额尔齐斯河江鳕精子冷冻保存研究

额尔齐斯河中蕴藏着丰富的冷水鱼类种质资源,江鳕(Lota lota)是其中之一,建立其精子冷冻保存技术和精子冷冻库,对种质资源保存具有重要意义。本研究利用无机盐、葡萄糖、蔗糖、胎牛血清等配制7种精子稀释液,以5∶1的比例稀释精液,激活后观察统计精子活力。结果显示,江鳕精子仅在SS、D15和CM中具有(13.33±2.89)%~(8.33±2.88)%活力。在此基础上配制22种梯度稀释液(SS-00~SS-10和D15-0~D15-7),以同样的方法稀释和观察精子活力。结果显示,SS-0(56.67±5.77)%、SS-2(63.33±5.77)%、SS-5(53.33±5.77)%和D15-7(63.33±5.77)%中精子活力较高,与鲜精活力(76.67±5.77)%接近(P0.05)。将二甲基亚砜(DMSO)和甲醇(MeOH)以3∶2比例配制成混合抗冻剂(DM),分别以5%~12%浓度加入到精子稀释液SS-5和D15-7中,以5∶1比例稀释精液,冷冻保存精子。结果显示,冷冻前,5%DM的SS-5和D15-7中精子活力(73.33±5.77)%与鲜精无显著差异(P0.05),当DM浓度升高到10%~12%时,精子活力接近于0;冷冻后,在DM浓度为6%的SS-5中,精子活力较高为(26.67±5.77)%(P0.05);在DM浓度为7%的D15-7中,精子活力较高为(26.67±5.77)%(P0.05)。本研究结果为额尔齐斯河江鳕精子冷冻保存提供了一定的理论和技术依据。     

钝吻黄盖鲽精子冷冻保存及生理特性分析

钝吻黄盖鲽(Pseudopleuronectes yokohamae)是鲆鲽鱼类中重要的天然捕捞和养殖对象,但由于生态环境变化、人工捕捞过度等因素,导致其种质资源数量降低,进行精子冷冻保存技术研究,对其种质资源保存具有重要意义.本研究以性成熟的雄性钝吻黄盖鲽为实验材料,对精子稀释液种类及成分、抗冻剂种类、激活精子海水盐度和冷冻精液授精实验等进行筛选,实验数据利用SPSS 19.0软件进行单因素方差分析和Student-Newman-Keuls分析.结果表明,利用MFs-3(8 g/L NaCl+0.65 g/L KCl+15 g/L Glucose)稀释液分别与20％1,2丙二醇(1,2-propylene glycol,PG)和20％乙二醇(ethylene glycol,EG)抗冻剂作为精子抗冻保存液时,冷冻效果最好,其中PG组对应的精子活力、快速运动时间和寿命分别为(95.26±0.39)％、(46.00±1.00)s和(124.33±4.04)s,EG组则为(95.15±0.41)％、(45.67±0.58)s和(124.00±3.00)s.利用盐度为10～50的人工配制的海水激活解冻后的精子,发现当盐度为30时,精子活力高达(95.07±0.69)％,与对照组相比不存在显著性差异.将PG组和EG组冷冻保存的精子解冻后分别与其卵进行授精实验,PG组受精率和孵化率为(80.08±0.68)％和(77.44±1.76)％,EG组则为(80.17±0.45)％和(77.92±1.33)％,与鲜精相比无显著性差异.利用计算机辅助精子分析系统(computer-aided sperm analysis,CASA)测定MFs-3+20％ PG和MFs-3+20％ EG冷冻保存的钝吻黄盖鲽精子的各项运动参数,结果显示,二者的曲线运动速度(curvilinear velocity,VCL)、直线运动速度(straight line velocity,VSL)、平均鞭打频率(beat cross frequency,BCF)、运动的直线性(linearity,LIN)和运动的前向性(straightness,STR)的数值差异性不显著.本研究利用MFs-3+20％ PG和MFs-3+20％ EG成功冷冻了钝吻黄盖鲽的精子,为钝吻黄盖鲽精子冷冻保存技术、人工杂交育种繁殖及种质资源库的建立奠定了基础.     

