Fibre optic spectrophotometry monitoring of plant nutrient deficiency under hydroponics culture conditions

In this paper, fibre optic spectrophotometry (FOSpectr) was adapted to provide early detection of plant nutrient deficiency by measuring leaf spectral reflectance variation resulting from nutrient stress(1,2). Leaf reflectance data were obtained from a local vegetable crop, Brassica chinensis var parachinensis (Bailey), grown in nitrate-nitogen (N)- and calcium (Ca)-deficient hydroponics nutrient solution. FOSpectr analysis showed significant differences in leaf reflectance within the first four days after subjecting plants to nutrient-deficient media. Recovery of the nutrient-stressed plants could also be detected after transferring them back to complete nutrient solution. In contrast to FOSpectr, plant response to nitrogen and calcium deficiency in terms of reduced growth and tissue elemental levels was slower and less pronounced. Thus, this study demonstrated the feasibility of using FOSpectr methodology as a non-destructive alternative to augment current methods of plant nutrient analysis.