Explore the vast range of titles available.

This is the first revision of the genus Chlorospatha Engl. (Araceae) since Michael Madison's 1981 treatment. The genus consists of three sections, two of which are newly established: Chlorospatha sect. Occidentales Croat & L. P. Hannon and Chlorospatha sect. Orientales Croat & L. P. Hannon. Included are 69 taxa (68 species and one variety) for Central and South America, of which 45 are new to science. These include 39 newly described species: C. bayae Croat & L. P. Hannon, C. boosii Croat & L. P. Hannon, C. bullata Croat & L. P. Hannon, C. caldasensis Croat & L. P. Hannon, C. caliensis Croat & L. P. Hannon, C. carchiensis Croat & L. P. Hannon, C. cedralensis Croat & L. P. Hannon, C. chocoensis Croat & L. P. Hannon, C. congensis Croat & L. P. Hannon, C. engleri Croat & L. P. Hannon, C. giraldoi Croat & L. P. Hannon, C. grayumii Croat & L. P. Hannon, C. hannoniae Croat, C. hastata Croat & L. P. Hannon, C. huilensis Croat & L. P. Hannon, C. jaramilloi Croat & L. P. Hannon, C. limonensis Croat & L. P. Hannon, C. litensis Croat & L. P. Hannon, C. longiloba Croat & L. P. Hannon, C. maculata Croat & L. P. Hannon, C. mansellii Croat & L. P. Hannon, C. morae Croat & L. P. Hannon, C. munchiquensis Croat & L. P. Hannon, C. nambiensis Croat & L. P. Hannon, C. narinoensis Croat & L. P. Hannon, C. noramurphyae Croat & L. P. Hannon, C. oblongifolia Croat & L. P. Hannon, C. portillae Croat & L. P. Hannon, C. pubescens Croat & L. P. Hannon, C. queremalensis Croat & L. P. Hannon, C. risaraldensis Croat & L. P. Hannon, C. sagittata Croat & L. P. Hannon, C. sizemoreae Croat & L. P. Hannon, C. stellasarreae Croat & L. P. Hannon, C. sucumbensis Croat & L. P. Hannon, C. timbiquensis Croat & L. P. Hannon, C. tokioensis Croat & L. P. Hannon, C. yatacuensis Croat & L. P. Hannon, and C. yaupiensis Croat & L. P. Hannon. Four additional and putative new species are described in detail at the end of the taxonomic treatment and are included in the key, but not formally named; they are labeled Species 1 to 4 and are assumed to be new. They were collected as sterile plants and will be formally described only after recollection in fertile condition. Two combinations are made: C. plowmanii (Madison) Croat & L. P. Hannon and C. croatiana Grayum var. enneaphylla (Grayum) Croat & L. P. Hannon. Species diversity of Chlorospatha is greatest in the Andes of Colombia and the western Andes of northernmost Ecuador, and diminishes from northernmost Colombia into Central America and from central Ecuador southward to the border with Peru. Costa Rica has two taxa (one species, one variety), Panama four taxa (three species, one variety), Colombia 45 taxa (44 species, one variety), and Ecuador 24 species. Endemism is highest in Colombia, with 43 species currently considered endemic, followed by Ecuador with 23 endemic species, and Central America with two endemic species.

