Distribution of Biominerals and Mineral-Organic Composites in Plant Trichomes

Biomineralization is a common phenomenon in plants and has been shown to be chemically, functionally and topologically diverse. Silica and calcium carbonate have long been known as structural plant biominerals and calcium phosphate (apatite)–long known from animals–has recently been reported. Strikingly, up to three different biominerals may occur in a single trichome in, e.g., Urticaceae and Loasaceae, and in combination with organic compounds, can form organic/inorganic composite materials. This article presents an extension of previous studies on the distribution of these biominerals in Loasaceae trichomes with a focus on their spatial (three-dimensional) distribution and co-localization with organic substances. Light microscopy and scanning electron microscopy with high-resolution EDX element analyses of sample surfaces and sections illustrate the differential distribution and composition of the different biomineral phases across cell surfaces and cell walls. Raman spectroscopy additionally permits the identification of organic and inorganic compounds side by side. All three biominerals may be found in a nearly pure inorganic phase, e.g., on the plant surfaces and in the barbs of the glochidiate trichomes, or in combination with a larger proportion of organic compounds (cellulose, pectin). The cell lumen may be additionally filled with amorphous mineral deposits. Water-solubility of the mineral fractions differs considerably. Plant trichomes provide an exciting model system for biomineralization and enable the in-vivo study of the formation of complex composite materials with different biomineral and organic compounds involved.

Baseline Data of the Fungal Phytobiome of Three Sorghum (Sorghum bicolor) Cultivars in South Africa Using Targeted Environmental Sequencing

Plant-associated fungi, or the mycobiome, inhabit plant surfaces above ground, reside in plant tissues as endophytes, or are rhizosphere in the narrow zone of soil surrounding plant roots. Studies have characterized mycobiomes of various plant species, but little is known about the sorghum mycobiome, especially in Africa, despite sorghum being one of the most important indigenous and commercial cereals in Africa. In this study, the mycobiome associated with above- and below-ground tissues of three commercial sorghum cultivars, as well as from rhizosphere and surrounding bulk soil samples, were sequenced using targeted sequencing with the Illumina MiSeq platform. Relative abundance differences between fungal communities were found between above-ground and below-ground niches, with most differences mostly in the dominant MOTUs, such as Davidiellaceae sp. (Cladosporium), Didymellaceae sp. 1 (Phoma), Fusarium, Cryptococcus and Mucor. Above-ground communities also appeared to be more diverse than below-ground communities, and plants harboured the most diversity. A considerable number of MOTUs were shared between the cultivars although, especially for NS5511, their abundances often differed. Several of the detected fungal groups include species that are plant pathogens of sorghum, such as Fusarium, and, at low levels, Alternaria and the Ustilaginomycetes. Findings from this study illustrate the usefulness of targeted sequencing of the ITS rDNA gene region (ITS2) to survey and monitor sorghum fungal communities and those from associated soils. This knowledge may provide tools for disease management and crop production and improvement.

A Review of Methods and Techniques for Detecting Frost on Plant Surfaces

Severe frost usually has adverse impacts on agricultural production, resulting in crop freeze injury, poor crop yield, and crop quality reduction. Timely and accurate detection of frost plays an important role in cold damage warnings, prevention, and control. Current frost detection methods mostly use physical properties such as light, electricity, and heat, or the judge and quantify using environmental factors such as temperature and wind speed. However, it is difficult to detect and accurately identify the frosting phenomenon in real time during field trials because of the complex environment, different plant types, and interference by many factors during observation. To provide an overview of the analytical tools for scientists, researchers, and product developers, a review and comparative analysis of the available literature on frost mechanisms, correlations, and characteristics are presented in this study. First, the mechanisms of the frost formation process, frost level, and the significance of detection, are introduced. Then, the methods and techniques used to measure frost on plant surfaces are synthetically classified and further compared. Moreover, the key points and difficulties are summarized and discussed. Finally, some constructive methods of frost detection are proposed to improve the frost detection process.

Investigation about wetting ability (surface tension) of water used for preparation of pesticide solutions

<p class="042abstractstekst">The investigation about surface tension of water used for preparation of pesticide solutions reveals it is quite diverse and changeable without any logical correlation towards location, time, and type of water source. Moreover, spraying with solutions with lower surface tension give bigger flow rates due to the lower resistance of fluid to the nozzles. The conducted trials show that plant surfaces with more rough texture require to be sprayed with pesticide solutions with lower surface tension. The wax content of the surfaces has no significant impact on surface tension requirement.</p><p> </p>

