Interferência interespecífica entre Amaranthus hybridus L. e Amaranthus viridis L.

O objetivo deste trabalho foi estudar a interferência interespecífica entre duas espécies de Amaranthus -- A. viridis e A. hybridus ¾, esta última com dois biótipos distintos (verde e roxo); ambas ocorriam associadas em dois locais. Nas populações de cada local foram feitos ensaios de substituição independentes, em vasos, nos quais observou-se que as populações que germinam mais prontamente são as que vencem em competição, ou seja, se estabelecem e produzem maior número de sementes. Houve tendência de A. hybridus (tipo verde) dominar tanto A. hybridus (tipo roxo) como A. viridis, e de A. hybridus (tipo roxo) dominar A. viridis. Em cultivo misto, houve casos em que as espécies estavam competindo pelos mesmos recursos, ou explorando recursos diferentes do ambiente, ou mesmo com antagonismo mútuo.

Competição intra-específica entre Amaranthus hybridus L. e Amaranthus viridis L.

Ensaios de competição intra-específica foram conduzidos sobre Amaranthus viridis L. e A. hybridus L., a última espécie com dois biótipos distintos, tipo verde e tipo roxo. Os três ensaios, conduzidos separadamente, utilizaram cinco densidades de sementes por vaso. Em termos gerais, as sementes germinadas prontamente foram a razão do surgimento da próxima geração, visto que estabeleceram plântulas rapidamente e estas venceram em competição. A partir de certo número de sementes semeadas (20 por vaso), o número de plantas adultas obtidas revelou-se independente do número de sementes semeadas, o que indica que a capacidade de suporte do ambiente, ao invés do tamanho do banco de sementes no solo, é a razão da regulação do tamanho populacional; a mesma observação aplica-se à produção de matéria seca. Sob condições de competição, as espécies A. hybridus - tipo verde e A. viridis produziram maior quantidade de biomassa para reprodução (22% a 34%) do que A. hybridus - tipo roxo (15% a 18%). As primeiras, portanto, revelaram-se mais estrategistas-r que a última.

Diferenças morfológicas entre Amaranthus cruentus, cv. BRS Alegria, e as plantas daninhas A. hybridus, A. retroflexus, A. viridis e A. spinosus

O pseudocereal amaranto, com as espécies Amaranthus caudatus, A. cruentus e A. hypochondriacus, domesticado pelas populações indígenas antes que a América fosse descoberta, tem se adaptado aos sistemas produtivos dos cerrados. A planta apresenta panículas apicais, divididas em pequenos ramos com frutos do tipo pixídio, com uma semente cada. Estas germinam rapidamente em presença de umidade, após atingirem a maturação fisiológica. No início da fase vegetativa, o amaranto cultivado pode confundir-se com espécies de plantas daninhas do mesmo gênero (A. hybridus, A. retroflexus, A. viridis e A. spinosus), as quais estão associadas à expansão agrícola. As diferenças morfológicas tornam-se mais visíveis após o florescimento: ramificações com flores axilares e terminais, em contraste com o amaranto, no qual a inflorescência (panícula) é apical; as sementes claras das espécies cultivadas contrastam com as das invasoras, que são escuras. BRS Alegria (A. cruentus), cultivar pioneiro no Brasil, apresenta plantas com 180 cm, das quais a panícula ocupa 48 cm; maturação fisiológica aos 90 dias; resistência ao acamamento; e 0,68 g por 1.000 sementes, com produção de 2,3 t ha¹ (sementes) e 5,6 t ha-1 (biomassa total). As sementes nas plantas daninhas são menores, germinam gradativamente e podem permanecer no solo por muitos anos, infestando as áreas. As diferenças morfológicas detectadas na experimentação demonstram que as espécies são distinguíveis; elas contribuem para orientar a produção de sementes e o cultivo comercial de amaranto, enfatizando as características de adaptação, em contraste com as das invasoras do mesmo gênero botânico.

