In vitro photodynamic inactivation of plant-pathogenic fungi Colletotrichum acutatum and Colletotrichum gloeosporioides with Novel Phenothiazinium photosensitizers.

The increasing tolerance to currently used fungicides in both clinical and agricultural areas is of great concern. The nonconventional light-based approach of antimicrobial photodynamic treatment (APDT) is a promising alternative to conventional fungicides. We evaluated the effects of APDT with four phenothiazinium derivatives (methylene blue [MB], new methylene blue N [NMBN], toluidine blue O [TBO], and the novel pentacyclic phenothiazinium photosensitizer [PS] S137) on conidia of three fungal species (Colletotrichum acutatum, Colletotrichum gloeosporioides, and Aspergillus nidulans). The efficacy of APDT with each PS was determined, initially, based on photosensitizer MICs. Additionally, the effects of APDT with two selected PSs (NMBN and S137) on survival of conidia were evaluated. The subcellular localization of the PS in C. acutatum conidia was determined. The effects of photodynamic treatments on leaves of the plant host Citrus sinensis were also investigated. APDT with S137 showed the lowest MIC. MICs for S137 were 5 µM for the three fungal species when a fluence of 25 J cm(-2) was used. APDT with NMBN (50 µM) and S137 (10 µM) resulted in a reduction in the survival of the conidia of all species of approximately 5 logs with fluences of ≥15 J cm(-2). Washing of the conidia before light exposure did not prevent photodynamic inactivation. Both NMBN and S137 accumulated in cytoplasmic structures, such as lipid bodies, of C. acutatum conidia. No damage to orange tree leaves was observed after APDT.

Estudo farmacobotânico de duas espécies de Anileira (Indigofera suffruticosa e Indigofera truxillensis, Leguminosae) com propriedades farmacológicas / Pharmacobotanical studies of wild indigo species (Indigofera suffruticosa and Indigofera truxillensis, Leguminosae,) with pharmacological properties

Indigofera suffruticosa e Indigofera truxillensis são espécies de Leguminosae que se destacam no gênero por suas propriedades farmacológicas. O objetivo deste trabalho foi estabelecer um controle de qualidade morfológico para as matérias-primas vegetais obtidas destas duas espécies, por meio de análises da superfície e organoléptica do pó foliolar e estudos anatômicos e histoquímicos dos folíolos, do caule e da raiz. A análise dos pós mostrou que a forma e ornamentação dos tricomas tectores são bons caracteres diagnósticos da matéria-prima pulverizada com partículas maiores que 53 µM, e que o odor em I. suffruticosa é forte e desagradável, com sabor fracamente amargo não persistente e em I. truxillensis é fraco e agradável e de sabor muito amargo e persistente. As espécies apresentaram estrutura anatômica de folíolos, entrenós caulinares e raízes laterais muito semelhantes; exceto pela epiderme papilosa em ambas as faces foliolares em I. truxillensis e apenas na face adaxial em I. suffruticosa. Compostos fenólicos foram detectados nos folíolos e alcalóides foram detectados nos caules e nas raízes (em maior quantidade nestas) de ambas as espécies. A presença de alcalóides nas raízes de I. suffruticosa e I. truxillensis é semelhante à observada em espécies de leguminosas ictiotóxicas incluídas no "complexo timbó", cujas raízes são tóxicas devido à presença de rotenóides.

The Leguminosae genus Indigofera has two important pharmacological species, Indigofera suffruticosa and I. truxillensis. The present work aims to establish a morphological quality control for vegetal drugs obtained from these two species through the analyses of surface and organoleptic features in leaflet powder, and also through anatomical and histochemical studies in leaflet, shoot and root. Powder analyses evidenced that shape and ornamentation of the simple trichomes are good diagnostic characters for the sprayed drug, with particles bigger than 53 µm; moreover, odor was strong and awkward, with non-persistent, weakly bitter taste in I. suffruticosa, and weak and pleasant, with more persistent, bitter taste in I. truxillensis. Similar anatomical structures were found in leaflets, cauline internodes and lateral roots in both species, except for papillose epidermic cells that occurred in both leaflet sides in I. truxillensis, and only on the adaxial side in I. suffruticosa. Phenolic compounds were found in leaflets, and alkaloids in shoots and roots (greater amount) of both studied species. The occurrence of alkaloids in roots of I. suffruticosa and I. truxillensis seems to be similar to that observed in ichthyotoxic legume species that belong to the so-called "timbó complex", whose roots are toxic due to rotenoids.

