Abstract: To explore the effects of low phosphorus stress on photosynthesis,chlorophyll fluorescence and endogenous hormones of sainfoin (Onobrychis viciaefolia),the nutrient solution sand culture method was used in this experiment. No. 5 with low phosphorus tolerance and No. 1 with low phosphorus sensitivity were used as test materials,and normal phosphorus (1.00 mmol · L^-1 KH₂PO₄) and low phosphorus (0.01 mmol · L^-1 KH₂PO₄) stress treatments were set,the changes of morphology,photosynthesis and endogenous hormone contents were measured after different stress days. The results showed that low phosphorus stress inhibited the growth and photosynthesis of sainfoin,under low phosphorus stress,except for photochemical quenching coefficient,chlorophyll fluorescence parameters of the tested sainfoin decreased,with the extension of stress time,the change trend of zeatin (ZT),abscisic acid (ABA),auxin (IAA) and gibberellin (GA₃) and their ratios in the aboveground and underground parts of the two materials were not consistent,and the low phosphorus tolerance coefficients of ZT,GA₃,IAA and ABA of above ground and below ground in the low phosphorus tolerant material were higher than those of the phosphorus sensitive material. Correlation analysis showed that IAA was significantly correlated with photosynthesis and chlorophyll fluorescence,and ABA was negatively correlated with IAA,ZT and GA₃. The results of this study can provide a theoretical basis for the study of low phosphorus tolerance characteristics of sainfoin.

Key words: Sainfoin, Low phosphorus stress, Photosynthesis, Endogenous hormones, Low phosphorus resistance coefficient

摘要： 为探究低磷胁迫对红豆草(Onobrychis viciaefolia)光合作用、叶绿素荧光以及内源激素的影响，本试验采用营养液沙培法，以耐低磷5号和磷敏感1号红豆草为试验材料，设置常磷(1.00 mmol·L^-1 KH₂PO₄)和低磷(0.01 mmol·L^-1 KH₂PO₄)胁迫处理，于不同胁迫天数后测定形态、光合以及内源激素含量变化。结果表明：低磷胁迫抑制红豆草生长和光合作用，在低磷胁迫下，除非光化学淬灭系数外，供试红豆草叶绿素荧光参数均下降。随着胁迫时间的延长，2份红豆草材料地上和地下部玉米素(ZT)、脱落酸(ABA)、生长素(IAA)和赤霉素(GA₃)及其之间的比值变化趋势不一致，耐低磷红豆草地上和地下部ZT，GA₃，IAA，ABA耐低磷系数大于磷敏感材料。相关性分析表明，IAA与光合作用和叶绿素荧光显著相关，ABA与IAA，ZT，GA₃呈负相关。研究结果可为红豆草耐低磷特性研究提供理论基础。

关键词: 红豆草, 低磷胁迫, 光合作用, 内源激素, 耐低磷系数