The Reproductive Biology Of Ammopiptanthus Cheng F.(Fabaceae)

The genus Ammopiptanthus (Fabaceae) , a typical evergreen broadleaf shrub in the northwestern desert of China, is comprised of two species: A. mongolicus and A. nanus. Both are half endemic and relict species in China. In this paper, we observed and compared the sex system, flowering phonology, characteristics of breeding system, pollination ecology and pattern of fruit and seed set in two species in the Turpan Eremophytes Botanical Garden, and as well as in A. nanua under different habitat (the ex-situ conservation of Turpan Eremophytes Botanical Garden and the natural condition of wuqia country), and analyzed the variance of sex system in A. nanus under the ex-situ conservation for the first time. The main results were as follows:(1) Floral organogenesis: A. mongolicus presented hermaphroditic in both natural and ex-situ conservation condition, while A. nanus presented hermaphroditic in natural condition and andromonoecy in Turpan Eremophytes Botanical Garden. The order of floral ontogeny in the hermaphroditic of A. nanus is sepals, petals, outer stamens plus carpel, inner stamens. Order of sepals initiation was un-directional, the time of initiation was partly overlap between outer stamen and inner stamen whorl and antesepalous stamen was earlier than antepetalous. The formation of male flowers should be attributed to no development of pistils primordium, not pistils abortion of hermaphroditic. The results showed that the change of environmental condition played an important role on the sex system of A. nanus, but no on A. mongolicus.(2) Flowering phenology: in ex-situ conservation, two species of Ammopiptanthus are similar in terms of flowering frequency, the flowering order of inflorescences, flowering amplitude curves, and the mean longevity of individual flower, but considerably different in the onset, the flowering duration of individuals, the flower numbers per inflorescences, the duration, and its distribution frequency and flowering amplitude . The results showed that the similarity in flowering parameters in two species of A.mmopiptanthus may be explained by their phylogeny, while the differences, which are hereditary, may result from their evolutionary history and heterogeneous habitats. The flowering frequency, the flowering order of inflorescences and the mean longevity of individual flower under different environment conditions were almost the same, while the date started flowering and duration, the flowers per inflorescences, the duration and flowering amplitude of inflorescences in A. nanus were...