Dichogamy in Salicornieae species: establishment of floral sex phases and evaluation of their frequency and efficacy in four species

Dichogamy in Salicornieae species is not clearly described in literature, and its efficiency remains untested. In this work we aim to establish the pathway for flower development, the degree of interaction between the two sexes, and the efficiency in overcoming selfing. Flower development was studied in six populations of four Salicornieae species at the Odiel Marsh Natural Park (Huelva, SW Spain) by calculating the percentage of different floral phases established in accordance with the position of their stamens and stigmas. To study the sexual functionality of each phase, the lengths of the perianth, stigma, and ovule were measured, and the number of germinated pollen grains on the stigmas was counted. In the Arthrocnemum macrostachyum and Salicornia ramosissima populations, the stigma protrudes from the perianth when the anthers have shed their pollen. In the Sarcocornia fruticosa and Sarcocornia perennis populations, anthesis starts with the extrusion of one anther, but in the most common pattern the stigma protrudes from the perianth while the anthers are shedding their pollen. All species studied were morphologically protandrous, but only in one population of Arthrocnemum macrostachyum was the number of germinated pollen grains on the stigma significantly greater when the stigma was exserted than in the previous phases.