Residues from the Fundão Dam Accident in Brazil and their Effects on Photosynthetic Efficiency of Two Restinga Plant Species.

In 2015, a breach in the Fundão Dam in Mariana (Minas Gerais State, Brazil) resulted in the release of contaminated tailings into the Doce River basin. This accident increased the concentrations of arsenic (As), lead (Pb), cadmium (Cd), vanadium (V), and manganese (Mn) in the soil, posing a potential hazard to the physiology of native species. The purpose of this study was to assess whether chlorophyll a fluorescence (ChlF) in Allagoptera arenaria and Guapira pernambucensis changed following this accident when tested under different precipitation regimes in relation to soil properties and metal(loid) absorption.

Soil flooding and its outcome on cadmium and nutrient uptake affect photosynthetic activity in Inga laurina plants.

Urban areas next to mangroves are subject to progressive heavy metal contamination. Treelets of Inga laurina were collected in this ecosystem and cultivated for 30 days in waterlogged conditions and closed pots (WC) and at field capacity (FC), while exposed to different Cd concentrations (0, 50 and 100 mg·kg). Soil water conditions did not affect total Cd in plants, with Cd accumulating in roots and WC inducing less leaf chlorophyll while increasing carotenoids and chlorophyll ratio.

Cuticular wax composition contributes to different strategies of foliar water uptake in six plant species from foggy rupestrian grassland in tropical mountains.

The cuticle is the outermost region of the epidermal cell wall of plant aerial organs. The cuticle acts as a two-way lipid barrier for water diffusion; therefore, it plays a vital role in foliar water uptake (FWU). We hypothesised that the chemical composition of the cuticular waxes influences the FWU strategy that plants adopt in a foggy tropical ecosystem.

Photosynthetic heat tolerance in plants with different foliar water -uptake strategies.

Premise: The distribution and even the survival of plant species are influenced by temperature. In an old climatically buffered infertile landscape (OCBIL) in Brazil, we previously characterized different strategies for foliar water uptake (FWU). It is possible that photosystem II tolerance to heat and excessive light intensity varies among species with different FWU capacities.

Apoplast-symplast compartmentalization and functional traits of iron and aluminum in promeristematic tissues of nematode induced galls on Miconia spp.

The nutritive tissues of galls induced by Ditylenchus gallaeformans (Nematoda) have promeristematic capacity, which may turn these galls into sinks of Al on their Melastomataceae Al-accumulating hosts. Such a sink of Al may affect gall growth and mineral nutrient intake. Based on the fact that galls are good models for plant developmental studies, we aimed to understand how Al-accumulating host plants in the Cerrado environment deal with Al toxicity in subcellular levels.

The Neglected Reverse Water Pathway: Atmosphere-Plant-Soil Continuum.

The soil-plant-atmosphere continuum (SPAC) describes the continuous water movement from soil via plants to atmosphere. Here, we propose to name the reverse water pathway, driven by foliar water uptake, the atmosphere-plant-soil continuum (APSC). We highlight the different hydraulic resistances this reverse water movement has to overcome.

Immunocytochemistry and Density Functional Theory evidence the competition of aluminum and calcium for pectin binding in Urochloa decumbens roots.

Root growth is reduced in soils with low pH [H] and abundant soluble aluminum [Al], which can be a consequence of the interaction between Al and cell wall composition. The competition between Al and Ca toward binding to pectin molecules was evaluated in roots of Urochloa decumbens, an African grass highly adapted to acidic Al-rich soils. Variations in the composition and distribution of pectins can change the extensibility, rigidity, porosity, and adhesive properties of plant cell walls, which were tested in seedlings of U.

Foliar water-uptake strategies are related to leaf water status and gas exchange in plants from a ferruginous rupestrian field.

Premise: Fog is a frequent event in Brazilian rupestrian field and plays an important role in the physiology of several plant species. Foliar water uptake (FWU) of fog may be fast or slow depending on the species. However, fog water may negatively affect CO assimilation.

Nitric oxide precursors prevent Al-triggered auxin flow inhibition in roots.

Aluminum (Al) is an element widely distributed in soils, even though Al is one of the most detrimental cations to plant growth. The effect of nitric oxide (NO) precursors on indole-3-acetic acid (IAA) flow towards roots upon Al treatment is herein reported using two (wheat) cultivars with recognized differential Al tolerance. Roots of Al-tolerant seedlings with no treatment (control) accumulated higher amounts of NO than Al-sensitive ones.

Antioxidant metabolism in galls due to the extended phenotypes of the associated organisms.

