INFLUENCE DE LA TEMPERATURE NOCTURNE SUR LES ECHANGES GAZEUX DE LA TOMATE

The main results are :

• the water vapour exchanges are quite unaffected by night temperature. There is only a slight positive effect of warm nights.
• Nighttime respiration is very dependent on temperature : about zero at 7°C, it more than doubles between 10 and 20°C
• Daytime assimilation is best after 14°C N.T. (which is the growth N.T.): it is slightly reduced after 20°C (by the end of the day) and 10°C (both at beginning and end of the light period).

A single night at 7°C is sufficient to distrub strongly subsequent CO₂ assimilation, which is not only reduced, but also totally disconnected from transpiration and stomatal aperture.

• As a consequence, the 24 hours CO₂ balance of the plant is best at 14°C and 10°C N.T., and 20% less at 20°C and 7°C N.T.
• For older plants (110 to 130 days after sowing), night-time respiration is bigger, and more dependent upon temperature; daytime assimilation is less after 14°C than after 10°C N.T.

Download Adobe Acrobat Reader (free software to read PDF files)