Ecophysiological Aspects Research Articles

Seasonal variation in gas exchange and chlorophyll index of Palicourea racemosa in an open ombrophilous forest

Seasonal variation affects understory and canopy tree plants in different ways. Palicourea racemosa is an understory shrub from the Rubiaceae family and is subject to seasonal oscillations of the environment, which can affect plant ecophysiological responses. This species is widely distributed in humid forests from southern Mexico to southeastern Brazil and has broad economic and ecological importance for the regions of occurrence, being used for food, ornamental and traditional medicine purposes. It is of fundamental importance to know ecophysiological responses of this species throughout dry and rainy periods, to understand the dynamics of understory plants in tropical forests. This research aimed at evaluating the effects of seasonality on ecophysiological aspects of P. racemosa at the Mata do Pau-Ferro State Park, municipality of Areia, Paraiba, Brazil. Over ten months, upper canopy structure indices were measured in ten individuals, climatic data were collected and their effects on gas exchange and chlorophyll indices in plants were evaluated. Results showed that the environmental variables correlated with the ecophysiological ones, with a strong association of soil moisture, rainfall and leaf area index of the upper canopy on ecophysiological aspects in P. racemosa plants, indicating that water availability and irradiance affect gas exchanges and photosynthetic pigment content. Except for intrinsic water use efficiency and instantaneous carboxylation efficiency, all ecophysiological variables showed significant differences over the months, showing the influence of seasonality on the ecophysiological responses of P. racemosa.

WEED PHYTOSOCIOLOGY AND DISTRIBUTION IN VINEYARDS IN THE SÃO FRANCISCO RIVER VALLEY

ABSTRACT Information on the different species that compose a weed community is essential for plant protection managements in production systems, which should include not only flora identification and diversity assessments, but morphological and ecophysiological aspects that can to show the potential effect of the agrosystem and guide the conduction of weed control strategies. Therefore, the objective of this work was to conduct a floristic and phytosociological surveying to identify the grouping patterns of weed populations in vineyards in the Petrolina-Juazeiro irrigated perimeter, in the Sub-Mid São Francisco River Valley, Brazil. The absolute and relative values of weed frequency, density, abundance, importance value index, population distribution level, and similarity between areas were evaluated in five properties. A high diversity of species of the families Poaceae, Malvaceae, and Asteraceae were found. The most important species found were Commelina benghalensis, Euphorbia hirta, and Cyperus aggregatus. The distribution of populations was mainly in aggregate and highly aggregate forms.

Influence of pipe material on biofilm microbial communities found in drinking water supply system

The biofilms and water samples from a model installation built of PVC-U, PE-HD and cast iron pipes were investigated using standard heterotrophic plate count and 16S rRNA Next Generation Sequencing. The results of the high throughput identification imply that the construction material strongly influences the microbiome composition. PVC-U and PE-HD pipes were dominated with Proteobacteria (54–60%) while the cast pipe was overgrown by Nitrospirae (64%). It was deduced that the plastic pipes create a more convenient environment for the potentially pathogenic taxa than the cast iron. The 7-year old biofilms were described as complex habitats with sharp oxidation-reduction gradients, where co-existence of methanogenic and methanotrophic microbiota takes place. Furthermore, it was found that the drinking water distribution systems (DWDS) are a useful tool for studying the ecology of rare bacterial phyla. New ecophysiological aspects were described for Aquihabitans, Thermogutta and Vampirovibrio. The discrepancy between identity of HPC-derived bacteria and NGS-revealed composition of biofilm and water microbiomes point to the need of introducing new diagnostical protocols to enable proper assessment of the drinking water safety, especially in DWDSs operating without disinfection.

A novel, rapid technique for clearing leaf tissues.

