Study On The Characteristics Of ¹⁵N Absorption, Partition And Translocation Of Strawberry(Fragaria Ananassa Duch Cv.'Selva') In Greenhouse

The characteristics of ¹⁵N absorption, partition and translocation of strawberry(Fragaria ananassa duch cv.'Selva') were studied. The results showed that:1. The technique of isotope ¹⁵N-labelled urea is used to study the characteristics of ¹⁵N absorption, partition and translocation of strawberry (Fragaria ananassa duch cv.'Selva). The maximum rate of ¹⁵N absorption and utilization was 59.33%. ¹⁵N was absorbed by the root rapidly. The rate of ¹⁵N absorption and utilization was 39.89% after applying nitrogen fertilizer for half a month.But in the following three months the rate of ¹⁵N absorbtion and utilization did not markedly change. The ¹⁵N distribution center changed with the growth and development of strawberry. Ndff% was etween 5.04～26.39%.2. After the ¹⁵N nitrogen fertilizer was fertilized in winter, ¹⁵N was firstly transported to the leaves .So the quantity of ¹⁵N in the leaves were remark- able higher than other organ .But the Ndff% of every organ all was very low,beween 5.34% and 18.36% .The ¹⁵N was absorbed quickly by strawberr- y and the rate of ¹⁵N absorbtion and utilization reach to 31.08% after ¹⁵N fertilized half a month. The rate of ¹⁵N absorbtion and utilization reach to 31.34% after ¹⁵N fertilized one month .There were great fruit that had riped for the three month and took away great ¹⁵N, so after the fruit was picked, the root absorbed ¹⁵N to recruit every organ , at this time.The rate of ¹⁵N absorbtion and utilization reach to 37.08%. The rate of ¹⁵N distrbution of every organ was different in the different period.3. The Ndff% of every organ was low ,between 4.47% and 11.63% ,after the ¹⁵N nitrogen fertilizer was fertilized in spring .But the NDFF% of the immature leaves , bud and fruit was higher than other organ . The quantity of ¹⁵N absorption was different from other organ.The rate of ¹⁵N absorbtion and utilization reach to 30.34% after the ¹⁵N nitrogen fertilizer fertilized for half a month . There was no great difference for one month (31.93%) .After three month ,the rate of ¹⁵N absorbtion and utilization became to remarkab- le descend (38.79%). With the growth of strawberry , the rate of ¹⁵N distrbu- tion of every organ was different.4. The rate of ¹⁵N absorbtion and utilization reach to 24.06% , after the ¹⁵N nitrogen fertilizer was fertilized for three month . The rate of ¹⁵N absorbtion and utilization became to descend thanks to the high temperature and light intensity .There was great freaky bud , fruit had taken place and the funct- ional leaves became to quickly aging . The Ndff% of every organ was all low, between 1.72% and 10.09%. The Ndff% of immature leaves , bud and fruit was higher than other organ. The rate of ¹⁵N distrbution of leaves was higher than other organ. Only when the fruit and bud quickly grew , the distrbution of leaves became to descend and the distrbution of bud and fruit became to ascend.5. The quantity of ¹⁵N absorption was different from one organ to another, after the ¹⁵N nitrogen fertilizer was fertilized in autumn. The Ndff% of every oagan was all low ,between 1.36% and 12.49%.The ¹⁵N can be absorbed quickly and the rate of ¹⁵N absorbtion and utilization reach to 31.01% .Then in the next month ,there was no great changes of the rate of ¹⁵N absorbtion and utilization(31.77%). After the ¹⁵N nitrogen fertilizer was fertilized for three month , the rate of ¹⁵N absorbtion and utilization became to remarkable ascend(40.98%). The rate of ¹⁵N distrbution of every organ was different in different period in autumn .6. The maximum rate of ¹⁵N absorbtion and utilization was 36.9%(the functional leaves); the lowest was 31.9%(the immature leaves) and 32.9%(the effete leaves) was in the middle.With the different treatments, the rate of ¹⁵N distrbution of every organ was different. The lowest rate of ¹⁵N distrb-ution (10.43%) and Ndff% (8.94%) of bud and fruit occurred when the functional leaves were treaded . The rate of ¹⁵N distrbution of every organ was low .7. The ¹⁵N nitrogen fertilizer treatment could significantly improve the net photosynthetic rates of different age leaves;the best effect was the treatment of the functional leaves;the worst effect was the immature leaves; the effete leaves was among them. When the functional leaves were treated, the avera- ge net photosynthetic rates of the functional leaves were significantly higher than the effete leaves,the effete leaves′were significantly higher than the immature leaves′and the immature leaves′were significantly higher than the functional leaves′that were not been treated with ¹⁵N nitrogen fertilizer. 8. The Ndff% of every organ was all low,between 3.36% and 20.62%, when the functional leaves were treaded with ¹⁵N nitrogen fertilizer at the same season . The rate of ¹⁵N absorbtion and utilization became more and more bigger(from 28.35% to 42.09%) with the growth of the strawberry.But the rate of ¹⁵N absorbtion and utilization of bud and fruit firstly ascended and lastly descended. At the very start of fruit growth ,the nitrogen nutrition was needed little. With the fruit quickly growth , the nitrogen nutrition quantity was needed more and more . The nitrogen nutrition in the leaves and roots were absorbed by the fruit .The rate of ¹⁵N distrbution of every organ was different .when the bud and fruit quickly grew , ¹⁵N(all the organ) was transported to the fruit .After the quickly growth , the ¹⁵N was stored in the subterranean organ.9. The Ndff% of every organ was different from plant to plant, between 0.62% and 20.62%. The maximum rate of ¹⁵N absorbtion and utilization occured in winter(36.9%) and lowest occured in summer (22.87%) in different season.The rate of ¹⁵N absorbtion and utilization in summer descended and was lower than other season because of the high temperature and light intensity. The rate of ¹⁵N distrbution of leaves was higher than the subterranean organ,because the ¹⁵N was treated on the functional leaves and the nitrogen nutrition needed by the subterranean organ was supplyed by the fine root.