大黄鱼精子的超低温冻存及细胞结构损伤的检测

为了解超低温冻存对大黄鱼精子细胞结构损伤的影响,本研究以Cortland溶液为稀释液,二甲基亚砜(DMSO)及乙二醇(EG)为抗冻剂,0.25 mL的麦细管为冻存管,两步降温法(平放在离液氮面3～4 cm处3～5 min后入液氮中保存)超低温冻存大黄鱼(Pseudosciaena crocea)精子,并用单细胞凝胶电泳(SCGE)技术检测了冻精的DNA损伤,荧光双染色-流式细胞术(FCM)检测了冻精的细胞膜性结构损伤.结果表明,DMSO及EG浓度在5％～20％时,冻精的活力与鲜精相比无显著差异;其中DMSO及EG浓度在10％时,冻精的激活率、运动时间、寿命分别为(87.00±2.45)％、(8.99±0.24) min和(13.11±0.65) min及(87.50±2.52)％、(8.45±0.48)min和(12.84±0.50) min; DMSO及EG浓度在25％和30％时,冻精的活力显著下降.SCGE检测显示,DMSO及EG浓度在5％～20％时,冻精的DNA损伤与鲜精相比差异不显著;DMSO及EG浓度为25％和30％时,冻精的DNA损伤明显加重;冻精的DNA损伤与抗冻剂DMSO及EG的浓度成正相关.FCM检测显示,DMSO及EG浓度在5％～20％时,冻精中线粒体及细胞膜结构保持完整性的精子比例与鲜精相比无显著差异;DMSO及EG浓度在25％和30％时,冻精中的线粒体及细胞膜结构保持完整性的精子比例明显下降.分析认为,较高浓度的DMSO及EG是引起冻精活力下降,DNA、线粒体及细胞膜结构损伤加重的主要原因;为确保大黄鱼冻精的质量,应以10％DMSO或10％EG为抗冻剂.     

星斑川鲽精子冷冻保存与生理特性分析

针对星斑川鲽(Platichthys stellatus)养殖群体中雄性个体较雌性小,产精液量低,限制了人工繁殖育苗和杂交育种开展等问题,本研究以性成熟的星斑川鲽为实验材料,对精子稀释液成分、稀释液渗透压、激活海水适宜温度和冷冻精液的适宜稀释比例等进行筛选,并用冷冻精液和鲜精分别与星斑川鲽卵进行受精和孵化实验,实验结果利用SPSS软件中单因素方差分析法和Student-Newman-Keuls进行比较分析。结果表明,利用Ts-2(37.65 g/L蔗糖+10.01 g/L KHCO3+1.21 g/L Tris碱)和SFs-4(60 g/L葡萄糖+10.01 g/L KHCO3+1.21 g/L Tris碱)冷冻保存的精子活力最高,分别为(56.67±5.78)%和(66.67±5.77)%。利用计算机辅助精子分析(computer assisted sperm analysis,CASA)系统对星斑川鲽精子进行分析,测定了用Ts-2和SFs-4保存的冷冻精液中精子运动方式的各项参数。结果显示,测定的各项参数(曲线运动速度(curvilinear velocity,VCL)、直线运动速度(straight line velocity,VSL)、平均鞭打频率(beat cross frequency,BCF)、运动的直线性(linearity,LIN)和运动的前向性(straightness,STR)表明,利用SFs-4保存的精子各项运动参数明显高于Ts-2。利用蔗糖、KHCO3和Tris碱配制不同渗透压稀释液中,在渗透压为319.94 Pa时,精子活力最高,为(61.67±5.00)%,与鲜精相比无显著差异(P0.05)。利用3~18℃海水激活精子,结果显示,当激活海水温度在12℃时精子活力最高,与鲜精相比无显著性差异(P0.05),而其他温度下显著低于鲜精活力(P0.05)。将解冻后的精液稀释10~40倍,与星斑川鲽卵受精,结果显示,在稀释20倍后冷冻精液的受精率最高。本研究利用Ts-2+20%二甲基亚砜(dimethyl sulfoxide,DMSO)和SFs-4+20%DMSO对星斑川鲽精子成功进行冷冻保存,为星斑川鲽精子冷冻保存、种质库的建立和应用提供理论和技术依据。     

