Study on Seasonal Variation of Mineral Elements Content in Pingguoli Pear Fruits

The mineral elements content in apple_pear fruits were changed regularly in a certain degree with the season.The content of N,P,K,Ca and Mg was the highest point in the young fruit period,it reduced with fruit expansion,and reached the lowest point in the mature period.The changes of Fe and B content were great,the content of Fe and B was high in the young fruit period,it reduced the lowest point at the end of July,then it showded increasing trend with the fruit growth.The changes of Zn and Mn content were smooth,the content of Zn and Mn showed decreasing trend and it had a little increase in the late period of fruit growth.Between fruits and leaves,Ca and Mn showed significant negative correlation,but P and K showed significant positive correlation.The content of P was the highest among the major element,about 55% of the total macroelements,and the content of nitrogen was the second.The content of iron was about 60% of the total microelements,the content of boron was the second,the elements of N,Ca and Mg are the five index of the fruit quality,which play a great function,the elements of Fe,Zn,B and Mn play an important role,the element of Fe has two index are the first in the five index of fruit quality.The multi_analysis showed that there are complicated interact between the mineral elements of fruit.The direct effects of various elements upon the total sugar content,interaction among elements,and their indirect effects upon total sugar content were made clear through path coefficient analysis.