PremiseClearing leaves is a highly useful practice for many taxonomic, ecological, physiological, and eco‐physiological aspects of research. Using traditional methods, the procedure for clearing a leaf (referred to as diaphanization) can take several days or even weeks. In our laboratory we developed a technique, originally used for dissociating wood, that yields excellent epidermal and leaf venation preparations clearly showing the details of epidermal cells, hydathodes, trichomes, leaf margins, and leaf venation, in a maximum of three days.Methods and ResultsA solution originally used to macerate wood (Franklin’s solution) was used to accelerate the process of clearing leaves. Using this approach, it is possible to obtain clear images of the leaf adaxial and abaxial epidermal surfaces and leaf venation. Our technique works with both fragile and sturdy leaves, as well as with thin roots and stems. A few examples are presented.ConclusionsFranklin’s solution is very simple to prepare and easy to manipulate. This new technique has the advantage of separating the leaf epidermal layers and venations, which can then be clearly observed.

Data-based agroecological zoning of Acrocomia aculeata: GIS modeling and ecophysiological aspects into a Brazilian representative occurrence area

Macauba palm (Acrocomia aculeata (Jacq.) Lodd.) is an emergent oleaginous crop with undeniable economical potential that occurs naturally from south Mexico to south Brazil. Besides its oils, every biomass component from its fruit has a great manufacturing value, for either food or energy-based sectors. Thus, this paper main objective is to estimate the productive potential of eight fruit components (among oil content, weight, volume and internal structures dry mass) for a wide natural occurrence area of macauba trees, the Minas Gerais State, in Brazil. Prediction was based on six environmental attributes: terrain altitude; temperature; precipitation; solar radiation; distance from hydrography; and water deficit, utilizing Random Forest regression methodology, Geographic Information Systems (GIS) and ecophysiological assumptions. All eight fruit components presented high predictability. Temperature was the most influencing factor in almost all evaluated fruit components. The generated predictive maps can support decision making regarding planting orientation or industrial implantation. It is worth mentioning that a given location may have good productivity for a specific fruit component while being disadvantageous for others. This indicates the need for proper planning, management and/or cultivation objective. The study area presents a broad variety of environmental features, suggesting a promising productive potential for the entire specie natural occurrence area. Crop cultivation in adapted ecophysiological areas require fewer resources, what leads to a more sustainable agricultural system, with reduced environmental stress and risk of economic loss.

Ecophysiology of nickel hyperaccumulating plants from South Africa - from ultramafic soil and mycorrhiza to plants and insects.

An overview of 30 years of studies related to South African nickel hyperaccumulators is presented. Only five species have so far been identified as Ni hyperaccumulator plants among very rich and diversified South African flora. All of them occur on soils derived from ultramafic (serpentine) rocks and belong to the family Asteraceae: Berkheya coddii Roessler, Berkheya zeyheri subsp. rehmannii var. rogersiana, Berkheya nivea, Senecio coronatus, Senecio anomalochrous. Several techniques and methods were used to investigate ecophysiological aspects of the Ni hyperaccumulation phenomenon, from basic field and laboratory studies, to advanced instrumental methods. Analysis of elemental distribution in plant parts showed that in most cases the hyperaccumulated metal was stored in physiologically inactive tissues such as the foliar epidermis. However, an exception is Berkheya coddii, which has a distinctly different pattern of Ni distribution in leaves, with the highest concentration in the mesophyll. Such a distribution suggests that different physiological mechanisms are involved in the Ni transport, storage location and detoxification, compared to other hyperaccumulator species. Berkheya coddii is a plant with high potential for phytoremediation and phytomining due to its large biomass and potentially high Ni yield, that can reach 7.6% of Ni in dry mass of leaves. Senecio coronatus is the only known hyperaccumulator with two genotypes, hyperaccumulating and non-hyperaccumulating, growing on Ni-enriched/metalliferous soil. Detailed ultrastructural studies were undertaken to characterize specialized groups of cells in the root cortex of Ni-hyperaccumulating genotype, that are not known from any other hyperaccumulator. The occurrence of arbuscular mycorrhiza (AM) in Ni-hyperaccumulating plants was found for the first time in South African hyperaccumulator plants, and this type of symbiosis has been proved obligatory in all of them. There is a significant influence of mycorrhiza on the concentration and distribution of several elements. Three highly specialized herbivore insects feeding only on Ni hyperaccumulator plants were identified: Chrysolina clathrata (formerly Chrysolina pardalina), Epilachna nylanderi and Stenoscepa sp. The Ni-elimination strategies of these specialised insects have been established. Microbiological studies have revealed several genera of fungi and bacteria isolated from B. coddii leaves as well as presence of specialised, Ni-resistant yeasts in the C. clathrata gut. Understanding ecophysiological response to harsh environment broadens our knowledge and can have practical applications in cleaning polluted environments through phytomining/agromining. Finally, conservation aspects are also discussed and lines for future research are proposed.

