ABSTRACT Presence of toxic compounds in marine coastal waters has increased exponentially since Industrial Revolution. In this way, we aimed to evaluate biochemical and physiological changes occurring within Hypnea musciformis after short-term exposure to gasoline. Hypnea musciformis was cultivated without gasoline and then exposed to various concentrations of it (0.001 % - 1.0 %, v/v) for periods of 30 min, 1 h, 12 h and 24 h. A Pricncipal Compound Analysis of UV-vis spectral window (200-700 nm) was able to discriminate gasoline-exposed samples according to both exposure time and gasoline concentration. Changes in carotenoid profile composition were observed. Decreased carotenoid content was associated to gasoline exposure time, being lutein and trans-β-carotene the major compounds found. Higher gasoline concentrations negatively interfered with phenolic compounds accumulation. In addition, increased gasoline concentrations corresponded to decreased intracellular starch grains content as well as increased its deposition on cell wall external surface. Data obtained allow us to conclude that gasoline can damage Hypnea musciformis physiology and cell morphology. This is important, considering Hypnea musciformis carotenoids and phenolics are potential biomarkers of environmental stress investigated, as well as its increased cell wall thickness to avoid gasoline diffusion.
ABSTRACT Salinity is an important abiotic factor since it is responsible for the local and/or regional distribution of algae. In coastal regions, salinity changes with prevailing winds, precipitation and tide, and particularly in extreme intertidal conditions. Acanthophora spicifera is a red seaweed that occurs in the supratidal region in which changes in abiotic conditions occur frequently. This study evaluated the effects of salinity on the metabolism and morphology of A. spicifera. Algae were acclimatized under culture conditions with sterilized seawater for seven days. Experiments used different salinities (15 to 50 psu) for seven days, followed by metabolic analyses. This study demonstrates that extreme salinities affect physiological parameters of A. spicifera, such as decrease in growth rate, as well as morphological parameters and concentrations of secondary metabolites. Acanthophora spicifera exhibited high tolerance to 25 to 40 psu, with little change in physiology, which favors the occurrence of this species in diverse environments. However, 15, 20, 45 and 50 psu were the most damaging and led to loss of biomass, depigmentation of apices, and the highest concentrations of antioxidant metabolites. The 50 psu treatment caused the greatest changes in general, greatly reducing a biomass and chlorophyll content, and facilitating the presence of endophytes.
The Brazilian Atlantic Forest is a biodiversity hotspot, and bromeliads are omnipresent in this biome. This study was aimed at characterizing both morphological and histochemical aspects of Vriesea friburgensis var. paludosa L.B. Sm. seeds. The seeds are filiform with a brown seed coat and yellowish-colored plumose appendages. Seeds are typically 4.4 mm long, 0.5 mm wide, and 1000 seeds weigh 683.8 mg. The seed coat presents phenolic compounds. Starch represents the main reserve compound in the endosperm; however, it is also present in smaller amounts in the embryo. The embryo occupies one-third of the seed and has a zone of constriction in the hypocotyl-radicle axis. The results of this work will contribute to the overall biology of V. friburgensis var. paludosa , as well as its taxonomic delimitation.
A Mata Atlântica é um hotspot de biodiversidade, e as bromélias são um grupo taxonômico bastante comum presente neste bioma. O objetivo deste estudo foi caracterizar os aspectos morfológicos e histoquímicos das sementes Vriesea friburgensis var paludosa L.B. Sm. As sementes são filiformes, com tegumento marrom e apêndices plumosos amarelados. Têm valores médios de 4,4 mm de comprimento, 0,5 mm de largura, e peso de 1.000 sementes de 683,8 mg. O tegumento apresenta compostos fenólicos. O amido é o principal componente de reserva no endosperma, porém ele também se apresenta em menores quantidades no embrião. O embrião ocupa um terço da semente e apresenta uma zona de constrição no eixo hipocotilo-radicula. Os resultados do presente trabalho contribuem na biologia e na delimitação taxonomia de V. friburgensis var. paludosa
The aim of this work was to study the cultivation of Gracilaria domingensis in a mussel farming urbanized area in Santa Catarina, Brazil. Relative growth rate was the parameter used to evaluate the cuttings attachment methods on the cultivation rope, cuttings density, cultivation period and cystocarpic versus unfertile thalli performance. The cultivation was feasible only when protected by net cages due to herbivory. The tie-tie attachment method presented the best results. No differences were observed when comparing the cuttings densities and reproductive phase. Future studies should evaluate the cost-effectiveness of producing the species in net cages and its potential as biofilter.
Tetraspore development was studied in Hypnea musciformis (Wulfen) J. V. Lamour. using light and electron microscopes, and techniques of histochemistry. Tetrasporangial differentiation arises from a cortex cell that enlarges. This cell undergoes mitosis to form a tetrasporangial mother cell and a stalk cell. The histochemichal study indicated that the cell wall layers are composed mainly of acidic polysaccharides, reacting with toluidine blue O, alcian blue and alcian yellow. The tetrasporangial mother cell is also stained with periodic acid Schiff, that detect neutral carbohydrates, and with coomassie brilliant blue, that detect proteins. The transformation of cortical cells into mature tetrasporangia involves a series of structural changes, especially of the chloroplasts and dictyosomes. The tetrasporangial mother cell rapidly becomes elongated, and a distinctive cell wall is formed before the onset of meiosis. During this elongation phase there is also an increase in the number of chloroplasts. The meiotic tetrasporocyte is characterized by extensive development of the perinuclear endoplasmic reticulum. Throughout meiosis, there is a continuous replication of chloroplasts as well as a synthesis of starch and the formation of vesicles with electron-dense contents. Cytokinesis begins with the formation of the cleavage furrow, produced by the infurrowing of the plasma membrane. This cleavage furrow formation is followed by mucilage deposition surrounding the tetraspores.
O desenvolvimento dos tetrásporos de Hypnea musciformis (Wulfen) J. V. Lamour. foi estudado com o uso dos microscópios de luz e eletrônico. Os tetrasporângios diferenciam-se a partir de células corticais. Essas células sofrem mitose dando origem à célula-mãe do tetrasporângio e à célula suporte. As técnicas histoquímicas indicam que a parede celular do tetrasporângio é composta especialmente de polissacarídeos ácidos, reagindo com azul do toluidina O, azul de alcião e amarelo de alcião. Os tetrasporângios são também corados com ácido periódico de Schiff, para carboidratos neutros, e com azul brilhante de coomassie, para proteínas. A transformação da célula cortical em célula mãe do tetrasporângio envolve uma série de mudanças estruturais, especialmente dos cloroplastos e dictiossomos. A célula-mãe do tetrasporângio alonga-se rapidamente e uma parede celular espessa é produzida antes da meiose. Durante essa fase de crescimento ocorreu aumento significativo no número de cloroplastos, grãos de amido e vesículas osmiofílicas. O tetrasporângio meiótico é caracterizado pelo desenvolvimento extensivo do retículo endoplasmático perinuclear. A citocinese tem início com a formação do sulco de divisão, formado pela invaginação da membrana plasmática. Concomitante à invaginação da membrana ocorre a deposição de mucilagem em torno dos tetrásporos.