This study aims to explore the impact of fly ash (FA) on two types of free-floating aquatic plants, Eichhornia crassipes and Pistia stratiote s, growing in two different locations. The stress caused by FA has led to a significant biochemical alteration in several leaf properties, including ascorbic acid, relative water, and chlorophyll, as well as anatomical changes in leaf, petiole, and stolon in the growing plants at highly contaminated sites (HCS) relative to the low contaminated site (LCS). According to the study, HCS plants lose total chlorophyll overall, have shallower ascorbic acid levels, and have higher RWC than LCS plants. These findings imply that both species are highly resilient to pollution. The assessment of the shape and size of the epidermis, cortex, palisade cells, air space, bundle sheath, xylem cavity, phloem cells, vascular bundle, parenchyma, pith of the leaves, petioles, and stolon in the HCS is shorter than the LCS. The APTI values of E. crassipes (8.407%) and P. stratiote s (9.681%) are higher in HCS than the values of E. crassipes (7.729%) and P. stratiote s (9.077%) in LCS. These results suggest that both species exhibit greater APTI values in plants from HCS, indicating their tolerance to pollution. We target six water bodies in HCS and LCS to assess the FA-containing water quality. We calculated the water quality using WA-WQI and CCME-WQI. The higher WA-WQI scores indicate higher water pollution levels. The value of WA-WQI is higher in HCS sites included in the KTPP colony (93.94), Amalhanda (91.43), and Barunan Ghoshpara (89.07) than in LCS sites such as in Kashinathpur (88.59), but the CCME-WQI scores are 64.33, 76.09 and 75.71 respectively. The investigation highlights that both species are exceptionally suitable as stress-tolerant plants for fly ash and possess the potential to serve as an option for the restoration of water bodies impacted by fly ash. This study will enhance our comprehension of the potential advantages of these plants, particularly in the phytoremediation of polluted aquatic ecosystems.

Main conclusion This study provides broad insight into the chloroplast genomes of the subfamily Monsteroideae. The identified polymorphic regions may be suitable for designing unique and robust molecular markers for phylogenetic inference. Monsteroideae is the third largest subfamily (comprises 369 species) and one of the early diverging lineages of the monocot plant family Araceae. The phylogeny of this important subfamily is not well resolved at the species level due to scarcity of genomic resources and suitable molecular markers. Here, we report annotated chloroplast genome sequences of four Monsteroideae species: Spathiphyllum patulinervum , Stenospermation multiovulatum , Monstera adansonii , and Rhaphidophora amplissima . The quadripartite chloroplast genomes (size range 163,335–164,751 bp) consist of a pair of inverted repeats (25,270–25,931 bp), separating a small single copy region (21,448–22,346 bp) from a large single copy region (89,714–91,841 bp). The genomes contain 114 unique genes, including four rRNA genes, 80 protein-coding genes, and 30 tRNA genes. Gene features, amino acid frequencies, codon usage, GC contents, oligonucleotide repeats, and inverted repeats dynamics exhibit similarities among the four genomes. Higher rate of synonymous substitutions was observed as compared to non-synonymous substitutions in 76 protein-coding genes. Positive selection was observed in seven protein-coding genes, including psbK , ndhK , ndhD , rbcL , accD , rps8 , and ycf2 . Our included species of Araceae showed the monophyly in Monsteroideae and other subfamilies. We report 30 suitable polymorphic regions. The polymorphic regions identified here might be suitable for designing unique and robust markers for inferring the phylogeny and phylogeography among closely related species within the genus Spathiphyllum and among distantly related species within the subfamily Monsteroideae. The chloroplast genomes presented here are a valuable contribution towards understanding the molecular evolutionary dynamics in the family Araceae.

More than 50 participants from around the world congregated at Rutgers University for 4 days to discuss the latest advances in duckweed research and applications. Among other developments in the field, exciting new information related to duckweed including genome sequencing, improved genetic transformation, and the identification of a novel plant growth promoting substance from bacteria were reported.

Aquatic plants have to adapt to the environments distinct from where land plants grow. A critical aspect of adaptation is the dynamics of sequence repeats, not resolved in older sequencing platforms due to incomplete and fragmented genome assemblies from short reads. Therefore, we used PacBio long-read sequencing of the Spirodela polyrhiza genome, reaching a 44-fold increase of contiguity with an N50 (a median of contig lengths) of 831 kb and filling 95.4% of gaps left from the previous version. Reconstruction of repeat regions indicates that sequentially nested long terminal repeat (LTR) retrotranspositions occur early in monocot evolution, featured with both prokaryote-like gene-rich regions and eukaryotic repeat islands. Protein-coding genes are reduced to 18,708 gene models supported by 492,435 high-quality full-length PacBio complementary DNA (cDNA) sequences. Different from land plants, the primitive architecture of Spirodela’s adventitious roots and lack of lateral roots and root hairs are consistent with dispensable functions of nutrient absorption. Disease-resistant genes encoding antimicrobial peptides and dirigent proteins are expanded by tandem duplications. Remarkably, disease-resistant genes are not only amplified, but also highly expressed, consistent with low levels of 24-nucleotide (nt) small interfering RNA (siRNA) that silence the immune system of land plants, thereby protecting Spirodela against a wide spectrum of pathogens and pests. The long-read sequence information not only sheds light on plant evolution and adaptation to the environment, but also facilitates applications in bioenergy and phytoremediation.

