Nutritive for insects attractantsin Asphodelus albus Miller flowers

Abstract

The studies on Asphodelus albus Miller flowers were conducted in the Botanical Garden of the UMCS in Lublin in the years 2004-2005. The flower nectaries location was determined in a stereoscopic microscope. The nectaring abundance was studied with a pipette method described by Jabłoński and Szklanowska (1979), while pollen efficiency determined after Warakomska`s ether method (1972). Pollen viability was computed in a sample of 400 grains after acetocarmine staining. The following measurements of pollen grains were made: the length of polar axis (P), equatorial longitudinal axis (EL) and equatorial transverse axis (ET). In Asphodelus albus flowers, there are three nectary glands located in the ovary septa whose outlets are situated in the upper part of the ovary. The nectar secretion starts in a dehiscing bud and persists until the withering stage of perianth leaves. Considering the size of monocolpate pollen grains of Asphodelus albus, they are ranked among great, whereas their shape assumed flattened and circular at the polar view. In the Poland climatic conditions, a pollen showed high vitality (98%). The Asphodelus albus plants constitute a valuable source of nutrition for the pollinators as a single flower generated on average 4,22 mg sugars and 0,2 mg of pollen grains.