This study examines the growth patterns, leaf morpho-anatomical traits and physiological characteristics of three ornamental taxa of Alocasia: A. melo, A reginae and Alocasia × morfontanensis ‘Bambino’. Using optical and scanning electron microscopy, the research obtained anatomical details of the leaves. Alocasia × morfontanensis ‘Bambino’ exhibited the highest leaf growth rate among the taxa studied, showing significant leaf number increases from the 8th to the 12th week after planting. Alocasia melo produced 2–3 new basal shoots after 20 weeks, whereas the other two taxa did not produce any. Alocasia melo displayed the greatest relative water content and leaf thickness, while A. reginae showed the highest chlorophyll stability. This study also revealed variations in the adaxial and abaxial leaf color, stomatal width, epidermal thickness, and elemental composition among the taxa involved, with A. melo containing rhodium and high levels of calcium on their leaf surface. These findings contribute to the understanding of the Alocasia leaf morpho-anatomy and growth, which is useful for optimizing Alocasia cultivation and production across diverse ecosystems.
Context Andropogon gayanus, commonly known as gamba grass, is one of the declared weeds of national significance in Australia. Past studies have focused on gross morphology of root structures, biogeochemical behaviour, and ecology, but there has been limited work on comparative descriptions of leaf micromorphology and anatomy. Aims We investigated and described its leaf micromorphology and anatomy to understand weed biology and ecophysiology. Methods Optical and scanning electron microscope examination of the adaxial and abaxial leaf surfaces of A. gayanus was carried out. We identified and generated a list of morphological characters that were used to compare several dried herbarium specimens of A. gayanus. Key results The leaf characters were consistent across all specimens examined, with minor differences in leaf pubescence, indicating this could be a plastic trait. Conclusions Andropogon gayanus leaves are well adapted to wet and dry tropical conditions. Plasticity in leaf surface pubescence possibly enhances its adaptability, increasing its success as a weed in Australian ecosystems. The success of A. gayanus in Australia could be because the environment compares favourably with the native environment of the species in Africa, where it has adapted to extremes of wet and dry conditions over a large geographical range. Implications Plant morphological and taxonomic studies of A. gayanus focused on describing characters of spikelets and caryopses are recommended to understand how reproductive structures aid in its successful proliferation.
Sargassum is the most diverse genus in the brown algal order Fucales, which is an ecologically important primary producer in marine ecosystems. The Philippines has about 73 species of Sargassum identified based solely on morphology, representing 18% of its reported global diversity. The genus is known for its morphological plasticity which makes identification of its species challenging. Taxonomy is particularly problematic in the Philippines where molecular data for Sargassum is lacking. We collected 34 samples of Sargassum from Eastern Samar, Philippines, an area known to have significant species diversity. Using newly designed primers to amplify the nuclear ribosomal internal transcribed spacer (ITS) region, we generated gene sequences and reconstructed the phylogeny of Sargassum to infer species diversity of the Eastern Samar samples. Based on morphological assessments of samples, we found S. corderoi, S. polycystum and five other morphotaxa. Molecular assessments, on the other hand, show the presence of only three morphotaxa. Bayesian inference, maximum parsimony and maximum likelihood generated almost identical trees which showed that S. corderoi and Sargassum sp. aff. siliquosum samples are nested in a clade of S. ilicifolium. This is the first time that S. corderoi has been reported in Eastern Samar. Another species, S. polycystum, formed a clade consisting of well-supported subgroups. This study is a step towards updating the taxonomic identification of Sargassum species found in the Philippines using molecular and morphological data. The biomarker used in our study could improve the identification of Sargassum species in a species-rich subtropical-tropical geographical area such as the Philippines, in phylogenetic studies of Sargassum.
