IN-VITRO POLLINATION AND FERTILIZATION IN MAIZE (ZEA-MAYS L) - TECHNICAL PROCEDURES AND PROSPECTS FOR THE DISSECTION OF THE DOUBLE FERTILIZATION PROCESS

In this review, we report the considerable worldwide progress accompli shed in Angiosperm fertilisation, especially in Zen mays L. In this sp ecies, the precise sequence of events during the process of double fer tilisation has been determined. A method of in vitro pollination which allows definition of the precise nutritional and environmental condit ions appears to be a suitable technique to study seed set, female rece ptivity and the effects of environmental stress on the fertilisation p rocess. A protocol for sperm cells and female gamete isolation has bee n described and offers a unique opportunity for studying gamete intera ctions. Different systems of in vitro fertilisation have been develope d including electrofusion, calcium-induced fusion of isolated gametes and sperm nuclei microinjection into the female cells. Regeneration of electrofused zygotes into fertile hybrid plants and culture of isolat ed fertilised embryo sacs provide new possibilities for investigating the early steps of fertilisation and embryogenesis at the cellular and molecular level.