Physiological effects of BA and ABA on caixin seedlings

Abstract

Adult caixin (<i>Brassica chinensis</i> var <i>parachinensis</i>) plants are widely consumed by Asians, yet potential health benefits of its seedlings are hardly explored. This study aimed to determine physiological effects of BA, ABA, and heat stress on caixin seedlings. BA application maintained juvenility of caixin seedlings, as concentrations of chlorophylls and carotenoids, and photochemical quenching of BA-grown seedlings were higher than control- and ABA-grown seedlings. Non-photochemical quenching (NPQ) of ABA-grown seedlings was higher than control- and BA-grown seedlings. Heat-stressed (45 &#0176;C, 15 min) ABA-grown seedlings showed lowered Fv/Fm decrease and smaller NPQ increase, suggesting that ABA partially alleviated effects of heat stress.Activity staining of native-PAGE gels in DDC and H&#8322O&#8322 revealed that all 3 SOD isoforms (Cu/Zn, Mn, Fe) were present. Transcript levels of Cu/ZnSOD, MnSOD and HSP90 increased due to ABA and/or heat applications. FeSOD expression level did not change during heat stress, and was absent in ABA-grown seedlings.