The Study On The Form And The Microstructural To The Epidermis Rustting Of Pyrus Bretschneideri Rehd During Storage

Being a region with typical continental climate, Kuala pear yielded in Xinjiang is famous for its color, taste and fragrance in the world. During storage of Kuala pear, rust spots are easy to be produced in the fruit peel tissues, which greatly reduce commodity value and have bad effect on exports and sales with much economy loss. In order to discover mechanism of rust spots disease, this paper studied on the occurrence regularity of Kuala pear, changes of microstructure and ultrastructure in the pear peel and metabolism detection of disease physiology during pear storage. Several conclusions had been drawn in the experiments.1 A survey on the incidence of peel rust spots in pear production area of Xingjiang(2008～2009) indicated that the incidence rate in the area of Aksu was in cold condition had the rate of 2% lower than those stored in controlled atmosphere. Kuala pear stroed under controlled atmosphere condition had the rate of 2-3% higher than in cold condition in Korla.It was about six mouth later after storage that rust spots began to generate in the pear from fruit calyx, then it spread to fruit trunk and fruit stalk.2 Researches showed that Kuala pear stroed under cold condition with higher temperature and high air humidity was easy to form rust spot in the peel, while to CA storage, there was a positive correlation between air humidity, gas composition and incidence rate.3 Studies showed that there was a positive correlation between physiological metabolism within the area of rust spot tissue and incidence rate. Compared with control, rust spots formation had a positive correlation with PPO, POD and PAL. Phenolics content within undamaged tissue was high than those in the rust spots tissue, and insignificant changes could be seen to the total acid content.4 Observed under electron microscope, there were no starch either in the cell of rust spots area or the control and dyeing part of lignin in the wall of rust spots area was more than the control of those undamaged tissue.It had perfect pectin layer among the cell wall of control, but absence could be found in the rust spots ones.5 Observed under transmission electron microscope with undamaged tissue as control, lignification was detected in the rust spots tissue of Kuala pear and cell tissue of peel kept health, but the outer layer of the peel arranged densely and deposition of dark substance formed rust spots in the peel. To the color of fruit cell, area with rust spots was lighter than the health. As far as cell membrane was concerned, the health part kept perfect, but rust spots section began to disappear gradually.