The flower stalk is the product organ of flowering Chinese cabbage (Brassica campestris L. ssp. chinensis var. utilis Tsen et Lee), which is cultivated extensively in South China.  Flower stalk formation and development, including bolting and flowering, determine the yield of flowering Chinese cabbage; however, the bolting and flowering mechanisms remain to be explored.  To elucidate these processes, we studied the effects of low-temperature and gibberellin (GA) treatments, and their interaction, on stem elongation, bolting time, flowering time, hormone content, and cell morphology in stem of flowering Chinese cabbage.  The results showed that both cold and GA treatments accelerated bolting time, stem elongation, and flowering time.  Moreover, cold and GA cotreated plants displayed additive positive effects.  In addition, cold treatments increased the GA, indole-3-acetic acid, and cytokinin contents and altered cell size in the shoot apices of flowering Chinese cabbage.  Treatment with uniconazole, a GA synthesis inhibitor, strongly delayed bolting time, stem elongation, and flowering time, whereas GA, but not cold treatment, rescued this inhibition, indicating that low temperature accelerates bolting and flowering not only through inducing GA in the shoot apices, but also other ways.  These results provide a theoretical basis for further dissecting the regulatory mechanism of bolting and flowering in flowering Chinese cabbage.

Lycopene, one of the strongest natural antioxidants known and the main carotene in ripe tomato, is very important for human health.  Light is well known to be one of the most important environmental stimuli influencing lycopene biosynthesis; specifically, red light induces higher lycopene content in tomato.  However, whether blue light promotes lycopene synthesis remains elusive and exactly how light stimulation promotes lycopene synthesis remains unclear.  We applied supplemental blue and red lighting on tomato plants at anthesis to monitor the effect of supplemental blue and red lighting on lycopene synthesis.  Our results showed that supplemental blue/red lighting induced higher lycopene content in tomato fruits; furthermore, we found that the expression of key genes in the lycopene synthesis pathway was induced by supplemented blue/red light.  The expression of light signaling components, such as red-light receptor phytochromes (PHYs), blue-light receptor cryptochromes (CRYs) and light interaction factors, phytochrome-interacting factors (PIFs) and ELONGATED HYPOCOTYL 5 (HY5) were up- or down-regulated by blue/red lighting.  Thus, blue and red light increased lycopene content in tomatoes by inducing light receptors that modulate HY5 and PIFs activation to mediate phytoene synthase 1 (PSY1) gene expression.  These results provide a sound theoretical basis for further elucidation of the light regulating mechanism of lycopene synthesis in tomatoes, and for instituting a new generation of technological innovations for the enhancement of lycopene accumulation in crop production.