I think I have to correct myself or at least through in some doubt of my former statement. I have read some articles that indicate that uptake rates are more or less independent of light or dark periods if it is the normal day/night schedule. You learn as long as you live.I do not know either but I do think that the accepted hypothesis is that uptake happens at the light period. The photosynthesis transform inorganic carbon into glucose, inorganic P into ATP and inorganic N into amino acids - altogether in the chloroplast
Sincerely Lasse
Sincerely Lasse