Variabilidade sazonal da condutância estomática em um ecossistema de manguezal amazônico e suas relações com variáveis meteorológicas

Rodrigues, Hernani José Brazão; Costa, Rafael; Ribeiro, João Batista; Filho, José Danilo da Costa Souza; Ruivo, Maria de Lourdes Pinheiro; Silva, João de Athaydes

doi:10.1590/s0102-77862011000200003

Cited by 14 publications

(18 citation statements)

References 14 publications

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“…Silva et al (2010) The PI 189 accession had the lowest mean value for net CO 2 assimilation and stomatal conductance ( Figures 1 and 2). These results are correlated, since stomatal conductance is directly related to the net rate of CO 2 assimilation, as low values may be associated with partial stomatal closure, reducing CO 2 entry to the rubisco carboxylation sites, thereby reducing net photosynthesis (DALLAGNOL et al, 2011;RODRIGUES, et al, 2011). Similar values for stomatal conductance of around 0.316 to 0.420 mol m -2 s -1 were reported by Silva et al (2010) The accessions showed no significant difference for internal CO 2 concentration (Figure 3).…”

Section: Resultssupporting

confidence: 59%

Photosynthetic characteristics in fig tree accessions for diversification of production

Ferreira

Rodrigues²,

Lisboa³

et al. 2019

AGRO@MBIENTE ON-LINE

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Photosynthesis allows plants, through metabolic reactions, to obtain products for their growth and development. Knowledge of and estimating the physiological variables involved in the photosynthetic process can be an advantage in choosing accessions for setting up an orchard. The aim of this study therefore was to evaluate some of the physiological characteristics involved in the photosynthetic process of six commercial accessions of the fig tree. The experiment was conducted in a completely randomised design, comprising six treatments and six replications, giving a total of 36 experimental units. The treatments consisted of the following fig accessions: ‘Roxo de Valinhos’, ‘Palestino’, ‘Figo Vermelho’, ‘PI 189’, ‘Cuello Negro’ and ‘Turco’. The net rate of CO2 assimilation, stomatal conductance, transpiration rate and internal leaf temperature varied statistically between accessions. Some accessions demonstrated the same performance as ‘Roxo de Valinhos’ for the photosynthetic variables. As such, the dependence of the domestic market on one single cultivar should be reviewed; however, further studies on other physiological and production characteristics should be carried out in order to validate each recommendation.

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Section: Resultssupporting

confidence: 59%

Photosynthetic characteristics in fig tree accessions for diversification of production

Ferreira

Rodrigues²,

Lisboa³

et al. 2019

AGRO@MBIENTE ON-LINE

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“…The VPD was calculated from the Tetens equation (Rodrigues et al, 2011;Vianello & Alves, 2012), which is obtained by the difference between saturation vapor pressure (e s ) and actual vapor pressure (e). To calculate the e s it was taken into consideration the air temperature value, according to the Eq.…”

Section: Methodsmentioning

confidence: 99%

“…The saturation vapor pressure depends on air temperature and as it increases, higher is the saturation vapor pressure. The actual vapor pressure depends on air relative humidity along with the saturation vapor pressure, and it increases increasing the relative humidity (Rodrigues et al, 2011;Vianello & Alves, 2012).…”

Section: Introductionmentioning

confidence: 99%

Sprayed liquid loss due to evaporation in different psychrometric conditions

Maciel

Teixeira

Zolnier

et al. 2017

Agraria

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Low relative humidity and high air temperature are favorable conditions for droplet evaporation, and this may cause financial losses for the farmer due to poor pest control, and also cause environmental contamination. Thus, the aim of this work was to evaluate the effect of temperature and relative humidity on pesticides spraying, and to estimate the spraying losses by evaporation depending on air psychrometric conditions. The experiment was carried out inside of a climate chamber to control the temperature and relative humidity, and thus to obtain different vapor pressure deficits. This study used the nozzle Lurmark LD11002 operating at the pressure of 300 kPa and the liquid was tap water. The loss by evaporation was studied in a completely randomized design with twenty vapor pressure deficits and three replications. Even obeying the recommendations of climatic conditions for pesticides application, there are losses of liquid due to evaporation. For the nozzle LD 11002 and working pressure of 300 kPa, the loss of pesticides due to evaporation can reach about 27% under weather conditions characterized by low wind velocity, high air temperature and low relative humidity.Key words: application technology; droplet evaporation; evaporation losses; spraying Perda de líquido pulverizado por evaporação em diferentes condições psicrométricas RESUMOBaixas umidades relativas e altas temperaturas do ar são condições propícias à evaporação de gotas, e esta, além de causar grande prejuízo ao agricultor devido a um deficiente controle fitossanitário, também pode contaminar o ambiente. Deste modo, objetivou-se com este trabalho avaliar os efeitos da temperatura e umidade relativa na pulverização de agrotóxicos e estimar a perda da pulverização por evaporação em função das condições psicrométricas do ar. O experimento foi realizado dentro de uma câmara climática para controle da temperatura e umidade relativa e, assim, obtenção de diferentes déficits de pressão de saturação de vapor d'água no ar (DPV). Este estudo utilizou uma ponta Lurmark LD11002 operando na pressão de 300 kPa e o líquido foi água. A perda estimada de líquido por evaporação foi montada em delineamento inteiramente casualizado com vinte déficits de pressão de vapor e três repetições. Mesmo obedecendo às condições climáticas recomendadas para uma aplicação de agrotóxicos segura, houve perda de líquido pulverizado por evaporação. Para a ponta LD 11002 e pressão de trabalho de 300 kPa, a perda de agrotóxicos por evaporação pode alcançar aproximadamente 27% sob condições meteorológicas caracterizadas por baixa velocidade do vento, alta temperatura e baixa umidade relativa do ar.Palavras-chave: tecnologia de aplicação; evaporação de gotas; perdas por evaporação; pulverização

