14份乡土狼尾草材料幼苗的耐冷性综合评价OA北大核心CSTPCD

The aim of this study was to explore the effects of low temperature stress on the physiological characteristics of Pennisetum alopecuroides seedlings and to develop a multivariate evaluation of the cold resistance of different P.alopecuroides germplasm lines.Seedlings of 14 native P.alopecuroides germplasm lines were grown in peat soil in pots and subjected to low-temperature stress (25 ℃ as the control,and cold treatments at 4,0,-5 ℃).Then,the contents of chlorophylls,carotenoids,malondialdehyde,and osmoregulatory substances were determined,as well as antioxidant enzyme activity.The cold resistance of the 14 materials was evaluated by principal component analysis and the membership function method.As the low temperature stress became more severe,the contents of chlorophylls,soluble sugars,and proline as well as catalase (CAT) activity in the test seedlings first increased and then decreased,the carotenoid content and superoxide dismutase (SOD) activity increased gradually,the soluble protein content first increased,then decreased,and then slightly increased,whereas peroxidase (POD) activity showed a different trend.There were significant positive correlations among the photosynthesis-related indexes.The results of principal component analysis showed that photosynthetic factors,plasma membrane system factors,and osmotic regulatory factors of P.alopecuroides under low temperature stress could be used as traits for multivariate evaluation of cold resistance.On the basis of the D values obtained using the membership function multivariate evaluation method,L10 had strong cold resistance,while L4,L1,and L2 had weak cold resistance.The results obtained by the membership function evaluation method are accurate,objective,and reliable.Therefore,this method can be used for the evaluation of cold resistance and for screening low temperature-tolerant germplasm resources of P.alopecuroides.