用0.25 mL细管冷冻保存猪精液

研究旨在建立优化的猪精液冷冻保存方法.实验表明,采用ZORLESCO(ZO)液对猪精液进行预稀释,室温平衡1 h.加入冷冻Ⅰ液后于5℃水浴平衡1.5 h,再加入冷冻Ⅱ液平衡2 h后装入0.25 mL细管,液氮面上3cm处平衡10 min投入液氮,采用37℃水浴解冻30 s,可获得最佳冷冻效果.解冻后的精子活力平均为0.58±0.03,质膜完整率为(63.2±1.2)%,顶体完整率为(51.4±2.6)%;精子畸形率最低,仅为(14.0±3.0)%.     

兔精液冷冻保存的初步研究

以家兔为试验动物,从精液解冻后的精子活率和复苏率2个指标,分别对3种稀释液(1:T ris0.25 m o l/L 蔗糖0.1 m o l/L 柠檬酸钠83 mm o l/L 卵黄10% 二甲基亚砜(DM SO)15%;2:配方1 葡萄糖0.47 mm o l/L;3:T ris 0.29 m o l/L 葡萄糖0.71 mm o l/L 柠檬酸钠67 mm o l/L 卵黄20% 甘油4%)、两种抗冻剂(甘油4%、DM SO 15%)、4°C下平衡时间(30、60、120、180 m in)三个方面进行了比较试验。公兔采精用假阴道法,采精后立即检查精子活率,达0.60以上的供试验用。结果表明:(1)3种稀释液中,用稀释液2稀释的精液,精子解冻后活率和复苏率显著高于稀释液1和稀释液3(精子活率:0.153 vs 0.103、0.109;复苏率:0.205 vs 0.137、0.147,P<0.01),而稀释液1和稀释液3之间差异不显著(P>0.05);(2)在稀释液2中,分别用4%甘油和15%DM SO作防冻剂,两者的精子解冻后活率之间(0.193 vs 0.261,P<0.01),复苏率之间(0.250 vs 0.340,P<0.01)差异极显著;(3)在4°C下平衡30、60、120、180 m in,结果发现,在30~60 m in之间,解冻后精子活率之间(0.261 vs 0.249),复苏率之间(0.340 vs 0.325)差异均不显著(P>0.05),但是随着平衡时间(120~180 m in)的增加,精子活率明显降低,精子几乎死亡。结论:采用稀释液2的配方,在4°C下平衡30~60 m in,可获得较好的兔精液冷冻保存效果。     

栉江珧和近江牡蛎的精子超低温冷冻保存

栉江珧(Atrina pectinata)和近江牡蛎(Crassostrea rivularis)是我国重要的海产经济贝类,建立其精子冷冻保存技术及精子冷冻库,对种质资源的保护和遗传育种具有重要意义.本研究对其精子冷冻保存过程中冷冻剂种类和浓度的选择、冷冻程序、平衡时间、保存体积、精液稀释方式、保存时间等多个影响因素进行了比较筛选,并利用显微镜直接检测和曙红Y(eosin Y)染色检测结合的方式检验精子存活率.结果表明,二甲亚砜(dimethyl sulfoxide,DMSO)作为抗冻剂的保存效果要明显优于甘油(glycerol,Gly),终浓度为8％～10％的二甲亚砜保存效果最好,其栉江珧和近江牡蛎精子活率均可达60％以上,而甘油保护下精子活率小于40％.精液的稀释方式采用将抗冻液等分为3份,依次与精液混合,每次间隔8 min,整个过程约30 min;此种精液稀释方式与一次性混合方式相比,精子活率可提高约30％.稀释后精液需要在4℃下平衡15～25 min,平衡样品与直接冷冻样品相比,精子活率提高约50％.精液降温程序为在样品投入液氮前,于液氮面以上15 cm处停留5 min,5 cm处停留10 min,精子活率可达60％以上;而未经此降温程序直接投入液氮中的样品精子活率接近0.与此降温程序相对应的样品冷冻体积在1.0～1.4 mL范围内为宜.冷冻180 d内复苏的精子活率由90％左右(鲜精)下降至60％左右,180 d后精子活率下降至56％左右.研究结果为栉江珧和近江牡蛎精子超低温冷冻保存、双壳类种质保护和遗传育种提供了理论和技术依据.     

