Can just one-second measurement of chlorophyll a fluorescence be used to predict sulphur deficiency in radish (Raphanus sativus L. sativus) plants?

Abstract

Nutrients deficiency (ND) in plants is one of the main factors adversely affecting plant growth and yield of agricultural and horticultural production. Usually detection of NDs in plants is based on visible symptoms or destructive chemical analysis. Recently chlorophyll a fluorescence is one of the most used approaches to investigate photosynthesis light-dependent reactions. It is widely accepted that it can inform about structural and functional changes in photosynthetic apparatus, especially under abiotic stresses including NDs. The aim of this research was to study the influence of sulphur deficiency on photosynthetic efficiency of two cultivars radish (Raphanus sativus L. sativus) – ‘Fluo HF1’ and ‘Suntella F1’, and to assess the potential of chlorophyll a fluorescence measurements in early detection of this stress. Our results showed the sulphur deficiency has decreased the electron transport rate, chlorophyll content, grana size, and, at some degree, net photosynthesis and stomatal conductance. The changes in photosynthetic machinery performance were observed earlier than the visible effects of sulphur deficiency. However, the photosynthetic apparatus of radish plants was not considerably affected by this stress. Some sensitive parameters of OJIP test were altered but we were not able to identify the sulphur deficiency stress based on the alteration of only one of these parameters. We conclude that the detection of specific stress reactions of plants to sulphur deficiency should be based on integrative analysis of the response of the photosynthetic machinery. Such stress induced reactions can be detected by Principal Component Analysis of a large number of JIP-test parameters.