Studies On Development Of Epidermis Structure And Russetting And The Effects Of Bagging On Them In Whangkeumbae Fruit

Whangkeumbae fruit was treated with paraffin-wax cut-section and transmission electron microscopy to investigate the ultra-structural and the micro-structural changes and characters in the epidermis structure during development. The result will help to know the cytological characters and the development that fruit dot and ressuetting shaped on Whangkeumbae fruit, and it will provide theoretic gist of cell on appearance quality. The main results were as follows:1. The cuticle of Whangkeumbae was thin, and the thickness was 3.3μm after flowering, and the thickness of the cuticle was 4.79/μm at the stage near mature. The thickness of the cuticle became thick at first and became thin later during entire development. The cuticle was the thickest 28~38d after flowering. Epidermis consists of 1 layer regular cells at flowering, and epidermis cells became irregular 18d after flowering. Epidermis cells became more irregular at the stage near mature, and they were invaded by cuticle.2. There were regular epidermis cells in the bagging Whangkeumbae, and the cuticle became thin and it was uniformity distributing and it did not invade the space of the epidermis cells. The cell wall was a obvious light-dark-light structure. The middle lamella was layer dark, dense, high electronic density cell. Cell wall of unbagging pear was relaxed, and the electronic density was lower than bagging pear. On the whole, the cell wall of bagging pear was more stable than unbagging pear. There were plenty of lipid droplets in the plastid of the bagging and unbagging fruit excerpt cell plastid, but there were some dark substance in the unbagging fruit, too.3. The development of fruit dot has four stages: stomata, lenticels, fruit dot shaped, and fruit dot increased. Fruit dot came from the lenticels, and the lenticels appeared at the place of the stomata. The size of fruit dot related to the size of lenticels.4. The bagging treatment can reduce the size of fruit dot and the area of the russetting. This treatment can reduce the lenticel's overlay value obviously, too. The lenticel's overlay value of bagging fruit dropped 48% than that of unbagging fruit 100d after bagging. The bagging treatment can also restrain the increasing of fruit dot diameter obviously. Fruit dotdiameter of bagging fruit dropped 28% than that of unbagging fruit 45d after bagging. It would effect on the size of fruit dot that the different development stage and the days of bagging. The earlier to bag, the smaller the fruit dot and russetting was, and so did the color of the fruit dot and russetting.