关键词: 百日草, 低钾胁迫, 水杨酸, 根系, 生长

Abstract: In order to ascertain whether exogenous salicylic acid can alleviate low potassium stress in plants,and provide new ideas and methods for improving plant tolerance to low potassium stress,the effects of different concentrations of salicylic acid［0(CK),0.25,0.50,0.75,1.00 mmol/L］on the growth of Zinnia elegans seedlings were studied using pot experiment under low potassium stress.The results showed that spraying salicylic acid increased the plant height and dry weight of the Zinnia elegans seedlings,and these two indexes showed a trend of increasing first and then decreasing with the increase of salicylic acid concentration，both of them reached the maximum when salicylic acid concentration was 0.75 mmol/L,the plant height reached 9.06 cm,71.27% higher than the control,and dry weight reached 0.19 g/plant,171.43% higher than the control.The root total length,total surface area，as well as the root length and surface area of the fine roots(diameter 0—0.3 mm) were the highest,and significantly higher than the control when treated with 0.75 mmol/L salicylic acid,which were 169.23%,141.63%,18.47% and 20.77% higher than the control group respectively.These results suggested that salicylic acid could alleviate the inhibition of low potassium stress on the growth of Zinnia elegans seedlings by promoting root growth,and 0.75 mmol/L was the best.

Key words: Zinnia elegans, Low potassium stress, Salicylic acid, Ｒoot system, Growth