Study on nitrogen stress distributing rule of canola

摘要

In this paper, in order to find a simple, quick and untouched method to check the level of nitrogen in canola, the spectral reflectance and SPAD values of the canola leaves of fifteen regions were measured by an ASD Field Spec(R) and SPAD 502 chlorophyll meter. The measurements were carried out at experiment field in Zhejiang University during growth season of 2004 to 2005. The authors combine the vegetal course of canola, and use SPAD 502 chlorophyll meter to investigate the distributing rule of chlorophyll concentration of the canola; Measure the third ramous of the canola from top, and analyze the variation rule of the chlorophyll concentration in different vegetal course. The spectral reflectivity property of canola leaves in different growing periods was analyzed, the spectral reflectance of the leaves were gradually getting smaller in the visible region and bigger in the near infrared region before flowering, but with reverse change after flowering. The authors also achieve the chlorophyll concentration and reflectance of 32groups of canola leaves and investigate the quantitative relationships between them by correlation analysis. The results reveal that they have good relationship in the range of 510-640nm and 685-720nm, and the peak of the correlation is at the wavelength of 707nm.