Heliotropic leaf movements in common beans controlled by air temperature
Material type: ArticleLanguage: English Description: 91:1162-1167Subject(s): LOC classification:- 37489
Item type | Current library | Collection | Call number | Copy number | Status | Date due | Barcode | Item holds | |
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Online Document | CIAT Library Web | Electronic Document | 37489 (Browse shelf(Opens below)) | Not For Loan (Restricted Access) | |||||
Journal Article | CIAT Library Document collection CINFOS | Document Collection CINFOS | 37489 (Browse shelf(Opens below)) | c.1 | Short Loan | 100056853 |
Se evaluaron los movimientos heliotropicos foliares en frijol (cv. Blue Lake Bush) en condiciones ambientales y de lab. Los movimientos heliotropicos foliares en plantas bien regadas fueron controlados en parte por la temp. y al parecer fueron independientes de la humedad atmosferica y de la concn. de CO2. Cuando las condiciones ambientales se mantuvieron constantes en el lab., el aumento en la temp. del aire hizo que las hojas de frijol se orientaran mas oblicuamente hacia una fuente de luz. El CO2 ambiental, el CO2 intercelular y la fotosintesis neta no se correlacionaron con los cambios inducidos por la temp. en los movimientos heliotropicos, ni afectaron directa ni significativamente estos movimientos. El efecto de la temp. del aire en los movimientos foliares no requiere mediacion de un cambio en el potencial hidrico foliar, en la transpiracion o en la conductancia foliar. La temp. del aire modifico la orientacion laminar en la luz mediante su efecto en la temp. del tejido en la region pulvinular, no en la lamina ni en el peciolo. Sin embargo, en la oscuridad no se expresaron los efectos de la temp. en los movimientos foliares. Los movimientos heliotropicos activos en respuesta a la temp. del aire permitieron que la temp. de la lamina permaneciera cercana al nivel termico optimo o fotosintesis. Este efecto de la temp. subyace a un patron de movimientos foliares comunmente observado en condiciones de buen riego: una tendencia de las hojas hacia enfrentar el sol mas oblicuamente en dias calientes que en dias frescos. (RA-CIAT) spa
Heliotropic leaf movements were examined in common beans (Phaseolus vulgaris cv. Blue Lake Bush) under outdoor and laboratory conditions. Heliotropic leaf movements in well-watered plants were partly controlled by temperature, and appeared to be independent of atmospheric humidity and CO2 concentration. When environmental conditions were held constant in the laboratory, increased air temperature caused bean leaves to orient more obliquely to a light source. Ambient CO2, intercellular CO2, and net photosynthesis were not correlated with the temperature-induced changes in heliotropic movements, nor did they significantly affect these movements directly. The effect of air temperature on leaf movements need not be mediated through a change in leaf water potential, transpiration, or leaf conductance. Air temperature modified laminar orientation in light through its effect on tissue temperature in the pulvinal region, not that of the lamina or petiole. However, under darkness the temperature effects on leaf movements were not expressed. Active heliotropic movements in response to air temperature allowed lamina temperature to remain close to the thermal optimum or photosynthesis. This temperature effect underlies a commonly observed pattern of leaf movements under well-watered conditions: a tendency for leaves to face the sun more obliquely on hot days than cool days. (AS) eng