Efeito da temperatura radicular na resistência ao movimento de água no cacaueiro (Theobroma cacao L.)

Amorim, Solange Maria Costa de; Valle, Raúl René

doi:10.1590/S0102-33061992000100004

Resumos

O efeito da temperatura radicular na resistência ao movimento de água foi estudada em plântulas de cacau (Theobroma cacao L. cv. Catongo) sob condições de casa de vegetação e a temperaturas radiculares de 10, 20, 30 e 40ºC, em folhas cobertas com papel de alumínio e sacos de polieteileno preto e em folhas descobertas. As folhas estavdf am localizadas na parte basal, intermediária e apical do caule. Mediram-se trocas gasosas foliares utilizando o sistema portátil de fotossíntese LI-6000. O potencial hídrico e o osmótico foram mensurados por psicrometria. O potencial de turgor foi estimado por diferença entre o potencial hídrico e o osmótico. Os resultados obtidos sugerem que a resistência ao movimento de água nas plântulas de cacau depende do fluxo transpiracional e que a variação dos gradientes do potencial hídrico na planta é determinada por temperaturas radiculares maiores de 30ºC. As trocas gasosas, a temperaturas radiculares diferentes, dependem do estado hídrico da planta.

Cacau; resistência ao movimento de água; temperatura radicular

The effects of root temperature on water movement resistance were studied on cacao (Theobroma cacao L. cv Catongo) seedlings under greenhouse conditions at root temperatures of 10, 20 30 and 40ºC, on leaves covered with aluminum foil and black plastic bags and on uncovered leaves. The leaves were located at the base, intermediates part and apex of the stem. Gas exchange measurements were done utilizing a LI-6000 portable photosynthetic system. Water and osmotic potential were measured by psychrometry. Turgor potential was estimated as the difference between water potential and osmotic potential. The results suggested that the resistance to water movement depends on the transpirational flux and that the water potential gradients across the plant vary at temperatures greater than 30ºC. Gas exchanges, at diferent root temperature, depend on the water status of the plant.

Cacao; Resistance to water movement; Root temperature

Efeito da temperatura radicular na resistência ao movimento de água no cacaueiro (Theobroma cacao L.)^* * Trabalho apresentado no XLI Congresso Nacional de Botânica, Fortaleza - CE.

Radicular temperature effects in water movement resistence in cacao tree (Theobroma cacao L.)

Solange Maria Costa de Amorim^I; Raúl René Valle^II

^IBiologa, M.S. Profª. Inst. de Biol. UFBA, Salvador, BA. 40210

^IIEng. Agr. Ph.D. Pesquisador CEPLAC/CEPEC C.P. 07, Itabuna, Ba. 45600

RESUMO

O efeito da temperatura radicular na resistência ao movimento de água foi estudada em plântulas de cacau (Theobroma cacao L. cv. Catongo) sob condições de casa de vegetação e a temperaturas radiculares de 10, 20, 30 e 40ºC, em folhas cobertas com papel de alumínio e sacos de polieteileno preto e em folhas descobertas. As folhas estavdf am localizadas na parte basal, intermediária e apical do caule. Mediram-se trocas gasosas foliares utilizando o sistema portátil de fotossíntese LI-6000. O potencial hídrico e o osmótico foram mensurados por psicrometria. O potencial de turgor foi estimado por diferença entre o potencial hídrico e o osmótico. Os resultados obtidos sugerem que a resistência ao movimento de água nas plântulas de cacau depende do fluxo transpiracional e que a variação dos gradientes do potencial hídrico na planta é determinada por temperaturas radiculares maiores de 30ºC. As trocas gasosas, a temperaturas radiculares diferentes, dependem do estado hídrico da planta.

Palavras-chave: Cacau, resistência ao movimento de água, temperatura radicular

ABSTRACT

The effects of root temperature on water movement resistance were studied on cacao (Theobroma cacao L. cv Catongo) seedlings under greenhouse conditions at root temperatures of 10, 20 30 and 40ºC, on leaves covered with aluminum foil and black plastic bags and on uncovered leaves. The leaves were located at the base, intermediates part and apex of the stem. Gas exchange measurements were done utilizing a LI-6000 portable photosynthetic system. Water and osmotic potential were measured by psychrometry. Turgor potential was estimated as the difference between water potential and osmotic potential. The results suggested that the resistance to water movement depends on the transpirational flux and that the water potential gradients across the plant vary at temperatures greater than 30ºC. Gas exchanges, at diferent root temperature, depend on the water status of the plant.

Key words: Cacao, Resistance to water movement, Root temperature.

