Flower nectary structure in Cornus alba L.

Abstract

The structure of the floral nectaries of Cornus alba was studied using light microscopy as well as scanning and transmission electron microscopy. It was found that the nectary gland of white dogwood had the shape of a fleshy ring surrounding the base of the style of the inferior ovary. Nectar secretion occurs through slightly depressed stomata, evenly distributed in the epidermis of the nectary. The nectariferous tissue is composed of over a dozen layers of heterogeneously structured cells. Between groups of cells with a typical structure, characteristic for the secretory tissue, cells occur with degenerated content and a high degree of vacuolization. In the area of the nectary gland cells, no vascular tissue elements were observed. The nectary was irrigated by the vasculature of the flower receptacle.

Floral nectar production and carbohydrate composition and the structure of receptacular nectaries in the invasive plant Bunias orientalis L. (Brassicaceae)

“…Carbohydrates for nectar synthesis may also originate from vascular bundles associated with the closely located sepal bundles which may be evidenced by the presence of starch in the secretory parenchyma of median nectaries and is congruent with the observations of other species (e.g. Davis et al 1986 , 1998 ; Ren et al 2007 ; Konarska 2011 , 2015 ). However, the role of starch in nectar formation cannot be completely excluded for the species studied, as partly hydrolyzed starch grains have been observed in the plastids of secretory parenchyma cells.…”

Comparison of the structure of floral nectaries in two Euonymus L. species (Celastraceae)

“…Similar observations of the mode of carbohydrate production and absence of vascularisation of the nectary were presented for several representatives of Lepidobotryaceae and Celastraceae by Link ( 1991 ) and Gomes and Lombardi ( 2013 ), whereas only phloematic bundles were observed in the nectaries of a few Celastroideae species by Matthews and Endress ( 2005 ), but not in E. latifolius . Nectaries devoid of their own vascular elements similar to those described for Euonymus have been reported from other species by many researchers (Fahn 1988 , 2000 ; Galetto 1995 ; Ma et al 2002 ; Ren et al 2007 ; Konarska 2011 ). However, most frequently, floral nectaries comprise simultaneously xylem and phloem (Caswell and Davis 2011 ; Sulborska 2011 ; Abedini et al 2013 ; Nores et al 2013 ) or only phloem (Hampton et al 2010 ; Zini et al 2014 ).…”

Floral Nectary Morphology and Proteomic Analysis of Nectar of Liriodendron tulipifera Linn.

“…Although L. tulipifera nectar is secreted through nectarostomata, the L. tulipifera flower nectary structure is very different than that of Brassicaceae flowers ( Kram and Carter, 2009 ) and even that of Magnolia stellata in the same Magnoliaceae family ( Erbar, 2014 ). As an apocarpous gynoecium flower, the nectary of L. tulipifera flowers was located on the modified orange–yellow part of petals, as in flowers of Helleborus and Symphyglossum ( Vesprini et al, 1999 ; Stpiczynska and Davies, 2006 ), whereas in most species, it encircles the ovary ( Brown, 1938 ; Zer and Fahn, 1992 ; Rivera, 2000 ; Konarska, 2010 ; Nocentini et al, 2012 ; Stpiczyñska et al, 2012 ; Lüttge, 2013 ; Stephens, 2013 ). Although this result was consistent with previous findings in plants in the Ranunculaceae family ( Kosuge, 1994 ), it was different from what has been seen in M. stellata in the same family ( Erbar and Leins, 2013 ).…”