番杏光合特性的研究

以番杏为试验材料,对其功能叶片的光合特性进行了研究.通过控光、控温、控二氧化碳进行光响应曲线、温度响应曲线和二氧化碳响应曲线的测定.结果表明:番杏的光饱和点在1800 μmol·m-2左右,光补偿点为67 μmol·m-2·s-1;光合作用的适宜温度范围为30～35℃,最适温度为35℃;二氧化碳的饱和点范围为1800～2000μmol/mol,二氧化碳的补偿点为61μmol/mol.     

青岛市城阳区主要绿化树种滞尘能力研究

对青岛市城阳区的21种园林植物进行了滞尘能力的测定.结果表明:不同树种的滞尘能力存在很大差异,其滞尘量能相差4倍以上;第一周滞尘量对总滞尘量的贡献最大;同一树种在不同位点滞尘量不同.因此,在城市绿化中选择滞尘能力强的树种,并进行合理配置,是提高城市道路绿地滞尘效应的有效途径.     

培养条件对毛栓菌木聚糖酶分泌的影响

研究了碳源、氮源、接种量、培养温度等培养条件对木聚糖酶分泌的影响;结果表明:麸皮作碳源、(NH4)2SO4作氮源有利于木聚糖酶的分泌,接种量、培养温度、装液量、对木聚糖酶的分泌有较大影响.     

6个辣椒自交系农艺性状配合力分析

为提高辣椒亲本的选配效率,以6个辣椒自交系为亲本,按照Griffing完全双列杂交的第四组方法配制15个杂交组合,对7个农艺性状进行了配合力分析。结果表明:671、678和716是较优良的亲本,671×716是较优良的杂交组合。株幅、果宽、每株果数和平均单果质量主要受加性效应控制,株高、果长和单株产量主要受非加性效应控制。根据性状间的相关性,株高可作为产量选择的间接指标。     

饲料中添加枯草芽孢杆菌对团头鲂幼鱼生长性能、肝脏抗氧化指标、肠道菌群结构和抗病力的影响

本试验旨在研究饲料中添加枯草芽孢杆菌对团头鲂幼鱼生长性能、肝脏抗氧化指标、肠道菌群结构和抗病力的影响。选取初始体重为(1.81±0.01)g的团头鲂幼鱼360尾,随机分为4组(每组3个重复,每个重复30尾),分别饲喂添加0(T0组,作为对照组)、2×10~7(T1组)、2×10~8(T2组)、2×10~9CFU/g枯草芽孢杆菌(T3组)的等氮等脂饲料。试验期为8周。结果表明:1)与对照组相比,T1组和T2组团头鲂幼鱼的增重率、特定生长率显著升高(P0.05),且T1组的饲料系数显著降低(P0.05)。2)与对照组相比,T1组团头鲂幼鱼的肝脏抗氧化酶(超氧化歧化酶、过氧化氢酶和谷胱甘肽过氧化物酶)活性显著升高(P0.05),同时该组肝脏丙二醛含量显著降低(P0.05)。3)各组全鱼水分、粗蛋白质、粗脂肪和粗灰分含量均无显著差异(P0.05)。4)变性梯度凝胶电泳(DGGE)图谱显示摄食不同添加量枯草芽孢杆菌饲料的团头鲂幼鱼的肠道菌群结构发生了改变。5)采用嗜水气单胞菌对鱼体进行攻毒,各组96 h后的累积死亡率未产生显著差异(P0.05),但T1组和T2组的累积死亡率低于对照组和T3组。由此可见,饲料中添加2×10~7CFU/g的枯草芽孢杆菌能够提高团头鲂幼鱼的生长性能、抗氧化能力,并改变肠道菌群结构,但对其体成分和抗病力没有显著影响。     

Heritability of, and genetic correlations among, forage and seed yield traits in Ladino white clover

Sixteen white clover genotypes and their half-sib progenies were grown in pure stand. Each clover progeny was also grown in a mixed stand that also included three grass varieties of different species. Dry matter (DM) yield was measured over 2 years and seed yield at the second year. Competitive ability of clover families was defined as the ratio between mixed stand and pure stand for clover DM yield. Narrow-sense heritability from parent-offspring regression of pure stand data was high to moderate (h²0.50) for DM yield, seed yield and most of their components. Persistence as predicted by stolon density showed negative genetic correlations with seed yield (r_g= -0.70) and DM yield (r₂= -0.60), whereas seed yield and DM yield tended towards a negative correlation (r₂=0.45). Sizes of different vegetative or reproductive organs were generally correlated positively. Evidence was provided that the set of parent genotypes represents well the genetic variation available within the Ladino gene pool. The results highlighted the difficulty of combining relatively short-term DM yield, persistence and seed yield into a unique plant type. Differences in competitive ability emerged only in the second year, better ability being related mainly to petiole length among the traits assessed in pure stand.     

