Effect of aluminum on productivity and mineral elements in soybean

Estudou-se a influência do alumínio sobre o desenvolvimento e o teor de alguns nutrientes em soja (Glycine max (L.) Merril), procurando-se determinar alguma possível diferença na tolerância a este cátion entre as cultivares IAC-5 e Santa Rosa. Plântulas com dez dias de idade foram submetidas a 0, 4, 8, 10 e 12 ppm de Al em solução nutritiva. Após 35 dias de cultivo, coletou-se o sistema radicular, o caule e as folhas, para a determinação do peso da matéria seca e dos teores de N, P, K, Ca, Mg, Fe e Al. A parte aérea de ambas as cultivares mostrou-se mais sensível ao Al que o sistema radicular. A cultivar IAC-5 acumulou mais matéria seca que a Santa Rosa no sistema radicular em relação à parte aérea; no entanto, as duas cultivares apresentaram respostas semelhantes, ao Al. Este cátion alterou significativamente a composição mineral das plantas, reduzindo, de maneira acentuada, o teor de Ca na parte aérea, e o de P e Mg, tanto na parte aérea como no sistema radicular. Observou-se um acúmulo de Al no sistema radicular; apenas uma pequena quantidade deste elemento foi translocada para a parte aérea. Os efeitos do Al foram pouco acentuados sobre o teor de K, mas evidenciaram-se sobre a distribuição de N, que se acumulou no caule, e sobre o teor de Fe. Em presença do Al, as duas cultivares estudadas não apresentaram diferenças marcantes, quanto à eficiência nutricional, e portanto não se justifica enquadrá-las em faixas distintas de tolerância.This paper deals with the effects of Al on the growth and mineral content in Santa Rosa and IAC-5 soybean (Glycine max (L.) Merril) cultivars. Ten day old seedlings were grown for an additional period of 35 days in a nutrient solution containing 0, 4, 8, 10 e 12 ppm of Al. Root, stem and leaf dry weights were obtained and samples analysed for N, P, K, Ca, Mg, Fe and Al content. Shoots were more sensitive to Al than roots in both cultivars. Although roots showed growth inhibition and morphological abnormalities, no drastic dry weight reduction was observed, as observed for the shoots. Cultivar IAC-5 showed a higher root dry matter accumulation than that of S. Rosa, but shoot dry weights were similar in both cultivars. Al caused a significant alteration in the plant mineral composition drastically reducing Ca content in the shoots. Reduction in P and Mg content was observed in both shoots and roots. The highest Al accumulation occurred in the root system, and a small amount was translocated to stems and leaves. Al effects in the K content were not so evident although, it had an influence on N content in shoots and Fe content in shoots and roots. The responses to Al were not significant enough to classify the two cultivars under distinct groups of tolerance

Comparative leaf anatomy of four species of Bromelioideae (Bromeliaceae) occurring in the Atlantic Forest, Brazil

