Walz MINI-PAM-II, Manual, Page: 31 / 130

Components and Setup Chapter 4
25
In the fluorescence mode, a light guide in the cap leads light from
a blue or a green LED located inside the spectrometer body to
the sample. The excited fluorescence reaches the spectrometer
body through a central hole in the cap. Green light penetrates
deeper into photosynthetic tissue than blue or red (Terashima et
al (2009) Plant Cell Physiol 50:684-697). Therefore, the two exci-
tation colors permit probing the effect of varying depths of pene-
tration of excitation light on the shape of fluorescence spectra.
The spectrometer automatically compensates for the spectral
sensitivity of the detector.
For reflection measurements, a halogen lamp is employed
whose emission is transferred through another light guide to the
sample (Fig. 14, page 24).
From reflection measurements, reflectance (R) is derived by di-
Fig. 15: MINI-SPEC/MP .