Chlorophyll a Fluorescence – a Novel Tool for Diagnosis of Manganese Deficiency in Crops

Keywords: manganese, deficiency, latent, diagnosis, manganese efficiency, chlorophyll a fluorescence.

Manganese deficiency is one of the major unsolved nutritional problems in agriculture in Northern Europe. During the past 15 years the occurrence and severity of this nutritional disorder has increased significantly. Remediation of the problem is challenged by the fact that manganese deficiency is not easily diagnosed, neither by analysis of soil or plant tissue. In addition, foliar manganese sprayings are rather inefficient. It has been observed that barley genotypes with the ability to grow with low amounts of plant available manganese can be used to minimise the risk of mild manganese deficiency. However, the mechanisms of manganese efficiency are not well understood and often inconsistently expressed. Consequently, diagnostic tools sensitive to latent manganese deficiency are urgently needed. It is well known that manganese limitation affects photosynthetic performance because of the non-redundant role of manganese in photosystem II. We here present a non-destructive diagnostic tool based on chlorophyll a fluorescence for monitoring photosynthetic performance thereby enabling a specific diagnosis of manganese deficiency in plants.

Pai Pedas, Sidsel B Schmidt, Kristian H Laursen and Søren Husted, University of Copenhagen, Faculty of Science, Department of Plant and Environmental Sciences, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark.

20 pages, 4 figures, 70 references.