The Development Regularity Of Peach Flower And Fruit And The Judgment On Fruit Economic Characters In Greenhouse

Based on the greenhouse cultural practice of peach trees in north China ,the research had been carried out in the demonstration garden of horticulturalscience and engineering college of Shandong Agricultural University andsome dominant areas of protective peach production in Shandong provincewith Shuguang nectarine ( Prunus persica var. nectarine Maxim. cv.Shuguang), Zaohongzhu nectarine(Prunus persica var. nectarina Maxim. cv.Zaohongzhu), Chunjie peach[Prunus persica (L.) Batsch.] and several othernectarine varieties from the year 2003 to 2005. The key research contentswere just as following: Firstly, the effects of different night temperature onpeach flower organ development and effects of sugar concentration in culturemedium on peach pollen activity in greenhouse. Secondly, peach fruit qualitydevelopmental physiology and the process mathematics simulation ingreenhouse. Thirdly, fuzzy comprehensive judgments on economic charactersof peach in greenhouse in Shandong province. Lastly, some treatments onimproving the peach fruit quality in greenhouse, which included bagging, CO2enrichment, spraying PP333 and light reflecting film covering. The main resultsare as follows:1. when the night temperature was 6℃and 9℃during the florescence,color of petals were pink and the anther could dehisce normally torelease the pollens. The treatment of 12℃made the pistil shorterand anther smaller. 9℃was the best temperature for growth of pistil anddevelopment of ovary diameter. Sum of pollen and rate of blighted pollenraised and pollen volume dropped as the enhancing of the night temperature.Pollen volume, polar axle length, and equatorial axle length all reached themaximum in the 9℃treatment. The pollen both had smaller volume buthigher activity in the 9℃and 12℃treatment. After considering all things ofthe effects of night temperature on flower organ development, we thought itwas appropriate to control the night temperature from 6℃to 9℃.Germination rate of pollen was advanced to some extent as enriching thesugar concentration in the culture medium, and they all had their own properconcentration for germination. It was 10 percents for Chunjie peach, but it wasfrom 10 percents to 15 percents for others. Pollen germination rate of nectarinevariety was more higher than Chunjie peach, while Chunjie peach had thebiggest pollen tube growth. Different kinds of pollen had different tolerance tothe sugar concentration. The tolerance of Chunjie peach was much weakerthan other nectarines which had a high germination rate even if theconcentration was above 20 percents.2. During the course of the peach fruit quality development, the changes ofseveral key quality indexes were just as following: vitamin C, soluble protein,chlorophyll and carotenoids contents in the fruit skin decreased during fruitdevelopment, whereas contents of total sugars, total soluble solids and theratio of sugar/acid increased. At the end of fruit development, the contents oftitratable acids, total sugars, vitamin C and carotenoids all changed notably.Starch content was very low in peach fruit and decreased during the course ofthe fruit development ,increased only at the early days. Trends of dry weightchanged from low to high in 50days after blossom, and then changedirregularly. Changes of soluble protein content had the same rhythm with fruitdevelopment, it decreased from the maximum at first, and then had a relativesteady contents. Power function was adapt to simulate the course of Chunjie peach fruitvolume and mean single weight development. The developmental curve ofShuguang nectarine accorded with one factor-high rank equation, while thesimulation result of the mean single weight curve showed that it was oneelement-high rank equation not power function that fit much better. Thedevelopmental curve of Zaohongzhu nectarine fruit volume and mean singleweight both accorded with the one element-high rank equation, and therelative coefficient both reached a noticeable high level.3. According to the basic principles of fuzzy mathematics, comprehensivejudgment on twelve economic characters, including fruit yields, quality, etc.,of seventeen cultivars of greenhouse peach cultivated in Shandong provincewas given in this paper. Results of the comprehensive judgment showed thatChunjie peach, Shuguang nectarine, Zaohongzhu nectarine and Huaguangnectarine had the best comprehensive economic character, while Lichun,Zaohongbaoshi and Chaohongzhu nectarine had the poorest one. Thus,Shuguang nectarine and Chunjie peach should be encouraged to plant on alarge scale, while Huaguang nectarine should be cultivated only in somecertain areas where were convenient to traffic and market. Mayfire was anexcellent pollination cultivar, which should be cultivated with others.4. Peach fruit would pigmentize quickly and brightly after the fruit bag wasremoved, the pigmentation index and the fruit surface smooth finishcoefficient raised remarkably. Bigging had no significant effect on meansingle weight and soluble solids. Vitamine C and soluble protein droppednoticeably when compared with CK. Soluble sugar and the ratio of sugar toacid both had a slight drop to the CK. In order to improve peach fruit quality remarkably, the time of sprayingPP333 should be from the 20th day to the 38th day after full blossom. Solublesolids and soluble protein contents of 20th day treatment were much higherthan CK. There was a slight increase in soluble sugar and total acids, so wasthe ratio of sugar to total acids. There was no significant effect on Vitamine Ccontents when using PPP333. Treatments of different periods all could makethe pigmentation index be higher than CK, and the effect of the treatmentwould become worse and worse as the treatment date delaying. The full illumination in greenhouse was 95100 lx in a sunny day, whichwas only 69.82 percents of the full illumination in open field. The illuminationintensity among lines could be enlarged at 57 percents to 93 percents and31percents to 41 percents among trees by light reflecting film covering, so didthe mean single fruit weight , soluble protein, and the pigmentation index. Thefruit dry weight contents reached 8.3 percents, which was remarkably higherthan CK.