Search

Ludwigia palustris (L.) Ell. is an aquatic perennial herb present in several regions of Italy, which is one of its native countries. In this research, micropropagation and encapsulation protocols were established from axillary buds of L. palustris. Shoots proliferated on half-strength Murashige and Skoog medium without growth regulators. Different culture vessels were tested. Shoots in GROWTEK bioreactor showed the highest fresh and dry weight and total length while the plantlets grown in the RITA bioreactor showed the highest shoot number per explant. Encapsulation of L. palustris microcuttings with sodium alginate formed small and whitish beads which were stored for 14 or 28 days at 7° or 25°C. Storage for 14 days at both temperatures gave the best results but prolonged storage at 25°C decreased the shoot viability to 73%. After 4 weeks of recovery, all the plantlets showed the typical features of the species. Even though the latest Italian IUCN Red List does not mention L. palustris, conservation measu...

Background Among cereals, rice has a genetic propensity to accumulate high levels of cadmium (Cd) in grains. Xylem-mediated root-to-shoot translocation rather than root uptake has been suggested as the main physiological factor accounting for the genotypic variation observed in Cd accumulation in shoots and grains. Several evidence indicate OsHMA2 – a putative zinc (Zn) transporter – as the main candidate protein that could be involved in mediating Cd- and Zn-xylem loading in rice. However, the specific interactions between Zn and Cd in rice often appear anomalous if compared to those observed in other staple crops, suggesting that root-to-shoot Cd translocation process could be more complex than previously thought. In this study we performed a complete set of competition experiments with Zn and Cd in order to analyze their possible interactions and reciprocal effects at the root-to-shoot translocation level. Results The competition analysis revealed the lack of a full reciprocity when considering the effect of Cd on Zn accumulation, and vice versa, since the accumulation of Zn in the shoots was progressively inhibited by Cd increases, whereas that of Cd was only partially impaired by Zn. Such behaviors were probably dependent on Cd-xylem loading mechanisms, as suggested by: i) the analysis of Zn and Cd content in the xylem sap performed in relation to the concentration of the two metals in the mobile fractions of the roots; ii) the analysis of the systemic movement of 107Cd in short term experiments performed using a positron-emitting tracer imaging system (PETIS). Conclusions Our results suggest that at least two pathways may mediate root-to-shoot Cd translocation in rice. The former could involve OsHMA2 as Zn2+/Cd2+ xylem loader, whereas the latter appears to involve a Zn-insensitive system that still needs to be identified. Electronic supplementary material The online version of this article (doi:10.1186/s12284-016-0088-3) contains supplementary material, which is available to authorized users.