Introduction

Flower development has intrigued man since the dawn of time. Firstly flowers are very attractive for their ornamental value and fragrance. Secondly, the flower forms the place in which the plants' reproductive organs and cells are formed. Therefore, development of efficient reproductive organs and cells is of vital interest for the maintenance of life on earth. For these reasons, flowers have also a considerable commercial value both in the area of the production of cut flowers and pot plants and in the area of plant breeding.

A typical dicot flower consists of four concentric whorls of floral organs. The outermost whorl contains the sepals. The main function of these floral organs is the protection of the vulnerable young flowerbud. The second whorl consists of the petals which are often very showy and serve an important function in the attraction of pollinators. Whorl three consists of the stamens in which the male gametes are formed. Whorl four consists of the carpels which are often fused to form a pistil. In the ovary of the pistil the egg cells are present within the ovules. Upon fertilisation, the pollen tube grows towards the ovules and the egg cells, and in a double fertilisation event the egg cell and the central cell are fertilised by the two male reproductive cells.

Floral induction, floral development and plant reproduction have been studied already for a long time especially at morphological and physiological levels.