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.     

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。     

臭豆碱在大鼠组织中残留的研究

大鼠按6.82mg/kg单剂量口服臭豆碱;用反相离子对高效液相色谱法测定了攻毒后不同时间肝脏、肾脏、脑组织中臭豆碱的质量浓度,数据经DASver1.0药代动力学软件处理.结果表明,臭豆碱在肝脏、肾脏、脑组织符合一室模型,其动力学参数分别为:(1)肝脏组织:Tmax2.5 min,Cmax12095.84μg/l,T1/2 118.55 min,T1/2ka0.000 min,AUC 1807361.08μg/l·min,Vd/F15.256 l/kg,CL/F 0.009l/min/kg;(2)肾脏组织:Tmax60 min,Cmax13747.80μg/l,T1/2 113.34 min,T1/2ka 16.19 min,AUC 3033978μg/l·min,Vd/F 16.193l/kg,CL/F 0.005l/min/kg.(3)脑组织:Tmax20 min,Cmax 1260.09μg/l,T1/2 142.05 min,T1/2 ka 16.90 min,AUC 319068.95μg/l·min,Vd/F9.82 l/kg,CL/F0.048 l/min·kg-1.臭豆碱灌服后,具有吸收快、分布迅速、消除快、蓄积时间短的特点.     

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.     

Impacts of rising atmospheric carbon dioxide on model terrestrial ecosystems

In model terrestrial ecosystems maintained for three plant generations at elevated concentrations of atmospheric carbon dioxide, increases in photosynthetically fixed carbon were allocated below ground, raising concentrations of dissolved organic carbon in soil. These effects were then transmitted up the decomposer food chain. Soil microbial biomass was unaffected, but the composition of soil fungal species changed, with increases in rates of cellulose decomposition. There were also changes in the abundance and species composition of Collembola, fungal-feeding arthropods. These results have implications for long-term feedback processes in soil ecosystems that are subject to rising global atmospheric carbon dioxide concentrations.     

Magnetic microstructure of magnetotactic bacteria by electron holography

Off-axis electron holography in the transmission electron microscope was used to correlate the physical and magnetic microstructure of magnetite nanocrystals in magnetotactic bacteria. The magnetite crystals were all single magnetic domains, and the magnetization directions of small superparamagnetic crystals were constrained by magnetic interactions with larger crystals in the chains. Shape anisotropy was found to dominate magnetocrystalline anisotropy in elongated crystals. A coercive field between 300 and 450 oersted was determined for one chain.     

基于mtDNA D-loop序列分析青海省果洛州牦牛遗传资源的母系遗传多样性及群体遗传结构

为从分子水平上对青海省果洛藏族自治州牦牛遗传资源进行系统评估,分析其母系遗传多样性、群体遗传结构和群体遗传分化,本研究对甘德、班玛、久治和玛多牦牛群体共152头个体进行线粒体DNA（mtDNA）D-loop区测序,并从GenBank下载已公布的37条达日牦牛和32条玛沁牦牛的相应序列,对这6个牦牛群体mtDNA D-loop序列进行综合分析。结果表明：1）221条牦牛mtDNA D-loop序列（636~638 bp）比对分析共检测出57个变异位点,包括8个单一多态位点和49个简约信息位点。根据D-loop序列间核苷酸变异共确定了45种单倍型,其中班玛、达日、甘德、久治、玛多、玛沁牦牛群体分别拥有1、6、5、4、7、6种特有单倍型。2）6个牦牛群体总的单倍型多样度和核苷酸多样度为0.901和0.014,表明其母系遗传多样性丰富。其中,甘德牦牛的单倍型多样度最高（Hd=0.951）,久治牦牛的单倍型多样度最低（Hd=0.818）。3）遗传分化和基因流分析表明,除久治牦牛与班玛、甘德、玛沁牦牛群体间分化程度均呈中等遗传分化水平（0.05≤F_ST<0.15）,基因交流相对贫乏外,其他牦牛群体间F_ST值较小（0<F_ST<0.05）,分化程度弱,基因交流相对频繁。4）聚类分析表明久治、甘德、班玛3个牦牛群体间亲缘关系较近,而玛多、玛沁、达日3个牦牛群体间亲缘关系较近。5）系统发育分析显示6个牦牛群体中除久治牦牛由3个母系遗传支系（即Mt-Ⅰ、Mt-Ⅱ和Mt-Ⅲ）组成外,其他群体均由Mt-Ⅰ和Mt-Ⅱ 2个母系支系组成,推测果洛藏族自治州中久治牦牛群体有3个母系起源,其他牦牛群体均有2个母系起源。综上,青海省果洛藏族自治州6个牦牛群体均拥有特殊的母系遗传信息且母系遗传多样性较为丰富;各牦牛群体间遗传分化程度整体较弱;久治、甘德和班玛3个牦牛群体间亲缘关系较近,而玛多、玛沁和达日3个牦牛群体间亲缘关系较近;除久治牦牛群体有3个母系起源外,其他牦牛群体均有2个母系起源。本研究为青海省果洛藏族自治州牦牛遗传资源的合理保护和开发利用提供了理论基础。     

施磷量对超级稻南粳44产量和品质的影响

 以超级稻南粳44为材料,研究施磷量对水稻产量和品质的影响。结果表明,大田基施磷肥(P2O5)  0.0~225.0  kg/hm2,单位面积穗数、每穗粒数随着施磷量的增加而降低,结实率、千粒重则先升后降。各品质指标值与施磷量的相关均未达到显著水平,但施磷能提高糙米率、整精米率、垩白面积、垩白度,降低峰值黏度、热浆黏度、崩解值、冷胶黏度和回复值,而精米率、垩白米率、蛋白质含量、直链淀粉含量、起始糊化温度、消减值和到达峰值黏度时间对磷素的反应不明显。施磷主要是增加垩白面积从而增加垩白度,对垩白面积、垩白度、消减值影响较大,而糙米率、到达峰值黏度时间和起始糊化温度基本不受影响。综合产量和品质性状,水稻生产中应适量施磷(在土壤营养中等或偏上土壤上施85.7 kg/hm2为宜),过量施用不仅低产低效,还会加重生态污染。