3. Results
3.1. Endogenous NO level, isoflavone content and activity and gene
expression of isoflavone biosynthetic-enzymes in soybean sprouts
Results showed that NO level of the soybean sprouts treated
with UV-B was much higher than that of the control (Fig. 1A), indicating
that UV-B exposure induced NO generation. The highest NO
level was observed on day 2 after UV-B treatment (Fig. 1A), which
was 9.2 times that of the control. UV-B-induced NO generation
decreased to the level of the control by treatment with 0.5 mM
cPTIO, which could be reversed through application of SNP. It could
be concluded that NO increase in soybean sprouts was truly
induced by UV-B radiation.
Besides, UV-B exposure up-regulated the activity (Fig. 2A–D)
and gene expression levels (Fig. 2E–H) of biosynthetic-enzymes
and the content of isoflavone (Fig. 1B). Moreover, the highest activity
of isoflavone biosynthetic-enzymes was observed on day 4 or 6