Premise of the study: The first family-wide molecular phylogeny of the Araceae, a family of about 3800 published species in 120 genera, became available in 1995, followed by a cladistic analysis of morpho-anatomical data in 1997. The most recent and comprehensive family-wide molecular phylogeny was published in 2008 and included species from 102 genera. We reanalyzed the molecular data with a more complete genus sampling and compared the resulting phylogeny with morphological and anatomical data, with a view to contributing to a new formal classification of the Araceae. Methods: We analyzed 113 aroid genera and 4494 aligned nucleotides that resulted from adding 11 genera to the 2008 molecular matrix. We also analyzed 81 morphological characters in the context of the molecular phylogeny, using an extended version of the 1997 morpho-anatomical data set. Key results: The resulting maximum-likelihood phylogeny is well resolved and supported, and most of the 44 larger clades also have morphological or anatomical synapomorphies as well as ecological or geographic cohesion. Of the 44 clades, 16 are here newly circumscribed and informally named. However, some relationships remain poorly supported within the Aroideae subfamily. The most problematic placement is Calla within Aroideae, which conflicts with the distribution of morphological, anatomical, and palynological character states. Conclusions: The comparison of the molecular analysis with morphological and anatomical data presented here represents an important basis for a new formal classification for the Araceae and for the understanding of the evolution of this ancient family, a monocot group known in the fossil record from the early Cretaceous.

Transgenerational plasticity (TGP) refers to the influence of ancestral environmental signals on offspring’s traits across generations. While evidence of TGP in plants is growing, its role in plant adaptation over successive generations remains unclear, particularly in floating plants facing fluctuating environments. Duckweed (Lemna minor), a common ecological remediation material, often coexists with the harmful bloom-forming cyanobacterium Microcystis aeruginosa, which releases a highly toxic exudate mixture (MaE) during its growth. In this study, we investigate the TGP of duckweed and its adaptive role under stress from MaE during the bloom-forming process. We found that exposure to MaE induces significant phenotypic plasticity in duckweed, manifested by alterations in morphological, physiological, and transcriptomic profiles. Specifically, MaE exposure significantly affected duckweed, promoting growth at low concentrations but inhibiting it at high concentrations, affecting traits like biomass, frond number, total frond area, and photosynthetic efficiency. Additionally, the activities of antioxidant enzymes, together with the levels of proline, soluble sugars, and proteins, are elevated with increasing MaE concentrations. These plastic changes are largely retained through asexual reproductive cycles, persisting for several generations even under MaE-free conditions. We identified 619 genes that maintain a ‘transcriptional memory’, some of which correlate with the TGP-linked alterations in morphological and physiological traits in response to MaE stress. Notably, progeny from MaE-exposed lineages demonstrate enhanced fitness when re-exposed to MaE. These results enhance our comprehension of the adaptive significance of TGP in plants and suggest feasible approaches for utilizing duckweed’s TGP in the bioremediation of detrimental algal blooms.

