The Characteristics Of ～(15)N Absorption And Utilization In Strawberry And Influence Of Nitrogen On The Process Of Physiology Maturity Of Its Fruit

The experiment of potted strawberry was carried out in the green house of Shandong Agriculture University from 2001~2003. The technique for stable isotope 15N-labelled nitrogen was used to study the rule of 15N-nitrogen absorption, distribution and utilization of strawberry in different dressing stage and different nitrogen fertilizer level. The field experiment was carried out in the plastic shed house of Jinan Modern Agriculture Demonstration District in 2002. The influence of different level nitrogen fertilizer after flower on maturity physiology of fruit in strawberry was searched after. The main results were following:1. The rate of nitrogen fertilizer utilization under high level was higher than the rate under low level when 15N-labelled nitrogen fertilizer was used as base fertilizer. While the result was contrary when used as dressing fertilizer. Under the same level of nitrogen fertilizer, the rate of nitrogen fertilizer utilization is highest when fertilizer was dressed half dose before and after flower respectively, which was 48.57%; the rate was higher when fertilizer was dressed before flower, which was 37.55%; and the rate was lowest when fertilizer was dressed after flower, which was 22.92%. The rate of N-distribution in each organ existed greater distinction in different dressing stages. The rate of N-distribution in vegetative tissues when fertilizer was dressed before flower took up 84.93%; and when fertilizer was dressed half dose before and after flower, the rate in vegetative tissues was 65.35%; and the rate in reproductive tissues were 34.66%. While the distribution rate inreproductive tissues when fertilizer was dressed after flower was greatly improved, which was 47.04%. At different dressing stage, 15N in each organ all attributed little to total nitrogen. When different level nitrogen fertilizer was dressed in the same stage, the rate of 15N distribution in flower and leaf under low level fertilizers was higher than the rate under high level.2. The content of chlorophyll in strawberry leaf increased, and the total yield of strawberry fruit trended to increase with the increment of nitrogen fertilizer. The single fruit weigh was biggest under the treat of low level nitrogen fertilizer, the single fruit weigh was lowest under high level nitrogen and it was lower than the weight under control. Low level nitrogen fertilizer maked the yield of strawberry fruit to decline, but it maked the single fruit weigh to improve greatly, and improve the ratio of commodity fruit significantly.3. Aspartic acid, Glutamic acid, Alanine acid and Leucine acid were the primary amino acids among 17 amino acids in 'Hada' strawberry fruit. And the content of Aspartic acid was highest, which amount covering the total was 21.27~26.83%. There was significant correlation between Aspartic acid and total amino acid contents: yaa=4.2545+1.6763xAsp(r=0.6858**). The amount of nitrogen fertilizer had greater influence on these primary amino acids. With the increment of nitrogen fertilizer, the content of proteins and amino acids trended to increase, but the rate of indispensable amino acids covering the total trended to decline. At different level of nitrogen (low level, middle level and high level), the contents of proteins and amino acids both firstly descended then ascended with the process of fruit maturity. While the contents under control (no nitrogen fertilizer) trended to descend at all times. There was also significant correlation between proteins and amino acids contents: yPr=1.2665+3.4259xaa(r=0.7664**)。Among free amino acids, the amplitude of Aspartic acid and Glutamic acid was most significant in the maturity process; other main amino acids such as Isoleucine, Leucine, Phenylalanine etc had different content change in different ripening stage; among indispensableamino acids, Histidine and Arginine had great variety in the process of maturity. Nitrogen had great influence on Glutamic acid in the prophase of fruit maturity. 4. The main ingredients of soluble sugar in strawberr...