不同水氮处理对红松容器苗生长及生理特性的影响OA

One-year-old container-grown P.koraiensis seedlings were used as experimental material.During the growing season(May to August),seedlings were subjected to two irrigation regimes:sufficient irrigation(substrate water content main-tained at 75%-85%of field capacity)and water-saving irrigation(substrate water content maintained at 55%-65%of field capacity),combined with three nitrogen application levels:low N(11.35 mg N per seedling),medium N(22.70 mg N per seedling),high N(34.05 mg N per seedling),plus a zero-N control.Seedlings were harvested in late Septem-ber,and the effects of irrigation and nitrogen levels on seedling height,root collar diameter,biomass,root morphology,needle morphology,photosynthetic physiology,and non-structural carbohydrate(NSC)content were analyzed.The results showed that the irrigation and nitrogen levels showed significant interactive effects on root collar diameter,root biomass,stem biomass,total plant biomass,needle surface area,soluble sugar in roots,stems and needles,starch in roots,and to-tal non-structure carbohydrate in roots,stems and needles of P.koraiensis container seedlings.Under sufficient irrigation,seedlings treated with high nitrogen exhibited significantly greater root collar diameter,soluble sugar in all organs,root starch,and total non-structure carbohydrate in all organs than those under other treatments.Root collar diameter was 6.16%higher than under low nitrogen,soluble sugar in roots,stems and needles increased by 44.70%,75.87%and 27.47%,respectively,root starch was 18.18%higher,and total non-structure carbohydrate in roots,stems and needles increased by 38.40%,61.53%and 26.97%,respectively.Under water-saving irrigation,seedlings under moderate ni-trogen treatment exhibited significantly higher root biomass,stem biomass,total plant biomass,soluble sugar in various or-gans(roots,stems and needles),root starch,and total non-structural carbohydrates in various organs(roots,stems and needles)than those under other treatments.Compared to the high nitrogen treatment,root biomass,stem biomass and total plant biomass increased by 40.00%,50.00%and 28.57%,respectively,soluble sugar in roots,stems and needles in-creased by 15.36%,25.10%and 24.94%,respectively,root starch was 11.69%higher,and total non-structure carbo-hydrate in roots,stems and needles increased by 14.56%,20.88%and 24.45%,respectively.Overall,although seed-lings under sufficient irrigation×high nitrogen showed the best growth performance,photosynthetic physiology and non-structure carbohydrate accumulation,no significant differences were observed between this treatment and water-saving irri-gation×medium nitrogen.Considering growth performance,photosynthetic physiology and non-structural carbohydrate con-tent comprehensively,water-saving irrigation combined with medium nitrogen application is the appropriate water-nitrogen coupling regime for one-year-old P.koraiensis container seedlings,which can improve seedling quality while achieving wa-ter and fertilizer conservation.