甘薯苗期耐低氮基因型筛选及不同氮效率类型综合评价

【目的】建立甘薯品种(系)耐低氮能力评价体系,筛选耐低氮基因型甘薯材料和评价不同氮效率类型,为研究耐低氮甘薯生理机制和挖掘氮高效基因奠定基础。【方法】采用水培试验,以来自国内外不同薯区的126份甘薯品种(系)为材料,低氮胁迫(0 mmol·L^(-1)纯氮)和正常施氮(14 mmol·L^(-1)纯氮)处理下,收集126个品种(系)地上干重、地上干物质增加量、地下干物质增加量、总干物质增加率、根冠比、蔓长、根长、叶数、叶绿素相对含量(CCI)、氮积累量和氮素生理利用效率11个性状表征值,计算各指标耐低氮胁迫指数。利用综合隶属函数法,进行主成分分析、回归分析和聚类分析,综合评价各甘薯品种耐低氮能力和氮效率类型。【结果】1)低氮水平条件下,不同供试甘薯品种(系)的地上干重、地上部干物质增加量、地下部干物质增加量、总干物质增加率、根长、蔓长、叶数、CCI、氮素积累量的均值低于正常氮处理,根冠比和氮素生理利用效率的均值高于正常氮处理;2)不同品种(系)的地上干重、地上部干物质增加量、地下部干物质增加量、总干物质增加率、根冠比、根长、蔓长、叶数、氮素积累量和氮素生理利用效率的变异系数高于正常氮处理,且其增幅排序为地上干物质增加量>总干物质增加率>地下干物质增加量>叶数>地上干重>氮素生理利用效率>氮积累量>根长>根冠比>蔓长;3)对11个指标的耐低氮胁迫指数进行主成分分析,3个主成分的累计方差贡献率达到72.67%,计算综合评价值Y;4)地上干重、地上部干物质增加量、地下部干物质增加量、总干物质增加率、叶数、蔓长、根长、根冠比、氮积累量、氮素生理利用效率的耐低氮胁迫指数与Y值的相关性达到极显著水平(P<0.01),其中,地上部干物质增加量、地下部干物质增加量、总干物质增加率、氮积累量和地上干重5项耐低氮胁迫指数的相关性较高,相关系数分别为0.85、0.86、0.81、0.79和0.73;5)建立Y值回归方程,选定耐低氮能力评价的8个指标,并进行系统聚类,划分甘薯基因型为耐低氮型、中间型、不耐低氮型3类;并对3种耐低氮甘薯类型的农艺性状和氮效率性状进行方差分析。【结论】地上干重、地上部干物质增加量,地下部干物质增加量、根长、蔓长、叶数、氮素积累量和氮素生理利用效率作为甘薯耐低氮能力评价的指标;13104-2/紫薯1号、宜宾红心薯、浙紫薯2号、渝紫3号、渝紫6号、漯紫1号和渝紫香10号7个为耐低氮型甘薯品种;耐低氮型品种的各性状表现好于中间型和不耐低氮型,其中,地上干重、地上部干物质增加量、地下部干物质增加量、蔓长和氮积累量差异显著。

新疆春小麦品种氮效率类型的鉴定

为给新疆氮高效春小麦品种筛选和合理施用氮肥提供理论依据,本研究以7个新疆主栽春小麦品种为材料,在田间试验条件下,采用4个氮水平处理(即不施氮N0:0 kg/hm^(2)的纯N;低氮LN:100 kg/hm^(2)的纯N;中氮MN:200 kg/hm^(2)的纯N;高氮HN:300 kg/hm^(2)的纯N),用主成分分析法比较了不同施氮水平处理下小麦9项性状指标(株高,穗长,叶面积指数,穗粒数,穗粒重,单位面积穗数, SPAD值,千粒重和产量)的差异,以此为依据划分各品种的氮效率类型。结果表明,不同性状的变异系数呈现出较大的差异,其中,叶面积指数(X3)、穗粒重(X5)、SPAD值(X7)和产量(X9)这4项指标在各性状指标均值方面达到显著水平。X4 (穗粒数)、X7 (SPAD值)和X9 (产量)这3项指标与新疆春小麦氮效率利用显著相关,可作为鉴定新疆春小麦品种氮效率类型的关键指标。依据各品种在不同施氮处理下氮效率利用的差异,可将7个新疆主栽春小麦品种分为氮高效型、低氮高效型、高氮高效型和氮低效型4种氮效率类型。其中,‘新春37’为氮高效型;‘新春43’和‘新春47’为氮低效型;‘核春614’和‘新春48’为低氮高效型;‘核春137’和‘核春615’为高氮高效型。本研究对新疆春小麦氮高效品种的选育和推广应用具有一定的参考价值。