Bromeliaceae, comprising 3172 species, is one of the most important families of the Brazilian Atlantic Forest owing to its high degree of endemism and occurrence in different habitats. The subfamily Bromelioideae is the most representative of Bromeliaceae and the best represented in the state of Minas Gerais, Brazil, with 120 species. The objective of this study is to compare the leaf anatomy of four species found in two areas of the Atlantic Forest: Serra do Brigadeiro State Park, Minas Gerais, Brazil ( Wawra and (Baker) Leme) and a forest fragment located within Bom Sucesso Farm, Viçosa, Minas Gerais, Brazil ( E. Morren and Bertol.), relating environmental characteristics to the habit. Leaf samples were studied using light and scanning electron microscopy and histochemical tests with Sudan, phloroglucinol, and ruthenium red stains. Leaves of and showed several adaptations to the epiphytic habit, including scales on both surfaces, thickened epidermal cell walls, presence of silica bodies, hypodermis with sclerified cells, water-storing tissue (hydrenchyma), and air channels formed by stellate cells in the chlorenchyma. The epiphytic species and the terrestrial species have similar overall structure, including a well-developed parenchyma and extravascular fiber groups. Leaves of the terrestrial species and the epiphytic species also show structural similarities, such as lack of extravascular fibers and less developed parenchyma. Similar characteristics in species from different habitats may either reflect microclimatic conditions under which these species occur or genetically fixed characteristics.Les Bromeliaceae, comprenant 3172 espèces, constituent une des familles les plus importantes de la forêt atlantique brésilienne par son fort degré d'endémisme et par sa présence dans différents habitats. La sous-famille des Bromelioideae, la plus représentative des Bromeliaceae, est la mieux représentée dans l'état de Minas Gerais, au Brésil, avec 120 espèces. L'objectif de l'étude consiste à comparer l'anatomie foliaire de quatre espèces trouvées dans deux régions de la forêt atlantique : parc de l'état « Serra do Brigadeiro », MG, Brésil ( Quesnelia strobilispica Wawra et Wittrockia gigantea (Baker) Leme), et un fragment forestier localisé sur la ferme « Bom Sucesso », Viçosa, MG, Brésil ( Billbergia euphemiae E. Morren et Bromelia antiacantha Bertol.), en reliant les caractéristiques environnementales avec l'habitat. Les auteurs ont étudié les feuilles à l'aide de la microscopie photonique et électronique par balayage, ainsi que des colorations au Sudan, phloroglucinol, et rouge de ruthénium. Les feuilles du B. euphemiae et du W. gigantea montrent plusieurs adaptations à l'habitat épiphyte, incluant des écailles sur les deux surfaces, des parois cellulaires épaissies, la présence de corps siliceux, un hypoderme avec des cellules sclérifiées, des tissus accumulateurs d'eau (hydranchymes) et des canaux aérifères formés par des cellules stellées, dans le chlorenchyme. L'espèce épiphyte, B. euphemiae, et l'espèce terrestre, Q. strobilispica, possèdent en général des structures similaires, incluant un parenchyme bien développé et des groupes de fibres extra-vasculaires. Les feuilles de l'espèce terrestre, B. antiacantha, et de l'espèce épiphyte, W. gigantea, montrent également des similarités de structures comme l'absence de fibres extra-vasculaires et un parenchyme moins développé. La similitude des caractères chez des espèces provenant de différents habitats peut refléter soit les conditions microclimatiques sous lesquelles ces espèces se développent, ou encore des caractéristiques génétiques fixées

Distribution, structural and ecological aspects of the unusual leaf nectaries of Calolisianthus species (Gentianaceae)

Nectaries in leaves of Gentianaceae have been poorly studied. The present study aims to describe the distribution, anatomy, and ecological aspects of extrafloral nectaries (EFNs) of three Calolisianthusspecies and in particular the ultrastructure of EFNs in Calolisianthus speciosus during leaf development, discussing its unusual structure. Leaves of Calolisianthus species were fixed and processed by the usual methods for studies using light, scanning microscopy and transmission electron microscopy (TEM). Ion chromatography was used to analyze the nectar exudates of C. speciosus. The distribution patterns of nectar secretion units were analysed by ANOVA and t-tests. Two EFNs that can be seen macroscopically were observed at the bases of C. speciosus and C. pendulus leaves. Such large nectaries are absent there in C. amplissimus. Another similarly large EFN is observed at the apex of each leaf in all species. The EFNs at the base of the young leaves in C. speciosus are visited by ants during the rainy season. EFNs are formed by several nectar secretory units (nectarioles) that are present throughout the leaves. Each nectariole is formed by rosette cells with a central channel from which the nectar is released. Channels of old C. speciosus and C. pendulus EFNs were obstructed by fungi. TEM of EFNs in young leaves showed cytoplasms with secretion, small vacuoles, mitochondria, cell wall ingrowth, and plasmodesmata. TEM of EFNs in old leaves demonstrated dictyosomes, plastids, mitochondria, segments of endoplasmatic reticulum, and lipid droplets. The nectar contains sucrose, glucose and fructose

Efeito de tricomas, aleloquímicos e nutrientes na resistência de Lycopersicon hirsutum à traça-do-tomateiro

