2nd Dec.

Baldocchi D, Falge E, Gu L, et al. FLUXNET: A new tool to study the temporal and spatial variability of ecosystem-scale carbon dioxide, water vapor, and energy flux densities[J]. Bulletin of the American Meteorological Society, 2001, 82(11): 2415.

The most inspiring sentence:

"The response of canopy-scale CO2 exchange to sunlight varies with cloud cover as clouds alter the direction of incoming sunlight and how it penetrates into a canopy."

There are various variables in plants' response to light. Be careful to data analysis!!!