Anatomical Characterization of the Adventitious Roots of Mate (Ilex paraguariensis A. St.-Hil.) Mini-cuttings

Abstract Leaves of mate is one of the main non-timber forest products marketed in South America, which makes establishment of new plantations of great interest. However, vegetative propagation of mate plantlets presents difficulties, which may be associated with the complexity of adventitious root formation. The aims of this study were to anatomically characterize the adventitious roots of mate-clone mini-cuttings and investigate the relationship of phenols and starch with adventitious rooting competence in mini-cuttings treated or not with indole-butyric acid (IBA). The mini-cuttings of four clones were collected at 0, 30, and 60 days of cultivation, fixed in a solution containing 1% glutaraldehyde and 4% formaldehyde, pre-infiltrated and infiltrated in (2-hydroxyethyl) methacrylate, and sectioned in a microtome. Ferric chloride and toluidine blue were used to detect phenolic compounds and lugol to identify starch. Adventitious roots formed in mini-cuttings treated with IBA presented disorganized xylem and phloem and poles irregularly but exhibited sclerenchyma vessel elements and tracheid cells indicating functionality. Differences in the rhizogenic ability of mate clones mini-cuttings were not due to the presence of anatomical barriers or the accumulation of phenolic compounds but be associated with the presence and distribution of starch grains in vegetative propagules.

Plant growth, nutrients and potentially toxic elements in leaves of yerba mate clones in response to phosphorus in acid soils

ABSTRACT Native to subtropical region of South America, yerba mate is responsive to P under some conditions, but the degree of influence of genetic and soil on the growth and composition of the leaf is unknown. The aim of study was to evaluate plant growth, nutrients and potentially toxic elements in leaves of yerba mate clones in response to P application in acid soils. In greenhouse condition, two yerba mate clone seedlings were grown (210 days) in pots, each clone in a completely randomized design in factorial scheme (with and without P; four acid soils). The elemental composition of leaves and the growth of plants were determined. Phosphorus promoted plant growth, but this was not accompanied by increased P in leaf tissue in all conditions tested. The P effect on the elemental composition varied: decrease/null (N, K, Mg, Mn, Cu, Ni, B, Mo, Al, Cd); increase/null (C/N, C, Ca, Fe, V); increase/decrease/null (Zn, Ba, Pb) and; null (Cr). The soils affect the elemental composition of the leaves, especially Mn, with accumulation greater than 1000 mg kg-1. The Ba, Pb, Al and Zn in the leaves varied among clones. Yerba mate response to P was affected by edaphic and plant factors.

Substâncias fenólicas, flavonoides e capacidade antioxidante em erveiras sob diferentes coberturas do solo e sombreamentos / Phenolic Substances, Flavonoids, and Antioxidant Capacity in Herbs under Different Soil Covers and Shadings

RESUMO Objetivou neste trabalho analisar a concentração de polifenóis totais, flavonoides e capacidade antioxidantes por meio dos métodos ABTS e FRAP, em erveiras jovens cultivadas em solo coberto e com sombreamento. Mudas de erva-mate foram submetidas aos tratamentos com solos cobertos e desnudos em sombreamentos de 0, 18, 35 e 50%, após sete e onze meses de cultivo, verão e outono, respectivamente. Foram coletadas folhas maduras para realização dos extratos utilizados para as análises de compostos fenólicos por meio da reação de oxirredução com reagente de Folin-Ciocalteu, flavonoides por método colorimétrico e capacidade antioxidante por frente ao radical ABTS e poder de redução do ferro (FRAP). O teor de compostos fenólicos foi maior nos tratamentos com 35% de sombreamento em comparação ao grupo dos flavonoides e capacidade antioxidante, o que foi demonstrado pela correlação do sombreamento com estes parametros. No método FRAP a maior correlação demonstra que o outono é a melhor época de colheita por apresentar maior concentração de compostos fitoquímicos. Ficou evidente a influência positiva dos sombreamentos (35 e 50%) no teor de compostos fenólicos e flavonoides relacionados à capacidade antioxidante e à qualidade da erva-mate para atender ao mercado consumidor.

ABSTRACT This study aimed to analyze the concentration of total polyphenols, flavonoids, and antioxidant capacity, by the methods ABTS and FRAP, in young herbs grown in covered and shaded soil. Yerba mate seedlings were subjected to treatment with bare and covered soils in shadings of 0, 18, 35, and 50%, after seven and eleven months cultivation, summer and fall, respectively. Mature leaves were collected to perform the analyses of phenolic compounds by redox reaction with Folin-Ciocalteu reagent, of flavonoids by colorimetric method, and of antioxidant capacity by ABTS radical and FRAP (iron reduction method). The content of phenolic compounds was higher in the treatments with 35% shading in correlation with the group of flavonoids and antioxidant capacity. In the FRAP method, the higher correlation shows that autumn is the best time to harvest because of the higher concentration of phytochemical compounds. The positive influence of shading (35 and 50%) was evident in the content of phenolic compounds and flavonoids related to antioxidant capacity and better quality of yerba mate to meet the consumer market.

Plano de amostragem presença-ausência para Oligonychus yothersi (McGregor) (Acari: Tetranychidae) na cultura da erva-mate / Presence-absence sampling plan for Oligonychus yothersi (McGregor) (Acari: Tetranychidae) on mate-tea orchard

O ataque de ácaros na cultura da erva-mate tem freqüentemente provocado perdas pela queda precoce das folhas. Assim, há necessidade de se monitorar a população desses artrópodes e adotar estratégias de manejo. O objetivo deste trabalho foi avaliar a confiabilidade da amostragem presença-ausência para Oligonychus yothersi (McGregor) na erva-mate. O trabalho foi realizado em um erval comercial, em Cascavel, PR, de abril de 1999 a julho de 2000. Coletas quinzenais de 240 folhas foram feitas em diferentes partes de 10 plantas escolhidas ao acaso. A contagem dos ácaros nas folhas foi realizada em laboratório com auxílio de microscópio estereoscópico. Foi determinado o padrão de agregação através dos coeficientes a e b da lei da potência de Taylor; a proporção de folhas infestadas e o número de amostras requeridas foram estimados através de modelo matemático. O. yothersi apresentou distribuição agregada. A proporção de folhas infestadas calculada pelo modelo matemático mostrou ser um parâmetro confiável para estimar a densidade populacional do ácaro. O número de amostras requeridas foi pequeno, viabilizando a aplicação prática do método de amostragem presença-ausência para O. yothersi na cultura da erva-mate.

Mite infestations to the culture of mate-tea frequently causes losses by the premature fall of the leaves. So, it is necessary to monitor the population of these arthropods, and to adopt management strategies for their control. The objective of this research was to evaluate the trustworthiness of presence-absence sampling for Oligonychus yothersi (McGregor) on mate-tea orchard. This study was conducted in Cascavel, Paraná State, from April 2001 to July 2000, in a mate-tea tree commercial plantation. Biweekly sampling of 240 leaves were collected in different parts of 10 plants, and the number of mites was counted. The aggregation pattern was determined through the coefficients a and b of Taylor's power law. The proportion of infested leaves and the number of required samples were estimated through mathematical model. The mite O. yothersi presented aggregate distribution. The proportion of infested leaves calculated by means of mathematical model showed to be a trustworthy parameter to estimate the population density of the mite. The number of required samples was small, making feasible the practical application of the presence-absence sampling method for O. yothersi in the culture of mate-tea.