Abstract:

In this study，results of liquid chromatography analysis showed sucrose content in leaves of cucumber seedlings under shading treatment was slightly higher than control. While galactinol，raffinose and stachyose contents of shading leaves were lower than that of control. The change of galactinol synthase activity was consistent with galactinol synthase genes expression level，which of shading leaves were lower than control；the activity of raffinose synthase is not significantly different between shading leaves and control，while the transcription level of raffinose synthase genes under shading condition was significantly lower than control；the activity of stachyose synthase of shading leaves was lower than control，and the expression level of stachyose synthase genes was consistent with the activity. In addition，the expression level of SNF1-related protein kinase 1 gene（SnRK1）of shading leaves was higher than control at 12：00 am of first day under 6 h shading treatment，which indicated that SnRK1 occurred in response of shading stress. Together，these results suggested that under shading stress the gene expression and activities of galactinol synthase，stachyose synthase，and SnRK1 in cucumber were regulated to maintain the content of sucrose，provide the energy for growth，and ensure the survival of leaves.

Key words: Cucumis sativus, galactinol synthase, raffinose synthase, stachyose synthase, SNF1-related protein kinase 1