Abstract This study investigates the role of mutualistic interactions in facilitating the invasion of Ulex europaeus (Fabaceae) in the southern Brazilian highland grasslands. We assessed its reproductive phenology, floral resources, pollinator interactions, and seed dispersal mechanisms. Observations revealed that U. europaeus flowers predominantly during winter, with peak flowering occurring in August. During this period, no native species were in bloom, and Apis mellifera was the sole pollinator observed. Pollen analysis showed that honeybees carried U. europaeus pollen almost exclusively in winter, but diversified their loads in spring when other species began flowering. We also confirmed seed dispersal by native ant species, although grazing animals did not contribute to seed dispersal. Our findings suggest that the successful invasion of U. europaeus is enhanced by its interaction with A. mellifera, a species with which it co-evolved in its native range, despite limited interaction with native pollinators. Additionally, seed dispersal by native ants further contributes to its spread. These mutualistic relationships, especially with A. mellifera, play a significant role in the species' spread and dominance, potentially threatening local biodiversity. Understanding these ecological interactions is crucial for developing strategies to control the spread of U. europaeus and mitigate its impacts on native ecosystems.

ABSTRACT Propolis primarily comprises resins, waxes, pollen, and several compounds collected by honeybees and mixed with secreted fluids. Globally, red propolis production is limited to a few regions, and San Andrés Island (Colombia) is one of these locations. This study aims to outline the palynological profile of red propolis produced by Apis mellifera on San Andrés Island, Colombia, to identify its relationship with the local vegetation. Red propolis samples were collected for the production year 2022 from two apiaries located on the island. Red propolis samples were initially treated with ethanol and KOH for pollen grain analysis, followed by the standard acetolysis techniques. After the palynological analysis and botanical identification, 76 pollen types were identified, associated with 32 plant families, 61 genera, and 42 species. Leguminosae and Asteraceae were the botanical families with the most representative, each with seven pollen types. Pollen types such as Mimosa pudica, Cecropia peltata, and Byrsonima crassifolia exhibited the highest importance values within the pollen spectrum. Most pollen types were associated with arboreal and shrubby taxa, predominantly distributed in forest formations and vegetation characteristic of anthropic areas. The analyses highlighted the distribution and diversity of pollen types within red propolis samples from San Andrés Island.

Abstract Plant phenological responses are highly sensitive to micro- and macroclimatic changes, which can be intensified by anthropogenic disturbances in the Caatinga. This study investigates the differences in the phenological timing (i.e., phenological mismatches) of vegetative and reproductive phenophases of Myracrodruon urundeuva Allemão (Aroeira) in a young and mature anthropogenic forest area within the same Caatinga fragment. We tested the effects of temperature and precipitation on the temporal variation of the phenophases. For one year, plants from a young forest area (21 years) and a mature forest area (over 90 years) were monitored monthly to record vegetative phenophases (leaf emergence, senescence, and leaf abscission) and reproductive phenophases (flowering and fruiting). We calculated the activity (presence/absence) and phenological intensity of the plants. Circular statistics were used to study phenological patterns in both forests. Compared to the mature forest, the younger forest exhibited increased leaf emergence and a prolonged period of leaf abscission. Early fruiting observed in the anthropized forest may affect its reproductive success, depending on annual precipitation patterns for the germination of its recalcitrant seeds. Decreased rainfall and higher temperatures in the Brazilian semi-arid region increase the vulnerability of this tree, potentially aggravated by anthropogenic disturbances.

Abstract We present two taxonomic novelties in Garcinia (Clusiaceae): a new species to the Brazilian Atlantic Forest, Garcinia bahiensis Mouzinho & L.Marinho sp. nov. ined., endemic to the hygrophilous forests of southern Bahia state, whose specimens were previously determined as G. macrophylla Mart.; and the redescription of G. guacopary (S.Moore) M.Nee, a species distributed in the transition areas between the Amazon and Cerrado domains that were neglected in previous studies. The taxonomic treatment consists of morphological descriptions, photographic plates, distribution maps, and morphological discussions with related species. Regarding G. guacopary, we present images of live specimens and their current known distribution for the first time, with a considerable range expansion, besides the designation of a lectotype. After G. bahiensis description, segregated from a broader G. macrophylla concept, Garcinia no longer shares species between the Amazon and Atlantic Forest domains.

