Stress induced plant resistance and enzyme activity varying in cucumber.

When pathogens penetrate plant cells, some chemical secretions are elicited, and the mechanical signals in plant cell may be induced by the simultaneous physical pressure to change. Based on the previous cognitions, we investigated the plant resistance and the variation of anti-disease enzyme activity in cucumber leaves after mechanical stress loading. Results showed that the appropriate mechanical stimulation could significantly improve plant resistance and alter the activity of phenylalanine ammonial lyases (PAL) and POD, leading to synthesis of lignin. However, we found that the effects of the stress on these cellular fundamental events were eliminated when the adhesion between plasma membrane and cell wall was disrupted. We speculated that mechanical signal transduction in plants depend on the adhesion of plasma membrane-cell wall.