Fig. 4

Confocal images of purified plastids and analysis of pigment content. Confocal images of chloroplasts A, intermediate plastids (B) and mature chromoplasts (C) suspensions isolated from green, breaker and fully mature pericarp of kumquat, respectively. Images are overlays of chlorophyll autofluorescence emitted at 650–700 nm (red) and carotenoid autofluorescence emitted at 500–600 nm (green), respectively. The extracts mainly containing chlorophyll appear red, those only containing carotenoids appear green, and those containing both chlorophyll and carotenoids appear yellow. Bar, 25 μm. The excitation wavelength was 488 nm. The peaks of fluorescence emission around 520–550 nm and 680 nm correspond to carotenoids and chlorophylls in citrus fruit, respectively. Measurement of chlorophyll concentration (D), chlorophyll/carotenoid ratio (E) and carotenoid concentration (F) in kumquat fruit at green, breaker and orange color stages, respectively. The pigment concentration is recorded with the unit of μg g ⁻¹ fresh weight