Stomatal ontogeny of the vegetative and floral organs of some Papilionaceae

Abstract

The structure and development of stomata on the vegetative and floral organs of Vigna unguiculata Walp., and the vegetative organs of Phaseolus radiatus L. and P. aconitifolius Jacq. are described. Paracytic, anisocytic, and anomocytic stomata are present on the same surface of different organs of the plants investigated except on the stem and petiole of V. unguiculata, the bract of P. radiatus, and the petiole, stipule, and stipel of P. aconitifolius where the last type is absent. Stomata with only one subsidiary cell are found on the leaf, petiole, sepal, and petal of V. unguiculata. Diacytic stomata occur on the stipel of P. radiatus and the stem, stipule, and stipel of P. aconitifolius. Paracytic stomata are by far the commonest on each organ. The frequency of different types of stomata on different organs in the plants investigated is tabulated. The ontogeny of different kinds of stomata on each organ is mesogenous, but the perigenous type may be found on the petal and pericarp of V. unguiculata and the stipule of P. radiatus. The variation in stomata is due to: (a) a diversity in stomatal types even on the same surface, and (b) an increase in the number of subsidiary cells. The subsidiary cells divide, or additional subsidiary cells are derived from adjacent epidermal cells. The present study also supports the inclusion of the species concerned in the tribe Phaseolae.