ADEQUAÇÃO DE MODELOS PROBABILÍSTICOS À EVAPOTRANSPIRAÇÃO DE REFERÊNCIA NO SUBMÉDIO DO VALE DO RIO SÃO FRANCISCO

ADEQUAÇÃO DE MODELOS PROBABILÍSTICOS À EVAPOTRANSPIRAÇÃO DE REFERÊNCIA NO SUBMÉDIO DO VALE DO RIO SÃO FRANCISCO EDGO JACKSON PINTO SANTIAGO1; FRANK GOMES-SILVA 1; ANTONIO SAMUEL ALVES DA SILVA1; JOSÉ RAMON BARROS CANTALICE1; MOACYR CUNHA FILHO1 E JOSÉ DOMINGOS ALBUQUERQUE AGUIAR1 1 Departamento de Estatística e Informática-DEINFO, Programa de Pós-Graduação em Biometria e Estatística Aplicada-PPGBEA, Universidade Federal Rural de Pernambuco-UFRPE, Rua Dom Manoel de Medeiros s/n, Dois Irmãos, CEP: 52.171.900, Recife, Pernambuco, Brasil. [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]. 1 RESUMO A evapotranspiração consiste no processo de perda de água do solo, da planta, e é fundamental para produção vegetal, constituindo uma das principais variáveis agrometeorológicas. Apesar disso, são escassos trabalhos que relacionam adequabilidade de distribuições de probabilidade a dados de evapotranspiração. O objetivo desse trabalho foi testar a aderência de diferentes distribuições de probabilidade à dados de evapotranspiração de referência, selecionando as mais adequadas para este fim. Esse estudo foi realizado com dados de evapotranspiração de referência obtidos pelas estações meteorológicas da Universidade Federal do Vale do São Francisco (UNIVASF) em Petrolina, PE e Juazeiro, BA. Foram ajustadas as distribuições Gama, Weibull, Log-Normal, Beta, Exponencial, Log-Logística e Log-Logística Exponenciada. Os maiores p-valores foram obtidos para as distribuições Log-Logística e Log-Logística Exponenciada, possivelmente devido à leve assimetria positiva destas aos dados de evapotranspiração. Pelo teste da razão de verossimilhanças, a distribuição Log-Logística Exponenciada adequou-se mais aos meses de janeiro, agosto e dezembro em Juazeiro e Petrolina, somando-se a esta última o mês de novembro. As distribuições Log-Logística e Log-Logística Exponenciada foram as mais adequadas para modelar a evapotranspiração. A partir dessas distribuições, foram estimados valores de evapotranspiração para diferentes níveis de probabilidade, sendo janeiro o mês com maior demanda hídrica provável. Palavras-chave: transpiração, evaporação, demanda hídrica, distribuição log-logística, irrigação. SANTIAGO, E. J. P.; GOMES-SILVA, F.; SILVA, A. S. A.; CANTALICE, J. R. B.; CUNHA FILHO, M.; AGUIAR, J. D. A. ADJUSTMENT OF PROBABILISTIC MODELS TO THE REFERENCE EVAPOTRANSPIRATION IN THE SUB-MEDIUM OF SÃO FRANCISCO RIVER VALLEY 2 ABSTRACT Evapotranspiration is the process of water loss from soil and plant surfaces, and it is essential for plant production, constituting one of the main agrometeorological variables. Nevertheless, there are few studies that relate the adequacy of probability distributions to evapotranspiration data. The objective of this work was to test the adherence of different probability distributions to reference evapotranspiration data by selecting the most suitable ones for this purpose. This study was carried out with daily evapotranspiration reference data obtained by the meteorological stations of the Federal University of Vale of São Francisco (UNIVASF) in Petrolina, PE and Juazeiro, BA. The Gamma, Weibull, Log-Normal, Beta, Exponential, Log-Logistics and Exponentiated Log-Logistics distribution were adjusted. The highest p-values ​​were obtained for the Log-Logistics and Exponentiated Log-Logistics distributions. The highest p-values were obtained for the Log-Logistics and Exponentiated Log-Logistics distributions, possibly due to the slight positive asymmetry of those to the evapotranspiration data. By testing the likelihood ratio, the Exponentiated Log-Logistics distribution was more suitable for the months of January, August and December in Juazeiro and Petrolina, adding to the latter the month of November. The Log-Logistics and Exponentiated Log-Logistics distributions were the most suitable to model evapotranspiration. From these distributions, evapotranspiration values ​​were estimated for different levels of probability, with January being the month with the highest probable water demand. Keywords: transpiration, evaporation, water demand, log-logistics distribution, irrigation.

Integration of chemosensing and carbon catabolite repression impacts fungal enzyme regulation and plant associations

Fungal metabolism and enzyme production are regulated by nutrient availability and by interactions with the living environment. We investigated the mechanisms underpinning adaptation of the biotechnological fungus Trichoderma reesei to decaying plant biomass versus living plants. We found that concentration-gated response to glucose, the main molecule sensed from dead plant biomass, is mediated by a conserved signaling pathway downstream of G protein-coupled receptors (GPCRs), while the carbon catabolite repressor CRE1 is critical for glucose concentration gating. The GPCRs CSG1 and CSG2 are further required for root colonization and formation of appressorium like structures on plant surfaces. Acceleration of sexual development in the presence of plant roots and their interactions with fruiting bodies indicates preferential association with plants. Our results reveal a complex sensing network governing resource distribution, enzyme production and fungal development that explains previously observed phenomena in fermentations and opens new perspectives for industrial strain improvement and agriculture.

Barrier properties of fungal fruit body skins, pileipelles, contribute to protection against water loss

The permeability of intact fungal fruit body skins (pileipelles) with respect to water and oxygen was determined for the first time. Methods that have been successfully applied to plant surfaces were used to study isolated pileipelles. Mechanically isolated skins from five genera of Basidiomycota (species of Amanita, Russula, Stropharia, Tapinella, and Tricholomopsis) were mounted between two compartments simulating the inner (fruit body) and the outer (aerial) space. Fluxes of water and oxygen across the skins were measured. Water loss via intact skins differed markedly from evaporation of water from a water surface. The skins reduced water loss by factors of 10 to 30, with permeability ranging from 2.8 to 9.8 × 10−4 ms−1. Oxygen permeability was much lower and ranged from 0.8 to 6.0 × 10−6 ms−1. Chloroform-extractable substances play a minor, but significant role as transport barrier during water permeance. Water and oxygen permeability were dependent on the humidity in the aerial compartment. Higher humidity in the air increased permeability and the hydration/water content of the skins. The ecological implications include impacts to fungal growth, sporulation and spore release.