The effect of gravity on surface temperature and net photosynthetic rate of plant leaves.
Adv Space Res
; 28(4): 659-64, 2001.
Article
em En
| MEDLINE
| ID: mdl-11803969
ABSTRACT
To clarify the effects of gravity on heat/gas exchange between plant leaves and the ambient air, the leaf temperatures and net photosynthetic rates of plant leaves were evaluated at 0.01, 1.0, 1.5 and 2.0 G of 20 seconds each during a parabolic airplane flight. Thermal images of leaves were captured using infrared thermography at an air temperature of 26 degrees C, a relative humidity of 15% and an irradiance of 260 W m-2. The net photosynthetic rates were determined by using a chamber method with an infrared gas analyzer at an air temperature of 20 degrees C, a relative humidity of 50% and a photosynthetic photon flux of 0.5 mmol m-2 s-1. The mean leaf temperature increased by 1 degree C and the net photosynthetic rate decreased by 13% with decreasing gravity levels from 1.0 to 0.01 G. The leaf temperature decreased by 0.5 degree C and the net photosynthetic rate increased by 7% with increasing gravity levels from 1.0 to 2.0 G. Heat/gas exchanges between leaves and the ambient air were more retarded at lower gravity levels. A restricted free air convection under microgravity conditions in space would limit plant growth by retarding heat and gas exchanges between leaves and the ambient air.
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Bases de dados:
MEDLINE
Assunto principal:
Fotossíntese
/
Voo Espacial
/
Temperatura
/
Ausência de Peso
/
Folhas de Planta
/
Gravitação
Idioma:
En
Revista:
Adv Space Res
Assunto da revista:
MEDICINA AEROESPACIAL
Ano de publicação:
2001
Tipo de documento:
Article
País de afiliação:
Japão