Fig 1.
Diagram of the flavonoid pathway.
The enzymes for each step are italicized, with the following enzymes required for anthocyanin biosynthesis: chalcone synthase (CHS), chalcone isomerase (CHI), flavanone-3-hydroxylase (F3H), dihydroflavonol-4-reductase (DFR), anthocyanidin synthase (ANS), anthocyanidin reductase (ANR) and UDP-glucose: flavonoid-3-O-glycosyltranferase (UFGT).
Table 1.
Low light treatment of purple pak-choi seedlings in a phytotron.
Fig 2.
Effects of low light treatment on chlorophyll a (A), chlorophyll b (B), carotenoid (C) and anthocyanin (D) content in leaves of purple pak-choi seedlings. The data are the mean of three replicates, and SDs are shown as vertical bars. The means marked with different letters indicate significant differences between treatments at p<0.05, as determined with Duncan’s multiple range test. Different lower-case letters at each time point indicate significant differences between treatments. FW is the abbreviation of fresh weight.
Fig 3.
Effects of low light treatment on photosynthetic rate (Pn) (A), stomatal conductance (Gs) (B), intercellular CO2 concentration (Ci) (C), and transpiration rate (Tr) (D) of purple pak-choi seedlings. The data are the mean of three replicates, with SDs shown as vertical bars. The means marked with different letters indicate significant differences between treatments at p<0.05, as determined with Duncan’s multiple range test. Different lower-case letters at each time point indicate significant differences between treatments.
Fig 4.
Effects of low light treatment on the MDA (A) content and the soluble protein (B) content in leaves of purple pak-choi seedlings. The data are the mean of three replicates, with SDs shown as vertical bars. The means marked with different letters indicate significant differences between treatments at p<0.05, as determined with Duncan’s multiple range test. Different lower-case letters at each time point indicate significant differences between treatments. FW is the abbreviation of fresh weight.
Fig 5.
Effects of low light on guaiacol peroxidase (G-POD) (A), catalase (CAT) (B), ascorbate peroxidase (APX) (C) and superoxide dismutase (SOD) (D) activities in the leaves of purple pak-choi seedlings. The data are the mean of three replicates, with SDs shown as vertical bars. The means marked with different letters indicate significant differences between treatments at p<0.05, as determined with Duncan’s multiple range test. Different lower-case letters at each time point indicate significant differences between treatments.
Fig 6.
Effects of low light on chalcone synthase (CHS), chalcone-flavanone isomerase (CHI), flavanone-3- hydroxylase hydroxylation (F3H), activities in the leaves of purple pak-choi seedlings.
The data are the means of three replicates, with SDs shown as vertical bars. The means marked with different letters indicate significant difference between treatments at p<0.05, as determined with Duncan’s multiple range test. Different lower-case letters at each time point indicate significant differences between treatments.
Fig 7.
A model of purple pak-choi grown under low light stress.
The 45 degree upward sloping black arrow indicates a rise, and the 45 degree downward sloping black arrow indicates a descent.