Studies On The Rules Of Growth And Development Of Nectarina And Characteristics Of N In Greenhouse

The research was conducted with 16 4-year-old'Shuguang' nectarine trees in greenhouse and 16 trees alike in open field and 4 trees cultivated in pots. The results are as follows:1) Protected cultivation had obvious effects on the shoot growth during all the growing season. Both the year's accumulated shoot length and the new shoot length at any time of the growing period in the greenhouse exteeded one in the open field at same phemophase. 2) The quality of leaves in greenhouse was different from the one of leaves in open field. For example, the chlorophyll content of leaves in greenhouse was higher than in open field. So were the SLW , the rate of thick ness of palisade tissue to total leaf thickness .Compared with the open field, photon use efficiency (PUE) of leaves in greenhouse for the weaker light became higher and PUE for the stronger light became lower than in open field. Average Pn in a sunny day in the greenhouse was lower than average Pn in open field. Certain changes of photosynthetic characteristics of single nectarine leaf happened to adapt the light conditions in the greenhouse. The light saturation was lower in greenhouse than in open field, and so was the light compensation point.3) Compared with the fruits grown in the open field, the development of fruits grown in greenhouses showed the longer stageâ… ,the shorter stage â…¡,the longer FDP(fruit development period., and the quality of nectarine was lower in general. For example, the average single fruit weight was lower in greenhouse than in open field, so were soluable solid substance content ,the total acid content, total sugar content. However, the Vc content was higher in greenhouse than in open field.4) Total N content in leaves throughout a year has similar trend both in greenhouse and in open field , but total N content in leaves in greenhouse was lower than in open field at the same phenophase. The result also fited to the total N content in roots.5) 15N-urea experiment showed that the rate of N absorbed by root to N fertilization was lower in greenhouse than in open field.6) N had great positive effects on the output per tree, it can also improve the quality of fruit including average fruit weight. Nitrogen stimulated increases were associated with the extended fruit development period and increased fruit sink capacity. N has great positive effect on the quality of leaves in greenhouse, it can improve the chlorophyll content, SLW, average leaf area, the total N content, and the pore density. We also found that the light saturation and compensation point also were higher treated with higher N than treated with low N or CK.7) With the increase of N fertilization in greenhouse, the output of nectarine per tree also increased. However, the fruit quality was worse in general. For example,the soluble solid substance content was lower,so was the content of Vc. However, the titrable acid content was higher in fruit in greenhouse than in open field .In a word ,high N fertilization had bad effect on the quality of fruit .