Production of arabica coffee in response to phosphate fertilization

Nos últimos anos surgiu uma corrente de pesquisadores indicando a necessidade de uso de doses elevadas de fósforo (P), visando melhorar a produtividade dos cafezais, e evitar o ciclo bienal de produção do cafeeiro. Diante dessa indicação torna-se necessário, avaliar e quantificar, em variadas condições de cafezais, a resposta a doses de P. O presente trabalho tem como objetivo, avaliar a influência da aplicação de doses e fontes de P2O5, sobre a produtividade do cafeeiro, teores de P lábeis do solo, os teores de P e dos outros nutrientes nas folhas, flores, casca e grãos de café. Para tanto foram realizados dois experimentos. O primeiro foi conduzido no período 2007 a 2010, na área Experimental da UFV em um cafezal da cultivar Oeiras, espaçado 2 x 1 m, que no inicio do experimento, estava com 4 anos de idade. As doses de 33, 83, 166, 333 e 666 kg de P2O5 ha-1, aplicadas na forma de fosfato mono potássico, constituíram o fator em estudo. Os tratamentos foram aplicados em quatro blocos casualizados sendo dispostas cinco plantas homogêneas e competitivas por parcela. A adubação fosfatada foi realizada em duas parcelas no período chuvoso. Nos tratamentos que receberam doses menores de P2O5, o potássio (K) foi suplementado com KCl, de modo a se fornecer a mesma dose de K para todos os tratamentos. Foram fornecidos 400 kg de nitrogênio (N) ha-1 na forma de uréia dividida em três parcelas e micro nutrientes via foliar. O segundo trabalho foi conduzido no período de outubro de 2009 a abril de 2011, em uma lavoura localizada no município de Porto Firme, MG. Foi utilizada uma lavoura de cultivar Paraíso, no espaçamento de 3,0 x 0,6 m, que no início do experimento, estava com dois anos de idade. O delineamento adotado foi em blocos casualisados com três repetições em esquema fatorial (4X2)+1 compreendendo 4 fontes P2O5: fosfato natural reativo (PNR), superfosfato simples (SS), superfosfato triplo (ST), fosfato monopotássico (FMK) em duas doses (80 e 320 kg de P2O5 ha-1). O tratamento adicional consistiu-se de ausência de P. Cada parcela experimental foi constituída por duas linhas de 5m, sendo as duas plantas centrais e uniformes de cada linha adotadas como úteis. A adubação fosfatada foi realizada de uma única vez, na face superior das plantas na projeção da copa. Nos tratamentos onde foram utilizadas fontes de P2O5 que não tinham K em sua formulação, e o tratamento de menor dose de P2O5 da fonte de FMK, o K foi suplementado com KCl, de modo a se fornecer a mesma dose de K para todos os tratamentos. Assim, na primeira parcela de adubação todos os tratamentos receberam 209 kg de K2O por hectare. Foram feitas mais duas adubações de 95,5 kg ha-¹ K2O na forma de KCl para todos os tratamentos. Foram fornecidos 400 Kg de N na forma de uréia divididos em três parcelas e micronutrientes via foliar. Avaliaram-se a produtividade, altura de planta (AP), emissão de ramos plagiotrópicos (ERP), números de internódios por ramo plagiotrópico (NIRP), teores de macro e micro nutrientes em folhas, cascas e frutos, e as características químicas do solo nas camadas de 0-20 e 20-40. Observou-se que não houve efeito significativo das diferentes doses de P nas variáveis: AP, ERP, NIRP nos dois experimentos. As análises de solo indicaram aumento significativo das concentrações de P no solo extraído pelos extratores Mehlinch-1 e Resina trocadora de cátions e ânions. No experimento 1, foi observado que a produtividade no primeiro ano de avaliação não apresentou diferença significativa entre as doses de P, mas nos últimos dois ciclos observou-se diferença, atingiu-se 90% da produtividade máxima com a dose de 113 kg ha-1 de P2O5, porém a máxima eficiência econômica foram obtidos com as doses de 322,7 kg ha-1 de P2O5, na safra de 2009 e de 341,66 kg ha-1 na safra de 2010. No experimento 2, não houve interação, quanto a produtividade, entre as fontes e as doses nos dois ciclos produtivos. Para doses de P2O5 não houve resposta significativa do cafeeiro com relação à produtividade. Na comparação dos tratamentos que receberam P com a testemunha, verificou-se que esse último tratamento apresentou produtividade média estatisticamente inferior. As fontes FMK, ST e SS apresentaram produtividades estatisticamente iguais, mas essas apresentaram produtividades estatisticamente superiores à fonte FNR. Esses resultados mostram a importância da adubação fosfatada, com fontes solúveis, para atender adequadamente as exigências nutricionais dos cafeeiros e alcançar produtividades desejadas. Maiores teores de P no solo foram obtidos com a aplicação de maiores doses de P2O5, sendo os valores médios extraídos pela resina mista maiores que os extraídos pelo extrator Mehlich 1.In recent years appeared a group of researchers that indicate high doses of phosphorus (P) aiming to improve the coffee productivity, and thus avoid the biennial cycle of production this crop. According this statement, become necessary to evaluate in different conditions of this crop the response of phosphorus doses when applied in the soil. This study aimed to evaluate the influence of application rates and sources of P2O5 on the coffee yield, content of labile P in the soil, as well as the levels of P and other nutrients