Flora最新文献

Urbanization is among the main drivers of global biodiversity changes. Urban areas are increasing faster, particularly in global biodiversity hotspots. Therefore, more evidence is needed on how urban gradients drive plant traits and interactions with herbivores in neotropical regions. Here, we investigated how urbanization intensity and habitat permeability affect metrics (species richness, composition and vegetation cover), functional traits, and herbivory of plant communities, focusing on spontaneous native and non-native species in a neotropical city in Brazil. Non-native species represented 64.6 % of the occurrences, and habitat permeability had a stronger influence on plant communities than urbanization intensity. The intensity of urbanization decreased the species richness and increased the specific leaf area in native and non-natives plants. Habitat permeability also affected species composition. Permeable habitats had higher vegetation cover, herbivory, and height of the non-native communities. Life forms as geophyte for non-natives, chamaephyte, and hemicryptophyte for natives, and zoochoric dispersal syndrome were more frequent in permeable habitats. Impermeable habitats had higher frequencies of therophyte life form, and autochoric dispersal syndrome for native species. The higher vegetation cover, the lower direct interference from humans, and the permeability of habitats allowed more different functional traits within plant community and more interactions between plants and herbivores along the urbanization intensity gradient. The permeability of urban habitats, in a medium-sized neotropical city, has greater influence on the variation of the plant community than the intensity of urbanization. This highlights the importance of the presence of permeable areas in supporting plant biodiversity within highly paved urban gradients.

Peliosanthes meghalayensis, a new species from Wari Chora gorge in Meghalaya, NE India, is described and illustrated. It is similar to P. pumila from Khasia, NE India, in its small habit and having flowers fewer than 10, but differs chiefly by the knobby rhizome, broader leaf blades with closer transversal veinlets, slightly larger cernuous flowers, and pistils with 6 distinct ridges. On the other hand, in Assam, NE India, we rediscovered P. subspicata, which had been known only by old collections made in NE India and Bangladesh in the 19th century. We supplementarily describe and illustrate it based on living collections. We treated P. bipiniana as conspecific with P. subspicata.

Capsule-type fruits are predominant in Bromeliaceae. However, the late divergent subfamily Bromelioideae generally presents fleshy fruits, which display a diverse range of morphologies even in related genera; however, there is almost no information regarding their anatomical and ontogenetic aspects. In this study we evaluate the fruit ontogeny of species from the major lineages of Bromelioideae, to better understand the possible paths in which fleshiness can be achieved in the subfamily. Flowers at pre-anthesis and anthesis, and fruits of Acanthostachys strobilacea, Billbergia pyramidalis, and Bromelia antiacantha were collected and processed with standard methods for analysis under light microscopy. Two basic ontogenetic pathways for achieving fleshiness were identified among the examined species. In the two former species, belonging to the core Bromelioideae, the pericarp development occurs solely through cell expansion and anticlinal cell division in the mesocarp. Conversely, in B. antiacantha, belonging to the tankless lineages, the pericarp development proceeds via both periclinal and anticlinal cell divisions of the outer and inner mesocarp. The analysis of fruit anatomy in the species included in this study highlights unprecedented traits of Bromelioideae fruits, such as the presence of the pericarp´s massive extra-carpellary portion in B. antiacantha, which contains many mucilage channels and fibrous tissue, and an intrusive septum in the carpellary portion, which acts as the main nutritive portion of the fruit. Additionally, in the present study, unique features of the ovary and the fruit, essential for characterizing the species were detailed, including the elongated placental tissue and the aliform projections of A. strobilacea. Our observations highlight distinct developmental processes to fleshy fruit formation in Bromelioideae. In this way, exploring the fruit ontogenetic diversity in Bromelioideae offers an exciting opportunity for future investigations. Besides, the unique fruit features identified bring out the importance of fruits as tools for genus delineation within this subfamily.

