XVI International Botanical Congess
Stoma-like structures occur on floral nectaries of angiosperms representing at least 80 families. Although their pores can serve for nectar escape, a finely-tuned control mechanism that regulates nectar flow through them has yet to be demonstrated in species studied to date. Here we investigated whether stomatal number was related to nectar-sugar production per flower. Such a trait has potential relevance to crop-breeding programmes, as seed yields in both Brassica rapa and Vicia faba are increased by bee visitation. Results indicated that the relationship was weak, in fact, plants possessing relatively large numbers of stomata per floral nectary yielded the smallest quantities of nectar sugar per flower.