Vacuole Proteins in Secondary Phloem Parenchyma Cells of Three Meliaceae Species
The secondary phloem in the trunk and branchlet of three species in Meliaceae, Swietenia macrophylla L., Chukrasia talularis A. Juss. and Melia azedarach L., was examined using light microscopy and electron microscopy. The vacuole protein bodies are found in most of the phloem parenchyma cells except companion cells. The protein nature of the bodies was demonstrated by the mercury - bromophenol blue reaction and enzymatic digestion with pepsin. Electronmicroscopical observations show that the protein bodies are electron-dense granules in central vacuoles. In the terminal branchlet, the protein bodies are extremely abundant before flushing in spring and most of them disappear in the inner phloem after flushing. This suggests that the vacuole protein bodies have a storage function.