烤烟新品系Y2001团棵期生理特性和产量产值对氮素的响应

Responses of Physiological Characteristics at Cluster StageꎬYield and Output Value to Nitrogen of a New Flue-Cured Tobacco Line Y2001

为揭示烤烟新品系Y2001低氮条件下生长势强的内在机理,本研究采用大田小区试验法,以中烟100(Nicotiana tabacum cv.Zhongyan 100)为对照、烤烟品系Y2001为研究对象,测定不施氮、30 kg/hm^(2)(低氮)、60 kg/hm^(2)(中氮)和90 kg/hm^(2)(高氮)4个不同施氮水平下,两品种(系)烤烟团棵期生理和生长发育特性及氮素效应指标。结果表明,(1)与中烟100相比,Y2001叶片氮含量和干物质积累量均在低氮条件下增幅较大、中高氮条件下增幅较小,其氮素农学效率和氮肥表观回收效率表现为低氮处理显著高于中高氮处理,其氮素干物质生产效率则相反;氮肥梯度上,Y2001茎和根的氮素农学效率和干物质生产效率显著低于中烟100;Y2001各处理叶片氮素生产力均较高、根茎较低。(2)氮肥梯度上,Y2001叶片的叶绿素指数(Chl)相对稳定无显著变化、类黄酮指数(Flav)逐渐减小、氮平衡指数(NBI)逐渐增大,中烟100叶片的Flav逐渐减小、Chl和NBI逐渐增大;与中烟100相比,Y2001叶片的Chl无氮处理较高,各处理NBI均较高、Flav较低。(3)氮肥梯度上,Y2001根茎叶中氮磷钾积累量的增幅接近,中烟100钾的增幅大于氮和磷;与中烟100相比,Y2001根茎叶中氮和钾积累量表现为低氮处理较高、中高氮处理较低。(4)从产量和产值看,Y2001和中烟100最佳施氮量分别为30 kg/hm^(2)和60 kg/hm^(2)。综上,与中烟100相比,Y2001低氮时较强的养分吸收能力、较高的叶片氮素生产能力和干物质分配比例可能是其叶片生产能力较强的重要原因;而相对稳定的叶片氮含量和Chl、相对平衡的氮磷钾吸收能力可能是其叶片生产受土壤养分状况影响较小的重要原因;Y2001替代中烟100可在氮肥减施30 kg/hm^(2)的同时产值增加6600元/hm^(2)。

In order to reveal the internal mechanism of strong growth of new flue-cured tobacco line Y2001 under low nitrogen conditions,the field plot experiment was conducted,with Nicotiana tabacum cv.zhongyan 100 as control.The physiological and developmental characteristics and nitrogen effect indexes of the two flue-cured tobacco varieties were studied under four different nitrogen application levels including no nitro-gen,30 kg/hm^(2)(low nitrogen),60 kg/hm^(2)(medium nitrogen)and 90 kg/hm^(2)(high nitrogen)at cluster stage.The results were as follows.(1)Compared with Zhongyan 100,the nitrogen content in leaves and dry matter accumulation of Y2001 increased more under low nitrogen condition and less under middle and high ni-trogen conditions.The nitrogen agronomic efficiency and apparent nitrogen recovery efficiency of Y2001 under low nitrogen treatment were significantly higher than those under middle and high nitrogen treatments,but the nitrogen dry matter production efficiency was the opposite.On the nitrogen gradient,nitrogen agronomic effi-ciency and dry matter production efficiency of stems and roots of Y2001 were significantly lower than those of Zhongyan 100.The nitrogen productivity of Y2001 leaves under different treatments were all higher,but those of roots and stems were lower.(2)On the nitrogen gradient,the chlorophyll index(Chl)of Y2001 leaves was relatively stable without significant change,the flavonoid index(Flav)decreased gradually,and the nitrogen balance index(NBI)increased gradually.The Flav of Zhongyan 100 leaves decreased gradually,while Chl and NBI increased gradually.Compared with Zhongyan 100,the Chl of Y2001 was higher under no nitrogen treatment,while the NBI under all treatments were higher and the Flav was lower.(3)On the nitrogen gradi-ent,the accumulation of N,P and K in Y2001 roots,stems and leaves increased at similar rates,while that of K in Zhongyan 100 increased by a greater amplitude than that of N and P.Compared with Zhongyan 100,the accumulation of N and K in roots,stems and leaves of Y2001 were higher under low nitrogen treatment and lower under medium and high nitrogen treatments.(4)In terms of yield and output value,the optimal nitrogen application rate for Y2001 and Zhongyan 100 were 30 kg/hm^(2) and 60 kg/hm^(2),respectively.To sum up,com-pared with Zhongyan 100,Y2001 had higher nutrient absorption,nitrogen production capacity and dry matter proportion under low nitrogen conditions,which might be the important reasons for its stronger leaf production capacity,the relatively stable nitrogen content and Chl of leaves and the relatively balanced NPK absorption capacity might be the important reasons for the leaf production less affected by soil nutrient status.Replacing Zhongyan 100 with Y2001 could increase the output value by 6600 yuan/hm^(2) when nitrogen fertilizer applica-tion reduced by 30 kg/hm^(2).