Characterization of Rice (Oryza sativa L.) Physiological Responses to α-Tocopherol, Glycine Betaine or Salicylic Acid Application

The impacts of α-tocopherol, glycine betaine (GB) and salicylic acid (SA) applications on higher plants have been the subject of many studies, with special emphasis on oxidative stress tolerance under adverse conditions. However, little work has been carried out on rice responses to α-tocopherol, GB or SA under non-stress conditions, in which yield could potentially increased. This study determined the effects of α-tocopherol (2.3 kg ha), GB (2.0 kg ha) or SA (12.9 g ha) application on rice morphology, phenology and physiology under non-stress conditions. The applications did not affect production of tillers, biomass, phenology, or pollen germination; however, plant height, leaf characteristics and physiology, spikelet fertility (SF), panicle and grain characteristics and yield were affected. Plants treated with α-tocopherol, GB or SA showed 6%, 13% and 13.5% increases in grain yield as a result of decreased respiration and increased membrane integrity and SF.