in the leaves, flowers, bark and coffee grains. For this, two experiments were conducted in field conditions. The first assay was carried out in the period 2007 to 2010 at the experimental field of the UFV in an area with the Oeiras cultivar aged of 4 years old, with spacing of 2 x 1 m. Doses of 33, 83, 166, 333 and 666 kg of P2O5 per ha, applied as mono-potassium phosphate, represented the main factor studied. The treatments were applied in four randomized blocks being arranged five homogeneous plants per plot. Phosphorus fertilization was applied in two times during the rainy season. In the treatments with lower doses of P2O5, the potassium (K) was added as KCl, so as to provide the same amount of K for all treatments. The quantity of 400 kg ha-1 of nitrogen (N) per ha was provided as urea applied on three times as well as micronutrients through foliar spray. The second assay was conducted from October 2009 to April 2011 in a crop of coffee located in the country of Porto Firme, MG. In that experiment it was used the cultivar Paraíso aged two years old, spaced 3.0 x 0.6 m. The experimental design used was of randomized blocks with three replications in a factorial scheme (4 x 2) + 1 comprising four sources of phosphate as following: reactive natural phosphate (RNP), simple superphosphate (SS), triple superphosphate (TS), and potassium dihydrogen phosphate (PDP) in two doses (80 and 320 kg/ha of P2O5). The additional treatment consisted of the absence of phosphorus. Each plot was consisted of two rows of 5m, being the two central plants of each line adopted as useful area. Phosphorus fertlization was performed only once on the soil, on the canopy projection of the plants. In the treatments with sources of P2O5 and without K as well as treatment with lower doses of P2O5 (PDP), the K was supplemented with KCl, so as to provide the same amount of K in all treatments. Thus, in the first parcel of fertilization, all treatments received 209 kg ha-1 of K2O. In addition, were made two additional fertilization with 95.5 kg ha-1 of K2O per ha in all treatments, using KCl. The quantity 400 kg ha-1 of nitrogen (N) divided in three portions was provided as urea and applied on three times as well as micronutrients through foliar spray. It was evaluated the yield, plant height (PH), production of plagiotropic branches (PPB), number of internodes per plagiotropic branch (NIPB), content of macro and micro nutrients in the leaves, bark and fruits, as well as soil chemical characteristics at 0-20 and 20-40 of depth. There was no significant effect of the different doses of P tested in relation to the variables PH, PPB, EIPB in both assays. Soil analyses indicated significant increase in concentrations of P in the soil extracted by both the extractors: Mehlinch-1 and exchange resin of cations and anions. In experiment 1, it was observed that the productivity in the first year showed no significant difference between the P doses, but in the last two seasons it was observed significant difference for this parameter, reaching 90% of maximum yield with the dose of 113 kg ha-1 of P2O5. However, 90% of the maximum economic efficiency was obtained with doses of 322.7 kg ha-1 of P2O5 in 2009 and with 341.66 kg ha-1 of P2O5 in 2010. In experiment 2, there was no effeect interaction between sources and doses of phosphorus on the productivity in the two evaluated production seasons. Comparing the treatments that received P with the untreated plots, it was verified that this last treatment had significantly lower productivity. The sources PDP, TS and SS showed yields statistically similar, but these yields were statistically superior that observed with RNP. These results show the importance of fertilization with soluble phosphorus to achieve adequately the nutritional requirements of the coffee plants and get desired yields. Higher P levels in soil were obtained by applying greater doses of P2O5 and the average values extracted by the cations and anions exchange resin were higher than those obtaine by the Mehlich 1 extractor.Fundação de Amparo a Pesquisa do Estado de Minas Gerai

Somatic embryogenesis of Myrciaria aureana (Brazilian grape tree)

The aim of this research was to establish a long-term somatic embryogenic cultures that could be used for cryopreservation. For the induction of somatic embryogenesis, different levels of 2,4-D as well as the combination of 2,4-D and indole-3-acetyl-l-aspartic acid (IASP) were tested on cotyledons of zygotic embryos. The somatic embryogenic cultures were established and maintained up to 2 years through frequent subculturing on a medium containing 2,4D + IASP. Light, activated charcoal, and polyethylene glycol (PEG) were tested for the regeneration and maturation of somatic embryos, and the mature embryos were germinated in JADS medium. The combination of light and PEG provided the highest number of mature embryos. The somatic embryos obtained were smaller than zygotic embryos and lacked starch. There was an interaction between 2,4-D and IASP on the induction and regeneration of somatic embryo in Myrciaria aureana. The combination of light and PEG increased the number of mature embryos; however, charcoal was detrimental to the process

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