A NON-DESTRUCTIVE METHOD FOR ESTIMATING LEAF AREA OF Ceiba glaziovii (Kuntze) K. Schum.

The determination of leaf area is of fundamental importance in studies involving ecological and ecophysiological aspects of forest species. The objective of this research was to adjust an equation to determine the leaf area of Ceiba glaziovii as a function of linear measurements of leaves. Six hundred healthy leaf limbs were collected in different matrices, with different shapes and sizes, in the Mata do Pau-Ferro State Park, Areia, Paraíba state, Northeast Brazil. The maximum length (L), maximum width (W), product between length and width (L.W), and leaf area of the leaf limbs were calculated. The regression models used to construct equations were: linear, linear without intercept, quadratic, cubic, power and exponential. The criteria for choosing the best equation were based on the coefficient of determination (R²), Akaike information criterion (AIC), root mean square error (RMSE), Willmott concordance index (d) and BIAS index. All the proposed equations satisfactorily estimate the leaf area of C. glaziovii, due to their high determination coefficients (R² ≥ 0.851). The linear model without intercept, using the product between length and width (L.W), presented the best criteria to estimate the leaf area of the species, using the equation 0.4549*LW.

Ecofisiologia e rendimento forrageiro do capim elefante roxo em função de adubação nitrogenada

A maximização da produtividade vegetal é almejada em qualquer cultivo, inclusive de Pennisetum purpureum, entretanto, isto depende do estado nutricional das plantas, nesse aspecto o nitrogênio exerce função essencial. O objetivo da pesquisa foi avaliar os aspectos ecofisiológicos e o rendimento forrageiro do capim elefante roxo em função de adubação nitrogenada. O experimento foi realizado na Estação Experimental de Alagoinha, pertencente à Empresa Estadual de Pesquisa Agropecuária da Paraíba, localizada no município de Alagoinha, estado da Paraíba, Brasil. Utilizou-se o delineamento de blocos ao acaso, com cinco tratamentos e quatro repetições. Os tratamentos consistiram na aplicação de 0, 20, 40, 60 e 80 kg de N ha-¹. As variáveis avaliadas foram: índice de clorofila a, b e total, fotossíntese líquida, concentração interna de carbono, eficiência instantânea de carboxilação, eficiência do uso da chuva, pegada hídrica cultural, eficiência de uso do nitrogênio, produtividade de matéria verde e seca e capacidade de suporte para vacas leiteiras. O aumento das doses de N estimula positivamente os índices de clorofila, trocas gasosas, eficiência de uso da chuva, pegada hídrica cultural, produtividade e capacidade de suporte animal do capim elefante roxo, entretanto, reduz a eficiência de uso do N.

Stress factors in the photobiology of the reef coral Siderastrea stellata

The coral species Siderastrea stellata Verril 1868 is endemic and common in Brazil. This species is a colonial, massive, zooxanthellate coral and one of the most important reef builders in many reef areas. The photosynthetic symbionts are very sensitive to environmental variations, such as sedimentation and temperature variations, which can disturb the complex interaction between the animal host and endosymbiont. In this study, we simulated the conditions found in the field in a series of experiments that evaluated chlorophyll a fluorescence emissions. Chlorophyll a maximum quantum yield and Rapid Light Curves (RLCs) were generated using a red light pulse amplitude modulated fluorometer, Mini-PAM, in S. stellata colonies under different irradiance, temperature and burial levels. Moreover, the PSII fluorescence yield was tested using a chlorophyll a fluorescence spatial detection method, which was implemented for the first time using an imaging system for S. stellata coral species. S. stellata showed great adaptive capacity under different light regimes between 50 and 160 μmol photons m-2 s-1. When a moderate burial level factor was analyzed synergistically with temperatures below 18 °C, we observed resilient colonies. However, at critical burial levels and high temperatures (28 °C) after 10 days, lower maximum quantum yields of PSII chlorophyll a fluorescence were detected, exhibiting an abrupt decrease after 96 h of burial. Continuous evaluations of coral environments and a strong understanding coral ecophysiology are extremely important for the establishment of minimum health risk levels for coral reef environments and coastal management measures. We conclude that ecophysiological aspects are highly specific and should be evaluated according to the preconditions of organism acclimatization. The chlorophyll a fluorescence imaging technique was shown to be an efficient tool for evaluating the physiologic status of zooxanthellae over the surface of a coral such as S. stellata. In turn, the photobiology results indicated the life history of this species in the upwelling waters of the region, as this species had higher Fv/Fm values at lower temperatures and intermediary burial conditions than at higher temperatures.

