Yes green is reflected but the plants still protect themselves by producing their own sunscreen: (From
Wholesale Horticultural Supplies | Hydroponic Equipment - Stealth Garden)
"It has been proven that UV light influences photomorphogenic responses including gene regulation, flavonoid biosynthesis, leaf and epidermal cell expansion, stomatal density, and increased photosynthetic efficiency. However, don’t forget that UV radiation can also damage membranes, DNA, and proteins.
That’s why many plants undergo photomorphogenic changes designed to protect them from these rays when their photoreceptors sense the presence of radiation. For example, numerous agricultural crops can synthesize simple phenolic compounds and flavonoids that act as sunscreens and remove damaging oxidants and free radicals."
So the natural tendancy of plants is to protect themselves from too much UVA and UVB radiation. Having said that my sativas usually have lighter leaves because of their genetics, but their buds tend to be quite dark.