低氮胁迫下5个南瓜种质幼苗的生长生理响应及耐性综合评价OA

In order to screen pumpkin(Cucurbita moschata Duch.)germplasms with low-nitrogen toler-ance suitable for cultivation in Xinjiang,seedlings of five inbred lines(SPL25,BL24,DX-1,DXA25-1,DXA25-2)were used as materials.A substrate culture method was employed with low nitrogen(0.75 mmol/L)and normal nitrogen(7.00 mmol/L)treatments using Hoagland nutrient solution,and then changes in growth and physiological indices were analyzed.Stress tolerance coefficients were calculat-ed for each index,and a comprehensive evaluation was performed using principal component analysis and membership function method.The results showed that under low-nitrogen stress,plant height,leaf length,and leaf width of SPL25 and DX-1 showed no significant differences compared with the control(P>0.05).The contents of proline,soluble sugar,and soluble protein,as well as the activities of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT),and glutathione peroxidase(GPX),were signifi-cantly higher than those of the other three germplasms(P<0.05),while malondialdehyde(MDA)con-tent was significantly lower than that of other germplasms(P<0.05).The comprehensive evaluation values(D)were 1.82 and 1.62,respectively,markedly higher than those of DXA25-1(0.12),BL24(-0.53),and DXA25-2(-1.48).SPL25 and DX-1 were evaluated as strongly low-nitrogen tolerant materials,DXA25-1 and BL24 as moderately tolerant,and DXA25-2 as the most sensitive to low-nitrogen stress.In conclusion,SPL25 and DX-1 can serve as preferred materials for low-nitrogen tolerant pumpkin breeding and cultivation in Xinjiang.