In vitro propagation and shoot encapsulation as tools for ex situ conservation of the aquatic plant Ludwigia palustris (L.) Ell.

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 measures are proposed at local level because this species locally remains vulnerable mainly due to the loss of adequate habitats.Our protocol could be one of the methods for ex situ conservation of L. palustris particularly because its seed storage behavior is uncertain