Osmolaridade e taxa de diluição na ativação do sêmen criopreservado de prochilodus lineatus

The objective of this work was to evaluate the influence of activators with different osmolarities and dilution rate in the activation of cryopreserved semen of curimba (Prochilodus lineatus). We used four breeding males captured in the Fish- farming Station of CEMIG, Itutinga, MG. Semen samples were diluted in two solutions (DMSO + methanol and lactose + lactose) at 1:4 ratio and frozen. The rates (%) and duration (s) of sperm motility for treatments were assessed. Activators with respective osmolarities: 30, 99, 183 and 293 mOsm at dilution rates of 1:2, 1:4, 1:6, 1:8 (semen: activator) were used. The dilution rates of 1:2 and 1:8 influenced duration of motility in semen cryopreserved with DMSO. For the 1:2 dilution, the semen activated with the activator containing 30 mOsm, presented greater motility duration than semen activated with activators with 183 and 293 mOsm. However, for the activator with 30 mOsm, it was obtained longer motility duration at a dilution of 1:2 compared to 1:4 dilution. At 1:6 dilution rate, when the semen was activated with the activator 30 mOsm, the motility rate was higher than that provided by the semen that was activated with 293 mOsm. At the dilution rate of 1:8, the use of activator containing 99 mOsm showed longer motility duration in relation to use of the activator with 293 mOsm. Activators containing high osmolarities can provide lower rates and duration of motility in semen of curimba (Prochilodus lineatus) cryopreserved with cryoprotectants methanol or DMSO.Objetivou-se avaliar a influência de ativadores com diferentes osmolaridades e taxa de diluição na ativação de sêmen criopreservado de curimba (Prochilodus lineatus). Foram utilizados quatro reprodutores machos capturados na Estação de Piscicultura da CEMIG, Itutinga, MG. As amostras de sêmen foram diluídas em duas soluções (DMSO + lactose e metanol + lactose) na proporção de 1:4 e congeladas. Foram avaliadas as taxas (%) e duração (s) da motilidade espermática dos tratamentos. Na ativação foram utilizados ativadores contendo as respectivas osmolarida- des: 30, 99, 183 e 293 mOsm nas taxas de diluição de 1:2, 1:4, 1:6, 1:8 sêmen: ativador. A taxa de diluição 1:2 e 1:8 foram estatisticamente significa- tivas para duração da motilidade para o sêmen criopreservado com DMSO. Para a diluição 1:2, o sêmen ativado com o ativador contendo 30 mOsm, apresentou duração de motilidade maior em relação ao sêmen ativado com ativadores com 183 e 293 mOsm. No entanto, para a utilização do ativador com 30 mOsm, se obteve maior duração da motilidade na diluição de 1:2 em relação a diluição de 1:4. Na taxa de diluição 1:6, quando o sêmen foi ativado com o ativador de 30 mOsm, a taxa de motilidade foi superior à apresentada pelo sêmen que foi ativado com 293 mOsm. Na taxa de diluição de 1:8, o uso de ativador contendo 99 mOsm apresentou maior duração de motilidade em relação ao uso do ativador com 293 mOsm. Ativadores contendo altas osmolaridades podem proporcio- nar menores taxas e duração da motilidade em sêmen de curimba (Prochilodus lineatus) crio- preservado com os crioprotetores metanol ou DMSO

Carbono e nitrogênio de um Argissolo Vermelho sob floresta, pastagem e mata nativa Carbon and nitrogen of an Alfisol under forest, pasture and native forest

O monitoramento da matéria orgânica do solo (MOS) constitui um indicador da qualidade do sistema de uso adotado. No Sul do Brasil, são escassos os trabalhos que avaliam as alterações no carbono orgânico total (COT), nitrogênio total (NT) e a labilidade da MOS em sistemas de produção florestal. Diante desse contexto, este estudo teve como objetivo avaliar a concentração de COT e de NT no solo e na fração leve e livre (FLL) da MOS de um Argissolo Vermelho distrófico sob eucalipto após 13 e 20 anos de implantação, adotando-se a mata nativa e um sistema com produção de pastagem como áreas de referência. Além disso, foi quantificado o estoque de COT e de NT na serrapilheira e na liteira das áreas florestais. As avaliações foram feitas, aleatoriamente, em três trincheiras por área, nas camadas de 0,00 a 0,05; 0,05 a 0,10; 0,10 a 0,20 e 0,20 a 0,40m. Maiores concentrações de COT, de NT e da FLL foram verificadas na camada superficial, sendo estas favorecidas pela adição de resíduos vegetais e pela minimização das operações de revolvimento do solo.<br>The monitoring of soil organic matter content (MOS) has been considered soil quality indicator. Few studies, in Southern Brazil, have evaluated changes in the total organic carbon (COT), total nitrogen (NT) and in the lability of MOS in forestry systems. This study aimed to evaluate the COT, NT and free light fraction of MOS from 0.00 to 0.05, 0.05 to 0.10, 0.10 to 0.20 and 0.20 to 0.40m depths of the Alfisol under eucalyptus, native forest and pasture. In addition, it was quantified the stock of COT and NT in plant residues in forestry areas. The concentration of COT and NT and labile fractions of MOS increased favored by the addition of vegetables residues and by minimizing soil disturbance

Brazilian Flora 2020: Leveraging the power of a collaborative scientific network

International audienceThe shortage of reliable primary taxonomic data limits the description of biological taxa and the understanding of biodiversity patterns and processes, complicating biogeographical, ecological, and evolutionary studies. This deficit creates a significant taxonomic impediment to biodiversity research and conservation planning. The taxonomic impediment and the biodiversity crisis are widely recognized, highlighting the urgent need for reliable taxonomic data. Over the past decade, numerous countries worldwide have devoted considerable effort to Target 1 of the Global Strategy for Plant Conservation (GSPC), which called for the preparation of a working list of all known plant species by 2010 and an online world Flora by 2020. Brazil is a megadiverse country, home to more of the world's known plant species than any other country. Despite that, Flora Brasiliensis, concluded in 1906, was the last comprehensive treatment of the Brazilian flora. The lack of accurate estimates of the number of species of algae, fungi, and plants occurring in Brazil contributes to the prevailing taxonomic impediment and delays progress towards the GSPC targets. Over the past 12 years, a legion of taxonomists motivated to meet Target 1 of the GSPC, worked together to gather and integrate knowledge on the algal, plant, and fungal diversity of Brazil. Overall, a team of about 980 taxonomists joined efforts in a highly collaborative project that used cybertaxonomy to prepare an updated Flora of Brazil, showing the power of scientific collaboration to reach ambitious goals. This paper presents an overview of the Brazilian Flora 2020 and provides taxonomic and spatial updates on the algae, fungi, and plants found in one of the world's most biodiverse countries. We further identify collection gaps and summarize future goals that extend beyond 2020. Our results show that Brazil is home to 46,975 native species of algae, fungi, and plants, of which 19,669 are endemic to the country. The data compiled to date suggests that the Atlantic Rainforest might be the most diverse Brazilian domain for all plant groups except gymnosperms, which are most diverse in the Amazon. However, scientific knowledge of Brazilian diversity is still unequally distributed, with the Atlantic Rainforest and the Cerrado being the most intensively sampled and studied biomes in the country. In times of “scientific reductionism”, with botanical and mycological sciences suffering pervasive depreciation in recent decades, the first online Flora of Brazil 2020 significantly enhanced the quality and quantity of taxonomic data available for algae, fungi, and plants from Brazil. This project also made all the information freely available online, providing a firm foundation for future research and for the management, conservation, and sustainable use of the Brazilian funga and flora