Targeting Bacterial Biofilms by the Green Tea Polyphenol EGCG.

Bacterial biofilms are multicellular aggregates in which cells are embedded in an extracellular matrix of self-produced biopolymers. Being refractory to antibiotic treatment and host immune systems, biofilms are involved in most chronic infections, and anti-biofilm agents are being searched for urgently. Epigallocatechin-3-gallate (EGCG) was recently shown to act against biofilms by strongly interfering with the assembly of amyloid fibres and the production of phosphoethanolamin-modified cellulose fibrils. Mechanistically, this includes a direct inhibition of the fibre assembly, but also triggers a cell envelope stress response that down-regulates the synthesis of these widely occurring biofilm matrix polymers. Based on its anti-amyloidogenic properties, EGCG seems useful against biofilms involved in cariogenesis or chronic wound infection. However, EGCG seems inefficient against or may even sometimes promote biofilms which rely on other types of matrix polymers, suggesting that searching for ‘magic bullet’ anti-biofilm agents is an unrealistic goal. Combining molecular and ecophysiological aspects in this review also illustrates why plants control the formation of biofilms on their surfaces by producing anti-amyloidogenic compounds such as EGCG. These agents are not only helpful in combating certain biofilms in chronic infections but even seem effective against the toxic amyloids associated with neuropathological diseases.

Ecophysiological aspects of Tachigali vulgaris seedlings using different sources and doses of nitrogen

Ecophysiological aspects of Tachigali vulgaris seedlings using different sources and doses of nitrogen

ECOPHYSIOLOGICAL ANALYSIS OF Eucalyptus camaldulensis (DEHNH) SUBMITTED TO ATTACK FROM Thaumastocoris peregrinus (CARPINTERO & DELLAPE)

ABSTRACT Works correlating the effect of a bronze bug attack on ecophysiological aspects of eucalyptus can be used in selection programs for resistant genetic materials. The objective of this study was to evaluate the injuries caused by Thaumastocoris peregrinus (Carpintero & Dellape) through the ecophysiological analysis of Eucalyptus camaldulensis (Dehnh). The experiment was conducted in a completely randomized design, with two groups of plants, infested and non-infested, kept in a room at 25 ± 2 °C, relative humidity 60 ± 2% and a photoperiod of 12 hours. For 26 days, every 48 hours, the chlorophyll a fluorescence, using the electron transport rate (ETR) and the potential quantum efficiency (Fv/Fm), was measured, in addition to the leaf chlorophyll content of the plants. The variables observed were analyzed in relation to treatments and times using a mixed linear model, with plants and leaves being random effects. Plants protected from insect attack showed better results over the experimental period. However, the attack from the bronze bug negatively affected all the ecophysiological variables evaluated in E. camaldulensis, indicating a possible compromise of the photosynthetic apparatus of the plants.

