Some of the most striking features of Rhizophoraceae mangrove saplings are their voluminous cylinder-shaped hypocotyls and thickened leaves. The hypocotyls are known to serve as floats during seed dispersal (hydrochory) and store nutrients that allow the seedling to root and settle. In this study we investigate to what degree the hypocotyls and leaves can serve as water reservoirs once seedlings have settled, helping the plant to buffer the rapid water potential changes that are typical for the mangrove environment. We exposed saplings of two Rhizophoraceae species to three levels of salinity (15, 30, and 0–5‰, in that sequence) while non-invasively monitoring changes in hypocotyl and leaf water content by means of mobile NMR sensors. As a proxy for water content, changes in hypocotyl diameter and leaf thickness were monitored by means of dendrometers. Hypocotyl diameter variations were also monitored in the field on a Rhizophora species. The saplings were able to buffer rapid rhizosphere salinity changes using water stored in hypocotyls and leaves, but the largest water storage capacity was found in the leaves. We conclude that in Rhizophora and Bruguiera the hypocotyl offers the bulk of water buffering capacity during the dispersal phase and directly after settlement when only few leaves are present. As saplings develop more leaves, the significance of the leaves as a water storage organ becomes larger than that of the hypocotyl.
A global census of marine microbial life has been underway over the past several decades. During this period, there have been scientific breakthroughs in estimating microbial diversity and understanding microbial functioning and ecology. It is estimated that the ocean, covering 71% of the earth's surface with its estimated volume of about 2 × 1018 m3 and an average depth of 3800 m, hosts the largest population of microbes on Earth. More than 2 million eukaryotic and prokaryotic species are thought to thrive both in the ocean and on its surface. Prokaryotic cell abundances can reach densities of up to 1012 cells per millilitre, exceeding eukaryotic densities of around 106 cells per millilitre of seawater. Besides their large numbers and abundance, marine microbial assemblages and their organic catalysts (enzymes) have a largely underestimated value for their use in the development of industrial products and processes. In this perspective article, we identified critical gaps in knowledge and technology to fast-track this development. We provided a general overview of the presumptive microbial assemblages in oceans, and an estimation of what is known and the enzymes that have been currently retrieved. We also discussed recent advances made in this area by the collaborative European Horizon 2020 project ‘INMARE’.
When seedlings grow into young plants their tissue proportions change over time. Viviparous mangrove seedlings of the Rhizophoraceae are different from other young trees. They consist of a thickened cylinder-shaped hypocotyl that allows the seedlings to float and disperse before establishment. Despite the crucial role in the ecological and biogeographical success of mangroves, not much has been published about the internal development of mangrove seedlings in their early life stages. We used X-ray CT-scanning and light microscopy to investigate the internal development (i) over time and (ii) with hypocotyl height in seedlings of the mangrove species Bruguiera gymnorrhiza and Ceriops tagal. While light microscopy offered cell- and tissue identification in destructive transverse sections, X-ray CT-scanning allowed investigating the internal tissue development of living plants over time in a non-destructive way. Our results indicated that the vascular tissue proportionally increased over time and with hypocotyl height in both species in accordance with the growing importance of this tissue in the developing seedlings. As a result, the cortex, composed of an inner and outer zone, proportionally decreased over time and with height in both species. No clear trends over time and with height could be observed regarding the proportion of the pith tissue. A decrease in average density of all tissues together with height was discerned in both species indicating the seedlings were heavier at their base. The latter suggests a supporting role of the seedling base in tidal and wind action. The combination of CT-scanning and light microscopy offered the advantages of both methods in the developmental study of young mangrove plants, and opens perspectives in the study of internal development of young plants in general.
Many zooplankton species produce dormant stages to bridge episodes that are unfavorable for juveniles and adults. Although a variety of methods has been used to study the morphology and internal structure of these propagules, surprisingly little is known about links between propagule traits and life history characteristics such as dormancy, hatching behavior and fitness of emerging larvae. A major constraint is that most available methods are lethal to the embryo and processing can generate visual artefacts. Here, we investigate the potential of High Resolution X‐ray Computed Tomography (HRXCT or µCT scanning) to compile whole mount 3D reconstructions of the propagules of three zooplankton species that differ in size (∼200–1200 μm) and shape (spherical eggs vs. semi‐circular ephippia). Our results show that µCT scanning is a suitable technique for whole mount reconstruction of propagules. In addition, by combining the scanning procedure with a laboratory hatching experiment we showed that while eggs that were exposed to µCT scanning had significantly lower hatching fractions and lower motility of hatchlings than control eggs, some of the scanned eggs or larvae could still be used in subsequent life table experiments. Overall, µCT scanning represents a valuable, non‐invasive technique for internal and external characterization of zooplankton propagules and to study associations between propagule structure and life history traits.
No abstract
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.