Comparative Assessment of UV-B Priming on Vegetative and Reproductive Stages of Oat and Barley

Abstract

Barley and oat were irradiated with elevated UV-B (+ 3.6 kJ m−2 d−1; 280–315 nm) during the vegetative stage, and their performances were evaluated at the tillering and panicle development stages (PDS). Physiological and biochemical measurements revealed that barley and oat performed almost alike against UV-B at the tillering stage, but the stress imprints led barley to display better performance at the PDS. Chlorophyll content increased under elevated UV-B in both the test crops with a higher increase in barley. Also, efficient synthesis of UV-B-absorbing compounds, i.e. flavonoids and phenolics in barley at the PDS, protected the photosynthetic machinery. Both the crops showed stimulations in growth responses under elevated UV-B except for root length in oat at the PDS. At the PDS, the reduction in total biomass of oat was accompanied with increased biomass allocation to the root portion suggesting the limiting factor for growth was belowground. Results clearly showed that UV-B priming during the vegetative stage enhanced tolerance against stress at the PDS in barley, whereas oat showed recovery for most of the measured parameters except ascorbic acid and biomass. Therefore, improved plant tolerance against UV-B during the panicle growth in barley is meaningful for a higher productivity.