This study explored reflectance indices sampled with a ‘leaf reflectometer’ as measures of pigment content for
leaves of contrasting light history, developmental stage and functional type (herbaceous annual versus
sclerophyllous evergreen). We employed three reflectance indices: a modified normalized difference vegetation
index (NDVI), an index of chlorophyll content; the red/green reflectance ratio (RRED[ratio ]RGREEN), an index of
anthocyanin content; and the change in photochemical reflectance index upon dark–light conversions (ΔPRI), an
index of xanthophyll cycle pigment activity. In Helianthus annuus (sunflower), xanthophyll cycle pigment amounts
were linearly related to growth light environment; leaves in full sun contained approximately twice the amount
of xanthophyll cycle pigments as leaves in deep shade, and at midday a larger proportion of these pigments were
in the photoprotective, de-epoxidized forms relative to shade leaves. Reflectance indices also revealed contrasting
patterns of pigment development in leaves of contrasting structural types (annual versus evergreen). In H. annuus
sun leaves, there was a remarkably rapid increase in amounts of both chlorophyll and xanthophyll cycle pigments
along a leaf developmental sequence. This pattern contrasted with that of Quercus agrifolia (coast live oak, a
sclerophyllous evergreen), which exhibited a gradual development of both chlorophyll and xanthophyll cycle
pigments along with a pronounced peak of anthocyanin pigment content in newly expanding leaves. These
temporal patterns of pigment development in Q. agrifolia leaves suggest that anthocyanins and xanthophyll cycle
pigments serve complementary photoprotective roles during early leaf development. The results illustrate the use
of reflectance indices for distinguishing divergent patterns of pigment activity in leaves of contrasting light history
and functional type.