MORPHOLOGY AND HISTOLOGY OF THE NECTARY IN HUNGARIAN LOCAL PEAR CULTIVARS

Abstract

The topography, morphology and histology of the nectary of 12 Hungarian pear cultivars in a Hungarian cultivar collection (Ujfeherto) were studied over the past 3 years. The intrafloral nectary was receptaculo-ovarial, lining the adaxial surface of the plate-like receptacle and the apical part of the ovary. The gland was automorphic on the apical part, and in some cases also on the basal part, protruding out of the receptacular tissue. A narrow zone of the nectariferous tissue stretched along the style, allowing nectar accumulation in the gap between the style and the nectary. The pear nectary was covered by a smooth cuticle, the thickness of which varied slightly between cultivars and from season to season. In the medial longitudinal section of the flower the epidermal cells were palisad-like or squareshaped, sometimes papillate. Guard cells of nectar stomata could be found either at the level of the epidermal cells (mesomorphic type) or sunken a few cell rows below the epidermis (xeromorphic type). Below the stomata, among the cells of the glandular tissue, nectar-storing intercellular cavities of varying sizes could be found. The glandular tissue consisted of small, dark-staining cells. In some cultivars the nectariferous tissue could be well distinguished from the nectary parenchyma, consisting of larger, light-staining cells. In other cultivars a mosaic-like structure could be observed, where glandular cells were mixed with parenchyma cells, with no sharp distinction between the two tissue types. In some taxa there was a correlation between the size of the nectary and nectar production, which may be important in cultivar selection.