[Objective] The aim was to stud; effects of different application rates of nitrogen on photosynlhetic pigment, biomass and yield of winter highland barley seedlings in order to provide reference for healthy seedling and drought resisting of highland barley seedlings in Hegu agricultural area of Tibet. [Method] The content of photosynlhetic pigment, biomass and yield of winter highland barley seedlings treated by different application rales of nitrogen (0, 90, 180 and 360 kg/hm2) were determined, and the controlling effects of nitrogen on them were studied. [Result] During the determining period, the contents of Chl( a + b) , Chla and Chlb in winter highland barley leaves decreased firstly and then increased; Car content and biomass increased gradually; and Chla/b increased firstly and then decreased. Nitrogen fertilizer had certain controlling effect on the pholosynthelic pigment, biomass and yield of winter highland barley leaves. Car content decreased with the increase of nitrogen application rate on 14th, March, while Chl(a +b), Chla and Chlb showed no obvious rule. The contents of Chl(a + b), Chla, Chlb and Car, biomass, single yield and 1 000-grain weight all increased with the increase of nitrogen application rate since 14th, March, furthermore they all reached the maximum under the treatment of 180 kg/hm2 nitrogen. [Conclusion] It is suggested that proper nitrogen application rale (180 kg/ hm') may promote grain yield and healthy seedling by enhancing pholoaynthetic pigment contents and improving the ability of scavenging oxida-live radicals in linzhi area.%[目的]探讨不同施氮对冬青稞幼苗光合色素、生物量及产量的影响,为西藏河谷农业区青稞苗期抗旱及壮苗培育提供依据.[方法]以冬青稞果洛为材料,测定了不同施氮(0、90、180和360 kg/hm2,以纯氮用量计)处理下其幼苗期的光合色素含量、生物量和产量,研究了其氮素调控效应.[结果]在测定期间,叶片叶绿素(Chl)、叶绿素a(Chla)、叶绿素b(Chlb)含量呈先降低后上升趋势,类胡萝卜素(Car)含量和生物量呈逐渐增加趋势；叶绿素a/b呈先上升后降低趋势.氮肥对叶片的光合色素、生物量和产量有一定的调控效应,3月14日Car含量随施氮量的增加而减少,而Chl、Chla、Chlb规律不明显；3月14日以后Chl、Chla、Chlb、Car含量和生物量(含3月14日)以及籽粒单产和千粒重均随施氮量的增加呈增加趋势,并均以180 kg/hm2氮处理最大.[结论]在冬春干旱的林芝地区,适宜的施氮量( 180 kg/hm2)改善了青稞的光合色素性状,提高了清除活性氧的能力,从而有助于培育壮苗和籽粒产量的提高.
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