Upendar Rao GollaDepartment of Biological Sciences

IISER Bhopal

DETERMINATION IN

Bryophytes

Tracheophytes

Introduction to Plant Kingdom

Sex determination in Bryophytes

Sex determination in Bryophytes

Homosporous Ferns

The Plant Cell, Vol. 16, S61–S71

Sex determination in Angiosperms

1) Active-Y System of Sex Determination

Ex: Cannabis, Humulus, Silene, Asparagus – XY sex chromosomes

2) X-to-Autosome Balance System of Sex Determination

Rumex Acetosa: X-to-autosome ratio (≥1= females, ≤0.5= males)

3) Hormonal regulation of Sexuality

Mercurialis annua- three independent segregating genes-A1, B1,

B2.

Dominant B1-b2 genes influence the degree of “maleness”4) Evolution of Sexual Dimorphisms in Plants

Mutation causing male or female sterility. Ex: Asparagus

Despite all the above mechanisms in plants may have common origin- Selective pressure for increased genetic fitness

Sex determination in Angiosperms

Genotype Fenotipe

M_F_M_ffmmF_mmff

GinoeciousMonoeciousHermaproditeAndromonoecious

Genotipe Fenotipe

A_G_A_ggaaG_aagg

MonoeciousGinomonoeciousAndromonoeciousHermaprodite

Appearance on cucumber sex

Appearance on melon sex

Preserve plant life

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