte without meiosis from vegetative and asexual cells of sporophyte is refer to as:

Apogamy

Apospory

Polyembryony

Apomixes

Which of the following describe the process of apomixes? (DSSSB Exam)

Production of seed as a result of sexual reproduction

Production of seed without reproduction

Production of seed after reproduction

No production of seed even after reproduction

Polyembryony means: (DSSSB Exam)

i) Occurrence of single embryo in the seed

ii) No occurrence of embryo in seed

iii) Occurrence of more than one embryo in seed

Which of the following statemen is correct

a) i and ii

b) only iii

c) only i

d) only ii

Banana is a:

Parthenocarpy fruit

Aggregate fruit 

Composite Fruit

Polyembryony fruit

In a type of apomixes the adventive embryony, the embryo develops directly from

Nucellus or Integument

Zygote 

Synergid or antipodal cells

Accessory embryo sac

The process of formation of seed without fertilization in flowering plants is known as

Budding

Apomixes

Sporulation

Somatic Hybridization

Which of the following fruit is produced by parthenocarpy

Brinjal

Apple

Banana

Jackfruit

Identify the process in which seeds are produced without fertilization (NVS Exam)

Apomixes

Budding

Embryo transfer

Emasculation

When synergid and antipodal cell's form embryo this is called

Apogamy

Apomixes

Amphimixes

Polyembryony