Photosynthesis and biomass allocation of radish cv. “Cherry Belle” in response to root temperature and ozone

Abstract

To determine if ozone (O 3) and root zone temperature (RZT) affect plant biomass allocation and photosynthesis, radish ( Raphanus sativus) plants were grown in controlled environment laboratory chambers in one of four treatments: episodic O 3 (average delivery 0.063 μmol mol −1) with RZT at 13°C, episodic O 3 (same delivery) with RZT at 18°C, charcoal-filtered air with RZT at 13°C and charcoal-filtered air with RZT at 18°C. O 3 reduced total biomass and shoot biomass of radish at 13°C RZT but had no effect at 18°C RZT. Low (13°C) RZT decreased total biomass in both O 3 and charcoal-filtered air. RZT had no overall effect on biomass allocation, but O 3 lowered root-to-shoot ratios for plants grown at 18°C RZT. Photosynthesis was reduced for plants grown at 18°C RZT and O 3, but stomatal conductance was not affected by O 3 nor RZT. These results indicate that O 3 and low RZT decrease biomass, but that plant photosynthesis is decreased by O 3 and warm RZT.