Sargassum polycystum is an economically important seaweed endemic to Southeast Asian waters. Genetic diversity studies conducted for this alga have been based on samples from various areas in the Indo-Pacific region. Here, we examined the phylogenetic patterns of S. polycystum in Eastern Samar, Philippines using the nuclear ribosomal DNA (rDNA) region – including ITS1, 5.8S gene, and ITS2. The phylogenetic and haplotype analyses using these loci indicate that the Eastern Samar samples contain 13 haplotypes. Using the ITS2 region sequences alone (to include other Indo-Pacific samples), we found that the number of Eastern Samar haplotypes was reduced to six, with one common haplotype found in Singapore and Indonesia. Our findings indicate that the genetic diversity of Eastern Samar S. polycystum is substantially higher than previously suggested. Consistent with the previous hypothesis, the populations of S. polycystum in Southeast Asian waters indicate a range expansion. The study could extend our understanding of the genetic diversities of S. polycystum in the Philippines and elsewhere.
Resurrecting extinct species is a fascinating and challenging idea for scientists and the general public. Whereas some theoretical progress has been made for animals, the resurrection of extinct plants (de-extinction sensu lato) is a relatively recently discussed topic. In this context, the term 'de-extinction' is used sensu lato to refer to the resurrection of 'extinct in the wild' species from seeds or tissues preserved in herbaria, as we acknowledge the current impossibility of knowing a priori whether a herbarium seed is alive and can germinate. In plants, this could be achieved by germinating or in vitro tissue-culturing old diaspores such as seeds or spores available in herbarium specimens. This paper reports the first list of plant de-extinction candidates based on the actual availability of seeds in herbarium specimens of globally extinct plants. We reviewed globally extinct seed plants using online resources and additional literature on national red lists, resulting in a list of 361 extinct taxa. We then proposed a method of prioritizing candidates for seed-plant de-extinction from diaspores found in herbarium specimens and complemented this with a phylogenetic approach to identify species that may maximize evolutionarily distinct features. Finally, combining data on seed storage behaviour and longevity, as well as specimen age in the novel 'best de-extinction candidate' score (DEXSCO), we identified 556 herbarium specimens belonging to 161 extinct species with available seeds. We expect that this list of de-extinction candidates and the novel approach to rank them will boost research efforts towards the first-ever plant de-extinction.
The taxonomy of Neurachninane has been unstable, with its member genera consisting of Ancistrachne, Calyptochloa, Cleistochloa, Dimorphochloa, Neurachne, Paraneurachne and Thyridolepis, changing since its original circumscription that comprised only the latter three genera. Recent studies on the phylogeny of Neurachninae have focused primarily on molecular data. We analysed the phylogeny of Neurachninae on the basis of molecular data from seven molecular loci (plastid markers: matK, ndhF, rbcL, rpl16, rpoC2 and trnLF, and ribosomal internal transcribed spacer, ITS) and morphological data from 104 morphological characters, including new taxonomically informative micromorphology of upper paleas. We devised an impact assessment scoring (IAS) protocol to aid selection of a tree for inferring the phylogeny of Neurachninae. Combining morphological and molecular data resulted in a well resolved phylogeny with the highest IAS value. Our findings support reinstatement of subtribe Neurachninae in its original sense, Neurachne muelleri and Dimorphochloa rigida. We show that Ancistrachne, Cleistochloa and Dimorphochloa are not monophyletic and Ancistrachne maidenii, Calyptochloa, Cleistochloa and Dimorphochloa form a new group, the cleistogamy group, united by having unique morphology associated with reproductive dimorphism.
Tripogon loliiformis is a desiccation-tolerant grass that occurs throughout mainland Australia.There has been recent interest in this species as a model system for understanding desiccation tolerance in a native grass at the structural, molecular and physiological levels.However, not much is known about the biology and natural history of this species, despite its widespread geographic distribution and remarkable capability of withstanding prolonged drying.We provide an overview of the genus by consolidating information from a wide variety of sources.We report a variety of new and interesting observations on the general biology, ecology and desiccation response of T. Joliiformis and conclude by highlighting areas for future research.