Enhancing restoration success of rare plants in an arid-tropical climate through water-saving technologies: a case study of Scalesia affinis ssp. brachyloba in the Galapagos Islands

Arid tropical archipelagos, such as the Galapagos Islands, host a high concentration of endemic plant species, many of which require restoration intervention to recover from past environmental degradation. Water-saving technologies (WSTs) have potential for hastening restoration by providing plants with additional water during the early stages of growth. However, it remains unclear whether such technologies provide an advantage for plant species of arid-tropical regions. This study examined the effect of the water-saving technology Groasis Waterboxx® (Groasis) on the rare endemic plant species Scalesia affinis ssp. brachyloba during early stages of restoration. Survival was monitored for 374 individuals planted across six sites on Santa Cruz Island, Galapagos (326 with technology and 48 as controls). Kaplan-Meier survival analysis showed that the use of Groasis reduced mortality during the first two years of the seedling survival. A mixed-effect logistic regression that modelled plant survival as a function of total precipitation, maximum temperature, and WST treatment (Groasis and no-technology control) found that despite low overall survival rates, plants grown with Groasis exhibited a three-fold higher predicted survival by the end of the 3.7 year duration of the study. Finally, through a resampling method, we demonstrate that the effect of the WST treatment is not dependent on the unbalanced design typical of a restoration project framework. We conclude that water-saving technologies such as the Groasis Waterboxx® can enhance survival of rare plant species such as S. affinis ssp. brachyloba in restoration programs in arid-tropical regions.

Evolutionary genomics of oceanic island radiations

A recurring feature of oceanic archipelagos is the presence of adaptive radiations that generate endemic, species-rich clades that can offer outstanding insight into the links between ecology and evolution. Recent developments in evolutionary genomics have contributed towards solving long-standing questions at this interface. Using a comprehensive literature search, we identify studies spanning 19 oceanic archipelagos and 110 putative adaptive radiations, but find that most of these radiations have not yet been investigated from an evolutionary genomics perspective. Our review reveals different gaps in knowledge related to the lack of implementation of genomic approaches, as well as undersampled taxonomic and geographic areas. Filling those gaps with the required data will help to deepen our understanding of adaptation, speciation, and other evolutionary processes.

Adoption of Sustainable Agriculture Practices through Participatory Research: A Case Study on Galapagos Islands Farmers Using Water-Saving Technologies

Agriculture in the populated islands of the Galapagos Archipelago, a protected area due to its unique biodiversity, has been detrimental to its conservation but highly required to meet food necessities. A potential solution to make agricultural farming more sustainable is adopting water-saving technologies (WSTs). Therefore, this study aimed to test the effectiveness of using WSTs such as Groasis Waterboxx^® in three of the most valuable crops in the islands through participatory research with the involvement of a group of farmers from the Floreana and Santa Cruz islands and explore a possible transition to more sustainable agricultural practices. Capsicum annuum, Cucumis sativus and Solanum lycopersicum were cultivated using Groasis Waterboxx^® and compared to conventional irrigation practices (drip-irrigated controls) to assess the variability of productivity, the number of fruits and individual fruit weight (IFW). In addition, differences in plant traits were analyzed by crop, and island. Results suggested that WSTs such as Groasis Waterboxx^® may provide on-farm benefits regarding the yields of the studied traits. From this study, it is difficult to determine whether participation in such a research study will permanently change irrigation practices. However, the participant's responses to the study suggest an increase in their understanding of the use and benefits of WST.

The genomic basis of the plant island syndrome in Darwin's giant daisies

The repeated, rapid and often pronounced patterns of evolutionary divergence observed in insular plants, or the ‘plant island syndrome’, include changes in leaf phenotypes, growth, as well as the acquisition of a perennial lifestyle. Here, we sequence and describe the genome of the critically endangered, Galápagos-endemic species Scalesia atractyloides Arnot., obtaining a chromosome-resolved, 3.2-Gbp assembly containing 43,093 candidate gene models. Using a combination of fossil transposable elements, k-mer spectra analyses and orthologue assignment, we identify the two ancestral genomes, and date their divergence and the polyploidization event, concluding that the ancestor of all extant Scalesia species was an allotetraploid. There are a comparable number of genes and transposable elements across the two subgenomes, and while their synteny has been mostly conserved, we find multiple inversions that may have facilitated adaptation. We identify clear signatures of selection across genes associated with vascular development, growth, adaptation to salinity and flowering time, thus finding compelling evidence for a genomic basis of the island syndrome in one of Darwin’s giant daisies.

Many island plant species share a syndrome of characteristic phenotype and life history. Cerca et al. find the genomic basis of the plant island syndrome in one of Darwin’s giant daisies, while separating ancestral genomes in a chromosome-resolved polyploid assembly.

Interactions of griseofulvin with cyclodextrins in solid binary systems

Griseofulvin/cyclodextrin interactions were investigated in aqueous environment and in solid state. Two cyclodextrin derivatives (beta-cyclodextrin and 2-hydroxypropyl beta-cyclodextrin) were used to prepare different physical mixtures and kneaded systems, and the drug/cyclodextrin ratios were 1:1 and 1:2 mol/mol. Scanning electron microscopy (SEM), hot-stage microscopy (HSM), differential scanning calorimetry (DSC), thermogravimetry (TG), and X-ray powder diffractometry were employed to characterize pure substances and their kneaded counterparts and all of the binary systems. The solubility of griseofulvin was increased in accord with the quantity of cyclodextrin added. HSM examination revealed that 2-hydroxypropyl-beta-cyclodextrin was dissolved in the droplets of melted griseofulvin, but did not show any interactions between melted griseofulvin and beta-cyclodextrin particles. The presence of griseofulvin endothermic peak in the DSC curves of all binary systems suggests the absence of any griseofulvin/cylcodextrin inclusion compound in the solid state. In TG, data of weight loss owing to the dehydration of cyclodextrins was similar for both kneaded systems and physical mixtures. X-ray diffraction patterns exhibited the amorphous nature of 2-hydroxypropyl-beta-cyclodextrin and the crystalline nature of griseofulvin and binary systems. Griseofulvin dissolution profiles from all binary systems showed an improvement in drug dissolution, which indicates that an "in situ" drug/cyclodextrin inclusion compound was formed in the aqueous dissolution medium.