392 



T. T. Bannister and M. J. Vrooman 



illuminated for 2-3 hours. Subsequently, for enhaiacenient mea 

 surements, illumination was given in the sequence red, dark, blue, ~ 

 blue plus red, blue, dark, red, dark. Periods of ^4-8 minutes 

 insured attainment of 97*5^ of steady state rate. 



Like Myers suid Graham (1/, saturated rates of photosynthesis 

 of 20-60 pi O2 pl~^ cells hour~l were found. Respiratory rates, 

 estimated as described elsewhere v^) 



estimated as described elsewhere 

 cells hour'l 



', were about 1 pi O2 pi 



■1 



OBSERVED FUNCTIONS 



Due to the length of the measurements, the functions E(l2_, Ig) 

 and D(I-,, Ip) had to be characterized from the results of exper- 

 iments, each limited to 1, 2, or 3 planes intersecting the en- 

 hancement surfaces. Fortunately, the consistency among a number 

 of experiments permitted establishing the semi -quantitative char- 

 acter of the E and D surfaces with no more than modest quanti- 

 tative errors. 



Figs. 1 and 2 show the two surfaces obtained. Fig. 1 shows 

 thatf increased with blue illumination (far-red being constant), 

 reached a maximum for Pi/p2'^5> and declined slowly with further 

 increases in pj_. With blue constajit, E declined from a maximum 



4000 ciQt cm' i*e 



Fig. 1. E(p , p ). Contours of E estimated from ex- 

 perimentally aetermiaed profiles (dashed lines). 



