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Summary: To induce androgenesis in field pea, grass pea and the model legume species Medicago truncatula, isolated microspores of various genotypes of these three species were submitted to a range of abiotic stresses prior to and during their initial culture, in order to stimulate them to divide and form embryos. Some stress agents had a positive effect on androgenesis from the treated microspores. Submission of flower buds to a cold period prior to anther excision or microspore isolation, modifying the osmotic pressure of the medium during initial culture and electroporation of isolated microspores were the three major individual stress agents to have an impact on the efficiency of androgenetic proliferation and subsequent differentiation from the microspores of pea, grass pea and M. truncatula genotypes. A combination of osmotic and electric shocks significantly improved responses from isolated microspores and yielded microcalluses and then calluses, but only few underwent morphogenesis. Further work is under way to improve responses and extend them to other genotypes. The results reported here are, to the best of our knowledge, the first successful results from isolated microspores of these species. [Copyright &y& Elsevier]

The role of auxins in the morphogenesis of immature seeds of Medicago truncatula was studied, focusing on the transition from the embryo cell division phase to seed maturation. We analyzed seed development in vitro, by flow cytometry, and through the determination of the kinetics of seed fresh weight and size. Thus, seeds were harvested at 8, 10 and 12 days after pollination and cultured in vitro on a medium either without auxin or supplemented with indole-3-butyric acid (IBA) or naphthalene acetic acid (NAA) at 1 mg l(-1). All parameters studied were determined every 2 days from the start of in vitro culture. The results showed that both auxins increased the weight and size of seeds with NAA having a stronger effect than IBA. We further demonstrated that the auxin treatments modulate the transition between mitotic cycles and endocycles in M. truncatula developing seed by favoring sustained cell divisions while simultaneously prolonging endoreduplication, which is known to be the cytogenetical imprint of the transition from the cell division phase to the storage protein accumulation phase during seed development., (Copyright © Physiologia Plantarum 2012.)

The genus Lathyrus is best known because it includes a number of wild relatives of the protein pea which, despite being generally neglected and under-utilised, hold considerable potential as a useful genetic resource for the acquisition of interesting stress resistant traits important for a sustainable agriculture. However, also included in this genus are important commercially produced species with a significant ornamental value, among which the sweet pea (Lathyrus odoratus L.). Surprisingly though, there are no formal reports on the in vitro propagation of this species and, generally, these are scanty for in vitro approaches with all species of Lathyrus. Here, we describe simple, yet reliable strategies for the culture and multiplication of several landraces and species of Lathyrus including sweet peas.