Different morpho-anatomical strategies against desiccation in five species of Xerophyta genus in relation to their ecophysiological aspects

Although many works deal with different aspects of some Xerophyta plants individually as the typical model species of desiccation tolerant resurrection species, they do not deal with comparing species within the genus. In our study we mainly focus on different histo-anatomical characters which can play a special role in the mechanism of desiccation tolerance. Differences are shown among five species of Xerophyta genus which derive from three tropical African regions. On the leaf surface of X. scabrida glands are involved in the regulation of water uptake. Epidermal papillae of X. villosa can also reduce water loss by decreasing the stomata number. Special palisade cells of X. nandrasanae and X. scabrida take part in the water transport between the adaxial epidermis and the vascular bundles. In addition to retaining water, furrows of the leaf margins play an essential role in the folding of leaves during desiccation. Aquiferous parenchyma cells of X. scabrida, X. spekei and X. villosa can play a similar role due to their characteristic arrangement. Because of the considerable folding of parenchyma, Xerophyta species need extensive sclerenchyma tissue, which can help maintain leaf consistency in a desiccated state. The main photosynthetic pigments (chlorophylls and carotenoids) content, the net photosynthesis and the Fv/Fm fluorescence parameter of five Xerophyta species also reflect their unique adaptation to their proper microhabitat.

An atlas of larval organogenesis in the European shore crab Carcinus maenas L. (Decapoda, Brachyura, Portunidae)

BackgroundThe life history stages of brachyuran crustaceans include pelagic larvae of the Zoea type which grow by a series of moults from one instar to the next. Zoeae actively feed and possess a wide range of organ systems necessary for autonomously developing in the plankton. They also display a rich behavioural repertoire that allows for responses to variations in environmental key factors such as light, hydrostatic pressure, tidal currents, and temperature. Brachyuran larvae have served as distinguished models in the field of Ecological Developmental Biology fostering our understanding of diverse ecophysiological aspects such as phenotypic plasticity, carry-over effects on life-history traits, and adaptive mechanisms that enhance tolerance to fluctuations in environmental abiotic factors. In order to link such studies to the level of tissues and organs, this report analyses the internal anatomy of laboratory-reared larvae of the European shore crab Carcinus maenas. This species has a native distribution extending across most European waters and has attracted attention because it has invaded five temperate geographic regions outside of its native range and therefore can serve as a model to analyse thermal tolerance of species affected by rising sea temperatures as an effect of climate change.ResultsHere, we used X-ray micro-computed tomography combined with 3D reconstruction to describe organogenesis in brachyuran larvae. We provide a detailed atlas of the larval internal organization to complement existing descriptions of its external morphology. In a multimethodological approach, we also used cuticular autofluorescence and classical histology to analyse the anatomy of selected organ systems.ConclusionsMuch of our fascination for the anatomy of brachyuran larvae stems from the opportunity to observe a complex organism on a single microscopic slide and the realization that the entire decapod crustacean bauplan unfolds from organ anlagen compressed into a miniature organism in the sub-millimetre range. The combination of imaging techniques used in the present study provides novel insights into the bewildering diversity of organ systems that brachyuran larvae possess. Our analysis may serve as a basis for future studies bridging the fields of evolutionary developmental biology and ecological developmental biology.

Thermal ecology and microhabitat use of an arboreal lizard in two different Pantanal wetland phytophysionomies (Brazil)

Temperature is one of the main environmental variables shaping the evolution and biology of terrestrial ectotherms. The Pantanal is the largest continuous wetland in the World. However, a lack of knowlegde still exists on the thermal ecology of terrestrial ectothems from this wetland. In this context, the thermal ecology of the lizard Tropidurus lagunablanca Carvalho, 2016 (Squamata, Tropiduridae) was investigated in the Brazilian Pantanal. The thermal ecology and microhabitat use of lizards from a riparian forest was compared to lizards from a park savanna. At both studied areas, air and body temperatures of lizards did not differ between sexes. Mean T. lagunablanca body temperatures were higher at the savanna compared to the forest, while air temperatures were similar in both habitats. The main substrates were tree trunks, with a frequency of approximately 90% of the observations. Lizards from the savanna used higher perches than those from the forest despite -in average- trees were higher at the forest. Lizard sun and shade exposure was similar for both areas. Lizards from both habitats showed similar strong linear relationships between body and air temperatures. However, lizard behaviour of using tree trunk perches differently under different sunlight situations suggests that these lizards actively thermoregulate. Further research on the thermoregulation abilities of this species, with a null hypotesis and behavioral observations will shed light on lizard thermal biology. Studies on the ecophysiological aspects of these lizards should be a priority to understand how they will react to climate change and which conservation measures will be more effective concerning their preservation.

