The aim of our study was to investigate the underlying molecular mechanisms of exogenously supplied trehalose affecting wheat photosynthesis under heat stress. The amount of ATP synthase (ATPase), oxygen-evolving enhancer protein (OEE), PsbP, Rubisco, chloroplast fructose-bisphosphate aldolase (FBPA), and ferredoxin-NADP(H) oxidoreductase (FNR) were downregulated, while PSI reaction center subunits were upregulated under heat stress. However, in the trehalose-pretreated groups, the amount of FNR, cytochrome b 6 f complex, PSI reaction center subunits, ATPase, FBPA, and Rubisco were upregulated under normal growth conditions and heat stress. Besides, during the recovery period, the upregulation in CAB, PsbP, OEE2, and ATPase suggested that trehalose pretreatment might help to the recovery of PSII and PSI. These results indicate that trehalose pretreatment effectively regulates the levels of the photosynthesis-related proteins and relieves the damage of heat stress to wheat chloroplast.

In China, Scrophularia ningpoensis Hemsl (Scrophulariaceae) has been cultivated for many years; however, the effects of drought on the content of secondary metabolites in Radix Scrophulariaceae are still unknown. The study investigated the medicinal components of S. ningpoensis including harpagoside, aucubin, catalpol, harpagide, and cinnamic acid in relation to drought stress. Three ecotypes of S. ningpoensis at seedling stage were subjected to progressively three levels of osmotic stress for 10 days and then the superoxide anion content of leaves at different stages was determined, as well as the content of the components in the roots of S. ningpoensis detected by High-Performance Liquid Chromatography (HPLC). The contents of four iridoids glycosides in the roots along with the superoxide anion content in leaves under osmotic stress were higher than those with no osmotic stress in every ecotype, whereas cinnamic acid decreased. Drought stress could increase the iridoid glycosides and decrease the cinnamic acid content of roots in S. ningpoensis seedlings.