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Agradecimentos

À minha mãe Regina (in memoriam) cuja cooperação para a concretização desta dissertação de mestrado foi constante.

Recebido em 15-7-91.

Aceito em 4-6-92

ALVIM, P. de T. 1977. Cacao. In Ecophysiology of Tropical Crops. Ed. P. de T. Alvim & T.T. Kozlowski. Academic Press, Inc. 279-310 pp.
BARRS, H.D. 1971. Cycling variations in stomatal aperture, transpiration, and leaf water potential under constant environmental conditions. Ann. Rev. Plant Physiol 22: 223-236.
BEGG, J.E. & TURNER, N.C. 1970. Water potential gradients in field tobacco relations. Plant Physiol 46: 343-346.
BENNETT, J.M., CORTES, P.M. & LORENS, G.F. 1986. Comparison of water potential components measured with a thermocouple psychrometer and a pressure chamber and effects of starch hydrolysis. Agron J. 78: 239-244.
BLACK, R. C. 1979. The relationship between transpiration, water potential, and resistance to water movement in sunflower (Helianthus annuus L.) J. Exp. Bot. 30(15):235-243.
BOYER, J. S. 1974. Water transport in plants: Mechanisms os apparent changes in resistance during absorption. Planta (Berl.) 117: 187-207.
CONSTABLE, G. A. & RAWSON, H. M. 1980. Effects of leaf position, expansion, and age on photosynthesis, transpiration and water use efficiency of cotton. Aust. J. Plant Physiol. 7: 89-100.
FARQUHAR, G. D & SAHRKEY, T. D. 1982. Stomatal conductance and photosynthesis. Ann. Rev. Plant Physiol. 33: 317-345.
GOODE, J. E. & HIGGS, K. M. 1973. Water osmosis and pressure potencial relationships in apple leaves. J. Hort. Sci. 48: 203-215.
GRADMANN, H. 1928. Untersuchungen uber die Wasseverhaltnisse des Bodens als. Grundlage des Pflanzenwachstunis. Jarb.. Wiss. Bot. 69: 1-100.
HOAGLAND, D. R. 1948. Lectures on the inorganic nutrition of plants. Chronica Botanica Co. Walthan. Mass. USA. pp 48-71.
HONERT, T. C. VAN DEN. 1948. Water transport in plants as a catenary process. Disc. Farday Soc. 3: 146-153.
JONES, M. M. 1978. Osmotic adjustment in leaves of sorghum in response to water decits. Plant Physiol. 61: 122-126.
KRAMER, P. J. 1974. Fifty years of progress in water realtions reserch. Plant Physiol. 54: 463-471.
LYBECK, B.R. 1958. Winter freezing in relation to the resistance of sap in tall trees. Plant Physiol. 34: 482-486.
MACHADO, R. C. R. & ALVIM, P. DE T. 1981. Efeito da deficiência hídrica do solo sobre a renovação de folhas, floração e estado de água no cacaueiro. Revista Theobroma 11(3): 183-191.
NEUMANN, H. H., THURTHELL, G. E. & STEVENSON R. K. 1974. 'In situ' measurements of leaf water potencial and resistance to water flow in corn, soybean and sunflower at several transpiration rates. Can. J. Plant Sci. 54: 175-184.
SAS INSTITUTE. 1982. SAS user's guide: Statistics. Cary, N. C. USA. 584 p.
SCHOLANDER, P. F., HAMMEL, H. T., BRADSTREET, E. D. & HEMMINGSEN, E. A. 1965 Sap pressure in vascylar plants. Science 149: 339-346.
SPANNER, D. C. 1951. The Peltier effect and its use in the measrement of suction pressure. J. Exp. Bot. 2: 145-168.
TURNER, N. C., BEGG, E. J. & TOUNET, M. L. 1978. Osmotic adjustmente of sorghum and sunflower crops in response to water deficit and its influence on the water potencial at wich stomata close. Aust. J. Plant Physiol. 5: 597-608.
VALLE, R., MISHOE, J. W., JONES, J. W. & ALLEN, JR., L. H. 1985. Transpiration rate and water use efficiency of soybean leves adapted to différente CO2 environments. Crop Sci. 25: 477-482.
ZIMMERMAN. M. M. 1965. Effects of low temperature on the ascent of sap in trees. Plant Physiol. 39: 568-572.

*

Trabalho apresentado no XLI Congresso Nacional de Botânica, Fortaleza - CE.

Datas de Publicação

Publicação nesta coleção
13 Jun 2011
Data do Fascículo
Jul 1992

Histórico

Aceito
04 Jun 1992
Recebido
15 Jul 1991

This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.