First report of Amaranthus viridis resistance to herbicides

Due to the limited number of herbicides registered for the control of dicot weeds in cotton crops, ALS inhibitors have been used on an intensive and recurrent basis. Given that, cases of poor weed control have been described after application of these herbicides in the main cotton producing areas in Brazil, the purpose of the present work was to evaluate the occurrence of resistance to ALS herbicides in Amaranthus viridis biotypes from those areas. Dose-response curves were prepared after pre-emergence applications of trifloxysulfuron-sodium (0; 1.8; 3.7; 7.5; 15 and 30 g ha-1) and pyrithiobac-sodium (0; 35; 70; 140; 280 and 560 g ha-1), equivalent to 0, ¼, ½, 1, 2 and 4 times the recommended commercial rates. The selection of trifloxysulfuron-sodium resistant biotypes of A. viridis was confirmed in samples from Bahia (BA 7, BA 8, BA 9 and BA 11). However, no resistance to pyrithiobac-sodium was found for biotypes either from Bahia or from Mato Grosso do Sul.

Effect of nitrate and ammonium on the growth and protein concentration of Microcystis viridis Lemmermann (Cyanobacteria)

Cyanobacteria are a very important group in aquatic systems, particularly in eutrophic waters. Therefore studies about their success in the environment are essential. Many hypotheses have tried to explain the dominance of Cyanobacteria, and several emphasized the importance of various nitrogen sources for the success of the group. In this study, we measured the effect of ammonium and nitrate on the growth and protein concentration of Microcystis viridis (Cyanobacteria). This species is well-known because bloom formation in eutrophic waters. The study was carried out, in experimental batch cultures, using the WC medium with different nitrogen sources: ammonium, nitrate, ammonium + nitrate (50% ammonium + 50% nitrate) and ammonium at different concentrations (to test for possible NH4+ toxicity). Protein, ammonium and nitrate concentrations were measured at end of each experiment, whereas samples for cell counts were taken daily. Results showed that Microcystis viridis grew faster with ammonium (µ = 0.393 day-1) than with nitrate (µ = 0.263 day-1) and ammonium + nitrate (µ = 0.325 day-1). This pattern is explained by the metabolism of ammonium that presents higher uptake and assimilation rates than nitrate. Maximum cell concentration, however, was higher in the ammonium + nitrate treatment, followed by nitrate treatment. Higher protein concentration were observed in the treatment with nitrate. In the ammonium toxicity test, no difference between the control and NH4+ at 50% was found. Thus, the ammonium concentrations used in these experiments were not toxic. Our results suggest that Cyanobacteria is able to grow on both nitrogen sources even if ammonium may allow faster growth and bloom development.

Haematological responses of green mussel Perna viridis (Linnaeus) to heavy metals copper and mercury

Department of Marine Biology, Microbiology and Biochemistry, Cochin University of Science and Technology

Investigations on the Effects of Petroleum Hydrocarbons on the Marine Bivalves Perna viridis (Linnaeus) and Sunetta scripta (Linne')

The thesis deals with different aspects connected with the distribution and toxicity of PHC in crude oils in the aquatic environment and marine molluscs. Information has been gathered and presented on the present status of research in the field based on a thorough review of recent literature. It is seen from the literature that the resident time of PHC becomes lesser and lesser when crude oil is discharged in large quantities into the coastal waters where excess oxygenation light penetration, temperature availability and strong tidal currents persist. This results in the reduction of the onslaught of oil pollution. This probably shows that taxic insult of crude oil in tropical shores will be relatively lesser than that occurring in temperate and boreal waters. However, there is no record of major episodal oil pollution comparable in quantum and extent to that of Torrey Canyon or Amoco Cadiz which prevents a more reliable analysis on the issue. Considerable controversy exists on the method of estimation of PHC in seawater. However, Ultra-violet fluorescence spectroscopy has been widely recommended as an analytical tool for the determination of total hydrocarbons. Similarly representation of values as chrysene equivalents has been recognised as the most reliable method of Quantum representation.

Studies on isolation, purification and properties of Endoglucanase from the hepatopancreas of Perna viridis

In the attempt to find out catalytic potency and properties of the endoglucanase of green mussel, it could be highlighted that the enzyme is efficient in degrading carboxymethylcellulose to reducing sugars. The immobilized enzyme will find applications in the food industry, paper and pulp industry, wood preservation, alcohol and pharmaceutical industry.The purification method employed i.e. Sephadex G100 chromatography employing affinity and exclusion principles simplify the purification procedure.Addition of Mg2+ and Co2+ at 10mM concentrations enhances endoglucanase activity of green mussel.The immobilized endoglucanase can be used for deinking mixed office waste paper. The endoglucanase if supplemented with exoglucanase and B-glucosidase under appropriate conditions would help in the recycling of paper.