紫叶标记釉型光一温敏核不育系中紫S的选育及其配组的杂种优势

带标记的光一温敏核不育系在制种后对其F1能籍标记性状在苗期检出假杂种,减少在生产应用中的风险。本研究采用中国水稻研究所保存的一份带紫叶标记的釉型紫叶稻(CN-pl>和湖北省农科院粮作所育成的温敏核不育系W6154S杂交,在F2代选择紫叶稻回交一次后,以系谱法逐代选择而育成了带紫叶标记的光一温敏核不育系一中紫S0在杭州(     

Nitrogen Fixation by Hybrids of White Clover (Trifolium repens L.) and Trifolium nigrescens

Development of hybrids between white clover ( Trifolium repens L.) and Trifolium nigrescens provides a novel route for genetically improving the reproductive capacity of white clover, provided the hybrids are agronomically viable, particularly with respect to N₂ fixation. A comparative study of growth and rates of N₂ fixation over 21 days was conducted with the parental species, F ₁ hybrids and backcross hybrids, in flowing solution culture, without a supply of mineral N to the plants. T. nigrescens was unable to fix N₂ in association with the strains of Rhizobium leguminosarum biovar. trifolii selected for inoculation. Rates of N₂ fixation per plant increased in the order T. nigrescens < F ₁ hybrid < T. repens < backcross 1. Specific rates of N₂ fixation (days 0–21) increased in the order T. nigrescens < F ₁ hybrid < backcross 1 <  T. repens . Dry matter production and nodule biomass per plant increased at a higher rate in backcross 1 hybrids than in T. repens. The results suggest that the potential for N₂ fixation by backcross 1 hybrids is at least as great as that by T. repens .     

Photosynthetic responses in spring wheat grown under elevated CO2 concentrations and stress conditions in the European, multiple-site experiment ‘ESPACE-wheat’

Spring wheat cv. Minaret crop stands were grown under ambient and elevated CO₂ concentrations at seven sites in Germany, Ireland, the UK, Belgium and the Netherlands. Six of the sites used open-top chambers and one used a controlled environment mimicking field conditions. The effect of elevated CO₂ for a range of N application regimes, O₃ concentrations, and growth temperatures on flag leaf photosynthesis was studied. Before anthesis, flag leaf photosynthesis was stimulated about 50% by 650 compared with 350 μmol mol⁻¹ CO₂ at all sites, regardless of other treatments. Furthermore, there was no evidence of a decrease in photosynthetic capacity of flag leaves due to growth at elevated CO₂ before anthesis, even for low N treatments. However, photosynthetic capacity, particularly carboxylation capacity, of flag leaves was usually decreased by growth at elevated CO₂ after anthesis, especially in low N treatments. Acclimation of photosynthesis to elevated CO₂ therefore appears to occur only slowly, consistent with a response to changes in sink–source relationships, rather than a direct response. Effect of elevated CO₂ on stomatal conductance was much more variable between sites and treatments, but on average was decreased by ˜10% at 650 compared with 350 μmol mol⁻¹ CO₂. Carboxylation capacity of flag leaves was decreased by growth at elevated O₃ both before and after anthesis, regardless of CO₂ concentration.     

稗草影响大豆根瘤固氮的机制研究之一——水分干扰机制

在全自控人工气候室内系统研究了稗草对大豆根瘤固氮的水分干扰机制。稗草在每盆3株的密度下使播后53-63淹水期间及淹水期后1天的大豆单株根瘤固氮速率平均分别比无草对照提高了16.6%和30.0%,在每盆10株的密度下分别使其比无草对照提高了34.2%和67.5%。在不淹水的情况下播后30-70天,稗草在每盆3株和10株的密度下使其所在处理的平均日蒸发蒸腾量分别比无草对照增加了23.8%和50%,削弱了水分对大豆植株的供应水平;而土壤水分供应水平从其田间持水量的80%降低到35%时,大豆根瘤的氧气传导速率从0.38cm/s下降到0.20cm/s,净光合速率从18.81mg/dm#+2/h降低到4.04mg/dm#+2/h,每盆10株稗草对大豆单株结瘤量及根瘤固氮酶活性的抑制率则分别从8.2%和17.8%升高到18.3%和19.6%,其对大豆单株根瘤固氮速率的抑制率也随之从21.5%上升到33.1%。证明通过干扰土壤水分供应水平,首先影响大豆植株的同化物产量及根瘤内的氧气供应,进而影响大豆植株的根瘤形成和根瘤固 氮酶的固氮活性,是稗草影响大豆根瘤固氮的主要机制之一。