兔的人工授精研究总结

本文研究对兔的采精技术、精液性状、精液的冷冻保存和低温保存以及输精方法等问题进行了一系列试验。用自制的假阴道采精,春季西德长毛公兔平均每次滤精量0.89±0.310毫升,射出精子总数5.025±2.09亿,西德杂种公兔分别为0.66±0.322毫升和3.623±1.751亿;本地长毛公兔分别为0.8±0.324毫升和3.190±1.514亿。冬季西德长毛公兔平均每次滤精量0.675±0.175毫升,射出精子总数2.568±0.561亿;西德杂种公兔分别为0.947±0.368毫升和4.272±1.434亿。同品种但个体不同,滤精量和射出精子总数差异很大。精液冷冻保存,可用含有甘油和DMSO的Tris稀释液,在液氮中(-196℃)保存。用冷冻精液输精母兔230只,情期受胎率73.9％,平均每窝产仔数4.4只。精液低温保存试验,以用葡—柠—蛋—奶稀释液与葡—柠—蛋稀释液稀释在2～5℃中保存,效果较好,在农村中进行输精试验的结果,前者情期受胎率68.7±18.739％,后者63.72±12.987％,差异不显著(P>0.05),因后者配制较简便,目前在农村中乃推广此种。精液稀释倍数分三组,即1:10、1:15、1:20,试验结果以1:15为宜。输精时,发情母兔静注HCG50单位诱排,输精量0.5毫升,输入有效精子数1,000～1,400万,实践证明是适宜的。兔的人工授精技术已在广西14个县(市)重点推广,据不完全统计,两年来共输精母免约10万只次,抽查17,184只,平均情期受胎率62.90％,平均每窝仔数4.04只。     

牛IVF性控切割胚胎和整胚的冷冻保存研究

本研究分3个实验对比了采用不同处理的常规冷冻和玻璃化冷冻保存358枚体外受精(IVF)性控切割囊胚和326枚整胚的保存效果。结果表明：(1)用于冷冻整胚的常规方法对冷冻性控切割胚胎同样有效；(2)利用含10％EG 10％FBS的DPBS冷冻牛IVF控切割胚胎或整胚的效果明显优于用含10％甘油 0.4%BSA或1．4mol／LEG 0．1％PVOH的DMPBS；(3)采用微玻管玻璃化冷冻保存牛IVF性控切割胚胎的效果显著优于常规冷冻法。     

红景天多糖对猪精子冷冻保护效果的研究

研究旨在探索红景天多糖以及三种添加方案对猪精子冷冻保护效果的影响.实验1中,在冷冻保存I液中分别添加红景天多糖分别为0、2 mg/L、4 mg/L、6 mg/L、8 mg/L和10 mg/L;实验2中,在冷冻保存Ⅱ液中添加红景天多糖,浓度同实验1;实验3基于实验1和2,对比了三种红景天添加方案对猪精子冷冻效果的影响.研究结果表明:1、红景天多糖较适宜添加浓度为6 mg/L,能明显提高猪冷冻精子品质,并能为猪精子提供较好的抗氧化作用;2、三种添加方案中,在I液中添加(方案A)对猪冷冻精子保护效果明显优于方案B和C(P<0.05).     

低氮和干旱胁迫对富士和秦冠生长及氮素利用的影响

【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。     

Pasture Vegetation Elemental Analysis by Laser-Induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing.     

Faculty positions:Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Biodiversity and ecogeography of wild Lactuca spp. in some European countries

Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions.     

Macroinvertebrates in North American tallgrass prairie soils: effects of fire, mowing, and fertilization on density and biomass

The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils.     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Faculty positions: Center for Agricultural Resources Research,Chinese Academy of Sciences

正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology,     

Variation in quality parameters between and within 14 Nordic tree fruit and berry species

Abstract

A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species.     

Potassium Fixation and Release Characteristics in Rhizosphere and Nonrhizosphere Soils for a Rapeseed–Rice Cropping Sequence

Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L^?1 nitric acid (HNO₃) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L^?1 ammonium acetate (NH₄OAc) and 1.0 mol L^?1 HNO₃ extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils.