We have used specific antibodies against callose, pectins and arabinogalactan-proteins, all components of the cell wall involved in embryo development, to study their distribution during androgenesis induced in barley anthers in the hope that they might serve as markers of this process. Callose was found in the outer region of the intine in induced embryos and in the numerous plasmodesmata within these embryos. Anti-callose antibodies proved useful for following the evolution of these structures throughout the formation of the pollen embryo. The monoclonal antibodies JIM5 and JIM7, which recognise unesterified and methylesterified pectins respectively, were used to follow the evolution of the walls formed in the embryo. Methylesterified pectins were found both in the intine of non-induced vacuolated microspores and in the newly formed cell walls of the embryo whilst unesterified pectins were not seen in these young walls. JIM4 and JIM8 monoclonal antibodies were used to study arabinogalactan proteins. The AGP epitope located by JIM4 was not present in vacuolated microspores before induction but it did appear after the induction of androgenesis. Epitopes recognised by JIM8 were present in microspores before induction but not in induced microspores. These epitopes reappeared in embryogenic multicellular pollen grains. These results seem to confirm the role of this type of AGP as a signal molecule in the process of androgenesis.

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