Figure 7.

(a) Maximum quantum efficiency (Fv/Fm) of photosystem II (PSII); (b) photochemical electron transport rate (ETR); (c) relative PSII operating efficiency (ΦPSII); (d) chlorophyll a non-photosynthetic quenching (NPQ) in the leaves of raspberry plants grown under various red (R₆₆₀)–far-red (FR) light ratio. Means ± standard error (SE); means followed by the same letter were not different at p ≤ 0.05. Treatment 1—0% R₆₆₀ + 100% FR₇₃₀; Treatment 2—30% R₆₆₀ + 70% FR₇₃₀; Treatment 3—70% R₆₆₀ + 30% FR₇₃₀; Treatment 4—100% R₆₆₀ + 0% FR₇₃₀.