Reintroduction is a frequently used method to restore populations of endangered species. However, it has hardly been tested whether there is a pronounced genetic impact resulting from different propagule types used for restoration. To address this knowledge gap, we carried out a pilot study based on a 20-years practical experiment, in which new populations of the rare and endangered herb Armeria maritima ssp. elongata were founded using seeds and/or young plants. The experiment took place in a nature reserve protecting a declining nutrient-poor sand-dune habitat. To evaluate if there was an effect of propagule type on genetic variation of restored populations, we compared populations of A. maritima ssp. elongata started by direct seeding, planting of seedlings and both seeding & planting. Using molecular markers (AFLPs), we observed slightly higher levels of genetic diversity within restored compared to the source population. Genetic diversity was comparable in populations restored by different propagules, and genetic differentiation between the source and restored populations was absent. Our study provides a first piece of evidence that both seeds and young plants can be applied successfully in population restoration projects. We suggest to further test the impact of the reintroduction methods on restoration outcomes under different experimental settings, e.g. using species with different life history traits.

Cactus early life stages, especially in arid ecosystems, are typically the most vulnerable; seedlings face various abiotic and biotic filters to achieve survival and successful integration into their habitat. Thus, Pachycereus pringlei – endemic to Mexican Sonoran Desert – plays a crucial role in the arid areas of Baja California Sur, Mexico acting as a refuge and food source for wildlife. The present study evaluates P. pringlei emergence, survival, and seedling growth under different solar exposure (open and shaded areas) levels, both in greenhouse and natural conditions. The results indicated that natural conditions and moisture significantly influenced seedling emergence and survival. Lack of soil moisture led to compaction, which may have reduced porous spaces and restricted air and water circulation, thereby affecting root growth during the establishment phase. Conversely, the emerged seedling proportion under greenhouse shade was higher than in natural conditions. Additionally, these seedlings exhibited superior stem development, while those exposed to sunlight notably developed root systems. Low water potential was recorded, reaching down to -5.1 MPa for seedlings exposed to higher light levels. However, relative water content (RWC) values in tissues exceeded 70 %. No significant relationship was found between photosynthetic pigment concentration and different light conditions. Despite adapting cacti to xeric environments, the results suggest they may not be fully prepared to withstand prolonged drought episodes during the seedling stage. Nevertheless, some morphological traits, such as stem length, spines, and root area showed significant variations under different light conditions, facilitating photosynthesis light capture.

Restinga, a coastal sand environment, has low availability of organic matter, natural soil acidity, fast water drainage, high solar incidence, high salinity, strong winds and coastal flooding, which may require specific plant traits. This study analyzed the morphoanatomy of C. asiatica occurring in different microenvironments of Restinga and in an urbanized area to identify adaptive characteristics to each respective environment. Samples of roots, stolons, and leaves from sunny waterlogged dune slack, sunny wet dune slack, shaded wet dune slack, and shaded dry dune slack, and in an urbanized area were collected. Twenty three variables were measured, besides general histochemistry and soil characteristics. The one-way variance analysis (ANOVA) and principal component analysis (PCA) indicated that C. asiatica plants enhance different traits depending on the environment. Plants in shady microenvironments have greater petiole length, leaf area, fresh mass and leaf dryness compared to those occurring in sunny microenvironments. C. asiatica leaves are amphistomatic and in sunny microenvironments the chlorenchyma is more developed and has greater stomatal density on the abaxial surface. In urbanized areas, plants showed increased leaf area and fresh mass, and petiole thickening, and decreased leaf blade thickening. These traits may be related to the clay soil, which has greater water retention, and also to the shaded environment. Such adaptations allow the C. asiatica plants to maximize energy gain under different environmental conditions. Secretory canals were identified in all analyzed organs, which secreted acidic and neutral polysaccharides. We recorded for the first time the presence of hydathodes on the serrated margins of C. asiatica leaf blades. This study expands the knowledge on species occurring in coastal sand environments and the modifications presented to survive in distinct microenvironments of Restinga.

