Pathways of pollen development in anther culture or pollen culture are given below.
- Pathway I
- Pathway II
- Pathway III
- Pathway IV
Pathway I
Uninucleate pollen grain divides equally into two equal daughter cells. Both of these cells undergo divisions to give rise to a proembryonic mass. This proembryonic mass either directly (through embryo formation) or indirectly (through callus formation) may give rise to a haploid plant.
Examples – Datura
Pathway II
Uninucleate pollen grain divides unequally to yield generative and vegetative cell. Callus / embryo originate from vegetative cell alone, while the generative cell degenerates immediately or after undergoing one or two divisions.
Examples – Datura, tobacco, wheat, barley, chillies.
Pathway III
Uninucleate pollen grain divides unequally to yield generative and vegetative cell. Generative cell undergoes successive divisions to develop callus / embryo, while the vegetative cell does not divide or divides only to a limited extent forming a suspensor like structure
Examples – Hyoscyamus niger
Pathway IV
Uninucleate pollen grain divides unequally to yield generative and vegetative cell. Callus / embryo develop by repetitive divisions of both of these cells.
Examples – Datura
Factors influencing pathways of development, in Anther or Pollen culture
- Genotype
- Growth hormones
- Culture medium
- Growth (physical) conditions
- Stage of pollen development
- Pretreatments
Applications – Merits of pollen culture enlist merits, demerits and applications of the concept.