Biological Soil Crusts and Extremophiles Adjacent to Native Plants at Sabkhas and Rawdahs, Qatar: The Possible Roles

Several studies have investigated the biology of native plants (halophytes and xerophytes), biological soil crusts (BSC), as well as the associated and adjacent microorganisms. These studies concentrated on their eco-physiological aspects as well as the possible roles they might play in various life activities and industries. This article presents the mechanisms adopted by these living organisms to cope with the harsh environment, and the possible roles microorganisms might play to support native plants, some important examples from the flora of Qatar are presented to show these mechanisms. Special attention has been paid to the senescence and death of leaves or whole plants, since this strategy has been considered as an important option for escaping extreme environmental conditions. Discussion about solute accumulation (organic and inorganic) in all native living organisms in general and in microorganisms in particular, could result to further investigation to clarify their roles in such an ecosystem. Some case studies have been reported to discuss the ecological aspects at two main types of habitats in Qatar; Rawdahs and Sabkhas were chosen to show how native living organisms adapt in these habitats. This study discussed the general identification of BSC and microorganisms, as well as their possible roles in the soil biota. The possible methods and mechanisms exhibited by extremophiles to support native plants in coping with saline and arid lands have also been reported in this article. This study also discussed the recent outlook about the origin of metabolic activities in these living organisms to support the growth of native plants under stress conditions.

Molecular and ecophysiological aspects of semilunar synchronized spawning migration in the grass puffer

Molecular and ecophysiological aspects of semilunar synchronized spawning migration in the grass puffer

Ecophysiological and biochemical variation of the surf zone diatom asterionellopsis glacialis sensu lato from Santa Catarina, Southern Brazil

Abstract Patches formed by dense accumulations of diatoms in the surf zone (surf diatoms) are common on sandy beaches with intermediate to dissipative morphodynamic states. Their appearances are correlated with environmental factors such as the passage of cold fronts when onshore winds increase beach hydrodynamics, resuspending epibenthic stocks and accumulating them through the inner surf zone. In Santa Catarina state, Southern Brazil, two beaches are known to have frequent occurrence of accumulations of the surf diatom Asterionellopsis glacialis sensu lato: Rincão Beach (28°50' S) and Navegantes Beach (26°52' S). The high biomass of this alga and its central importance in the trophic structure of the coastal ecosystems suggest studies about its potential applications. In the present study, strains of A. glacialis were isolated, cultured under different conditions and evaluated for ecophysiological aspects: growth rate under different conditions, potential biological activities of exudates, biomass and lipid content, and fatty acid profile. A. glacialis cells in culture showed deformation, which were ameliorated by using agitation and silicon and phosphorus enriched culture media. Exudates of the strains showed no allelopathic effects, although previous studies have indicated activity. Lipid content showed variation depending on the strain and culture media. Values ranged from 9% to 13.6% by dry weight. In all strains saturated fatty acids and polyunsaturated fatty acids were identified. Some hypotheses were proposed to explain the variation of the lipid contents, fatty acid profiles and physiological features between strains of the same species. We believe that the fatty acids profile of this primary producer has important consequences in the sandy beach ecology.

Phenophases of rambutan (Nephelium lappaceum L.) based on extended BBCH- scale for Kerala, India

This study describes the different phenological growth stages of rambutan (Nephelium lappaceum L.) tree grown in India particularly in the state of Kerala where it has become one of the most treasured fruit particularly as a courtyard crop or on its fringes in the homegardens. A total of seven principal growth stages are described for bud, leaf, and shoot development, inflorescence emergence, flowering, fruit development, and fruit maturity according to the extended BBCH-scale. Within them fourty one secondary growth stages are also described. This detailed study on different phenophases of rambutan in relation to the prevailing environmental conditions can certainly serve as a basis for the standardization of agronomic and ecophysiological aspects of rambutan and thereby to promote the cultivation of this exotic fruit crop.

Ecophysiological aspects of the interaction between Cameraria ohridella and Guignardia aesculi on Aesculus hippocastanum

Ecophysiological aspects of the interaction between Cameraria ohridella and Guignardia aesculi on Aesculus hippocastanum