低磷胁迫对红豆草新品系幼苗生长及生理特性的影响

Effect of low-phosphorus stress on growth andphysiological characteristics of new sainfoinlines at seedling stage

摘要:

以红豆草新品系P1,P2,P3为材料,甘肃红豆草(CK1)、蒙农红豆草(CK2)为对照,研究不同供磷水平(0.01、0.30、0.60和1.00 mmol/L KH₂PO₄)对红豆草生长、根系形态和叶、根生理特性的影响,探讨红豆草适应低磷胁迫的机制。结果表明,低磷胁迫(0.01、0.30、0.60 mmol/L KH₂PO₄)显著降低了红豆草的株高、根体积、根表面积、根长和根尖数、叶片相对含水量、根系活力、根系可溶性糖、根系可溶性蛋白以及丙二醛(MDA)含量,但显著增加了叶片脯氨酸和MDA含量,叶片可溶性糖、可溶性蛋白、叶绿素含量及根系脯氨酸含量均随磷梯度的增加先升高后降低,且整个胁迫期间,红豆草叶片脯氨酸、可溶性糖和MDA含量均大于根系,而可溶性蛋白含量恰好相反。经隶属函数法分析得出红豆草新品系P2更耐低磷胁迫并优于2个对照,新品系P1和P3优于蒙农红豆草。

Abstract:

Sainfoin (Onobrychis viciaefolia),known as “the queen of forages”,is an important legume in temperate grasslands of northern China,whereas there is little information on the effect of phosphorus deficiency on physiological properties of sainfoin.In this study,using the new sainfoin lines P1,P2,and P3 as materials,O.viciaefolia ‘Gansu’ (CK₁) and O.viciaefolia ‘Mengnong’ (CK₂) as control,we investigated the effects of different phosphorus levels (0.01,0.30,0.60,and 1.00 mmol/L KH₂PO₄) on the growth,root morphology,leaf and root physiological characteristics of sainfoin,and explored the mechanism of sainfoin adapting to low-phosphorus (P) stress.Results showed that under low-P stress (0.01,0.30,and 0.60 mmol/L KH₂PO₄),there was a significant decrease in plant height,root volume,root surface area,root length and root tip number,leaf relative water content,root activity,root soluble sugar,root soluble protein,and MDA contents,respectively,while the contents of proline and MDA in leaves increased significantly;the contents of soluble sugar,soluble protein,chlorophyll in leaf and root proline content increased first and then decreased with the increase of phosphorus concentrations;meanwhile,the contents of proline,soluble sugar and MDA in leaf were higher than those in root,while soluble protein content was opposite during the whole period of stress.A subordinate function was used to rank their tolerance for phosphorus deficiency,and the order was: P2＞CK1＞P3＞P1＞CK2.