Brazilian Journal of Botany

Gleichenella pectinata (Willd.) Ching is a fern species with monomorphic fronds (i.e., the sterile and fertile fronds are similar morphologically) and is widely distributed in South America. In the present study, the chemical composition of waxes on fertile and sterile fronds was analyzed and the epi and intracuticular wax portions were extracted separately. The total intracuticular wax content (55.85 ± 10.55 µg cm−2) was significantly higher than the total epicuticular content (44.36 ± 6.29 µg cm−2) of fronds. However, total wax content did not differ between sterile (92.54 ± 7.44 µg cm−2) and fertile (107.90 ± 17.26 µg cm−2) fronds. A total of 32 compounds belonging to seven different classes were identified: alkanes (C25-C27), esters (C34), aldehydes (C26-C32), ketones (C27-C31), free fatty acids (C14-C28), and primary (C18-C35) and secondary alcohols (C33-C35). The most abundant classes in the waxes were ketones, aldehydes, fatty acids, and primary alcohols, with nonacosan-10-one, octacosanal, and octacosanoic acid as the most prominent compounds. While no qualitative differences were observed, epicuticular and intracuticular waxes quantitatively accumulated more ketones (46.73 ± 16.17%) and aldehydes (27.83 ± 6.11%), respectively. The accumulation of these compounds in epicuticular waxes may be related to the formation of specific waxy crystalloids. In general, with regard to frond fertility, there was no difference in wax content or composition. Compared to other ferns lineages, the waxes found for G. pectinata showed very similarities with waxes from Osmunda regalis L., another basal leptosporangiate species. A great number of differences were found comparing the G. pectinata frond waxes with eusporangiate and recent leptosporangiate ferns.

(Scytonema santannae, a new morphospecies of Cyanobacteria from the Atlantic rainforest, southeastern Brazil.) The genus Scytonema (Cyanobacteria) is one of the most common and important components of terrestrial biofilms in tropical and subtropical areas, mainly because of its nitrogen fixation capability and wide diversity of species. In the Brazilian Atlantic rainforest, Scytonema populations are frequently found growing on rocks, bark of trees, soil and among mosses, but are still underestimated and poorly characterized. In this article, we describe a new terrestrial morphospecies of Scytonema collected in the State Park of Ilha do Cardoso, an island located in the subtropical area of the Atlantic rainforest, State of São Paulo. The main features of the new species are remarkable mosaic-ornate sheaths and typical epiphytic growth on mosses on wooden substrates. The developmental process of mosaic-ornate sheaths has not yet been clarified, and hitherto, their occurrence was known only for two taxa (several populations of S. cf. stuposum and Brasilonema ornatum).

Acacieae Benth. (Leguminosae–Mimosoideae) comprises more than 1450 species and is composed of five genera in the current circumscription: Senegalia Raf., Mariosousa Seigler & Ebinger, Vachellia Wight & Arn., Acacia Mill., and Acaciella Britton & Rose. This work describes the diversity of the Tribe Acacieae in the state of Minas Gerais. The studies were based on the analysis of specimens from herbaria, field observations, and the collection of botanical materials. The study provides descriptions, illustrations, an identification key, common names, and data on the geographic distribution and flowering and fruiting of these species. Eighteen species belonging to this tribe were recognized in the state. For the first time, we report the occurrence of Senegalia velutina DC. in Minas Gerais. The species are distributed in the three biomes in the state: Atlantic Forest, Cerrado, and Caatinga. Senegalia bahiensis (Benth.) Seigler & Ebinger, S. giganticarpa (G. P. Lewis) Seigler & Ebinger, S. lacerans (Benth.) Seigler & Ebinger, S. lewisii (Bocage & Miotto) L. P. Queiroz, S. limae (Bocage & Miotto) L. P. Queiroz, S. martii (Benth.) Seigler & Ebinger, S. paganucci (Willd.) Seigler & Ebinger, S. pteridifolia (Benth.) Seigler & Ebinger, S. serra (Benth.) Seigler & Ebinger, and S. velutina have been designated for inclusion on the list of endangered species in Minas Gerais.

