多年生饲用狼尾草耐寒性评价研究OA

To clarify the key indicators for evaluating the cold tolerance of perennial forage Pennisetum spp.,a total of 42 Pennisetum germplasms were used as experimental materials in this study.Combining indoor low-temperature simulation with field trials,we analyzed the growth and physiological characteristics at the seedling stage and full growth period,overwintering rate,and their correlations of Pennisetum.The results showed that:Low-temperature stress significantly reduced seedling dry matter accumulation by 41.55%and plant height by 11.53%.The malondialdehyde(MDA)content in leaves and tiller nodes increased significantly by 90.43%and 108.48%,respectively.Osmotic regulation substances and antioxidant enzyme activities exhib-ited distinct responses to low temperature.A total of 9 indicators including soluble sugar and MDA contents in tiller nodes and leaves were screened out by principal component analysis to characterize cold tolerance at the seedling stage.Four accessions including'Sumu No.2''Guimu No.1',Hybrid Pennisetum No.7 and Sweet Elephant Grass exhibited strong cold tolerance with an above 75%overwintering rate,while WQ Hybrid Penni-setum and Chinese Forage Grass showed weak cold tolerance with a below 50%overwintering rate.The over-wintering rate was significantly negatively correlated with MDA content in tiller nodes,and significantly posi-tively correlated with bud soluble sugar content.Soluble sugar and MDA contents were crucial indicators for characterizing the cold tolerance of Pennisetum.This study provides a theoretical foundation for the breeding and innovation of new Pennisetum germplasms with high cold tolerance.