Future - Development Biology
Fertilization in flowering plants is essential for sustaining life on earth. Production of most crops depends on the effectivity of the fertilisation process. The emergence of new cultivars and plant improvement until recently depended exclusively on normal fertilisation. Therefore, the active involvement of a number of research techniques bears testimony to the fact that reproductive biology is emerging as one of the most exciting areas of plant biology. During the past decade major emphasis has been to understand the male gametophyte and the mechanism of incompatibility as these are crucial for the success of breeding programmes. The last five years have witnessed a surge of information on identification and control of haploid genome regulated activities during initial pollen germination and fertilisation. Characterization and structure of sperm cells and structure and composition of pollen tubes are also attracting considerable attention. Immunofluorescence techniques confirmed the presence of proteins in the pollen walls which enhanced our understanding of the acceptance and rejection (incompatibility) response. Immunological principles would help explain the nature of the product of the sporophyte cells involved in gametophytic and sporophytic incompatibility.
Isolation of entire embryo sacs and its individual cells opens up new possibilities for the study of fertilisation process and embryo-endosperm relationship. Some ingenious experimental studies with suspensor demonstrated its significance during early stages in providing growth support to the developing embryo. Labeling studies may finally reveal the site of biosynthesis of nutrients and growth hormones and the creditable role of the suspensor. With the aid of computerized imaging, the structure of sperm cells would become more clear, as yet incompletely understood. The immensely growing body of knowledge of various embryological structures mainly from biophysical and biochemical investigations have provided added impetus for probing these structures in living state. Identification and localization of various cellular constituents therefore acquire additional significance. A creditable method capable of analyzing biochemical events in single cells or small aggregates will provide ample details and thus answer to a myriad of questions. In embryological studies, now the principal criteria should be an estimation of the rate of success of any individual plant in parenting viable embryos. Towards this goal, together with several new techniques, embryologists can contribute extensively in making quantitative estimates of integral components of sexual process. This can also be used for a functional analysis of reproductive behavior in any flowering plant, including tests of the capacity of the male or female organs involved in reproduction process. It is thus surmised that rapid progress in techniques and consequently in approach has yielded valuable information in the area of angiosperm embryology. Further efforts will benefit our knowledge and enhance our understanding of various aspects of plant embryology hitherto unexplained.