N. Watanabe et E. Nakada, Seasonal variation of leaf colour in Syrian barley and its association with photosynthetic electron transport rate, CEREAL RES, 27(1-2), 1999, pp. 171-178
Leaves, formed at later developmental stage, in barley genotypes native to
Syria are lighter green than those adapted to wetter areas. In the present
study, six barley genotypes were objectively assessed for leaf colour throu
ghout a cropping season. Leaf colour was measured by using a chroma meter.
The L*, a* and b* axes provide a three-dimentional coordinate space of colo
ur that relates to human perception. L* measures psychrometric lightness. T
he a* axis transects the red and green hues, while the b* axis transects th
e blue and yellow hues. Syrian landraces showed considerably higher L* indi
cating that they have a lighter leaf colour. They had higher a* and lower b
* values than those of dark-green group until February, and then turned to
lower a* and higher b* values thereafter. This indicated the leaves of Syri
an landraces had lesser green and yellow hue in winter than in spring. The
relationship between leaf-colour variables and the photosynthetic electron
transport rates were also explored both in winter and in spring. It is cons
idered that low chlorophyll content and/or higher chlorophyll a/b reduces t
he risk of damage from photoinhibition.