M. Uz et O. Saygin, DETERMINATION OF THE LIGHT PATHLENGTH ELONGATION IN LEAVES BY MEASURING P700 QUANTITATIVELY, Photosynthesis research, 40(2), 1994, pp. 175-179
P700 absorption change signals were measured at 800 nm for plant leave
s and plant leaf extracts by illuminating with far-red light. The rati
o of the signal amplitudes for the two sample types shows the degree o
f optical signal intensification. The intensification is due to optica
l path-length elongation, itself caused by scattering. The intensifica
tion was found to be between 6 and 15 for different leaves. For spinac
h leaves, the intensification varied less than 10% among samples. By r
eplacing the air in the spongy layer of a leaf with an isotonic soluti
on it was shown that nearly half of the intensification is due to the
scattering at air-tissue interfaces. The comparison of the P700 signal
s of a leaf with its extract would seem to be a new technique for dete
rmining the optical scattering effects of leaves.