In vitro growth and organogenesis of Prosopis farcta plantlets (Fabaceae, Mimosoideae) in culture medium supplemented with various concentrations of Ca++ and Na+.

The objective of this study was to vary the mineral composition of the culture medium of Prosopis farcta seedlings per addition of Na+ and Ca++ ions with the aim to identify the culture media which support the growth and/or the expression of the in vitro plant organogenesis. The Na+ and Ca++ ions were added in the culture medium in various concentrations by taking the Gamborg medium, in which macroelements were diluted 10 times, as the basic one. After two months of culture, parameters relating to the vegetative development of plant seedlings and to the various expressions of organogenesis were measured.

[Intra-individual heterostyly in Atriplex halimus L. (Amaranthaceae)].

Classically, the Atriplex halimus L. female flower is perianthless, has two bracteoles, one ovary and one style. Considering bracteoles, one can distinguish, among the representatives of two Tunisian populations, three phenotypes of female flowers, each of them being distributed in three types according to the style length.

Flower architecture and sex determination: how does Atriplex halimus play with floral morphogenesis and sex genes?

•  Atriplex halimus , a monoecious Chenopodiaceae , produces flowers displaying two basic architectures. •  The first architectural pattern is made of staminate pentamerous flowers with an external whorl of yellowish tepals and an internal whorl of stamens. The second architectural pattern consists of female flowers with a single carpel enclosed within two opposite bracts.

[Polygamy in Atriplex halimus L. (Chenopodiaceae)].

It appears that up to now the inflorescence and flower morphologies of Atriplex halimus have been described incompletely. This species has been classified as monoecious or dioecious. Numerous observations and ontogenic studies have pointed to types of flowers morphologically and functionally hermaphroditic, never described until now.