Signaling mechanism mediating the anti-senescence effect of low-concentration chemical stressors sprayed onto bean seedlings

The anti-senescence effect of low-concentrations of some stress-inducing compounds of different toxicity and chemical nature such as Cd and Pb salts or 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) was investigated in the primary leaves of bean seedlings. In these leaves treated by spraying, chlorophyll content and photosynthetic activity increased, the active cytokinin content of roots and leaves was also significantly higher as compared to the control. These symptoms of stimulation could be eliminated by the inhibitors Li and PD [2-(2′-amino-3′-methoxyphenyl)-oxanaphthalen-4-one] added to each agent, indicating the involvement of PIP2-IP3/DAG and MAPK signaling pathways, respectively, in the response.