Mn. Merzlyak et al., Non-destructive optical detection of pigment changes during leaf senescence and fruit ripening, PHYSL PLANT, 106(1), 1999, pp. 135-141
Reflectance spectra in the visible and near infra-red range of the spectrum
, acquired for maple (Acer platanoides L.), chestnut (Aesculus hippocastanu
m L.), potato (Solanum tuberosum L.), coleus (Coleus blumei Benth,), leaves
and lemon (Citrus limon L,) and apple (Malus domestica Borkh,) fruits were
studied, An increase of reflectance between 550 and 740 nm accompanied sen
escence-induced degradation of chlorophyll (Chl), whereas in the range 400-
500 nm it remained low, due to retention of carotenoids (Car), It was found
that both leaf senescence and fruit ripening affect the difference between
reflectance (R) near 670 and 500 nm (R-678 - R-500), depending on pigment
composition, The plant senescing reflectance index in the form (R-678 - R-5
00)/R-750 was found to be sensitive to the Car/Chl ratio, and was used as a
quantitative measure of leaf senescence and fruit ripening. The changes in
the index were followed during leaf senescence, and natural and ethylene-i
nduced fruit ripening, This novel index can be used for estimating the onse
t, the stage, relative rates and kinetics of senescence/ripening processes.