THE IMMUNOLOCALIZATION OF NUCLEAR ANTIGENS DURING THE POLLEN DEVELOPMENTAL PROGRAM AND THE INDUCTION OF POLLEN EMBRYOGENESIS

The immunolocalization of nuclear antigens, combined with cytochemical procedures as well as in situ hybridization and recent in situ molecu lar methods, has been applied at different steps of pollen development to characterize the functional organization of the nucleus during the formation of the male gametophyte in an agronomically interesting pla nt, Capsicum annuum L. Pollen embryogenesis has been induced in pepper and the first stages of the process have been studied at the cellular level. Low temperature processing methods including cryosections and Lowicryl sections were very convenient for performing the various in s itu techniques used in the pollen grains. Different molecular probes f or localizing DNA, RNA, snRNPs, specific nucleolar proteins, various r RNA species, and DNA/RNA hybrids provided positive results in the poll en nuclei. The data obtained, and the changes observed in the organiza tion of the nuclear compartments during pollen development, are relate d to the variations in gene activity undergone by the male gametophyte . The methodology used is proposed as a very convenient approach to lo calize molecules and events involved in the nuclear function in both g ametophytic and sporophytic pollen development. (C) 1995 Academic Pres s, Inc.