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“…The vapor pressure deficit (VPD) was obtained from the Equation 1: The saturated vapor pressure (e s ) was calculated using the psychrometric chart available at http://physics.holsoft.nl/physics/ ocmain.htm. The partial vapor pressure (e a ) was obtained according to Rodrigues et al (2011) …”

Section: Methodsmentioning

confidence: 99%

Efficiency of cover materials in preventing evaporation in drought-stressed soybeans grown in pots

Ferreira¹,

Neiverth²,

Maronezzi³

et al. 2015

RCA

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ABSTRACT:There are few studies in the specific literature on the use of cover materials to control evaporation in drought-stressed plants grown in pots under greenhouse conditions. The use of these materials is of great importance to ensure that water loss occurs only through transpiration. Thus this study aimed to investigate the efficiency of different cover materials -polyethylene, marble, polystyrene, and polyvinyl chloride (PVC) -in controlling evaporation in black and in silver pots cultivated with the soybean cultivar BR 16 and subjected to drought under greenhouse conditions. The plants were kept at 100% field capacity until they reached the V 3 stage. The different cover materials were then applied to the substrate surface, irrigation was suspended, and the plants were evaluated with regard to water loss and temperature of leaf and substrate for nine consecutive days. The experiment was repeated without plants to assess evaporation. Substrate water potential was measured on the last day in both experiments. Although all the cover materials showed uniformity between the replicates with respect to water loss, polyethylene and PVC presented higher substrate water potential and leaf turgor after nine days of suspended irrigation; however, PVC led to soil compactions, restricting its use. Therefore, among the materials tested, polyethylene is the most suitable to control evaporation in pots cultivated with soybean plants subjected to drought, with no influence of pot color. (Oya et al., 2004;Stolf et al., 2009). The effect of the external color of pots -black or silver -was also investigated with respect to water loss through evaporation. RESUMO: Materials and MethodsThe experiments were conducted under greenhouse conditions. Soybean cultivar BR 16 seeds were previously treated with carboxin + thiram (200 g L -1 ) and phypronyl (250 g L -1 ) and then allowed to germinate for 96 h at 25 °C on Germitest  paper moistened with water (2.5-fold volume relative to the weight of the dry paper) (Brasil, 2009). Thereafter, the seedlings were inoculated with Bradyrhyzobium japonicum (Nitro-Super F-45 Premium  ) and planted in 1 L pots (dimensions: 15 cm external diameter × 10 cm base × 11 cm height) filled with substrate (soil/sand/organic compounds, 3:2:2), so that each pot contained one seedling. The greenhouse temperature was set at 28 ± 1 °C, with cooling system actuation when temperature reached 29 °C, and heating system actuation when temperature reached values below 16 °C. The internal temperature and relative humidity (RH) were recorded in a thermohygrograph (Hobo U14-002, Onset  ) every 5 min. The vapor pressure deficit (VPD) was obtained from the Equation 1: The saturated vapor pressure (e s ) was calculated using the psychrometric chart available at http://physics.holsoft.nl/physics/ ocmain.htm. The partial vapor pressure (e a ) was obtained according to Rodrigues et al. (2011) from the Equation 2:s a RH 100x e e = (2)The experimental design was completely randomized with a 2 × 5 (pot color × cover mate...

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Variabilidade sazonal da condutância estomática em um ecossistema de manguezal amazônico e suas relações com variáveis meteorológicas

Cited by 14 publications

References 14 publications

Photosynthetic characteristics in fig tree accessions for diversification of production

Photosynthetic characteristics in fig tree accessions for diversification of production

Sprayed liquid loss due to evaporation in different psychrometric conditions

Efficiency of cover materials in preventing evaporation in drought-stressed soybeans grown in pots

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