Animal-induced galls are considered extended phenotypes of their inducers, and therefore plant morphogenesis and metabolism may vary according to the species of gall inducers. The alterations in vacuolar and apoplastic polyphenols, carotenoids, chlorophyll fluorescence rates, PSII quantum yield, and phospholipid peroxidation were studied in galls induced by Ditylenchus gallaeformans (Nematoda) on Miconia albicans and M. ibaguensis (Melastomataceae), and by an unidentified Eriophyidae (Acarina) on M.

Belowground microbes mitigate plant-plant competition.

Dimorphandra wilsonii, a Cerrado endemic Fabaceae tree, is threatened by land-use changes. The few remaining individuals occur in areas dominated by alien grasses like Urochloa decumbens. We tested the impact of nitrogen (N) availability and symbionts' presence on mitigating the effects of competition from U.

Morphology, ultrastructure, and element uptake in Calophyllum brasiliense Cambess. (Calophyllaceae J. Agardh) seedlings under cadmium exposure.

Cadmium (Cd) is a metal known for its genotoxicity and cytotoxicity, much concerned for its potential environmental and human health impacts. This study evaluates the toxic effect of Cd in Calophyllum brasiliense plants. The plants were cultivated for 30 days in full nutrient solution in order to adapt, and for 15 days in nutrient solution without Cd or with 4, 8, 16, and 32 μmol Cd L.

Different salt concentrations induce alterations both in photosynthetic parameters and salt gland activity in leaves of the mangrove Avicennia schaueriana.

Mangrove sites are constantly under tidal regimes, where there is variation of dissolved oxygen and saline content in water. This study evaluated the effects of varying salinity in Avicennia schaueriana, an abundant species in the sea-mangrove-river interface. Seedlings of A.

Morphology, ultrastructure and mineral uptake is affected by copper toxicity in young plants of Inga subnuda subs. luschnathiana (Benth.) T.D. Penn.

Toxic effects of copper (Cu) were analyzed in young plants of Inga subnuda subs. luschnathiana, a species that is highly tolerant to flooding and found in Brazil in wetlands contaminated with Cu. Plants were cultivated in fully nutritive solution, containing different concentrations of Cu (from 0.

Nitric oxide increases tolerance responses to moderate water deficit in leaves of Phaseolus vulgaris and Vigna unguiculata bean species.

Drought stress is one of the most intensively studied and widespread constraints, and nitric oxide (NO) is a key signaling molecule involved in the mediation of abiotic stresses in plants. We demonstrated that a sprayed solution of NO from donor sodium nitroprusside increased drought stress tolerance responses in both sensitive (Phaseolus vulgaris) and tolerant (Vigna unguiculata) beans. In intact plants subjected to halting irrigation, NO increased the leaf relative water content and stomatal conductance in both species.

Seeds' physicochemical traits and mucilage protection against aluminum effect during germination and root elongation as important factors in a biofuel seed crop (Ricinus communis).

We determined the length, volume, dry biomass, and density in seeds of five castor bean cultivars and verified notable physicochemical trait differences. Seeds were then subjected to different toxic aluminum (Al) concentrations to evaluate germination, relative root elongation, and the role of root apices' rhizosphere mucilage layer. Seeds' physicochemical traits were associated with Al toxicity responses, and the absence of Al in cotyledons near to the embryo was revealed by Al-hematoxylin staining, indicating that Al did not induce significant germination reduction rates between cultivars.

Nodulation in Dimorphandra wilsonii Rizz. (Caesalpinioideae), a threatened species native to the Brazilian Cerrado.

The threatened caesalpinioid legume Dimorphandra wilsonii, which is native to the Cerrado biome in Brazil, was examined for its nodulation and N(2)-fixing ability, and was compared with another, less-threatened species, D. jorgei. Nodulation and potential N(2) fixation was shown on seedlings that had been inoculated singly with five bradyrhizobial isolates from mature D.

Morphophysiological differences in leaves of Lavoisiera campos-portoana (Melastomataceae) enhance higher drought tolerance in water shortage events.

Lavoisiera campos-portoana Barreto (Melastomataceae) has two kinds of leaves, pubescent and glabrous, and branches may have one or both types of leaves at the same moment. The plant is endemic to high altitude rocky fields in Brazil where rainfall is very seasonal. We predicted that these two leaf types are adaptations to different regimes of water availability.

Cloning and characterization of drought-stimulated phosphatidic acid phosphatase genes from Vigna unguiculata.

Under environmental stresses, several lipolytic enzymes are known to be activated and to contribute to membrane lipid turnover and generation of second messengers. In animal cells, phosphatidic acid phosphatase (PAP, EC 3.1.