不同氮效率木薯品种根系形态、构型及氮吸收动力学特征  

Root morphology, configuration and nitrogen absorption kinetics of cassava cultivars with different nitrogen efficiencies

作　　者：康亮[1,2] 梁琼月 姚一华[1] 蒋强 董蒙蒙[1] 顾明华 何冰[1] KANG Liang;LIANG Qiong-yue;YAO Yi-hua;JIANG Qiang;DONG Meng-meng;GU Ming-hua;HE Bing(College of Agriculture,Guangxi University/State Key Laboratory of Conservation and Utilization of Subtropical Agricultural Biological Resources,Naning,Guangxi,530004,China;Pharmaceutical College,Guangxi Medical University,Naning,Guangxi,530021,China)

机构地区：[1]广西大学农学院/亚热带农业生物资源保护利用国家重点实验室,广西南宁530004 [2]广西医科大学药学院,广西南宁530021

出　　处：《植物营养与肥料学报》2019年第11期1920-1928,共9页Journal of Plant Nutrition and Fertilizers

基　　金：广西自然科学基金项目（2016GXNSFDA380038,2016GXNSFBA380220）;广西研究生教育创新工程（YCBZ2017013,YCSW2018039）

摘　　要：【目的】比较分析低氮(N)条件下不同氮效率木薯品种的根系形态、构型及吸收动力学变化,以阐明木薯氮高效吸收机制,为指导木薯生产和木薯品种选育提供理论基础。【方法】于2015年在广西大学国家重点实验室温室大棚内进行了试验。盆栽试验采用双因素(品种×氮水平)区组设计。供试木薯品种包括氮高效品种华南10号(SC10)与氮低效品种华南205(SC205)。氮水平包括不施氮(N0)和施N 55.2 mg/kg土(N1)。每盆装10kg土,种植1株幼苗。木薯出苗60天后,取出并洗净根系,利用根系扫描仪EPSON2000进行根系图像采集,利用WinRHIZO PRO根系分析软件分析图片,获得根系形态指标。将整株植株分成根、茎、叶三个部分,测量干重和氮含量。根系分层试验在大型根系观测系统中进行。吸收动力学试验采用改进常规耗竭法,并比较分析了木薯根系形态、根系构型特征及硝态氮吸收动力学参数差异。【结果】N1和N0条件下,氮高效品种SC10生物量和氮素积累量均显著高于氮低效品种SC205(P<0.05)。N0条件下,SC10的整株生物量降幅为37.4%,SC205的降幅为69.4%,品种SC10的降幅显著低于SC205(P<0.05);SC10的根、茎、叶和全株氮积累量均显著高于SC205,全株氮积累量为SC205的152%。与N1相比,N0处理的木薯品种SC10总根长、根系表面积和细根根长的降幅分别为11.0%、10.0%和20.4%,SC205的降幅分别高达35.9%、27.7%和50.2%,两个品种下降幅度差异显著(P<0.05)。低氮诱导木薯根系分布下移,SC10根系呈上宽下窄三角形,最深可达180 cm土层;SC205根系呈椭圆形,最深达130cm土层。氮素吸收动力学试验结果发现SC10、SC205的Km分别为3.27和7.87 mmol/L,表明SC10根系对NO3–的亲和性更高。【结论】氮高效品种SC10的根系对硝态氮的亲和力(Km)几乎是氮低效品种SC205的两倍。在氮素胁迫条件下,氮高效品种可形成优于氮低效品种的根系构型,特别是根系【Objectives】The root morphological configuration and nitrogen(N)absorption kinetics were compared between N efficient and inefficient cultivars of cassava under low N stress,which would help to illustrate the key indicator for the N efficiency and provide reference for cassava breeding and production.【Methods】A pot experiment was conducted in the solar tunnel of National Key Laboratory,Guangxi University.A two-factor(cultivar×N level)split-plot design was employed.The two cassava cultivars were Nefficient SC10 and inefficient SC205,which were grown under N stress(no nitrogen application,N0)and normal N supply(applying N 55.2 mg/kg soil,N1).At 60 days after emergence of cassava,the whole root system was taken out of pot carefully and washed by water.The root images were taken using EPSON 2000 root scanner and analyzed using WinRHIZO PRO root analysis software.The plant was divided into root,stem and leaf and weighed,and the N contents were assayed.Root lamination test was conducted inside the large root observation system.The nitrogen absorption kinetics was tested using modified exhaustion method.The root morphology and configuration characteristics and the NO3–-N uptake kinetic parameters of the two cultivars were compared.【Results】Compared with N1,the dry weight of plant and N accumulation in plant were significantly decreased in N0.The decrease in SC10 were by 37.4%and 46.2%,respectively,and those in SC205 were by 69.4%and74.1%,respectively,significantly higher decrease was in SC205 than in SC10.Under the N0 condition,the N accumulation in roots,stems and leaves of SC10 were all significantly higher than those of SC205,and the N accumulation in whole plant of SC10 was152.5%higher of that of SC205.The decrease of the total root length,root surface,fine root length of SC10 were by11.0%,10.0%and 20.4%,respectively,whereas those of SC205 were by 35.9%,27.7%and 50.2%,respectively in N0.Significantly higher decrease was in SC205 than in SC10.Low N condition induced root growth to deeper soil.Under N0

关 键 词：木薯 氮素 根系形态与构型 硝态氮亲和力 

分 类 号：S53[农业科学—作物学]