Physiological Effects Of Some Heavy Metals On Perna Viridis (Linnaeus)

No serious attempt has so far been made in India to make use of the ‘Mussel watch’ concept as a useful tool for pollution monitoring of the marine and estuarine environment. The recently conducted 'National seminar on mussel watch’ by the Cochin University of Science and Technology (13-14 Feb, 1986) discussed the technical aspects related to mussel watch programme and the application of sentinel organism concept to the coastal areas of India. It is well known that the biological and physiological characteristics of the organism inhabiting tropical waters such as those prevailing in India, and the ecological as well as the environmental characteristics of temperate areas, where mussel watch programmes are already in existence differ greatly. So it is essential to adopt the techniques and standards developed for temperate species to the situations and conditions in India. In this context it is a prerequisite to collect information on physiology and other biological indices of stress of possible sentinel organisms like P.viridis. In consideration of the above, P. viridis which is a potential sentinel organism, is selected for the present study

Morphological, behavioral and biological aspects of Azya luteipes Mulsant fed on Coccus viridis (Green)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

BRACHYURAN CRABS (DECAPODA, BRACHYURA) ASSOCIATED WITH THE GREEN SPONGE AMPHIMEDON VIRIDIS (DEMOSPONGIAE) FROM ITAGUA BEACH, SOUTH-EASTERN COAST of BRAZIL

This study provides information on the community structure of brachyuran crabs associated with the green sponge, Amphimedon viridis Duchassaing & Michelotti, 1864, from a beach on the south-eastern coast of Brazil. Monthly collections from May 2002 through August 2003 were carried out on the rocky bottoms off Itagua Beach (23 degrees 27'07 '' S 45 degrees 02'49 '' W). Crabs on the green sponge banks were hand-caught during snorkelling sessions, and 638 crabs belonging to 31 species, 19 genera, and 10 families were obtained. Biological parameters, including sponge volume, number of individuals, density, richness, diversity, evenness, and dominance changed considerably over time. Species recruitment and foraging habit are some of the factors that drive the richness, dominance, and diversity patterns of this community. The green sponge banks are important sites for recruitment, refuge, and feeding of many species of brachyurans. Therefore, they are also important for the conservation of this group on the south-eastern coast of Brazil.

Sazonalidade e dieta frugívora do saí-andorinha Tersina viridis (Illiger, 1911) em reflorestamento da mata ciliar do Rio Mogi Guaçu, São Paulo, Brasil

Segundo a literatura, Tersina viridis (Illiger, 1911) possui hábito gregário sazonal em deslocamentos locais. Os reais motivos desses deslocamentos ainda são poucos conhecidos. em reflorestamento de mata ciliar do rio Mogi-Guaçu, SP, foi possível quantificar a variação sazonal mensal na densidade populacional durante um ano. O número de indivíduos aumentou substancialmente durante a estação seca e ausência durante a estação chuvosa, assim, caracterizando um comportamento fortemente sazonal de ocorrência nesse local. Provavelmente T. viridis possui algumas rotas de deslocamentos quando aparecem em grandes agregados no período mais seco na região do interior do estado de São Paulo e vizinhanças. A grande abundância de algumas espécies de plantas ornitocóricas pode ser alguns dos motivos que determinam a rota desses deslocamentos na região estudada, e não o padrão geral da fenologia da frutificação das espécies ornitocóricas.

Propagação assexuada de chacrona (psychotria viridis ruiz & pavon) via estaquia foliar

This study aimed to assess the asexual propagation of Psychotria viridis by leaf cuttings. The treatments were: A - Whole leaf cuttings, B - leaf cuttings with the top third cut off; C - with the lower third of the cuttings removed; D - with cuts on the primary vein of leaf cuttings, and E - poles with cuts on the leaf's secondary veins. The cuttings were immersed in distilled water for a period of 70 days. In all the treatments, the rooting was observed to occur in the region of the cut, or the place where the incision in the vein was. Current assay shows the feasibilities of Psychotria viridis leaf stalks and concludes that cuttings at the nerve ends highlight rooting in so far as the leaf stalks remain in permanent contact with the plant.

Aspectos biológicos de Azya luteipes Mulsant, 1850 (Coleoptera: Coccinellidae) em Coccus viridis Grenn, 1889 (Hemiptera: Coccidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)