CORRELATION OF SPAD-502 METER READINGS WITH PHYSIOLOGICAL PARAMETERS AND LEAF NITRATE CONTENT IN BETA VULGARIS

摘要

A Minolta SPAD-502 leaf chlorophyll meter was used for the rapid and nondestructive evaluation of leaf chlorophyll, physiological parameters and nitrate concentrations of the field cultured plant Beta vulgaris L. This research included nondestructive field measurements of leaf chlorophyll with the SPAD meter and physiological parameters such as photosynthesis rate, transpiration rate and stomata conductance measured with a LCI portable photosynthesis system. Also, the extracted leaf total chlorophyll (TCHL) and nitrate content were measured by spectrophotometric methods. Leaf extracted TCHL was linearly and positively correlated to SPAD readings. A linear correlation has also been observed between SPAD readings and the physiological parameters of the leaves, such as photosynthesis, transpiration and stomata conductance. SPAD readings may be used as an indirect indicator of Beta vulgaris L. nitrogen status since these readings were related linearly to NO_3~- leaf concentration.