7个白杨无性系耐低氮性综合评价OA

[Objective]This research aimed to explore the growth and physiological response of 7 poplar clones under low nitrogen stress,and to select excellent poplar clones with strong low nitrogen tolerance from them.[Method]A pot experiment was conducted on 7 poplar clones,including 84K,Maobaiyang 30,Qinbai-yang 1,Qinbaiyang 3,Qinbaiyang 5,and Xibeiyang 1 and Xibeiyang 3.Seedlings were subjected to two nitrogen treatments:1 mmol/L NH₄NO₃(control,CK)and 0.01 mmol/L NH₄NO₃(low nitrogen,LN).After 60 days of treatment,growth and physiological parameters of poplar clones seedling were measured.Comprehensive evaluation of low nitrogen tolerance was conducted using correlation analysis,principal component analysis,and membership function analysis.[Result]Compared with CK,the growth indicators(seedling height increment,ground diameter increment,plant biomass),chlorophyll content,net photosynthetic rate,nitrogen accumulation(NH4+-N,NO3--N,NO2--N),and the activities of various enzymes(nitrate reductase(NR),nitrite reductase(NiR),glutamate synthase(GOGAT),and glutamine synthase(GS))of 7 poplar clones under low nitrogen treatment were significantly reduced.Under low nitrogen stress,the decrease in NH4+-N content in the leaves and roots of 7 poplar clones seedlings was significantly higher than that of NO3--N,NO2--N,indicating that the 7 clones were more inclined towards ammonium loving tree species.The correlation analysis results showed that there was a significant correlation between the growth and physiological indicators of poplar clonal seedlings.Principal component analysis integrated all measurement indicators into three component factors and divided them into nitrogen accumulation factors and nitrogen metabolism factors.The results of the membership function analysis showed that the order of low nitrogen tolerance of the 7 tested poplar clones from strong to weak was 84K>Xibeiyang 3>Xibeiyang 1>Qinbaiyang 1>Qinbaiyang 5>Qinbaiyang 3>Maobaiyang 30.[Conclu-sion]Among the 7 clones of poplar seedlings,84K,Xibeiyang 3,and Xibeiyang 1 have strong low nitrogen toler-ance and can be used as the main promotion and artificial afforestation tree species in soil poor areas.