INFLUENCE OF MICROCLIMATIC CONDITIONS ON NECTAR EXUDATION

IN GLECHOMA HIRSUTA W. K.

MARINA MAČUKANOVIĆ-JOCIĆ¹ AND L. DJURDJEVIĆ²

¹Faculty of Veterinary Medicine, Department of Botany, 11000 Belgrade, Serbia and Montenegro; ²Siniša Stanković Institute for Biological Research, 11060 Belgrade, Serbia and Montenegro

Abstract - The nectar production of Glechoma hirsuta W. K. grown under different microclimatic habitat conditions was evaluated by determining the total daily nectar quantity per flower, diurnal dynamics of nectar secretion, the nectar secretion rate, and sugar concentration. Comparative analyses of nectar production in Glechoma hirsuta grown in a forest and on a test plot confirmed that this process varied as a function of microclimatic parameters (atmospheric humidity and air temperature), but did not reveal a close relationship between these parameters and sugar concentration in nectar. More intensive nectar secretion, with a decreasing tendency during the day, and higher total daily nectar volume per plant (1.603 ml/flower) were measured in the forest habitat. Diurnal variation in nectar production with two secretion peaks was found at both localities, and the secretion patterns were rather similar. Regarding the nectar secretion rate, G. hirsuta is a slow producer, secreting less than 0.07 ml/h.