Analysis of Phosphorus, Potassium and Calcium Accumulation in Grape Leaves by Synchrotron Radiation X-Ray Fluorescence

Abstract

Grape (Vitis vinifera L.) requires 16 essential nutrients in balance quantity. When elements are deficient or imbalances, growth and yield will be significantly reduced. Nutrient deficiency in grape can be diagnosed by chemical analysis. However, it is time consuming technique and requires large amount of plant samples. Synchrotron radiation X-ray fluorescent (XRF) has been used to detect certain types of mineral nutrients in various materials. It is a fast technique and requires small amount of samples. The objectives of this research are to study plant nutrient status and to study the possibility of using the XRF for plant nutrient analysis in grape leaves. The experiment design was randomized complete block design (RCBD) with 3 replications. Seven methods of irrigation and fertilizer applications were applied to grape variety Marroo Seedless. Leaf nutrients including phosphorus, potassium and calcium were analyzed by chemical and synchrotron XRF technique. The results showed that, with the chemical analysis, phosphorus and potassium contents in the leaves of all treatments except control (no fertilizer application) were in the sufficient range. Leaves calcium content in most treatments were in the deficient range except treatments with calcium application. Synchrotron XRF analysis results showed similar trend as chemical analysis. The regression and correlation analysis indicated the significantly positive correlation of the plant nutrient contents between the synchrotron XRF technique and the chemical method (R2 = 0.76, 0.77 and 0.90). The results implied that the synchrotron XRF technique could be applied for nutrient analysis and the diagnosis of nutrient status in grape.