新疆粳稻审定品种氮效率类型的鉴定

在田间试验条件下,对3个施氮水平下的6个新疆粳稻审定品种8项性状指标进行考查和分析,划分各品种的不同氮效率类型,为氮高效水稻品种的筛选和指标鉴定提供依据。在不同施氮水平下,对粳稻品种各性状的相对值进行描述性统计分析表明,不同性状的变异系数呈现出较大的差异;就各性状的平均值而言,叶面积指数和SPAD值在不同施氮水平间的差异达极显著水平;就氮效率综合值而言,不同施氮水平间因品种不同而表现出较大差异。依据品种在不同施氮水平下的氮效率综合值,将各品种划分为氮高效型、低氮高效型、高氮高效型和氮低效型4种氮效率类型。新稻41号为氮高效型;新稻36号和新稻45号为低氮高效型;新稻11号为高氮高效型;新稻44号和新稻47号为氮低效型。相关性分析表明,有效穗数、叶面积指数和SPAD值可作为新疆粳稻品种成熟期氮高效评价的关键鉴定指标。

Nitrogen removal by three types of bioretention columns under wetting and drying regimes

The behaviors of inorganic nitrogen species in three types of bioretention columns under an intermittently wetting regime were investigated. The mean NH+4—N, NO-3—N and total N(TN) removal efficiencies for the conventional bioretention column(Col. T1) are 71%, 1% and 41%, for layered bioretention column with less permeable soil layer(Col. T2) the efficiencies are 83%, 84% and 82%, and for the bioretention column with submerged zone(Col. T3) the values are 63%, 31% and 53%, respectively. The best nitrogen removal is obtained using Col. T2 with relatively low infiltration rate. Adsorption during runoff dosing and nitrification during the drying period are the primary NH+4—N removal pathways. Less permeable soil and the elevated outlet promote the formation of anoxic conditions. 30%–70% of NO-3—N applied to columns in a single repetition is denitrified during the draining period, suggesting that the draining period is an important timeframe for the removal of NO-3—N. Infiltration rate controls the contact time with media during the draining periods, greatly influencing the NO-3—N removal effects. Bioretention systems with infiltration rate ranging from 3 to 7 cm/h have a great potential to remove NO-3—N.

Simulation Study on Purification Efficiency for Nitrogen in Different Types of Wetlands in Sanjiang Plain, China

The purification law of nitrogen in Deyeuxia angustifolia, Carex lasiocarpa and Deyeuxia angustifolia-Carex lasiocarpa combined wetland systems in the Sanjiang Plain, China was studied by field simulation experiment. The results indicate that the removal rates of TN, NH4^＋-N and NO3^--N in above three types of wetlands present an obvious logarithm growth trend along with the time. There are evident removal effects for NH4＋-N and NOa--N in water bodies of wetlands after the 30th day of experiment, with the removal rates over 80.0%, but the removal rate of TN is slightly low, being 63.1%-74.3%. NO3 -N is most quickly removed by the combined wetland, and NH4^＋-N by Deyeuxia angustifolia wetland. The removal speeds of TN by the three wetland systems are comparatively slow, of which the Deyeuxia angustifolia wetland is the fastest. In consideration of plant growth season, Deyeuxia angustifolia wetland has much more practical application value in purifying nitrogen. These results can provide references for the study on the purification function of wetlands and the control of non-point source pollution in Northeast China.

黄淮海中南部玉米氮高效品种筛选及产量性状分析

以40个玉米品种为研究对象,采用田间试验方法,对10个重要性状在2个供氮水平(高氮水平270kg/hm;低氮水平,不施氮)进行调查、计算和分析,对玉米氮效率类型进行划分和评价。结果表明,除穗行数外,其他9个性状在2个供氮水平上均存在极显著差异。相关分析表明,在2个供氮水平下,子粒产量与干物质积累量、穗长、行粒数、穗粒数、百粒重和单穗粒重均呈显著正相关。通径分析表明,在低氮水平下,对子粒产量直接作用较大的性状依次为穗粒数>百粒重>单穗粒重>行粒数;在高氮水平下,依次为单穗粒重>穗粒数>行粒数>百粒重。根据2个供氮水平下的子粒产量,将供试玉米品种分为4种类型,即双高效型、低氮高效型、高氮高效型和双低效型,分别占比30%、15%、27.5%和27.5%。