Effect of the rol genes from Agrobacterium rhizogenes on polyamine metabolism in tobacco roots

Plants of the mangrove species Pelliciera rhizophoreae and Avicennia germinans, exhibit pronounced oscillations in stomatal aperture under certain climatic conditions. During these oscillations, changes in transpirational water loss were closely followed by those in leaf water potential (ψ1) as indicated by continuous monitoring with an in situ dewpoint hygrometer. With this instrument, it was possible to measure dynamic changes in ψ1 for several days under constant conditions. Subsequently, the leaf was detached from the shoot and a pressure-volume (PV) curve was established by repeatedly weighing the leaf, still attached to the hygrometer during short interruptions of the water potential recordings. The pressure-volume relationship was then used to derive other water relations parameters from these water potential data. Thus, the procedure described herein allows a continuous analysis of the relevant components of bulk leaf water relations. Oscillations in water potential were also measured with single leaves using a pressure chamber. Water relations data obtained with these two different methods were in good agreement. In addition, osmotic potentials derived from the PV-analysis were well within the range of those determined cryoscopically using extracted cell sap.     

Low genetic diversity within Caribbean patches of Pelliciera rhizophorae, a Neotropical mangrove species with reduced distribution

Genetic diversity was analyzed within 12 populations of the pinuela mangrove Pelliciera rhizophorae from the American Caribbean and Pacific coasts using ten microsatellite molecular markers. Low diversity was found within the Caribbean populations (allelic richness = 2.131, Ho = 0.059, He = 0.133); whereas the Pacific ones were significantly richer (allelic richness = 4.041, Ho = 0.238, He = 0.372), notably in central populations such as Chame and Utría (total alleles: 12 and 9, respectively). Deviations between observed and expected heterozygosity under Stepwise Mutation Model were detected in the Panamanian Caribbean and Ecuadorian populations indicating recent bottlenecks. Based on these results, we are introducing the first recommendations about use of genetic criteria for recovering and conservation of this mangrove species.     

Population Genetic Structure of Neotropical Mangrove Species on the Colombian Pacific Coast: Pelliciera rhizophorae (Pellicieraceae)1

Pelliciera rhizophorae is a Neotropical mangrove species whose distribution is mostly restricted to the Pacific Coast, between the Gulf of Nicoya (Costa Rica) and the Esmeraldas River (Ecuador). In the Caribbean, patches of Pelliciera have been found in Nicaragua, Panama, and Colombia. The genetic variation and the population structure of P. rhizophorae were evaluated in six zones of the Colombian Pacific, using AFLP molecular markers. Of the 225 amplified fragments produced, 155 (69%) were polymorphic in 57 individuals of P. rhizophorae collected in the localities of Virudó, Charambirá, La Plata Island, Tumaco, Milagros, and Chontal. Genetic diversity within populations varied significantly, with the lowest levels of within‐population variation (H_ep= 0.081 and 0.090, respectively) in La Plata Island and Tumaco; and the highest level of variation (H_ep= 0.187) in Chontal. In the Colombian Pacific, P. rhizophorae was significantly structured, with 26.5 percent of the variation found among populations, which was an evidence of substructure within populations. Genetic differentiation was not related to the geographic distance between zones. This suggests that the population dynamics of P. rhizophorae could be associated with historic processes influenced by ecological and environmental factors such as the movement of pollen by birds, the displacement of propagules by marine currents, and the spatial distribution of favorable habitats.     

Development and characterization of the first microsatellite markers in the mangrove species Pelliciera rhizophorae Triana & Planchon

Pelliciera rhizophorae is a unique Neotropical mangrove species belonging to Pelliciera genus. We isolated eight microsatellite loci from this species. All loci were polymorphic and showed three to nine alleles per locus in Colombian Pacific and Caribbean populations. Polymorphic information content ranged from 0.46 to 0.69. Two loci (PeRh‐14 and PeRh‐19) showed null alleles on the Caribbean coast, which suggest genetic differentiation between Pacific and Caribbean populations of P. rhizophorae. Development of these microsatellite loci constitutes a new molecular tool to carry out studies in the genome of the species and to evaluate its population dynamics.