Poster: Vegetative Development

Abs # 432: Structural characterization of reserves mobilization in the seed corms of konjak (Amorphophallus konjac K. Koch) on and after sprouting

Presenter:	Kawasaki, Michio , kawasaki@agr.nagoya-u.ac.jp
Authors	Kawasaki, Michio  (A)   Tarumi, Kazuhiro  (A)   Taniguchi, Mitsutaka  (A)   Miyake, Hiroshi  (A)
Affiliations:	(A): Graduate School of Bioagricultural Sciences, Nagoya University

The seed corms of konjak contain plenty of starch and glucomannan. The starch is accumulated in amyloplasts of parenchyma cells of pith. The glucomannan is accumulated in central vacuoles of idioblasts in pith and cortex. Calcium oxalate crystals which are embedded in glucomannan are formed in many idioblasts. These reserves mobilization in the seed corms on and after sprouting was investigated by optical microscopy and scanning electron microscopy using the samples fixed by the quick freezing-vacuum freeze-drying method. Drastic decomposition of starch granules initiated at the start of sprouting, whereas drastic decomposition of glucomannan particles initiated from about 14 days after sprouting. When leaves began to expand at about 28 days after sprouting, great mass of starch was depleted although some amount of glucomannan remained in seed corms. It is suggested that sprouting depends heavily on energy from starch and leaves expansion depends heavily on energy from glucomannan. The decomposition of the two carbohydrates in seed corms progressed generally from the regions distant from the regenerate plant bodies to the regions adjacent to the bodies. At 28-42 days after sprouting, erose and perforated calcium oxalate crystals were also observed. Therefore, it is possible that calcium in calcium oxalate crystals is reused for initial growth of konjak although it has been recognized that the crystals in the seed corms of konjak are not reused.