Atmospheric evaporative demand and water deficit on the ecophysiology of Rubber seedlings

The search for genetic materials resistant to adverse weather conditions has been a major focus in studies on species of economic interest. The objective of the present study was to assess the growth and photosynthesis of rubber seedlings clones under two conditions of atmospheric evaporative demand, characterized by fluctuations in temperature (TEMP) and vapor pressure deficit (VPD), associated to two water regimens. Hevea brasiliensis Muell. Arg (RRIM 600 and FX 3864) clones were assessed in two microclimates, at low (TEMP 21.2 ºC and VPD 0.29 Kpa) and high (TEMP 26.9 ºC and VPD 1.49 Kpa) atmospheric evaporative demand, under two water regimens: water deficit and well-watered. Water deficit 50% water availability was sufficient to reduce the net CO2 assimilation rate, leaf area and total chlorophyll of the clones studied that impacted growth in both microclimates. The effects of water deficit on growth and net carbon assimilation rate were intensified under high atmospheric evaporative demand. However, when comparing the two clones studied, RRIM 600 showed greater growth and photosynthesis without water restriction. The FX 3864 clone, despite the high CO2 assimilation values under high atmospheric demand and without water restriction, showed a reduced growth. The results of this study form an important basis for the selection of genotypes with the potential to develop in adverse climatic conditions. In this sense, the RRIM 600 genotype is recommended as a promising material that would best adapt under adverse climatic conditions.

Delimitação de sítios ambientais homogêneos no Estado do Espírito Santo, com base no relevo, solo e clima / Definition of environmental sites in Espírito Santo state based on relief, soil and climate

Este trabalho teve como objetivo definir sítios ambientais homogêneos no Estado do Espírito Santo, a fim de indicar o uso potencial do solo de todo o seu território. Técnicas estatísticas multivariadas foram empregadas sobre informações do relevo, coordenadas geográficas, dados do solo e clima. A disponibilidade hídrica e a evapotranspiração real e potencial foram determinadas a partir do resultado do balanço hídrico climatológico. Inicialmente, foi executada a análise de componentes principais (ACP) sobre os dados climáticos e, em seguida, a de agrupamento nas informações do relevo, solo, nos escores climáticos provenientes da ACP e nas coordenadas geográficas. Os dois primeiros eixos da ACP explicam cerca de 85,3 por cento da variância total acumulada. Após a rotação dos componentes principais, as melhores variáveis correlacionadas ao primeiro eixo foram a amplitude térmica, a temperatura média anual, seguida da evapotranspiração real. Foram definidos seis sítios ambientais para o Estado do Espírito Santo e alguns apresentaram similaridades ao clima. As variáveis topográficas foram os fatores de maior influência na diferenciação dos sítios. A metodologia se mostrou adequada na definição dos sítios.

The objective of this study was to define homogeneous environmental sites in the state of Espírito Santo, Brazil which may possibly be used to indicate potential soil use for the entire state. Multivariate statistics techniques were employed using information of the relief and geographical coordinates, as well as soil and climatic data. Water availability and real and potential evapotranspiration were determined from the results of the climatological water balance. Initially a principal component analysis (PCA) for the climatological data was performed. Subsequently, a grouping analysis was executed on the relief, soil and climatic data provided by the PCA and geographical coordinates. The first two axes of the PCA define roughly 85.3 percent of the total accumulated variance. After rotation of the principal components, the variables that best correlated to the first axis were the thermal amplitude, average annual temperature, followed by real evapotranspiration. Six environmental sites were defined for the state of Espirito Santo, some presenting climatic similarities. The topographic variables were the factors of greatest influence on the sites differentiation. The methodology was appropriate in defining the sites.

Condições microclimáticas em cultivo de café conilon a pleno sol e arborizado com nogueira macadâmia / Microclimatic alterations in a conilon coffee crop grown shaded by macadamia nut tree

Medições microclimáticas (radiação fotossinteticamente ativa - RFA, temperatura do ar, umidade relativa do ar e velocidade do vento) foram realizadas em um cultivo de café Conilon (Coffea canephora Pierre) cultivado a pleno sol e arborizado com nogueira macadâmia (Macadamia integrifolia Maiden & Betche), no Município de São Mateus, Espírito Santo (ES) (18°43'S; 39°54'W; 39m), durante o período de setembro de 2008 a junho de 2009, com o objetivo de apresentar os efeitos do cultivo arborizado no microclima. Os resultados obtidos mostraram diferenças na transmissividade à RFA dentro do sistema arborizado em relação ao pleno sol, com variações de 18 a 88 por cento e de 17 a 87 por cento quando comparados em dois episódios de amostragem. A transmissividade média da RFA provocada pelas árvores de macadâmia variou de 65 a 59 por cento durante as duas épocas de amostragem. Com relação à velocidade do vento, ocorreu uma redução média de 72 por cento em sua incidência no cultivo arborizado. As diferenças na transmissividade de radiação e na incidência de ventos proporcionaram diferentes regimes de temperatura do ar e umidade relativa do ar, com maior efeito sobre os valores diurnos e no ponto de amostragem próximo ao renque de macadâmias, em que a média da temperatura máxima do ar foi até 2,2°C inferior ao cultivo a pleno sol.

Microclimatic measurements (photosynthetically active radiation - PAR, temperature and relative humidity of air and wind speed) were made in a Conilon coffee crop (Coffea canephora Pierre), grown in two different conditions: shaded by macadamia nut trees (Macadamia integrifolia Maiden & Betche) and unshaded. The experiment was carried out at Sâo Mateus, Espirito Santo State, Brazil (18°43'S; 39°54'W; 39m), between September 2008 and June 2009, aiming to show the effects of shading crop system into the microclimate. The obtained results had inside shown differences in the transmission of PAR in the shaded crop, with variations of 18 to 88 percent and 17 to 87 percent when compared the two sampling episodes . The average transmission of PAR caused by macadamia nut trees varied of 65 to 59 percent during the sampling episodes. The wind speed was reduced by 72 percent at the shaded crop. The differences in the transmission of PAR and the incidence of winds produced different values of temperature and relative humidity of the air with the greatest effect during day-light values period and at the sampling nearest point to macadamias nut trees, where the average maximum temperature was up to 2.2°C lower than the unshaded ones.