IIITemperatura base e filocrono em duas cultivares de oliveira Base temperature and phyllochron in two olive cultivars Recebido para publicação 22.02.12 Aprovado em 07.07.12 Devolvido pelo autor 07.08.12 CR-6829

Os modelos de simulação são ferramentas utilizadas na área de agrometeorologia para quantificar o desenvolvimento de culturas agrícolas e florestais. O trabalho teve como objetivo comparar os modelos do Filocrono (linear) e de Wang e Engel (não linear) para estimar o desenvolvimento foliar, através do aparecimento de folhas, nas cultivares de oliveira 'Arbequina' e 'MGS ASC315' durante a fase de muda. O experimento foi instalado no campo experimental da Empresa Agropecuária de Minas Gerais (EPAMIG), Maria da Fé (MG), sob o delineamento inteiramente casualizado e organizado em arranjo fatorial, sendo duas cultivares e nove épocas de transplantio com 15 repetições em cada tratamento. Os coeficientes dos modelos foram estimados pelos dados obtidos nas três primeiras épocas de transplantio e as demais épocas foram utilizadas para avaliar o desempenho dos modelos. As respostas dos modelos foram divergentes para os dois modelos. O modelo de Wang e Engel foi mais eficiente para a cultivar 'Arbequina', com raiz do quadrado médio do erro (RQME) de 3,41 folhas, enquanto a cultivar 'MGS ASC315' teve a RQME de 6,58 folhas. O modelo do Filocrono se mostrou mais eficiente para a cultivar 'MG ASC315' com RQME de 2,98 folhas, inferior ao da cultivar 'Arbequina', com RQME de 7,49 folhas.

Neurogenesis in the adult brain appears to be phylogenetically conserved across the animal kingdom. In pigeons and other adult non-oscine birds, immature neurons are observed in several prosencephalic areas, suggesting that neurogenesis may participate in the control of different behaviors. The mechanisms controlling neurogenesis and its relevance to defensive behaviors in non-oscine birds remain elusive. Herein, the contribution of the environment to behavior and neurogenesis of pigeons was investigated. Adult pigeons (Columba livia, n = 6/group), housed in standard (SE) or enriched environment (EE) for 42 days, were exposed to an unfamiliar environment (UE) followed by presentation to a novel object (NO). Video recordings of UE+NO tests were analyzed and scored for latency, duration and frequency of angular head movements, peeping, grooming, immobility and locomotion. Twenty-four hours later, pigeons were submitted to the tonic immobility test (TI) and number of trials for TI and TI duration were scored, followed by euthanasia 2 h later. Brains were immunohistochemically processed to reveal doublecortin (DCX), a marker for newborn neurons. Compared to those housed in SE, the pigeons housed in EE responded to a NO with more immobility. In addition, the pigeons housed in EE presented longer TI, more DCX-immunoreactive (DCX-ir) cells in the hippocampus and fewer DCX-ir cells in the lateral striatum than those housed in SE. There was no correlation between the number of DCX-ir cells and the scores of immobility in behavioral tests. Together, these data suggest that enrichment favored behavioral inhibition and neurogenesis in the adult pigeons through different, parallel mechanisms.

The wild grass species Brachypodium distachyon (L.) has been proposed as a new model for temperate grasses. Among the biotechnological tools already developed for the species, an efficient induction protocol of somatic embryogenesis (SE) using immature zygotic embryos has provided the basis for genetic transformation studies. However, a systematic work to better understanding the basic cellular and molecular mechanisms that underlie the SE process of this grass species is still missing. Here, we present new insights at the morpho-histological, histochemical, and molecular aspects of B. distachyon SE pathway. Somatic embryos arose from embryogenic callus formed by cells derived from the protodermal-dividing cells of the scutellum. These protodermal cells showed typical meristematic features and high protein accumulation which were interpreted as the first observable steps towards the acquisition of a competent state. Starch content decreased along embryogenic callus differentiation supporting the idea that carbohydrate reserves are essential to morphogenetic processes. Interestingly, starch accumulation was also observed at late stages of SE process. Searches in databanks revealed three sequences available annotated as BdSERK, being two copies corresponding to SERK1 and one showing greater identity to SERK2. In silico analysis confirmed the presence of characteristic domains in a B. distachyon Somatic Embryogenesis Receptor Kinase genes candidates (BdSERKs), which suggests SERK functions are conserved in B. distachyon. In situ hybridization demonstrated the presence of transcripts of BdSERK1 in all development since globular until scutellar stages. The results reported in this study convey important information about the morphogenetic events in the embryogenic pathway which has been lacking in B. distachyon. This study also demonstrates that B. distachyon provides a useful model system for investigating the genetic regulation of SE in grass species.

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The production and quality of strawberries may vary according to cultivar, transplant origin, and the system of plant cultivation. The objective was to evaluate the effect of different organic substrates and different transplant origins on strawberry production and fruit quality. The experiment was conducted in a randomized complete block design with a 2x2x4 factorial scheme using two cultivars (Albion and Camarosa) obtained from different origins (National-Brazilian and Imported-Argentine) and four combinations of substrates: (crushed sugarcane bagasse [70%] + organic compost [30%], crushed sugarcane bagasse [70%] + Carolina® commercial substrate [30%], burnt rice husks [70%] + organic compost [30%], and burnt rice husks [70%] + Carolina® commercial substrate [30%]). The experimental unit was composed of eight plants, with repetition in four blocks. The quality parameters of titrable total acidity, total soluble solids, ratio of sugar / acidity, firmness, and pulp coloration (chroma, hue angle, and L*, a* and b*) were evaluated, as were the production parameters of total number of fruits, total fruit production, average fruit mass, non-commercial fruit production, commercial fruit production and total productivity. The substrate influences the strawberry production variables. Fruit yield was highest in the Camarosa cultivar grown on the S3 substrate mixture. The cultivar, the transplant origin and the cultivation substrate influence fruit AT. SST and AT / SST are influenced only by cultivar and transplant origin. Chroma differs between plants with different transplant origins. Camarosa of National origin cultivated in burnt rice husks + organic compost presented the best production results and fruit quality.

Foi multiplicado in vitro, o abacaxi ornamental Ananas comosus var. erectifolius, induzindo o estiolamento de segmentos nodais com posterior regeneração de brotações. Os eixos caulinares foram inoculados nos meios de cultura: MS sem regulador de crescimento; MS + 10 µM de ácido indolbutírico (AIB); MS + 10 µM de ácido naftalenoacético (ANA); MS + 10 µM de ácido indolacético (AIA), e mantidos no escuro, a 25±2ºC. Aos 60 dias após a inoculação, avaliaram-se número de brotos/explante, número de nós/broto, comprimento de brotos, distância entre os nós e número total de nós/explante. O meio MS + 10 µM de ANA promoveu os maiores valores para número de brotos e número total de nós/explante. Para a regeneração de brotos, foram utilizados segmentos nodais, oriundos de eixo caulinar (explante) estiolados in vitro, contendo dois nós, nos meios: MS sem regulador de crescimento; MS + 4,44 µM de 6-benzilaminopurina (BAP); MS + 8,88 µM de BAP e MS + 13,32 µM de BAP. As culturas foram incubadas sob fotoperíodo de 16 horas, a 25±2ºC. Aos 30 dias, não houve diferença no número de brotos regenerados por nó entre os meios testados, enquanto aos 45 e 60 dias de cultivo, a adição de BAP teve efeito positivo sobre o número de brotos regenerados por nó, quando comparado com o meio sem a adição desta citocinina.