Responses in growth and dynamics of the shade-tolerant species Theobroma subincanumto logging gaps in the Eastern Amazon.

Aim of study: To assess responses of the shade-tolerant species Theobroma subincanum in relation to canopy gaps created by reduced impact logging (RIL). Materials and methods: A managed forest in themunicipality ofMoju, Pará state,Brazil, harvested in 1997 through RIL was monitored during 12 years (1998-2010). Nine logging gaps were selected and classified in small, medium, and large. Four 10 m x 50 m strips starting from the gap?s border towards the forest and following the directions of cardinal points were installed. Each strip was divided in five 10 m x 10 m plots. Density, diameter distribution (DBH ≥ 5 cm with intervals = 5 cm), and diameter growth were measured. Main results: No significant changes in seedling density of T. subincanum were found, and its diameter distribution followed the reverse ?J? shape during all monitoring time. T. subincanum presented diameter growth of 0.15 cm year-1 with highest Periodic Annual Increment in diameter up to three years, and stabilization in nine years after RIL. The species responded to a growth gradient inversely proportional to the gap?s border distance (p = 0.001) but not to gap size and plots direction in cardinal points around the gap. Research highlights: Shade-tolerant species such as T. subincanum have sensible and positive growth responses to disturbances caused by RIL even when seedlings received low amounts of indirect sunlight. These positive responses should be considered in the management of production forests

Edaphoclimatic and genetic influence on soil water availability factor for different sugarcane varieties.

Sugarcane is grown in all Brazilian states; however, water stress is the main limiting factor of crop productivity in most farming environments (FEN). Thus, the objective was to verify the water availability factor in the soil (factor f) between FEN and sugarcane varieties. The assay was conducted in the Central and Southern Regions of Goiano, in Red Latosol with distinct physical-water attributes among the FEN

How to enhance the agronomic performance of cactus-sorghum intercropped system: planting configurations, density and orientation.

Clarifying cultivation techniques and making production systems more efficient are practices that have been much sought after in agricultural systems in recent decades. In this context, the forage yield, biological efficiency, and competitive ability, of different cultivation strategies for intercropping forage cactus and sorghum were determined in biosaline production systems from 2018 to 2020 in Brazil. Four experiments were carried out, comprising: 1) cropping configurations for the forage cactus-sorghum intercropping system; 2 and 3) planting densities for the forage cactus intercropped with sorghum with an east-west and north-south row orientation, respectively; and 4) planting densities for the forage cactus and sorghum. Each experiment used a randomised block design with four replications. The intercropped forage cactus and sorghum showed higher productivity than the monocropped systems. The indices of biological efficiency (LER, ATER, LEC and SPI with mean values equal to 1.6, 1.8, 0.6 and 29.0, respectively) and competitive ability (ALGY in average 870.6) show better performance under the intercropped system compared to the single crops. The increased planting density resulted in an increase in productivity under the intercropped forage cactus-sorghum system (on average an increase of 69.4% dry matter). In turn, the orientation had no influence on the productivity of the intercropping system but offered better conditions for the forage cactus when cultivation was in an east-west direction (21.7 Mg ha􀀀 1 of dry matter) compared to north-south (17.5 Mg ha􀀀 1 of dry matter). Intercropping forage cactus and sorghum using biosaline agriculture is an excellent alternative for a production system in semi-arid environments, especially at higher planting densities (50,000 and 100,000 plants ha􀀀 1)

Lineage tracing of acute myeloid leukemia reveals the impact of hypomethylating agents on chemoresistance selection

Chemotherapy-resistant cancer recurrence is a major cause of mortality. In acute myeloid leukemia (AML), chemorefractory relapses result from the complex interplay between altered genetic, epigenetic and transcriptional states in leukemic cells. Here, we develop an experimental model system using in vitro lineage tracing coupled with exome, transcriptome and in vivo functional readouts to assess the AML population dynamics and associated molecular determinants underpinning chemoresistance development. We find that combining standard chemotherapeutic regimens with low doses of DNA methyltransferase inhibitors (DNMTi, hypomethylating drugs) prevents chemoresistant relapses. Mechanistically, DNMTi suppresses the outgrowth of a pre-determined set of chemoresistant AML clones with stemness properties, instead favoring the expansion of rarer and unfit chemosensitive clones. Importantly, we confirm the capacity of DNMTi combination to suppress stemness-dependent chemoresistance development in xenotransplantation models and primary AML patient samples. Together, these results support the potential of DNMTi combination treatment to circumvent the development of chemorefractory AML relapses

Monitoring energy balance, turbulent flux partitioning, evapotranspiration and biophysical parameters of Nopalea cochenillifera (Cactaceae) in the Brazilian Semi-Arid environment.

The in-situ quantification of turbulent flux and evapotranspiration (ET) is necessary to monitor crop performance in stressful environments. Although cacti can withstand stressful conditions, plant responses and plant?environment interactions remain unclear. Hence, the objective of our study was to investigate the interannual and seasonal behaviour of components of the surface energy balance, environmental conditions, morphophysiological parameters, biomass yield and water relations in a crop of Nopalea cochenillifera in the semi-arid region of Brazil. The data were collected from a micrometeorological tower between 2015 and 2017. The results demonstrate that net radiation was significantly higher during the wet season. Latent heat flux was not significant between the wet season and dry season. During the dry-wet transition season in particular, sensible heat flux was higher than during the other seasons. We observed a large decline in soil heat flux during the wet season. There was no difference in ET during the wet or dry seasons; however, there was a 40% reduction during the dry-wet transition. The wet seasons and wet-dry transition showed the lowest Evaporative Stress Index. The plants showed high cladode water content and biomass during the evaluation period. In conclusion, these findings indicate high rates of growth, high biomass and a high cladode water content and explain the response of the cactus regarding energy partitioning and ET

Avanço da agrometeorologia da palma forrageira: radiação fotossinteticamente ativa interceptada e absorvida pela cultura.

Resumo: A palma é a cactácea forrageira mais cultivada no mundo, todavia, ainda negligenciada do ponto de vista de mudanças do uso da terra. A interação de uma superfície e a atmosfera varia com o tipo de interface (solo-planta-clima). Para este tipo de inferência, a radiação fotossinteticamente ativa interceptada ou absorvida é mundialmente usada. Pouco se dispõem de dados de interceptação ou absorção de radiação pela palma. Neste estudo, objetivou-se mensurar a fração e a quantidade de radiação fotossinteticamente interceptada e absorvida por esta espécie ao longo do ciclo. O experimento foi conduzido no município de Serra Talhada, PE, em uma área de 1,1 hectare de palma. Medidas de radiação solar global incidente e refletida, radiação fotossinteticamente ativa acima e abaixo da cultura, dados meteorológicos de uma estação do Instituto Nacional de Meteorologia e de índice de área do cladódio (IAC) foram usados nesta pesquisa. Equações foram geradas utilizando como variável independente o tempo térmico (TT, oC dia). Observou-se três fases de acúmulo de radiação interceptada e absorvida pela palma, em resposta ao incremento do IAC. Ao final de 482 dias, a palma interceptou 1902 MJ m-2 dos quais 1461 MJ m-2 foram absorvidos, correspondendo a 73% e 62% da radiação fotossinteticamente incidente acima da cultura, nesta ordem. Esta informação é essencial para o avanço da pesquisa de modelagem da palma forrageira