| Summary: | 碩士 === 國立臺灣大學 === 植物學研究所 === 83 === The type, morphology and distribution of calcium crystals and trichomes were investigated in the mature leaves of nine species(eight genera) of Moraceae. According to the composition of calcium crystals, the nine species were classified into three groups. In Mours australis, the cytochemical test showed that the frame of the body of cystolith was made by polysaccharide,protein and callose, and the calcium carbonate crystal accumulated within. The oxalate crystals, surrounded by the crystal sheath, was formed in the vacuoles. As the portions of tonoplast fused with the plasma membrance, the cell wall formed around the crystal tips. The formation of calcium crystals in the leaves of Morus australis at different levels of calcium supply was studied. The results showed that the density of lithocysts was not affected by the different concentrations of calcium supply. According to the calcium concentration increments the size of the cystoliths also increased. Besides, no oxalate crystal was found in the leaf veins of 1/8Ca plant group. However, there are many crystals in the leaf veins of both the 1Ca and 5Ca plant groups, and the density of crystals is higher in the 5Ca group. In the transplanting experiments, after the transplantation (5Ca→ 1/8Ca), in the previously formed mature leaves the number and size of lithocysts and cystoliths didn''t change, but those of the calcium oxalate crystals in the veins decreased obviously. While after the transplantation(1/8Ca → 5Ca), both the size of cystoliths and the number and size of calcium oxalate crystals in the previously formed mature leaves increased significantly. The formation of calcium crystals in the newly formed mature leaves is almost the same as that in the leaves from the plants grown only in the latter solution without transplantation.
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