Regulation of Water Loss by Citrus Leaves

Hall, Anthony E.; Camacho-B, Saul E.; Kaufmann, Merrill R.

doi:10.1111/j.1399-3054.1975.tb03766.x

Cited by 60 publications

(32 citation statements)

References 9 publications

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“…Lange et al (16) have proposed that the mechanism may involve "peristomatal transpiration," in which case the appropriate humidity parameter would be the humidity gradient between leaf and air since this represents the driving force for water vapor loss through the cuticle of the guard cells. The parameter used in these and other studies (3,11,23,24), the humidity difference between leaf and air, is just a more convenient measure of the humidity gradient. Guard cells may respond directly to changes in relative humidity through effects on the elasticity of the guard cell walls.…”

Section: Discussionmentioning

confidence: 99%

Stomatal Response to Environment with Sesamum indicum. L.

Hall

Kaufmann²

1975

Plant Physiol.

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Leaf resistance of Sesamum indicurn L. increased when the humidity gradient between leaf and air was increased, at moderate temperatures, even though calculated carbon dioxide concentrations within the leaf decreased slightly. Mesophyll resistance remained relatively constant when humidity gradients were changed, indicating that the increases in leaf resistance were mainly caused by reductions in stomatal aperture and that nonstomatal aspects of photosynthesis and respiration were not affected. Low carbon dioxide concentrations inside the leaf decreased but did not eliminate resistance response to the humidity gradient. Internal carbon dioxide concentrations had little effect on resistance in humid air but had moderate effects on resistance with large humidity gradients between leaf and air. Stomatal response to humidity was not present at high leaf temperatures. Effects of humidity gradients on photosynthetic and stomatal responses to temperature suggested that large humidity gradients may contribute to mid-day closure of stomata and depressions in photosynthesis.The adaptation of plants to arid environments should be influenced by stomatal response to environment since optimal stomatal apertures would vary with changes in evaporative demand and with the changes in climate that influence net photosynthesis and the thermal balance of the plant. It is also probable that optimal stomatal apertures would depend upon phenotypic attributes such as heat tolerance and intrinsic photosynthetic capabilities, and upon the adaptive strategy of the plant (e.g., whether rapid growth or water use efficiency is more important).It has been suggested that stomata respond to several environmental parameters including radiation, internal CO2 concentrations, humidity gradients, and temperature. Interactions between these parameters are poorly understood and the control mechanisms for stomatal response are subject to controversy. Negative feedback relationships between leaf water status and stomatal aperture (4,21) (1,2,6,9,15,20). It has also been proposed that stomata may respond to the humidity gradient between leaf and air independently of effects 'This work was supported by National Science Foundation Grant GB 39856 to M. R. K.caused by changes in bulk leaf water status (3,12,16,23). This response system would provide an adaptive advantage in arid environments because it could prevent the development of water stress in the metabolically active cells within the leaf (23), and because it would promote the efficient use of water by plants (12). It has been suggested that stomata do not respond directly to humidity (18,22,28). Stomatal response to temperature is also a controversial subject with reports of stomata opening, closing, or not being affected by increases in temperature (1 8, 24). Stomatal response to temperature is important in relation to the maintenance of evaporative cooling and net photosynthesis, and to the avoidance of desiccation in hot, dry climates.The extent to which internal [CO,], humidity gradients,...

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Section: Discussionmentioning

confidence: 99%

Stomatal Response to Environment with Sesamum indicum. L.

Hall

Kaufmann²

1975

Plant Physiol.

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“…o C e 25 o C (Kriedmann, 1971;Hall et al, 1975;Khairi & Hall, 1976;Habermann, 1999). A redução na taxa de fotossíntese com o aumento do DPV ar e da temperatura está relacionada, respectivamente, com a queda da condutância total da folha e da condutância do mesófilo (Khairi & Hall, 1976;Machado et al, 1994;Medina et al, 1998Medina et al, , 1999.…”

Section: Resultados E Discussão Climaunclassified

Variação sazonal da fotossíntese, condutância estomática e potencial da água na folha de laranjeira 'Valência'

Machado¹,

Medina

Gomes

et al. 2002

Sci. agric. (Piracicaba, Braz.)

