Induction of Embryos in Ab Initio Pollen Cultures of Nicotiana

Abstract

Angiosperm pollen grains, being haploid, may be considered analogous to microbes. Their totipotency (1) makes them potentially ideal for genetic studies. However, culture of pollen grains direct from the plant (ab initio culture) to give embryos in high frequency has so far proved difficult. This can be ascribed to lack of knowledge about pollen capable of embryo formation. An important contribution towards the identification of such pollen is the work of Horner and Street (2). These authors indicated that in a Burley cultivar of Nicotiana tabacum pollen grains capable of embryogenesis are smaller than those destined to form gametes. In the cultivar Badischer Burley their number can be increased by subjecting plants raised in long days and high temperature to short days and a lower temperature just prior to flowering (3). Nonetheless, it remained to be confirmed that the small pollen grains are capable of embryogenesis because in culture only a few embryos were formed.