Abstract:

In order to study the presenility pathogenesis of walnut leaves, changes of main mineral elements contents in presenility leaves at different stages and healthy leaves at the same stages were measured. The results showed that N contents in healthy leaves at different stages were 23.4,21.4,22.9,19.8 g·kg^-1 respectively, but in presenility leaves were 22.3,18.2,18.6,17.6 g·kg^-1 respectively. N contents in healthy leaves were higher than that of presenility leaves except at the initial stage of the disease. P contents in healthy leaves at different stages were 1.3,1.5,1.5,1.4 g·kg^-1 respectively, but in presenility leaves were 1.1,1.4,0.6,0.6 g·kg^-1 respectively, P contents in healthy leaves were significant higher than that of presenility leaves, in the later stage of the disease P content in healthy leaves was very significant higher than that of presenility leaves. Mn contents in healthy leaves were very significant higher than that of presenility leaves after middle stage of the disease. Ca contents in healthy leaves at different stages were 34.7,30.9,34.1,35.5 g·kg^-1 respectively, but in presenility leaves were 33.3,34.3,37.9,43.3 g·kg^-1 respectively, Ca content in presenility leaves was very significantly higher than that of healthy leaves in the later stage of the disease. Fe contents in healthy leaves were very significant higher than that of presenility leaves in the middle and later stage of the diseases. There exited significant negative correlations between Mn contents and disease process, the correlation coefficient was -0.975 0. There exited significant positive correlation between Ca contents and disease process, the correlation coefficient was 0.952 6. There exited very significant negative correlations between the ratios of Mn/Ca and Mn/Fe, the correlation coefficients were -0.993 4 and -0.991 4. The path coefficients showed that the direct path coefficient of Ca was -3.921,and it was the largest; next was Mn, that was -2.959; total N was the lowest, only -0.249.

Key words: early fruit walnut, leaf presenility, mineral element