Consórcio couve-coentro em cultivo orgânico e sua influência nas populações de joaninhas.

O consórcio de culturas é comumente praticado na produção de hortaliças devido a diversos benefícios econômicos. Em alguns casos, podem reduzir infestações de pragas por favorecer a conservação dos inimigos naturais nos agroecossistemas. Avaliou-se a viabilidade agronômica do consórcio de couve e coentro, sob manejo orgânico, com base em parâmetros fitotécnicos, além de sua influência sobre populações de joaninhas (Coleoptera: Coccinellidae), na comparação com os respectivos cultivos solteiros. O coentro, representando a cultura secundária, foi utilizado com a finalidade de fornecer recursos para as joaninhas. O estudo foi realizado em área do Sistema Integrado de Produção Agroecológica em Seropédica-RJ. O experimento consistiu dos consórcios: 1) couve consorciada com coentro, cujas quatro linhas de plantas foram colhidas na fase vegetativa (consórcio I), e 2) couve consorciada com coentro, cujas plantas das duas linhas internas (próximas à linha da couve) foram colhidas na fase vegetativa e as duas linhas externas foram cortadas após floração (consórcio II). Em ambos consórcios foram avaliados os parâmetros fitotécnicos da couve e do coentro na fase vegetativa (padrão comercial), enquanto que no consórcio II, também se avaliou as populações de joaninhas, por meio de coletas semanais de adultos, em comparação com a couve em cultivo solteiro. O delineamento experimental foi em blocos ao acaso com quatro repetições. O coentro não interferiu na produtividade da couve consorciada e sua introdução contribuiu positivamente para a abundância e diversidade de espécies de joaninhas. O índice de equivalência de área para o consórcio I, com referência aos rendimentos de biomassa aérea fresca, foi superior em 92% em relação ao cultivo solteiro. Este resultado demonstra a viabilidade do consórcio I, no manejo orgânico adotado, para plantios de outono nas condições edafoclimáticas da Baixada Fluminense

Photosynthetic quantum efficiency in south‐eastern Amazonian trees may be already affected by climate change

Tropical forests are experiencing unprecedented high‐temperature conditions due to climate change that could limit their photosynthetic functions. We studied the high‐temperature sensitivity of photosynthesis in a rainforest site in southern Amazonia, where some of the highest temperatures and most rapid warming in the Tropics have been recorded. The quantum yield (F v /F m ) of photosystem II was measured in seven dominant tree species using leaf discs exposed to varying levels of heat stress. T 50 was calculated as the temperature at which F v /F m was half the maximum value. T 5 is defined as the breakpoint temperature, at which F v /F m decline was initiated. Leaf thermotolerance in the rapidly warming southern Amazonia was the highest recorded for forest tree species globally. T 50 and T 5 varied between species, with one mid‐storey species, Amaioua guianensis , exhibiting particularly high T 50 and T 5 values. While the T 50 values of the species sampled were several degrees above the maximum air temperatures experienced in southern Amazonia, the T 5 values of several species are now exceeded under present‐day maximum air temperatures

TRY plant trait database - enhanced coverage and open access

Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives