| In this experiment caryopsis of wheat , root crop of sweet potato, fruits of chestnut and caltrop, tubers of potato and taro, protocorm of water chestnut, rhizome of lotus and root-like tubers of yam were used as material, the morphology and development of amyloplast were studied by scanning electron microscopy and resin embedding combined with semi-thin section technology. The main results were shown as follows:(1)Different plants had different kinds of amyloplasts, even thought different parts or times of the same plant , the amyloplasts were not the same. Great starch granules in wheat were cobblestone-shaped, as well as small starch granules were spherical. Amyloplasts in sweet potato were spherical. Amyloplasts in potato were oval. Amyloplasts in taro were spherical or oval. Amyloplasts in chestnut were mostly spherical or oval. Amyloplasts in caltrop were oval, ellipse or cylindrical. Amyloplasts in lotus were long grain shape or irregular shape. Amyloplasts in yam were oval, round or cylindrical. Amyloplasts in water chestnut were mostly round or oval. Starch grains in amyloplasts of wheat and corn were single, but starch grains in amyloplasts of rice endosperm were complex tablets.(2) The 7th day after flowering,the endosperm cells in wheat start to accumulate starch. large cobblestone-shaped amyloplasts were first formed. In the 10 days, the amount is continuously growing, the volume is gradually increasing. Small starch granules which were mostly spherical occurred at the 16th day of flowering, and distributed close to endosperm cell wall where there was more endoplasmic reticulum, so that we conjectured that it had relationship between endoplasmic reticulum and small starch granules occurrence.(3) The development of amyloplasts in wheat had relationship with position. The amyloplasts in abdominal had better growth than central and back. In addition, there are not amyloplast in the aleurone layer cells. And the sub-aleurone layer cells occurred later, the amyloplasts in which growed later and smaller than in the endosperm cells.(4) The wheat endosperm cells underwent nucleus deformation and chromatin condensation. And the phenomenon became more obvious as endosperm development proceeding. The endosperm nucleus deformation happened at the 7th day after flowering, and the deformation became more and more sever with increasing days after flowering. In later days of endosperm developing, the deformation of nucleus aggravated with the accumulation of amyloplasts. Residues only existed in the gap of amyloplasts. |
