干旱区生态环境知识资源中心

The flower and hypocotyl development of three mangrove tree species of the southern Baja California Peninsula were analyzed comparing four microtopographic flooding conditions and in relation to five environmental factors (relative humidity, rainfall ambient temperature, solar radiation and speed). The main objective was to evaluate the effects of an arid environment on the reproductive effort of the mangrove species present. Between 1 June to 5 November 2006 weekly measurements were made at three sites in La Paz Bay. During each visit we recorded the development of buds to flowers (anthesis) and eventually, if there was successful pollination, to propagule (viviparous embryo or hypocotyl) until they detached from the mother tree some time later. This was done for three selected stems of one tree per species for the four microtopographic conditions. Our results indicate that nearly 25 % of all flowering plants passed to hypocotyls and relative humidity and rainfall were the variables most associated with flower development. We found that humidity triggers the reproductive effort of mangroves species in this arid region and that the microhabitat coast (BO) is the best condition for the development of flowers to hypocotyls for all three species on the eastern Baja California Peninsula. Because of exposure to the sea the trees are not water stressed at these sites.