Atuna indica (Bedd.) Kosterm (Chrysobalanaceae) and Hydnocarpus longipedunculatus Robi. Sasidh. & Jose (Achariaceae) are two threatened evergreen trees, endemic to the southern Western Ghats, India. We investigated the population ecology and the genetic diversity of these species. The population ecological study comprised of demography, vertical, spatial and age-wise (ontogeny) distribution, along with the Importance Value Index (IVI) of target species in the community. Dominant Inter Simple Sequence Repeat (ISSR) primers are employed for Genetic diversity analysis. The small population size, clumped and under canopy distribution pattern are the primary population ecological impediments of target species. In addition, the extremely low number of reproductive individuals in A. indica intensifies the concern. Genetic studies revealed better diversity and gene flow compared to other threatened species. The construction of hydroelectric dams followed by water reservoir formation in natural habitats plausibly reduced the population size and it reflects in genetic diversity results. The present study warrants the protection of natural habitats and ecological niche model-based restoration programs.

A pot experiment was conducted to assess the effect of foliar application of thiourea on two mung bean (Vigna radiata (L.) Wilczek) varieties (NM-2006 and NM-2011) under salt stress. Experiment was laid-out in a completely randomized design with four replicates. Two salt treatments [non-saline (control) and 75 mM NaCl] were applied to 28-day-old mung bean plants. Three levels of TU [0 (water spray), 10, and 20 mM] were foliarly sprayed after 1 week of salt treatment. Data for various growth and physio-chemical attributes were collected of 64-day-old mung bean plants, while two plants were left for obtaining yield. Salt stress significantly decreased all growth and yield attributes, while increased anthocyanin, relative membrane permeability (% RMP), malondialdehyde, total soluble sugars, total soluble proteins, activities of catalase and peroxidase enzymes, total phenolics, free proline, and glycinebetaine contents. Foliar application of varying TU levels significantly increased shoot and root fresh and dry weights, shoot and root lengths, seed yield per plant, pod fresh and dry weights, number of seeds per plant, 100-seed weight, chlorophyll b (in NM-2006), total soluble sugars, total soluble proteins, POD activity, and total phenolic contents, while decreased RMP (%), total free amino acids, and GB contents. Of the two mung bean varieties, NM-2006 was superior to NM-2011 in most of growth and physio-chemical attributes under both salt stress and non-stress conditions as well as foliarly applied varying levels of TU. Overall, 20 mM TU proved more effective in reducing adverse effects of salt stress in both mung bean varieties.

Adenium obesum (Forssk.) Roem. & Schult. is an important plant for the floriculture sector. Detailed information on floral structures is scarce and important for breeding programs, especially considering the great phenotypic variability. The objective of this study was to describe the floral events, morphology and anatomy of three A. obesum (Forssk.) Roem. & Schult. accessions (ICA-rt, ICA-wd and ICA-ps) relating these traits to the ornamental value and to species propagation. The accessions bloomed throughout most of the evaluation period, and their flowers opened during the morning. The time elapsed from initiation until the opening of the bud ( ≈ 32 days), as well as the floral longevity ( ≈ 27 days), was longest for ICA-rt accession. The morphological and anatomical analysis detected phenotypic diversity in A. obesum (Forssk.) Roem. & Schult. Variations in the reproductive organs, levels and types of male sterility, as well as a reduced female fertility, were reported. Hercogamy and functional dioecy were registered. The high floricultural potential of ICA-rt accession was identified, in view of its morphological, morphometric and floral longevity features. These results may inspire several new studies on A. obesum (Forssk.) Roem. & Schult. in the fields of applied genetics and plant breeding.

Polyunsaturated fatty acids (PUFAs) are essential in the animal diet, notably eicosapentaenoic and docosahexaenoic acids (EPA and DHA, respectively), and in recent years, microalgae like marine diatoms are being considered as an alternative source of PUFA. Therefore, this study evaluated the effect of three nitrogen/phosphorus (N/P) ratios (21/1, 14/1 and 7/1) and two growth phases (exponential and stationary) on both EPA concentration and gene transcript levels, four front-end desaturases and two elongases, involved in EPA biosynthesis of the microalgae Phaeodactylum tricornutum Bohlin. The experiment was carried out for 12 days, and the samples were assessed for growth and nutrient intake; in addition, qPCR was performed, as well as an analysis of fatty acids. Gene transcript levels were growth phase-dependent, and only two genes, PTD6 and PTD5A, were responsive to N/P ratios. EPA levels in P. tricornutum biomass were shown to be growth phase-dependent, with higher concentrations in the exponential phase (28.64% of total fatty acids), irrespective of N/P treatments. In at least one N/P ratio (21/1), the transcription of one gene, PTD5A, could be associated with EPA levels. Data from gene transcript levels and EPA concentrations, as well as the lack of some EPA intermediates, might indicate some type of regulatory steps between gene transcription and actual EPA biosynthesis.