Flowering pattern, the structure of nectary surface and nectar secretion in two varieties of Ocimum basilicum L.

Abstract

The studies conducted in the years 2003-2004 covered two varieties of <i>Ocimum basilicum</i> L.: var. <i>purpurascens</i> Benth. and var. <i>lactucaefolium</i> I. The flower lifetime, daily flowering pattern, morphology of pollen grains and the abundance of nectar secretion of flowers were compared. The surface of the nectaries of <i>O. basilicum</i> var. <i>lactucaefolium</i> was observed using scanning electron microscopy (SEM). The automorphic nectaries of basil formed the following parts: a flat part from the side of the upper lip and a convex part with three protrusions on the opposite side. On the top of two outer protrusions, stomatal areas were located, responsible for nectar secretion. The stomata occurred at the level of other epidermal cells. On the average, nectar contained 42% of sugars. The sugar yield of flowers of var. <i>lactucaefolium</i> was 36% higher than this feature in var. <i>purpurascens</i>. In terms of their size, the pollen grains were rated as medium-sized. Their viability ranged 88-96%. The shape of the pollen grains was described as oblate and suboblate.