Determination of critical nitrogen dilution curve based on leaf area index for winter wheat in the Guanzhong Plain,Northwest China

Excessive use of nitrogen(N) fertilizers in agricultural systems increases the cost of production and risk of environmental pollution. Therefore, determination of optimum N requirements for plant growth is necessary. Previous studies mostly established critical N dilution curves based on aboveground dry matter(DM) or leaf dry matter(LDM) and stem dry matter(SDM), to diagnose the N nutrition status of the whole plant. As these methods are time consuming, we investigated the more rapidly determined leaf area index(LAI) method to establish the critical nitrogen(N_c) dilution curve, and the curve was used to diagnose plant N status for winter wheat in Guanzhong Plain in Northwest China. Field experiments were conducted using four N fertilization levels(0, 105, 210 and 315 kg ha-1) applied to six wheat cultivars in the 2013–2014 and 2014–2015 growing seasons. LAI, DM, plant N concentration(PNC) and grain yield were determined. Data points from four cultivars were used for establishing the N_c curve and data points from the remaining two cultivars were used for validating the curve. The N_c dilution curve was validated for N-limiting and non-N-limiting growth conditions and there was good agreement between estimated and observed values. The N nutrition index(NNI) ranged from 0.41 to 1.25 and the accumulated plant N deficit(N_(and)) ranged from 60.38 to –17.92 kg ha~(-1) during the growing season. The relative grain yield was significantly affected by NNI and was adequately described with a parabolic function. The N_c curve based on LAI can be adopted as an alternative and more rapid approach to diagnose plant N status to support N fertilization decisions during the vegetative growth of winter wheat in Guanzhong Plain in Northwest China.     

亚硝基谷胱甘肽还原酶 GSNOR1正调控植物对疫霉菌的抗性

疫霉属（ Phytophthora）卵菌引致马铃薯晚疫病等作物灾难性病害，严重威胁作物的可持续生产。由于病菌毒性变异，导致品种抗病性丧失问题突出。因此，挖掘植物广谱和持久抗病基因，并探索其在抗病育种中的有效利用具有重要的科学意义。亚硝基谷胱甘肽还原酶1（GSNOR1）是植物氮信号通路中高度保守的关键还原酶，其参与调节r基因介导的植物抗性和非寄主抗性。然而， GSNOR1参与抗疫霉菌的免疫功能和作用机理尚不清楚。本研究中，借助拟南芥与寄生疫霉菌互作的模式体系，首先发现拟南芥T-DNA插入突变体 gsnor1-3对寄生疫霉菌呈现感病表型。进一步利用病毒诱导的基因沉默（VIGS）降低烟草叶片中 GSNOR1同源基因的表达量，在此基础上，通过抗病表型分析以及一系列抗性相关功能的检测，结果表明，沉默本氏烟草 GSNOR1同源基因能够在寄生疫霉菌侵染植物的过程中削弱植物体内的活性氧（ROS）迸发、病程相关基因（PR genes）的诱导表达以及MAPK信号转导，从而增强了植物对疫霉菌的感病性。本研究揭示了植物 GSNOR1对疫霉菌具有高度保守的抗性功能，并初步解析了 GSNOR1正调控植物抗疫霉菌的作用机理，为进一步探索 GSNOR1在马铃薯抗晚疫病中的功能及其在抗病育种中的有效利用奠定了重要的理论 基础。     

青稞粮草双高新品种藏青27的选育与栽培技术

选育粮草双高型青稞新品种,既是西藏自治区粮食安全保障的要求,也是种植区农户种养结构改善的需要。藏青27以中晚熟高秆大粒丰产型新品种藏青320为母本,用中熟中秆大穗多粒的美国大麦品种做父本杂交,1987年形成杂交组合,2016年通过西藏自治区作物品种审定后推广。该品种在西藏全区多点生产比较示范中,平均产量为326.7 kg/667 m~2,比对照喜拉19号增产15.8%,丰产性较好。本文从选育过程、不同海拔种植地的播种期、播种管理、栽培等方面进行了阐述,以期为该品种的大面积推广提供参考。     

