Changes Of Mineral Elements In Leaves Of Red Raspberry And Effects Of Fertilization On Fruit Functional Components

As the third generation fruit,raspberry had been widely recognized by consumers in Europe and America,because of its special nutrition and healthy function,which has won the reputation of"King of Fruit"and"Golden Fruit"on the international market.Mineral elements were essential for the growth and development of red raspberry.The content of each element influenced the yield and quality of red raspberry directly or indirectly.The application of N,P,K fertilizer,in particular,had a significant effect on the yield and quality of red raspberry.In order to investigate the dynamic changes of mineral elements and functional components in leaves and fruits of red raspberry and the relationship between mineral elements and yield and functional components of red raspberry fruit,"Heritage"red raspberry was used as material,the field investigation and two-time saturated D-optimal design method were used to study the changes of mineral elements and functional components in leaves and fruits of red raspberry and the effects of different fertilization modes of N,P and K to provide a basis for rational fertilization of red raspberry.The main results were as follows:（1）The N contents in red raspberry leaves varied from 17.75 mg/g to 31.72 mg/g in the whole growth period,the variation range of P content was 4.57⁵.84 mg/g and the variation range of K content was 1.11².65 mg/g.The variation range of Ca content was5.53¹4.31 mg/g and the variation range of Mg content was 4.61-10.81 mg/g.The variation range of Fe content was 0.175⁰.656 mg/g and the variation range of Mn content was 0.023⁰.047 mg/g and the variation range of Cu content was 0.017⁰.054 mg/g.The variation range of Zn content was 0.017⁰.054 mg/g and the variation range of B content was 0.028⁰.077 mg/g.The N,P and K contents were decreased in the two leaf development period of red raspberry during the annual growth period,Fe,Zn and B showed an upward trend,while the Ca,Mg and Cu content showed some fluctuation,but the variation range was small.The N,Ca,Fe,Cu and B contents in fruit fluctuated greatly and the variation range of their contents were 10.07¹5.66 mg/g,2.60³.47 mg/g,0.11⁰.17 mg/g,0.054⁰.237mg/g,0.014⁰.023 mg/g respectively.The N,P,K,Ca,Mg,Fe,Cu,Zn and B contents in leaves were stable from July 18th to August 18th,therefore,from mid-July to mid-August could be used as a nutrition diagnostic period for all elements in leaves of red raspberry.The N,K and Fe content in leaves decreased significantly after May 3rd and the N,P and K content decreased after July 3rd and the P and K decreased significantly after September18th,so early May,early July and mid-September were the three key periods for fertilization of red raspberry.（2）SOD activity reached the highest that was 81.0765 U·g^-1FW at the end of the first fruiting period（September 3rd）;The anthocyanin content reached the highest that was0.1935 mg/g at the middle of the second fruiting period（October 18th）;The ellagic acid content reached the maximum of 12.9035 mg/g at the beginning of the second fruiting period（October 3rd）;The salicylic acid content reached the highest level that was 0.1105mg/g at the end of the second fruiting period（November 3rd）;The content of flavonoids reached the maximum of 0.5213 mg/g at the beginning of the first fruiting period（August3rd）.（3）The correlation between N and P,N and Cu,Ca and Mg,K and Mn,Ca and B content in leaf were very significant and the correlation coefficients were 0.88,0.70,0.88,0.61 and 0.91,respectively.The correlation between K and Ca,K and Mg,K and B,N and Zn,Cu and Zn,P and Zn content in leaf were also very significant,and the correlation coefficients were-0.51,-0.61,-0.78,-0.64,-0.74 and-0.66,respectively.The correlation between the each kind mineral element in leaf and K,Ca and Zn in fruit was significant and the proportion of significant correlation was 2/3.There correlation between leaf mineral elements and fruit functional components and fruit weight was low.The Ca and B content in leaf were significant positively related to SOD activity and flavonoids content in fruit,while P content was significant negatively related to SOD activity.The correlation between mineral elements and fruit weight was significant and the correlation coefficient between Fe content and fruit weight was 0.95.There was a significant positive correlation between Ca and SOD activity and total flavonoids and the correlation coefficients were0.92 and 0.95,respectively.The SOD activity was positively related to flavonoids content and the correlation coefficient was 0.910,while there was no significant correlation among other components.（4）The treatment of the mixture of N,P and K fertilizers had the most significant effect on the yield of red raspberry.Fertilization could significantly increase the SOD activity of red raspberry fruit and the best treatment was the mixture of N,P and K fertilizers.Fertilization had no significant effect on the single fruit weight and there was no significant difference between different fertilization treatments and control,while there was a negative effect on ellagic acid content.The contents of ellagic acid in 7 fertilizer treatments among the 9 fertilizer treatments were lower than that of the control.The treatment that the ratio of P and K fertilizer was 1:1 could significantly increase the content of flavonoids and N₃P₁K₃ treatment was the highest.The content of flavonoids of N₃P₁K₃treatment was 0.66 mg/g and that of P2K2 treatment was 0.60 mg/g,which was slightly lower than that of N₃P₁K₃.（5）The order of the effect of the N,P and K fertilizer on the yield of red raspberry was N>K>P;The order of the effect of P and K fertilizer on the quality of red raspberry was P>K.The integrated fertilization program with yield over 4500 kg/hm² and quality score above 80 was as follows:the range of N fertilizer was 82.26⁹8.24 kg/hm²,the range of P₂O₅ fertilizer was 97.25¹36.93 kg/hm²,the range of K₂O fertilizer was 104.66¹36.93kg/hm².The yield and quality of red raspberry were all excellent with that integrated fertilization program.