We report the floral scent composition of the endophytic holoparasite Rafflesia consueloae for the first time. Using a non-destructive in situ method that we developed, we identified 13 volatile compounds present in the scent of R. consuelaoe. Among the compounds detected were several benzenoids, organosilicons, an oligosulfide, a monoterpenoid, and a fatty acid-derived compound. Comparing the scent profiles of different reproductive stages, we found that all stages produced a similar set of volatiles, except for the flowers in bloom. The sulfur-containing dimethyl disulfide (DMDS), which is mainly responsible for the rotten smell of the flower, was only detected in the scent of full-bloom flowers indicating that its synthesis only takes place when the aperture is fully open and the flies are able to access the sex organs. Moreover, an analysis of the scent components of different floral parts from full-bloom flowers revealed that the different floral structures had varying scent profiles. The diaphragm and chamber floor produced the most volatiles. Notably, DMDS was only detected from the diaphragm and the central disk. Emission of putrid-smelling volatiles in these tissues may lure the flies into entering the floral chamber where the reproductive structures are located, thus increasing pollination success. Overall, this pioneering study of the R. consueloae floral scent composition provides valuable insights into the pollination mechanisms of the enigmatic Rafflesia genus and parasitic floral ecology in general.

The foliar epidermal anatomy of 22 Impatiens species from the family Balsaminaceae was studied. The study intended to determine whether the micromorphological characteristics of the genus Impatiens were taxonomically significant and would aid in the precise identification of the species. The qualitative and quantitative traits as well as diagnostic characteristics were identified using a Light microscope. Variations were observed in both adaxial and abaxial leaf micromorphological characters like the shape of the epidermal and guard cells, anticlinal wall pattern, lobes per cell, stomatal pore, distribution of stomata, type of stomata and the presence and nature of trichomes. Anomocyic stomata exclusively occurred in all the studied Impatiens species. Stomata were present on both the surface of I. scabriscula B. Heyne ex Walland I. balsamina L., while in rest of the studied species stomata restricted on abaxial surface. An elliptical pore is the dominant type of stomatal pore among the investigated impatiens taxa. Uniseriate multicellular trichomes were observed (I. tenella B.Heyne ex Hook., I. fruticosa Lesch ex DC, I. gardeneriana Wight, I. minor (DC.) Bennet, I. rufescens Benth ex Wight & Arn). For accurate species delineation and identification in the genus Impatiens, taxonomic keys have been developed based on foliar micromorphology.

Pholisma belongs to the family Lennoaceae, classified as obligate root holoparasites. Most existing studies are limited to addressing only P. arenarium. In this study, morphoanatomical and developmental aspects of flowers of the three species comprising Pholisma are described using histological embedding techniques in Paraplast and LR- White and observations by light microscopy and scanning electron microscopy. Similarities found in the three species include the presence of trichomes on the sepals, each carpel folding independently. Each carpel has transmitting tissue, and an empty cavity is distinguished in the centre of the style. The stigma is crateriform and of the wet type. Sporogenesis, gametogenesis, and floral development follow a similar pattern in the three species. Differences among species include the position of the stamens, pollen morphology, type of inflorescence, and colour of flowers and inflorescences. In P. arenarium, the stamens are located below the stigma height, and the pollen is tetracolporate and psilate; in P. sonorae, the stamens are at the same height as the stigma, and the pollen is tricolporate and reticulate; and in P. culiacana, the stamens are above the stigma height, and the pollen is tricolporate and psilate. The inflorescences in both P. arenarium and P. sonorae are cymes; the corolla colour is white with purple lines extending from the limb to the corolla tube. In contrast, the inflorescence in P. culiacana is a capitulum type, and the corolla colour is white with pink margins. The characters found in the three species of Pholisma are compared with some genera comprising the family Ehretiaceae.