Storage sites in seeds of Caesalpinia echinata and C. ferrea (Leguminosae) with considerations on nutrients flow

The seeds of Caesalpinia echinata and C. ferrea behaved as typical endospermic seeds, despite their different morphological classification (exendospermic seeds were described for C. echinata and endospermic seeds for C. ferrea). Then, the aim of this work was to compare, under ultrastructural and histochemical terms, the nature of the storage substances and their accumulation sites, as well as the nutrient flow in seeds of these species. Cotyledons in C. echinata accumulate carbohydrates, lipids and proteins, which are mobilized from the outer to the inner parts as revealed by the position of plasmodesmata. Endosperm in C. ferrea accumulates carbohydrates and in C. echinata accumulates substances during the initial embryogenic phases. Such tissue develops a chalazal haustorium that is responsible for the transport of substances into the endosperm itself and from it into the embryo, confirmed by the presence of transference cells.

As sementes de Caesalpinia echinata e C. ferrea comportam-se como endospérmicas, apesar de descritas na literatura como exendospérmicas e endospérmicas, respectivamente. Desta forma, o objetivo deste trabalho foi comparar, em termos ultra-estrutural e histoquímico, a natureza das substâncias de reserva e seus tecidos acumuladores, bem como o fluxo de nutrientes nas sementes destas espécies. Os cotilédones em C. echinata acumulam carboidratos, lipídios e proteínas, mobilizados da periferia para o centro, como visto pelo posicionamento dos plasmodesmas. O endosperma em C. ferrea acumula carboidratos e lipídios, e em C. echinata, acumula substâncias nos estádios iniciais da embriogênese. Este tecido desenvolve um haustório calazal agressivo, que transporta substâncias para o endosperma propriamente dito e deste para o embrião, fato confirmado pela presença de células de transferência no endosperma.

Anatomia dos órgãos vegetativos de Dieffenbachia picta Schott (Araceae) com ênfase na distribuição de cristais, laticíferos e grãos de amido / Anatomy of the vegetative organs from Dieffenbachia picta Schott (Araceae) with an emphasis on crystals, laticifers and starch grains

A distribuição dos cristais, laticíferos e grãos de amido foi estudada nos órgãos vegetativos de Dieffenbachia picta Schott (Araceae), conhecida por comigo-ninguém-pode, por tais estruturas serem citadas como responsáveis pela irritação mecânica e química provocada pela planta. A anatomia da folha, do caule aéreo, do rizoma e da raiz foi descrita por meio de seções histológicas coradas com azul de toluidina. A natureza química dos cristais e a presença de lipídios, alcalóides, grãos de amido e proteínas foram verificadas por reagentes diversos. Drusas e ráfides de oxalato de cálcio, associadas a lipídios, alcalóides e proteínas, ocorreram no interior de células presentes no parênquima de todos os órgãos, no colênquima caulinar e nos meristemas da raiz. O tempo de dissolução dos cristais das folhas jovem e adulta foi semelhante, o do caule foi maior que o da folha e o do rizoma maior que o da raiz. Grãos de amido, associados a proteínas, ocorreram no clorênquima do caule aéreo (forma de bastonetes) e rizoma (formas esférica e bastonete). Laticíferos ocorreram entremeando o colênquima e o parênquima; o látex continha ráfides, alcalóides e lipídios. Maior número de idioblastos cristalíferos e laticíferos foi observado no caule aéreo, sendo este, portanto, o órgão que mais representa perigo.