ABSTRACT This study examines a new strain, Limnospira fusiformis TL03, isolated from Lake Telamine in northwest Algeria. The strain was morphologically identified using a light microscope and molecularly characterized using its 16S rRNA gene sequence. The effect of salinity on growth and photosynthetic pigments was studied using a spectrophotometric method; different sodium chloride concentrations (0, 5, 15, 30, 45, and 60 g/l) in blue-green medium (BG11) cultured uniformly as homogenized cell suspension were tested. A morphological examination confirmed that the isolated strain belonged to the Limnospira genus. It has trichome lengths ranging from 210-2027 µm, as well as pitch and coil diameters ranging from 30-137 µm and 20-60 µm, respectively. The data from the 16S rRNA gene sequence analysis confirmed that the isolated strain was Limnospira fusiformis TL03 with 100% sequence similarity to Limnospira fusiformis SAG 85.79. The results also indicate that this strain can grow at various salt concentrations, with the highest optical density values (1.58 ± 0.014 and 1.56 ± 0.003) obtained in cultures containing 15 g/L and 5 g/L NaCl, respectively.

Abstract Tropical forests are biologically significant ecosystems, yet they face increasing pressure from human activities, which has led to the introduction of invasive plant species. Despite this, much of the existing literature on plant invasions in tropical forests focuses on Old World forests and grasses, leaving Neotropical forests relatively understudied. To address this gap, we aimed to investigate patterns of woody plant invasions in Neotropical forests with different levels of leaf deciduousness and identify the key factors that explain the richness of invasive woody plants. We conducted a systematic review of floristic surveys in Neotropical forests, gathering data on climate, environmental, and anthropogenic variables for each study site. Our analysis revealed that the richness of invasive plants increased with greater temperature seasonality, higher accessibility, and elevated per capita gross domestic product, while it decreased with increased canopy cover. Higher temperature seasonality and accessibility were strong positive predictors of invasive plant richness. Subtropical Neotropical forests are more susceptible to the establishment of invasive species due to the higher temperature seasonality. In addition, factors such as leaf deciduousness and increased human accessibility further contribute to the susceptibility of these forests to the arrival and establishment of invasive woody plants.

ABSTRACT The genus Piptadenia Benth. has undergone several changes in its circumscriptions throughout its history, given the difficulty of its phylogenetic placement. Considering that palynological contributions have been significant for differentiating taxa within the Mimoseae tribe , the present study aims to characterize the representatives of the genus as well as describe the pollen grains of some taxa still unpublished in the literature. Three types of pollen grains were identified based on the number of grains per polyad considering the number of pollen grains and their ornamentation. However, other palynological characters are similar among species, supporting the monophyly of the genus. All species showed similarities, especially regarding size and shape, varying mainly in the number of pollen grains composing the polyads (8, 12, and 16). This variation has already been confirmed by morphological and molecular data. This study presents unprecedented palynological characterization of the species: Piptadenia affinis, P. cuzcoënsis, P. gonoacantha, P. imatacae, P. killipii, P. micracantha, and P. robusta.

ABSTRACT The importance of understanding environmental changes has stimulated the study of plant functional traits, which reflect the species' ecological strategies and determine how they respond to environmental variations and climate change. We tested whether the functional traits and ecological strategies of the species Bactris hirta Mart. and Tetracera sp. in the seedling stage respond to water and soil nutrient availability and landscape variation. We evaluated leaf traits, (SLA, LDMC, ΨTLP, and ΨsFT) in thirteen fragments in Barcarena, Brazil. The SLA and LDMC were collected during periods of low and high water availability. We analyzed macronutrients, soil texture, and landscape metrics. Both species showed higher LDMC during periods of low water availability, despite no changes in SLA. The variation in leaf traits led to changes in CSR strategies; however, there was a prevalence of the stress-tolerance strategy. The ΨTLP and ΨsFT were more negative in palm species than in liana. The landscape and soil characteristics influenced resource allocation patterns and drought-related traits of the species, yet the species differed in the relationships among the variables. The ability of both species to show intraspecific variability may be an important mechanism contributing to the abundance and prevalence of palms and lianas in forest fragments.

Abstract This study aims to reevaluate the diversity of 16S rRNA gene sequences associated with Scytonema (Nostocales, Cyanobacteria). For that, we first conducted a search for ‘Scytonema’ sequences available in GenBank (NCBI) and aligned the results with reference strains from other Nostocales genera. The alignment totalized 383 OTUs and 800 nucleotide positions analyzed. A FastTree phylogenetic analysis revealed that the ‘Scytonema’ sequences are distributed across 15 distinct clades in addition to the Scytonema sensu stricto clade. These additional clades are positioned among Nostocales genera and phylogenetically distant from the type species, S. hofmanni. Within these clades, we had access to the strain Scytonema sp. CCIBt3568, identified as S. schmidtii, which we believe should be separated from Scytonema, and described as a new genus in the future. Additionally, Bayesian Inference and Maximum Likelihood phylogenies were performed with 97 OTUs and 971 bp, and the polyphyletic status of Scytonema as currently recognized was confirmed.

