Improved chilling resistance of Stylosanthes guianensis by combining salicylic acidwith sodium nitroprusside treatments

To explore the effects of exogenous salicylic acid (SA) and nitric oxide (NO) treatment on chilling resistance of Stylosanthes guianensis, 35～40 oldday seedlings were employed as experimental materials. Results indicated that separated treatment of SA or NO donor sodium nitroprusside (SNP) could improve activities of antioxidant enzymes of superoxide dismutase (SOD) and catalase (CAT), and contents of total soluble sugar, proline and relative water, and decrease relative electric leakage and malondialdehyde (MDA) content in leaves, thus alleviating negative injuries of chilling stress. Furthermore, combining SA with NO donor sodium nitroprusside treatments could improve the resistance to chilling stress much more than SA or NO treatment separately. It was suggested that both SA and NO are involved in signal transduction for controlling resistance to chilling stress.