胶孢炭疽菌株QZ-97a分生孢子货架期及对温度的耐受力

将不同含水量的胶孢炭疽菌婆婆纳专化型菌株QZ 97a分生孢子粉置于4℃和室温下,密闭或开放贮存。结果表明,4℃下密闭贮藏6个月,分生孢子萌发率和芽管长度无明显降低,室温贮藏降低也不明显。贮藏10个月后,各种贮藏方式孢子的活力都显著下降。但以4℃、含水量4%、密闭贮藏孢子活力较为稳定,420d孢子萌发率为70 4%,芽管长度为贮藏60d时的43 2%。含水量9 6%、开放室温下贮藏的孢子粉活力下降最大。因此,温度和孢子粉含水量是影响孢子货架期的两个主要因素。分生孢子粉对温度有一定的耐受性,随温度增高,敏感性增强,60℃下分生孢子的活力下降显著,处理6min,孢子芽管长度较对照下降50%。     

Proton accumulation accelerated by heavy chemical nitrogen fertilization and its long-term impact on acidifying rate in a typical arable soil in the Huang-Huai-Hai Plain

Cropland productivity has been signiifcantly impacted by soil acidiifcation resulted from nitrogen (N) fertilization, especialy as a result of excess ammoniacal N input. With decades’ intensive agricul...     

不同药剂对苹果树腐烂病伤口愈合效果研究

为探讨苹果腐烂病的有效防治方法,研究比较了春季休眠期和萌芽期用纯泥、多菌灵药泥、拂蓝克、人工树皮二代和愈合剂5种药剂处理对苹果树伤口愈合面积和形成愈伤组织鲜干重的影响。结果表明:休眠期形成的伤口愈合情况好于萌芽期形成的伤口;使用多菌灵药泥包裹处理伤口愈合面积、愈合比例最大,分别为7.05cm2和99.76%。愈伤组织鲜干重也最大,伤口愈合效果最好。建议春季在休眠期使用多菌灵药泥对苹果腐烂病进行伤口处理。     

凹凸棒石添加量对草莓栽培基质及果实品质产量的影响

在草莓品种京藏香栽培基质(草炭、蛭石、珍珠岩体积比为3∶1∶1)中分别添加基质质量的20%、15%、10%、5%凹凸棒石,以不添加凹凸棒石为对照(CK),观测凹凸棒石添加量对草莓栽培基质营养、草莓品质及产量的影响。结果表明,基质铵态氮、硝态氮、有效磷、速效钾含量随凹凸棒石的添加显著高于CK,pH随着凹凸棒石的添加而升高,EC值减小;添加量为20%时,草莓Vc含量、单果重显著高于对照处理,可溶性糖、可滴定酸、糖酸比差异不显著。随着凹凸棒石添加量的增加,草莓产量在添加量15%～20%时呈增大趋势,20%处理较CK增产11.97%,15%处理较CK增产5.33%。凹凸棒石添加量为基质质量的20%时,基质理化性状较好,草莓品质及产量较高。     

杨树品系对杨干象抗性研究初探

杨树不同品系对杨干象抗性差异很大,以美洲黑杨为亲本的多数外来品种对杨干象抗性差,也使杨干象种群迅速扩大。该文根据调查的3年生和4年生连续2 a的不同杨树品系的平均虫口密度,根据聚类分析的方法将其划分为高感虫品系、感虫品系、低抗虫品系、中抗虫品系和高抗虫品系5个级别,结合杨树品系的类型、形态特征等进行分析,为生产上选用杨树抗性品系和减少杨干象大发生的危害及抗虫育种等方面提供参考。     

60Co-γ射线辐射对香福禄考发芽率及幼苗长势的影响

用60Co-γ射线辐射香福禄考种子,观察其发芽率和幼苗生长情况。结果表明:30、60 Gy辐射对发芽率有促进作用,60、70 Gy辐射则对幼苗生长有很好的促进作用。