Elementary plant Biochemistry and Biotechnology (2+1)

Factors affecting androgenesis

1. Physiological status of the donor plants- The age of the donor plants and the environmental conditions under which it has been grown significantly affects the androgenic process. Generally, the buds from the first flush of flowers show better response than those borne separately. Exposures of donor plants to nutrient and water stresses reported to promote androgenesis.
2. Stage of pollen development- The pollen grains around the first mitosis is most responsive. The uninucleate microspores produce haploids while the binucleate pollen form plants of higher ploidy.
3. Anther wall factors- the pollen from one cultivar of tobacco would successfully develop into an embryo even if transferred into the anthers of another cultivar.
4. Genotype – hybrids are more androgenic than their parents.
5. Pretreatment of cultured anthers/pollen grains – application of certain physical (temperature shock, centrifugation, γ irradiation) and chemical (auxins) treatments to cultured anthers or pollen grains prior to standard culture room conditions, has proved essential or promotory for in vitro androgenesis.
6. Culture medium – addition of etherel (2-chloroethylphosphonic acid), sucrose, agar and other nutrients specific to certain genotype found to increase the success rate of androgenesis.
7. Culture density- the frequency of pollen embryogenesis was enhanced if the anther culture density was increased from 3 anthers per ml to 12-24 anthers per ml in Brassica oleracea.
8. Effect of gaseous environment- the composition of the gas mixture that surrounds the anthers has profound influence on the number of embryos produced in anther cultures. The removal of CO2 from the culture vessel resulted in decline in anther culture response in Nicotiana tobaccum.
9. Effect of light – Isolated pollen cultures are more sensitive to light than anther culture.