Abstract The plant cell walls are dynamic structures, whose pectin composition varies according to the developmental and functional stages and in response to external factors. Gall inducers change the functional profiles of their host organs, and herein, we explore how stem cell walls respond to gall development, particularly in the nutritive tissues consumed by the lepidopteran larva. The pectin composition of the non-galled stems of Marcetia taxifolia (Melastomataceae) in primary and secondary growth and of Lepidoptera stem galls in distinct stages of development were studied by immunocytochemistry. During the development of the stems of M. taxifolia, the changes in protein and pectin composition suggest that young stems are growing and elongating with the help of extensins, arabinogalactan-proteins (AGPs), and homogalacturonans (HGs). In the galls, the predominance of galactans indicates changes in the pectin composition, allowing cell wall stiffness in hyperplasic tissues. The chewing stimuli of the Lepidoptera induce the synthesis of galactans, arabinans, and HGs in nutritive cells, allowing the cell wall flexibility during the hyperplasic process and the porosity necessary for the translocation of water and nutrients toward the gall chamber.

Abstract A new species of Cecropia (Urticaceae) is described for Amazonas state, Brazil. Collecting and processing of the vouchers followed the usual procedures for botanical specimens. Parallel to the herbarium procedures, phylogenetic analyses were performed and photographs of the species in the field were obtained. The species shares morphological similarities with Cecropia membranacea and C. concolor, which are discussed in this paper. It appears as a sister group of C. membranacea in the phylogenetic analysis in a strongly supported clade. An identification key for all known Cecropia species from the Central Amazon is provided. The conservation status of the new species is Vulnerable since it was only collected in Manaus municipality, occurring in the edges and vicinity of secondary “terra firme” forests and anthropized urban areas. The species is the tenth described for the Central Amazon.

Abstract: Abscisic acid (ABA) is a naturally occurring plant hormone, and it is also a known stress hormone that acts in plant responses to abiotic stresses, especially drought. Dendrobium candidum production losses due to drought have prominent economic effects. The current study investigates the role of ABA in the drought stress tolerance of D. candidum. The influence of drought stress and foliar spray with ABA at different concentrations (5 mg/l, 10 mg/l, 15 mg/l) on physiological and biochemical parameters was analyzed. The stems and leaves of D. candidum were collected on Day 0, Day 6, and Day 12. The osmotic regulation ability, photosynthetic maintenance ability, and antioxidant ability of D. candidum under drought stress were measured. Additionally, the changes in growth and physiological characteristics of D. candidum under drought stress were studied after applying three concentrations of ABA. Exogenous ABA application effectively ameliorates the adverse effects of drought stress to improve drought resistance. In conclusion, 10 mg/l ABA resulted in leaf water status maintenance, photosynthetic performance, and antioxidative ability under drought stress.

Abstract We describe here the new species Luehea peruzziana Gerace, Bovini & Baumgratz, endemic to the Brazilian Atlantic Forest, and restricted to the state of Espírito Santo, in the south-eastern region of the country. Morphological description, illustration with details of vegetative and reproductive structures, and comments on taxonomy, distribution, phenology, and conservation status are provided. Furthermore, given the morphological similarity with L. ochrophylla Mart., a comparative analysis between these two taxa is reported.

Abstract Increased frequency and duration of droughts are projected due to climate change, with northeastern Brazil’s semi-arid region being one of the most affected globally. These changes in rainfall are expected to be particularly harmful to seedlings, impacting plant species’ population dynamics. We conducted a greenhouse experiment to assess how different water deficit levels affect the performance and morphophysiological responses of seedlings of Ouratea fieldingiana (Ochnaceae), a plant species endemic to the northeastern coast of Brazil. We hypothesized that higher water deficits would lead to significant reductions in seedling growth and alterations in morphophysiological traits. Overall, the seedlings demonstrated slow development, characterized by increased root allocation, fewer leaves, and a reduced leaf area ratio (LAR). Water stress further decreased growth, number of leaves, and relative water content (RWC%) while increasing floating leaf asymmetry (FLA). Furthermore, O. fieldingiana seedlings displayed limited capacity to acclimatize to very severe conditions, with all seedlings succumbing within the first 15 days. We conclude that severe water limitation may compromise the recruitment and survival of O. fieldingiana under prolonged drought scenarios, posing a significant risk to natural populations in the face of climate change.