Evaluating aquatic macrophytes for removing erythromycin from contaminated water: floating or submerged?

Water contamination by antibiotics is an emerging global problem, with impacts on both public health and the environment. Erythromycin has been encountered in bodies of water throughout the world, which demands the development of efficient remediation technologies. We investigated the physiological responses and phytoremediation capacity of four species of aquatic macrophytes, two floating (Salvinia molesta and Lemna minor) and two submerged (Myriophyllum aquaticum and Rotala rotundifolia). The plants were exposed to relevant environmental concentrations of erythromycin (0 and 1.7 µg l-1) in artificially contaminated water for seven days. Physiological evaluations evidenced the ability of that antibiotic to promote oxidative events in those plants, such as the activation of antioxidant enzymes (ascorbate peroxidase and/or catalase). S. molesta exposed to erythromycin demonstrated accumulations of hydrogen peroxide and oxidative damage (lipid peroxidation) that was reflected in growth reductions. The erythromycin removal efficiency of floating plants varied from 9 to 12%, while submerged species varied from 31 to 44%. As such, submerged macrophyte species demonstrated the most efficient removal of erythromycin from contaminated waters, and are therefore more indicated for antibiotic phytoremediation projects.

For the very first time, the capacities of floating and submerged plant species used for removing erythromycin from contaminated water were compared. Moreover, plant physiological responses were related to their phytoremediation capacity. Our results promise to have direct impacts on plant and environmental science as well as in toxicology since they will contribute to a better understanding of the effects of antibiotics in plants and indicate species for better performance of phytoremediation programs aiming to reclaim the antibiotic erythromycin.

Phytoremediation by ornamental plants: a beautiful and ecological alternative.

Phytoremediation is an eco-friendly and economical technology in which plants are used for the removal of contaminants presents in the urban and rural environment. One of the challenges of the technique is the proper destination of the biomass of plants. In this context, the use of ornamental plants in areas under contamination treatment improves landscape, serving as a tourist option and source of income with high added value. In addition to their high stress tolerance, rapid growth, high biomass production, and good root development, ornamental species are not intended for animal and human food consumption, avoiding the introduction of contaminants into the food web in addition to improving the environments with aesthetic value. Furthermore, ornamental plants provide multiple ecosystem services, and promote human well-being, while contributing to the conservation of biodiversity. In this review, we summarized the main uses of ornamental plants in phytoremediation of contaminated soil, air, and water. We discuss the potential use of ornamental plants in constructed buffer strips aiming to mitigate the contamination of agricultural lands occurring in the vicinity of sources of contaminants. Moreover, we underlie the ecological and health benefits of the use of ornamental plants in urban and rural landscape projects. This study is expected to draw attention to a promising decontamination technology combined with the beautification of urban and rural areas as well as a possible alternative source of income and diversification in horticultural production.

Development and dry mass accumulation in callalily at the initial cultivation stage / Desenvolvimento e acúmulo de massa seca em copo-de-leite em fase inicial de cultivo

The cultivation of the calla lily, despite its importance in the floriculture sector, is still limited due to the lack of knowledge of basic production techniques such as development and dry mass accumulation. These techniques facilitate more appropriate management, especially regarding the application of fertilizers, providing better nutrients utilization and greater yields. Thus, this study was aimed at evaluating the growth and development of calla lily plants, establishing growth curves according to dry mass accumulation. Acclimatized and micropropagated calla lily plantlets were grown in plastic pots containing coconut fiber as a substrate and fertilized with a modified formula of Malavolta. Treatments consisted of assessments at intervals of 30 days for 7 months. The design was in randomized blocks with four replications, in a total of 28 plots. Plants were evaluated by observing their growth characteristics and development of shoots, rhizome, roots, as well as production and flower quality. Development of the plants increased throughout the experimental period, with the maximum dry mass accumulation occurring at the end of the experimental period. Blooming was constant with the length of flower stalks increasing with along with the age of the plant.

O cultivo de Zantedeschia aethiopica, apesar de sua importância no segmento da floricultura, ainda é limitado pelo reduzido conhecimento em técnicas básicas de produção, como o desenvolvimento e acúmulo de massa seca. Essas informações permitem um manejo mais adequado, sobretudo referente à aplicação de fertilizantes, proporcionando melhor aproveitamento de nutrientes e maiores produções. Dessa forma, neste estudo, objetivou-se avaliar o crescimento e desenvolvimento de plantas de copo-de-leite, estabelecendo curvas de crescimento, considerando o acúmulo de massa seca. Para tanto, mudas micropropagadas e aclimatizadas de copo-de-leite foram cultivadas em vasos plásticos contendo como substrato fibra de coco e adubadas com a formulação modificada de Malavolta. Foram realizadas avaliações com intervalos de 30 dias, durante 7 meses, nos quais consistiram os tratamentos. O delineamento utilizado foi em blocos casualizados, com 4 repetições, totalizando 28 parcelas. As plantas foram avaliadas quanto às características de crescimento e desenvolvimento da parte aérea, rizoma, raízes, além de produção e qualidade das inflorescências. O desenvolvimento das plantas de copo-de-leite foi crescente ao longo do período experimental, sendo que o máximo acúmulo de massa seca total ocorreu ao final do período analisado. O florescimento foi constante com aumento do comprimento das hastes florais proporcional à idade das plantas.