We studied the distribution of crystals, laticifers and starch grains of the vegetative organs from dumb cane, Dieffenbachia picta Schott (Araceae), known in Brazil as "comigo-ninguém-pode" for such structures are meant to be responsible for mechanical and chemical irritation events carried out by the plant. We described the anatomy of leaves, aerial stems, rhizomes and roots with histological sections dyed in toluidine blue. We checked the chemical nature of crystals and the presence of lipids, alkaloids, starch grains and proteins with various reagents. Druses and calcium oxalate raphides - associated with lipids, alkaloids and proteins - were found in idioblasts spread in the parenchyma of all organs, in the collenchyma of the shoot and in the root meristems. Regarding the dissolution time, it was analogous for crystals in both young and old leaves; it was higher in stems than in leaves and higher in rhizomes than in roots. Starch grains associated with proteins were found in the chlorenchyma of the aerial stem (rod-shaped) and in rhizomes (spherical and rod-shaped). Laticifers were found interspersing parenchyma and collenchyma; raphides, alkaloids and lipids were found in latex. We found a higher number of crystals and laticifers in the aerial stem, and therefore such structure is the most dangerous organ if eaten or swallowed.

Components of fecundity and abortion in a tropical tree, Dahlstedtia pentaphylla (Leguminosae)

Studies were conducted on pollination and patterns of fruit and seed production to assess the potential factors causing high fruit and seed abortion in Dahlstedtia pentaphylla (Leguminosae) through analyses of relationships between flower position in the inflorescence and ovules and seeds within ovaries and fruits, and flower, fruit and seed abortion. No differences were found in pollination and fruit set as a function of inflorescence position. There was no relationship, neither between degenerating ovules and their position within the ovary, nor between developing seed and fruit position. Maternal resource limitation related to fruits and embryos, due to the high cost of fruit production and seed maturation, was one of the factors that led to a high abortion rate in D. pentaphylla.

Este trabalho estudou o efeito dos componentes de fecundidade na reprodução de Dahlstedtia pentaphylla, leguminosa neotropical com baixa produção de frutos e sementes. Para tal, foram analisadas as relações das posições das flores na inflorescência e dos óvulos/sementes no ovário/fruto ao aborto de frutos e sementes. Não ocorreram diferenças na deposição de pólen em flores e na formação de frutos em função da posição na inflorescência. Não se encontrou também relação entre aborto de óvulos/sementes e sua posição no ovário/fruto. A limitação dos recursos maternos aos frutos e aos embriões, devido ao alto custo de formação de frutos e maturação das sementes, foi um dos fatores responsáveis pelas altas taxas de aborto nesta espécie.

Lip anatomy and its implications for the pollination mechanisms of Bulbophyllum species (Orchidaceae).

BACKGROUND AND AIMS: The lip structure of six Brazilian and one Asiatic species of Bulbophyllum with wind-assisted fly pollination (B. involutum, B. ipanemense and B. weddellii) and non-wind-assisted fly pollination (B. epiphytum, B. glutinosum, B. regnellii and B. rothschildianum) was studied to investigate the presence of secretory tissues related to these pollination mechanisms. METHODS: The lip study was carried out through scanning electron microscopy (lip surface) and light microscopy (anatomical features). KEY RESULTS: In most of the species studied, the osmophores (odour glands) were located in the lobes and in the upper surface of the lip callus. Differences in the lip structure were observed between the two groups (the presence of a nectary and the extent of osmophore surface), depending on the mechanism of pollination. Nectaries were found in the cavity callus in B. ipanemense, B. involutum and B. weddellii, even though their pollinators were presumably attracted by the instinct to oviposit. CONCLUSIONS: These findings corroborate the hypothesis that, because pollination in these species is dependent on an unpredictable external factor (wind), nectar is necessary to keep the insect in the flower for a long period. Despite the occurrence of a liquid-like nectar in the flowers of B. epiphytum, B. glutinosum, B. regnelli and B. rothschildianum, no anatomical evidence for nectaries was found in the lips of these species, although a similar structure may occur in another region of the flowers. This observation agrees with the fact that pollination by lip movement in the latter species requires only gravity, with no additional mechanism being needed to keep the flies in the flower.