The objective of this work was to study the effect of trichomes, alellochemicals and minerals in the leaves of different canopy heights on the resistance of Lycopersicon hirsutum to tomato leaf miner, Tuta absoluta (Lepidoptera: Gelechiidae). Effects of 2-tridecanone (2-TD), 2-undecanone (2-UD), N, P, K, Ca and Mg levels, density and types of trichomes and leaf area on apical, medium and basal parts of plant dossel of L. hirsutum and L. esculentum on the oviposition and mines number of T. absoluta was studied. Production of 2-TD increased from the bottom to the top of the canopy. The apical part of plants of L. hirsutum showed more antibiotic effect on the caterpillar. T. absoluta oviposited more on leaves of the apical and medium portion of the plants than in the basal parts of L. esculentum.Estudos foram conduzidos com o objetivo de verificar o efeito de tricomas, aleloquímicos e nutrientes nas folhas de partes do dossel das plantas na resistência de Lycopersicon hirsutum à traça-do-tomateiro, Tuta absoluta (Lepidoptera: Gelechiidae). Foram quantificados os teores de 2-tridecanona (2-TD), 2-undecanona (2-UD), N, P, K, Ca e Mg, densidade e tipos de tricomas e tamanho das folhas nos terços apical, mediano e basal do dossel de plantas de L. hirsutum e de L. esculentum e estudaramse os efeitos destes fatores sobre características biológicas de T. absoluta. Observou-se elevação no teor de 2-TD da base para o ápice do dossel. Não se detectou diferença significativa quanto ao número de ovos de T. absoluta ao longo do dossel de L. hirsutum, constatando-se em L. esculentum maior oviposição nos terços apical e mediano do que no basal. As folhas do terço apical de L. hirsutum apresentaram maior efeito deletério sobre as larvas de traça

Morphophysiological aspects of Catuaí-Vermelho and Conilon coffee cultivars

O objetivo deste trabalho foi comparar cafeeiros das espécies Coffea arabica L. cv. Catuaí-Vermelho e C. canephora Pierre cv. Conilon quanto à fotossíntese líquida e a aspectos da anatomia foliar a esta relacionados. Verificaram-se taxas fotossintética líquida, transpiratória e de condutância estomática maiores em plantas de C. canephora. As plantas de C. arabica apresentaram menor eficiência do sistema "antena", e folhas menores, porém mais espessas. As duas espécies diferiram, ainda, quanto ao tipo, dimensões e número dos estômatos presentes na epiderme foliar: paracíticos em C. arabica e actinocíticos em C. canephora, e maiores, mas em menor número, em C. arabica.The objective of this work was to compare plants of the Coffea arabica L. cv. Catuaí-Vermelho and C. canephora Pierre cv. Conilon species in relation to the net photosynthesis rate and aspects of leaf anatomy. Coffea canephora plants presented higher net photosynthetic rate, transpiratory rate and leaf conductance rate than C. arabica plants, which presented smaller photochemical capacity of photosystem I, and shorter and thicker leaves than C. canephora. Both species differed also in relationship to the type, number and dimensions of stomata in the leaf epiderm: they are paracytics in C. arabica and actinocytics in C. canephora, and they are larger, but in smaller number in C. arabica

Morphophysiological aspects of Catuaí-Vermelho and Conilon coffee cultivars

O objetivo deste trabalho foi comparar cafeeiros das espécies Coffea arabica L. cv. Catuaí-Vermelho e C. canephora Pierre cv. Conilon quanto à fotossíntese líquida e a aspectos da anatomia foliar a esta relacionados. Verificaram-se taxas fotossintética líquida, transpiratória e de condutância estomática maiores em plantas de C. canephora. As plantas de C. arabica apresentaram menor eficiência do sistema "antena", e folhas menores, porém mais espessas. As duas espécies diferiram, ainda, quanto ao tipo, dimensões e número dos estômatos presentes na epiderme foliar: paracíticos em C. arabica e actinocíticos em C. canephora, e maiores, mas em menor número, em C. arabica.The objective of this work was to compare plants of the Coffea arabica L. cv. Catuaí-Vermelho and C. canephora Pierre cv. Conilon species in relation to the net photosynthesis rate and aspects of leaf anatomy. Coffea canephora plants presented higher net photosynthetic rate, transpiratory rate and leaf conductance rate than C. arabica plants, which presented smaller photochemical capacity of photosystem I, and shorter and thicker leaves than C. canephora. Both species differed also in relationship to the type, number and dimensions of stomata in the leaf epiderm: they are paracytics in C. arabica and actinocytics in C. canephora, and they are larger, but in smaller number in C. arabica