Barley anther culture-The switch of programme and albinism

Abstract

The switch of programme in barley anther culture is discussed with reference to the formation of green and albino plants. A theory of albinism is proposed based on the premise that at the critical microspore stage, plastids are in a state of metamorphosis preparatory to their role in the gametophyte generation. Pollen cells formed during the cold treatment which precedes culture of the anthers lack the usual gametophytic traits and have no divisional constraints, but they cannot develop green plastids because of deficiencies at the plastid level. Calluses derived from such cells give rise to albinos. Formation of green plants is equated with younger spores in which the two pollen cells are formed in culture rather than the pretreatment. Culture appears to have an important role in sporophytic expression apart from that in sustaining growth. Plastids in these younger spores are considered to be appropriate to greening, but may not be able to develop a photosynthetic apparatus because of deficiencies at the nuclear level. Formation of the pollen cells in culture, following the pretreatment, may be necessary for unmasking genes essential to greening. Ways of controlling the production of green plants at a level acceptable to breeders are suggested.