[1] ALVIM, P. de T. 1977. Cacao. In Ecophysiology of Tropical Crops. Ed. P. de T. Alvim & T.T. Kozlowski. Academic Press, Inc. 279-310 pp.

[2] BARRS, H.D. 1971. Cycling variations in stomatal aperture, transpiration, and leaf water potential under constant environmental conditions. Ann. Rev. Plant Physiol 22: 223-236.

[3] BEGG, J.E. & TURNER, N.C. 1970. Water potential gradients in field tobacco relations. Plant Physiol 46: 343-346.

[4] BENNETT, J.M., CORTES, P.M. & LORENS, G.F. 1986. Comparison of water potential components measured with a thermocouple psychrometer and a pressure chamber and effects of starch hydrolysis. Agron J. 78: 239-244.

[5] BLACK, R. C. 1979. The relationship between transpiration, water potential, and resistance to water movement in sunflower (Helianthus annuus L.) J. Exp. Bot. 30(15):235-243.

[6] BOYER, J. S. 1974. Water transport in plants: Mechanisms os apparent changes in resistance during absorption. Planta (Berl.) 117: 187-207.

[7] CONSTABLE, G. A. & RAWSON, H. M. 1980. Effects of leaf position, expansion, and age on photosynthesis, transpiration and water use efficiency of cotton. Aust. J. Plant Physiol. 7: 89-100.

[8] FARQUHAR, G. D & SAHRKEY, T. D. 1982. Stomatal conductance and photosynthesis. Ann. Rev. Plant Physiol. 33: 317-345.

[9] GOODE, J. E. & HIGGS, K. M. 1973. Water osmosis and pressure potencial relationships in apple leaves. J. Hort. Sci. 48: 203-215.

[10] GRADMANN, H. 1928. Untersuchungen uber die Wasseverhaltnisse des Bodens als. Grundlage des Pflanzenwachstunis. Jarb.. Wiss. Bot. 69: 1-100.

[11] HOAGLAND, D. R. 1948. Lectures on the inorganic nutrition of plants. Chronica Botanica Co. Walthan. Mass. USA. pp 48-71.

[12] HONERT, T. C. VAN DEN. 1948. Water transport in plants as a catenary process. Disc. Farday Soc. 3: 146-153.

[13] JONES, M. M. 1978. Osmotic adjustment in leaves of sorghum in response to water decits. Plant Physiol. 61: 122-126.

[14] KRAMER, P. J. 1974. Fifty years of progress in water realtions reserch. Plant Physiol. 54: 463-471.

[15] LYBECK, B.R. 1958. Winter freezing in relation to the resistance of sap in tall trees. Plant Physiol. 34: 482-486.

[16] MACHADO, R. C. R. & ALVIM, P. DE T. 1981. Efeito da deficiência hídrica do solo sobre a renovação de folhas, floração e estado de água no cacaueiro. Revista Theobroma 11(3): 183-191.

[17] NEUMANN, H. H., THURTHELL, G. E. & STEVENSON R. K. 1974. 'In situ' measurements of leaf water potencial and resistance to water flow in corn, soybean and sunflower at several transpiration rates. Can. J. Plant Sci. 54: 175-184.

[18] SAS INSTITUTE. 1982. SAS user's guide: Statistics. Cary, N. C. USA. 584 p.

[19] SCHOLANDER, P. F., HAMMEL, H. T., BRADSTREET, E. D. & HEMMINGSEN, E. A. 1965 Sap pressure in vascylar plants. Science 149: 339-346.

[20] SPANNER, D. C. 1951. The Peltier effect and its use in the measrement of suction pressure. J. Exp. Bot. 2: 145-168.

[21] TURNER, N. C., BEGG, E. J. & TOUNET, M. L. 1978. Osmotic adjustmente of sorghum and sunflower crops in response to water deficit and its influence on the water potencial at wich stomata close. Aust. J. Plant Physiol. 5: 597-608.

[22] VALLE, R., MISHOE, J. W., JONES, J. W. & ALLEN, JR., L. H. 1985. Transpiration rate and water use efficiency of soybean leves adapted to différente CO2 environments. Crop Sci. 25: 477-482.

[23] ZIMMERMAN. M. M. 1965. Effects of low temperature on the ascent of sap in trees. Plant Physiol. 39: 568-572.

Brasil

Brasil

Efeito da temperatura radicular na resistência ao movimento de água no cacaueiro (Theobroma cacao L.)

Radicular temperature effects in water movement resistence in cacao tree (Theobroma cacao L.)

Resumos

Datas de Publicação

Histórico