极晚熟杏品种冬杏杂交种子成苗特性研究

[目的J研究不同杏品种杂交组合的种子萌发和幼苗生长差异,为品种选育提供依据.[方法]以冬杏为母本,19个不同成熟期的新疆杏品种为父本进行杂交,对获得的杂交种子进行育苗,测定种子发芽率、播种出苗率、成苗率及幼苗的生长动态,分析各杂交组合之间成苗特性差异.[结果]杂交种子层积60 d后有10个组合发芽率大于60;,发芽率最高的为冬杏×毛拉肖,而冬杏×晚熟胡安娜、冬杏×旦杏和冬杏×卡拉玉吕克没有发芽率.播种成苗率较高的是冬杏×特尔湾玉吕克和冬杏×毛拉肖.冬杏×库曼提、冬杏×大果胡安娜、冬杏自然种子的出苗时间较早,且出苗整齐.在15个成苗的杂交组合中,以冬杏×特尔湾玉吕克、冬杏×毛拉肖生长势较强,其余13个杂交杏苗生长势较弱.[结论]冬杏杂交组合种子的发芽率、出苗率、成苗率之间差异较大,同时,发芽率高的组合成苗率也高;不同杂交组合种子实生幼苗的生长存在差异.     

梁山慈竹在退耕还林中的水土保持效应研究

利用小型径流观测场对比观测降雨时间集中的梁山慈竹林和未退耕种植红薯的耕地的17次降雨、10次水土流失过程进行效益对比,分析侵蚀量、径流量与降雨因子的关系。结果表明,退耕还梁山慈竹林的穿透降水率为89.14%,茎流率平均为1.57%,林冠截持降水率为9.29%;凋落物层的最大持水量约为27.54 t.hm-2,相当于水深2.4～3.3 mm,占降水量的14.46%～19.88%;与未退耕地相比,梁山慈竹林的平均径流量比耕地减少24.6%,而耕地侵蚀量约是林地的4.7倍,林地降水的泥沙侵蚀平均减少量达到78.56%。梁山慈竹有较好的水土保持作用,能够明显地减少地表径流和泥沙侵蚀。     

砂土、砂壤土强筋小麦保优增产技术研究

为了在豫东砂土和砂壤土生态类型区生产出品质达到国家标准的优质强筋小麦,在现行的生产、生态、技术条件下,采用田间小区试验方法,在等氮量的试验条件下,于拔节期和孕穗期2次追施氮肥,结果表明,砂土地强筋小麦比对照增产23.2%;砂土地强筋小麦在拔节期一次重追尿素225kg/hm2,籽粒粗蛋白质含量提高2.55个百分点,提高22.3%,湿面筋含量提高5.2个百分点,提高21.5%,面团稳定时间增加11.2min,弱化度由61降到12,如果把追氮时期再适当后移,其蛋白质、湿面筋含量和面团稳定时间又有所提高,弱化度又有所降低。由此说明,生育中后期追氮是提高砂土地强筋小麦产量和品质的关键措施。另外,应用新型增优剂对改善砂土、砂壤土地强筋小麦品质有一定作用,尤其对面团稳定时间的延长有较明显的作用。     

Maintenance of mycoplasma-like organisms occurring in Pyrus species by micropropagation and their elimination by tetracycline therapy

Pear explants ( Pyrus communis cv. Pine) infected with mycoplasma-like organisms (MLOs) were maintained for more than 3 years by micropropagation on Murashige and Skoog medium supplemented with gibberellic acid, indole butyric acid and benzyl amino purine. MLOs reached consistently higher concentrations in micropropagated explants than in samples from field-grown plants, although explants remained free from symptoms. MLOs could be eliminated by incorporation of 100/μg/ml oxytetracycline into the growth medium for a period of 4 weeks. These results have implications for plant propagation schemes of symptomless MLO-infected explants raised by micropropagation.     

小麦新品种花培5号的选育特点及应用前景

花培5号是河南省农业科学院农作物新品种重点实验室采用豫麦18与花4 3杂交,对其F₁代花药进行培养选育成功的小麦新品种,2006年通过国家审定。其选育特点是：亲本性状互补性好、遗传基础丰富;组合诱导率高,育种群体大;后代选择以群体表现为主,选择准确性高;进行异地产比试验,缩短了育种周期。花培5号经黄淮区试、生产试验和推广种植表现出丰产性、稳产性和广适性好,品质优良,适宜于黄淮南片麦区高中产水肥地中晚茬种植。     

Influence of Nitrogen Loading and Species Composition on the Carbon Balance of Grasslands

In a 12-year experimental study of nitrogen (N) deposition on Minnesota grasslands, plots dominated by native warm-season grasses shifted to low-diversity mixtures dominated by cool-season grasses at all but the lowest N addition rates. This shift was associated with decreased biomass carbon (C):N ratios, increased N mineralization, increased soil nitrate, high N losses, and low C storage. In addition, plots originally dominated by nonnative cool-season grasses retained little added N and stored little C, even at low N input rates. Thus, grasslands with high N retention and C storage rates were the most vulnerable to species losses and major shifts in C and N cycling.