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*Autor correspondente RESUMO: Em espécies perenes podem ocorrer variações nas taxas de trocas gasosas e nas relações hídricas em função da variação das condições ambientais, durante os diferentes meses do ano. Avaliaram-se, em laranjeira ´Valência´ enxertada sobre quatro espécies de porta-enxerto, mantida sem deficiência hídrica, as taxas de fotossíntese (A) e de transpiração (E), a condutância estomática (g) e o potencial da água na folha (Ψ Ψ Ψ Ψ Ψ f ), medidos nos períodos da manhã (9h00 às 11h00) e da tarde (13h00 às 15h00) nos meses de janeiro, março e julho em Campinas -SP. As espécies de porta-enxertos não tiveram efeitos sobre as variáveis medidas. Independente do porta-enxerto A, g e Ψ Ψ Ψ Ψ Ψ f foram menores no período da tarde. A queda de A deve estar relacionada com a queda de g que diminuiu em resposta ao aumento do déficit de pressão de vapor entre o ar e a folha (DPV ar-folha ) nos horários mais quentes do dia. Apesar de ocorrer fechamento parcial dos estômatos no período da tarde E foi similar ao período da manhã, devido ao aumento do DPV ar-folha . Também observou-se queda em A e em g no sentido de janeiro para julho. Sugere-se que a queda em A e em g ocorrida em março em comparação a janeiro esteja relacionada à queda da atividade de crescimento da planta, afetando as relações fonte-dreno, visto que as condições ambientais nestes dois meses foram semelhantes. As quedas de A e de g observadas em julho, em relação à janeiro e março, parecem estar relacionadas tanto à queda na temperatura noturna quanto à queda na atividade de crescimento. Palavras-chave: Citrus sinensis, trocas gasosas, transpiração, crescimento SEASONAL VARIATION OF PHOTOSYNTHETIC RATES, STOMATAL CONDUCTANCE AND LEAF WATER POTENTIAL IN 'VALENCIA' ORANGE TREESABSTRACT: Seasonal variation in environmental conditions may influence gas exchange rates as well as water relations in perennial species. This work was carried out to evaluate photosynthetic rates (A), transpiration (E), stomatal conductance (g) and leaf water potential (Ψ Ψ Ψ Ψ Ψ f ) in 'Valencia' orange trees grafted on four different rootstocks. Measurements were made twice a day: from 9h00 to 11h00 a.m. and from 1h00 to 3h00 p.m., during January, March and July. A and g were significantly lower and Ψ Ψ Ψ Ψ Ψ f was significantly more negative, in the afternoon. The decrease in A may be related to the reduction in g, due to the increase in the vapor pressure deficit between the air and the leaf (VPD air-leaf ) in the afternoon, when temperatures are higher. In spite of the partial stomatal closure in the afternoon, the values for E were approximately the same as those measured in the morning, due to the increase in the VPD air-leaf . A decrease in A and g could also be noted from January to July, that is, from the hot and humid summer months, to the colder and drier winter ones. It was suggested that the decrease in A and g observed from January through March, may be related to the decrease in plant growth rates, which could have influenced the sourc...

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“…The high leaf resistance to water vapor diffusion in citrus becomes a limiting factor for transpiration, giving plants similar maximal values in highly contrasting regions in terms of atmospheric demand. Besides the characteristics of high resistance to water vapor diffusion, citrus have some sort of adaptive response, when exposed to high atmospheric demand for a certain period (Hall et al, 1975;Syvertsen and Lloyd, 1994). Girardi et al (2010) observed in citrus trees that there was temporary reduction in sap flow in periods of maximum water stress, usually observed at noon, which can be attributed possibly to stomatal closure.…”

Section: Transpirationmentioning

confidence: 99%

Effect of partial soil wetting on transpiration, vegetative growth and root system of young orange trees

Vellame

Júnior

Coelho

2015

Sci. agric. (Piracicaba, Braz.)

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The wetted area fraction is a factor critical to the success of drip irrigation. This study aimed to evaluate the effect of partial soil wetting on transpiration, vegetative growth and root system of young orange trees. The experiment was carried out in a greenhouse where plants were grown in 0.5 m 3 boxes internally divided into compartments. The wetting of 12 % of soil area was tested on two types of soil cultivated with 'Valencia' orange trees grafted onto Rangpur lime and 'Swingle' citrumelo rootstocks. Transpiration was determined in 40 plants. Water extraction and root density were evaluated in the compartments. Transpiration is reduced by restriction in wetted soil area, and such reduction is influenced by the number of days after the beginning of partial irrigation, atmospheric evaporative demand and plant phenological stage.Mean transpiration of plants with partial irrigation was equivalent to 84 % of the mean transpiration of plants with 100 % of wetted soil area in the period studied. However, after 156 days of imposing partial irrigation there was no difference in transpiration between treatments. Plant acclimation was caused by an increase in root concentration in the irrigated area. After a period of acclimation, if the entire root system is wetted, soil water extraction becomes proportional to the percentage of wetted area after a short period of time. Despite the reduction in transpiration, there was no difference between treatments with 12 % and 100 % of wetted soil area in terms of vegetative growth.

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Regulation of Water Loss by Citrus Leaves

Cited by 60 publications

References 9 publications

Stomatal Response to Environment with Sesamum indicum. L.

Stomatal Response to Environment with Sesamum indicum. L.

Variação sazonal da fotossíntese, condutância estomática e potencial da água na folha de laranjeira 'Valência'

Effect of partial soil wetting on transpiration, vegetative growth and root system of young orange trees

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