Difference of Chlorophyll Fluorescence Parameters in Leaves at Different Positions and Its Relationship with Nitrogen Content in Winter Wheat Plant
For diagnosing nitrogen (N) nutrient status in winter wheat plant based on fluorescence parameters of leaves, two cultivars with Aikang 58 (mid-protein content) and Zhengmai 366 (high-protein content) were used in experiments with N application rates of 0, 90, 180, and 270 kg ha"1 in 2008-2009 and 2009-2010 growing seasons. The fluorescence parameters were measured in the first, second, third, and fourth leaves from the top of plant from jointing to maturity stage. The N contents and bio-masses of leaf and culm were determined through destructive sampling and chemical assay. The leaf N contents at different leaf positions were significantlycorrelated with fluorescence parameters from jointing to booting stage (P < 0.01). The correlation coefficients of N content with Fm, Fv, Fv/Fm, and Fv/Fo were 0.557, 0.601, 0.619, and 0.633, respectively. The fluorescence parameters of the top three leaves had small differences, which were much higher than those of the fourth leaf from the top. However, the differences reduced gradually with the increase of N application rate. This indicated a sensitive response of leaf position to N application. The differences of Fv/Fo and Fv/Fm between the fourth and the first leaves (LPD4-1) were significantly correlated with N content in plant (PNC) at jointing stage (R2 = 0.644 for Fv/Fo and R2 = 0.651 for Fv/Fm); whereas, the differences of Fv/Fo and Fv/Fm between the fourth and the second leaves (LPD4_2) had less accurate predictions with smaller R2 values (R2 = 0.626 for Fv/Fo and R2 = 0.592 for Fv/Fm). At booting stage, linear equations were obtained for Fo, Fv, and Fm differences (LPD4-n) between the fourth and the top three leaves (R2 = 0.726 for Fo, R2 = 0.791 for Fv, and R2 = 0.784 for Fm). Using independent datasets to predict PNC at jointing stage with the LPD4-1 and LPD4-2 equations based on Fv/Fo and Fv/Fm, the R2 values for LPD4-1 were 0.844 and 0.828 with relative errors of 13.0% and 16.7%, respectively; and the R2 values for LPD4-2 were 0.793 and 0.813 with relative errors of 16.9% and 18.4%, respectively. The result showed that the estimations were reliable. At booting stage, the best prediction of PNC was from the LPD4-n equation based on Fv and Fm, and R2 values were 0.831 and 0.815 with relative errors 13.2% and 16.4%, respectively. In conclusion, the LPD4-1 equation based on Fv/Fo at jointing stage and the LPD4-n model based on Fv at booting stage are applicable to estimate PNC of wheat.
Winter wheatNitrogen content in plantLeaf positionFluorescence parameters
国家科技期刊平台
NSTL
万方数据
维普