The picture emerging from the rapidly growing literature on host-associated microbiota is that host traits and fitness often depend on interactive effects of host genotype, microbiota, and abiotic environment. However, testing interactive effects typically requires large, multi-factorial experiments and thus remains challenging in many systems. Furthermore, most studies of plant microbiomes focus on terrestrial hosts and microbes. Aquatic habitats may confer unique properties to microbiomes. We grew different populations of duckweed (Lemna minor), a floating aquatic plant, in three microbial treatments (adding no, “home”, or “away” microbes) at two levels of zinc, a common water contaminant in urban areas, and measured both plant and microbial performance. Thus, we simultaneously manipulated plant source population, microbial community, and abiotic environment. We found strong effects of plant source, microbial treatment, and zinc on duckweed and microbial growth, with significant variation among duckweed genotypes and microbial communities. However, we found little evidence of interactive effects: zinc did not alter effects of host genotype or microbial community, and host genotype did not alter effects of microbial communities. Despite strong positive correlations between duckweed and microbe growth, zinc consistently decreased plant growth, but increased microbial growth. Furthermore, as in recent studies of terrestrial plants, microbial interactions altered a duckweed phenotype (frond aggregation). Our results suggest that duckweed source population, associated microbiome, and contaminant environment should all be considered for duckweed applications, such as phytoremediation. Lastly, we propose that duckweed microbes offer a robust experimental system for study of host–microbiota interactions under a range of environmental stresses.

The accumulation of arsenic (As) in rice ( Oryza sativa L.) grain poses a significant health concern in Bangladesh. To address this, we investigated the efficacy of various organic amendments and phytoremediation techniques in reducing As buildup in O. sativa . We evaluated the impact of five doses of biochar (BC; BC 0.1 : 0.1%, BC 0.28 : 0.28%, BC 0.55 : 0.55%, BC 0.82 : 0.82% and BC 1.0 : 1.0%, w/w), vermicompost (VC; VC 1.0 : 1.0%, VC 1.8 : 1.8%, VC 3.0 : 3.0%, VC 4.2 : 4.2% and VC 5.0 : 5.0%, w/w), and floating duckweed (DW; DW 100 : 100, DW 160 : 160, DW 250 : 250, DW 340 : 340 and DW 400 : 400 g m − 2 ) on O. sativa cultivated in As-contaminated soil. Employing a three-factor five-level central composite design and response surface methodology (RSM), we optimized the application rates of BC-VC-DW. Our findings revealed that As contamination in the soil negatively impacted O. sativa growth. However, the addition of BC, VC, and DW significantly enhanced plant morphological parameters, SPAD value, and grain yield per pot. Notably, a combination of moderate BC-DW and high VC (BC 0.55 VC 5 DW 250 ) increased grain yield by 44.4% compared to the control (BC 0 VC 0 DW 0 ). As contamination increased root, straw, and grain As levels, and oxidative stress in O. sativa leaves. However, treatment BC 0.82 VC 4.2 DW 340 significantly reduced grain As (G-As) by 56%, leaf hydrogen peroxide by 71%, and malondialdehyde by 50% compared to the control. Lower doses of BC-VC-DW (BC 0.28 VC 1.8 DW 160 ) increased antioxidant enzyme activities, while moderate to high doses resulted in a decline in these activities. Bioconcentration and translocation factors below 1 indicated limited As uptake and translocation in plant tissues. Through RSM optimization, we determined that optimal doses of BC (0.76%), VC (4.62%), and DW (290.0 g m − 2 ) could maximize grain yield (32.96 g pot − 1 , 44% higher than control) and minimize G-As content (0.189 mg kg − 1 , 54% lower than control). These findings underscore effective strategies for enhancing yield and reducing As accumulation in grains from contaminated areas, thereby ensuring agricultural productivity, human health, and long-term sustainability. Overall, our study contributes to safer food production and improved public health in As-affected regions.

MAIN CONCLUSION : Ten of 34 tested duckweed clones showed relatively higher salt tolerance. Salinity stress induced high level of starch accumulation in these clones, making them potential feedstock candidates for biofuel production. Duckweeds are promising as a new generation of crop plants that requires minimal input while providing fast biomass production. Two important traits of interest that can impact on the economic viability of this system are their sensitivity to salt and the starch content of the harvested duckweed. We have surveyed 33 strains of duckweed selected from across all 5 genera and amongst 13 species to quantify the natural variance of these traits. We found that there are large ranges of intraspecific variations in salt tolerance, while all species examined accumulated more starch in response to the initial stages of salt stress. However, the magnitude of the change in starch content varied widely between strains. Our results suggest that specific duckweed clones can be cultivated under relatively saline conditions, while increasing salt in the medium before harvesting could be used to increase starch in duckweed biomass for bioethanol production.