查看更多>>摘要：The use of seaweed extracts as biostimulants to promote enhancements in other seaweed crops is gaining momentum. Here we examined if the seaweed-derived biostimulant Ascophyllum marine plant extract powder - AMPEP, enhanced growth and thermal tolerance of cultured thalli of Neopyropia yezoensis when grown under optimal and sub-optimal temperature conditions. We also examined if enhancements could be transferred to new blades through archeospore germination. Area, specific growth rate, reactive oxygen species (ROS) and protein content of thalli were measured as indicators of potential enhancement. The application of AMPEP significantly increased growth rates in thalli of N. yezoensis grown under optimal temperature conditions, whilst the thalli showed no indications of improved thermal tolerance. The collated data suggested that growth enhancement could be transferred from treated thalli to newly formed blades, which developed from archeospores. This study provides new evidence of the far-reaching potential of using extracts of selected seaweeds as biostimulants to support the cultivation of economically important Neopyropia species.
Poole, JackieHutchinson, Jeffrey T.Hathcock, Christopher R.Han, David...
8页
查看更多>>摘要：Texas wild rice (Zizania texana Hitchc.) is an endemic, federally endangered aquatic macrophyte known only from the upper San Marcos River in central Texas. Annual surveys of Texas wild rice coverage have occurred for 30 years from 1989 to 2018, documenting the known coverage within its limited range. Texas wild rice exhibited a progressive increase in coverage from 1989 to 2018, but coverage increased following 2013 when plantings began. Based on an autoregressive model, the overall maximum coverage growth rate of Texas wild rice was estimated to be r(max) = 0.152 indicating a 15% increase in Texas wild coverage annually if discharge is maintained at an optimum of 3.99 m(3) s(-1). Significant (P < 0.05) increases in Texas wild rice coverage occurred in six of the seven upper segments of the river, while significant (P < 0.05) decreases occurred in five of the seven lower segments. The maximum discharge recorded during the survey was 175 m(3) s(-1) in 1998, which resulted in a 15.6% decrease in coverage during the 1999 survey, but Texas wild rice coverage increased during 2000. This endangered macmphyte exhibits resilience and resistance to high discharge events due to its fast growth rates, reproductive plasticity, high root-to-shoot ratios, and a perennial life cycle that contributes to its fast recovery following scouring. Decreased spring flows and associated declining water levels due to increased groundwater water extraction represents the greatest threat to the only known population of Texas wild rice as exposed plants become desiccated and suffer high mortality if the upper reach of the river becomes ephemeral.
查看更多>>摘要：The use of seaweed extracts as biostimulants to promote enhancements in other seaweed crops is gaining momentum. Here we examined if the seaweed-derived biostimulant Ascophyllum marine plant extract powder – AMPEP, enhanced growth and thermal tolerance of cultured thalli of Neopyropia yezoensis when grown under optimal and sub-optimal temperature conditions. We also examined if enhancements could be transferred to new blades through archeospore germination. Area, specific growth rate, reactive oxygen species (ROS) and protein content of thalli were measured as indicators of potential enhancement. The application of AMPEP significantly increased growth rates in thalli of N. yezoensis grown under optimal temperature conditions, whilst the thalli showed no indications of improved thermal tolerance. The collated data suggested that growth enhancement could be transferred from treated thalli to newly formed blades, which developed from archeospores. This study provides new evidence of the far-reachingpotential of using extracts of selected seaweeds as biostimulants to support the cultivation of economically important Neopyropia species.
查看更多>>摘要：European populations of common reed (Phragmites australis) are considered to build a single metapopulation with an extensive gene pool. Here we characterise the pattern of genetic diversity of 24 common reed populations in northeastern Germany and test how a disturbance by water salinity and mowing influences population genetic and morphological parameters. The investigation of in total 720 samples revealed them as uniformly tetraploid. The four haplotypes found and a set of eight SSR loci combined freely corroborating the hypothesis of a single large metapopulation. A MEMGENE plot based on pairwise genetic and geographic distances explained only 3.27% of genetic variation. Most of the genetic diversity was found within populations implying that gene flow over distances exceeding 10 km seems to be effectively mediated via seeds and pollen. Only in two cases, we encountered spread via rhizomes among different populations. Populations influenced by brackish water salinity show consistently higher values for Nei's unbiased gene diversity index, which we explain by higher disturbance (water salinity, water currents, stronger winds) creating more room for seedling establishment, and/or lower extension of clones. A structural equation model revealed both mowing and water salinity, but not genetic parameters, to have a negative effect on stem width, and put an effect on haplotype composition. Our results point towards a very effective gene flow in this species, a high degree of plasticity, and the importance of disturbance for the accumulation of genetic diversity, perhaps via seedling recruitment. Data Availability Statement: Sequence data that support the findings of this research have been deposited in GenBank with the accession code OK666430. Raw data for all samples, used in this study, and the quality plots of assignment loci as isoloci, have been deposited in Figshare [DOI: 10.6084/m9.figshare.16438668; 10.6084/m9. figshare.16438812].
查看更多>>摘要：Aquatic plants are generally underrepresented in herbaria due to geographic bias, rarity of species, and sampling bias towards terrestrial vascular plants. This constitutes a limitation to various lines of research (e.g., evolutionary and ecological studies) centered around aquatic plants. Plants in the genus Marathrum (Podostemaceae) have been suggested to be under-collected due to their highly modified phenotypes and to geographic bias. Marathrum (and Podostemaceae in general) live attached to rocks in river-rapids and waterfalls, which are difficult habitats to access. Here, we aimed to assess the number of historical records of Marathrum in Colombia, the country where the genus was first collected and where mountain ranges have been found to constitute a barrier to gene flow across populations. We expand past records with new records for the genus in Colombia and find that Marathrum are not uncommon in river-rapids and waterfalls in the country, but their underrepresentation in herbaria respond to several collection biases. We discuss the reasons for changes in the number of collections of Marathrum in Colombia through time, sources of collection bias in the group, and the relevance of occurrence records of Marathrum. The herbarium data reported in this study are publicly available in a digital repository to facilitate future research.
NSTL
Elsevier