Crescimento e produção de grãos da soja sob diferentes doses e fontes de fósforo em solos distintos / Soybean growth and yield under different doses and sources of phosphorus on distinct soils

A fertilidade dos solos das regiões tropicais é limitada pela baixa disponibilidade de fósforo e pela indisponibilização de boa parte do mesmo fornecido na adubação. Ainda existem muitas divergências sobre a melhor forma de utilização das diversas fontes fosfatadas disponíveis no Brasil. Objetivou-se, neste experimento, avaliar a produção de soja, sob a aplicação de diferentes doses e adubos fosfatados em dois tipos de solo. O trabalho foi realizado em casa de vegetação do Departamento de Ciência do Solo da Universidade de Lavras, em vasos de 3 dm³. Utilizaram-se dois solos sob cerrado: Neossolo Quartzarênico e Latossolo Vermelho Distroférrico típico. Foram testadas oito fontes (superfosfato triplo-ST, termofosfato magnesiano-TF, quatro fosfatos reativos importados: FR1, FR2, FR3 e FR4 e dois fosfatos naturais nacionais- FN1 e FN2) e quatro doses (0, 100, 300 e 600 mg dm-3) de fósforo, utilizando-se a soja como planta-teste. As fontes de solubilidade mais elevada ocasionaram as maiores produções e índices de eficiência em relação aos fosfatos naturais. Os fosfatos naturais importados e o FN2 apresentaram-se mais promissores em fornecer P para a cultura da soja, em relação ao superfosfato triplo, mesmo no primeiro cultivo, principalmente em solo com maior poder tampão de fósforo. A capacidade tampão de fósforo dos solos influenciou a eficiência das fontes de fósforo na cultura da soja.

The fertility of soils in tropical areas is limited by the low availability of phosphorus as well as by the unavailability of a great proportion of phosphorus supplied with fertilization. There are still some divergences about the best way of using the different sources of phosphorus available in Brazil. The aim of this experiment was to evaluate the soybean production as a result of the application of different phosphorous doses and fertilizers on two types of soils. The work was carried out in a greenhouse at Soil Science Department, Federal University of Lavras, in vases of 3 dm³ using two kinds of soils: Dystroferric Red Latosol and Quartzarenic Neosols. Eight sources (triple superphosphate-TF, four foreign reactive rock phosphate: FR1, FR2, FR3, and FR4 and two national rock phosphate FN1 and FN2) and four doses (0, 100, 300, and 600 mg dm-3) were applied. Soybeans were used as test plant. Sources with higher solubility showed the highest production and efficiency than natural phosphate. The natural phosphate imported from other countries and FN2 showed good results in supplying P for the soybeans, when compared to the triple superphosphate, even at the first year of culture, mainly on the soil with higher P buffer power. The phosphorus buffer capacity of the soils affected the efficiency of phosphorus sources on the soybean culture.

Soluções de condicionamento para conservação pós-colheita de inflorescências de copo-de-leite armazenadas em câmara fria / Conditioning solutions for post harvest conservation of calla lily in cold chamber

As informações sobre a conservação pós-colheita de copo-de-leite são escassas, apesar da sua importância comercial. Este trabalho teve como objetivo testar soluções de condicionamento para aumentar a durabilidade dessas inflorescências. Assim, testou-se o efeito do tratamento das hastes de copo-de-leite em soluções de condicionamento com hipoclorito de sódio (2 por cento), ácido cítrico (200mg L-1) e cloreto de cálcio (1000mg L-1). Avaliou-se também a influência da imersão pré-armazenamento das inflorescências em solução com Hidrosan® e a utilização deste conservante em solução de condicionamento das hastes para armazenamento em câmara fria. As inflorescências foram avaliadas diariamente quanto à durabilidade a partir do critério de classificação estabelecido (classes A1, A2, B e C) e pela medida do comprimento e largura da espata. O pré-tratamento das inflorescências em Hidrosan® ou a colocação das hastes neste conservante em câmara fria ou nos demais produtos não influenciaram na durabilidade das inflorescências de copo-de-leite, que apresentaram uma longevidade total de 11 dias. Os diferentes produtos avaliados não influenciaram na largura e no comprimento da espata. Observou-se que, independentemente dos tratamentos, a largura da espata aumentou até o 7° dia e o comprimento até o 8° dia, diminuindo após este período. O aumento das dimensões da espata caracteriza o processo de abertura e a redução da mesma indica a senescência pela murcha.

Information on post harvest conservation of calla lily is rare despite its commercial importance. This study was aimed at testing different conditioning solutions in order to increase inflorescence durability. The maintenance of calla lily stems on sodium hypochlorite (2 percent), citric acid (200mg L-1) and calcium chlorate (1000mg L-1) solutions was evaluated. The influence of a stem pre-storage immersion in Hidrosan® solution, as well as its use as a conditioning solution during storage in cold chamber was also evaluated. Inflorescences were daily evaluated for durability using an established classification criteria (classes A1, A2, B and C) and measurements of spathe length and width. Inflorescences treated with Hidrosan® or the maintenance of stems in this product or in any of the tested solutions showed no effect on calla lilyÆs inflorescences durability which presented a total longevity of eleven days. The different conditioning solutions evaluated had no effect on spathe length and width. Regardless the conditioning solutions, spathe width and length increased until the 7th and 8th days, respectively. Increase in spathe dimension characterizes the opening process and its reduction indicates senescence by wilting.