裹包密度和添加剂对天然牧草青贮品质的影响研究

以草甸草原牧草为试验原料,设置9个处理(每个处理3次重复),分别是LLAB(低密度,乳酸菌2.2×10^5cfu/g)、LCE(低密度,纤维素酶0.2g/kg)、LCK(低密度,无添加,CK),MLAB(中密度,乳酸菌2.2×10^5cfu/g)、MCE(中密度,纤维素酶0.2g/kg)、MCK(中密度,无添加,CK),HLAB(高密度,乳酸菌2.2×10^5cfu/g)、HCE(高密度,纤维素酶0.2g/kg)、HCK(高密度,无添加,CK)。60d青贮后开袋测定天然牧草营养品质、发酵品质和微生物数量。结果显示,天然牧草青贮中添加乳酸菌和纤维素酶,可以增加乳酸菌数量、乳酸含量和可溶性碳水化合物含量,提高牧草营养品质,降低纤维类物质含量和pH值。裹包密度较高时,营养品质和发酵品质越好。因此,添加乳酸菌和纤维素酶及高密度裹包有利于改善天然牧草青贮品质,且乳酸菌添加剂效果优于纤维素酶,高密度裹包优于低密度裹包。添加乳酸菌和高密度裹包可获得较好的天然牧草青贮饲料,可在草原牧区进行推广示范。     

天然产物化学课程案例教学模式

天然产物化学课程是大连海洋大学海洋化学专业研究生的必修课。随着现代高层次人才培养模式的改变,对教学模式改革的要求也越来越迫切。从案例教学模式设计、案例教学内容规划及案例教学模式实施体会等方面分别探讨了课程组教师针对天然产物化学课程进行案例教学模式研究的成果,并对取得的效果进行了分析。     

Asymbiotic biological nitrogen fixation in a temperate grassland as affected by management practices

Estimates of asymbiotic biological N fixation (BNF) in temperate grasslands are few with large variations. In the past six decades, European grasslands have been subjected to intensive management practices and presently it is not known how asymbiotic BNF is influenced by these practices. Our objective was to assess the impact of fertilizer application and mowing frequency on asymbiotic BNF in a Central European grassland. In 2008, we established a three-factorial experiment with two fertilizer treatments (no fertilizer application and combined nitrogen (N), phosphorus (P) and potassium (K) fertilization at 180–30–100 kg ha⁻¹ yr⁻¹), two mowing frequencies (cut once and thrice per year) and three sward compositions through the application of herbicides (control, monocot- and dicot-enhanced swards). Three years after the initial sward manipulation, there was no more difference in functional group composition. Between June 2011 and May 2012, we measured in-situ asymbiotic BNF using the acetylene reduction assay, calibrated with ¹⁵N₂-fixation method. Across treatments, asymbiotic BNF rates in the 0–5-cm soil depth ranged from 1.7 (±0.2 SE) kg ha⁻¹ yr⁻¹ for fertilized plots cut once a year to 5.7 (±2.3 SE) kg ha⁻¹ yr⁻¹ for unfertilized plots cut thrice a year. Fertilization decreased asymbiotic BNF, suggesting that the potential positive effect of increased soil P levels might have been overruled by the negative effect of increased soil mineral N levels. Intensive mowing stimulated asymbiotic BNF, which was probably due to an increase in rhizodeposition. Our calibration of the acetylene reduction assay with the ¹⁵N₂-fixation method resulted in a conversion factor of 0.61, which largely deviates from the theoretical conversion factor of 3. Furthermore, laboratory incubations under increased soil moisture and temperature conditions overestimated BNF rates compared to in-situ measurements. Thus, laboratory measurements with altered soil moisture, temperature or disturbed soil may lead to strong biases in estimates of asymbiotic BNF. Our results suggest that input of N through BNF may be considerable in temperate grasslands. We conclude that BNF studies should be conducted in-situ and that the acetylene reduction assay should be calibrated against ¹⁵N₂-fixation calibration for reliable estimates.     

高羊茅悬浮细胞系的建立及绿色植株的高频再生

将5个高羊茅品种的成熟种子经灭菌后，接种于含有不同浓度2，4—D和ABA的N4培养基上进行愈伤组织诱导。结果表明，不同浓度2，4—D和ABA对5个品种的愈伤组织诱导率有显著影响，以培养基中附加9mg/L 2，4—D和2mg/L ABA的诱导率最高。将经过数次继代改造后获得的高质量胚性愈伤置于AA液体培养基中进行悬浮培养，建立起来自3个品种的8个悬浮细胞系，其中6个悬浮细胞系经高渗预处理后能高频再生出绿色植株，基本克服了以往研究中再生白化植株的现象。     

两种植物生长调节物质处理对水稻多胚苗频率的影响

 选用3份水稻多胚材料(PM13,PJ-1和PM14)进行2,4-D,6-BA浸种和喷穗试验.结果表明,用这两种植物佳长调节物质浸种和喷穗对水稻多胚苗频率有不同程度的影响:a.以5ppm2,4-D和10ppm,20ppm6-BA浸种的提高了多胚苗频率,但对不同材料(基因型)的影响程度有差异;b.用5ppm6-BA和5ppm2,4-D+20ppm6-BA,20ppm2,4-D+20ppm6-BA,10ppm2,4-D+20ppm6-BA喷穗效果好,提高程度均达到极显着水准,此外,5ppm-BA和5ppm2,4-D+20ppm6-BA处理的不定胚频率提高也达极显着水准.植物生长调节物质喷穗还诱导出孤雌生殖,证实了多胚现象与无融合生殖之间有显着的相关.     

用优势树全高和胸径的关系评价红松林的立地质量

柞树红松林，鱼鳞云杉红松林，云冷杉红松林，椴树红松林，枫桦红松林和春榆，水曲柳红松林是小兴安岭南坡红松天然林中常见的６个立地类型。不同立地类型红松优势树高，胸径和年龄三者之间关系分析的结果表明年龄在决定红松优势树高，胸径和年龄三者之间关系分析的结果表明年龄在决定红松优势树高上的意义不大，而优势树高与胸径的相关性密切，符合Ｒｉｃｈａｒｄｓ方程。采用优势树在一定胸径（４０ｃｍ）时的高度值表达立地指数，     

频谱复合音对幼龄豚鼠耳蜗电位的作用分析

研究在鼓阶或前庭阶记录由频谱复合音诱发的耳蜗电位，应用微机化生理药理实验教学系统，对幼龄豚鼠耳蜗的不同声音刺激予以记录分析。实验结果表明持续声短纯音诱发耳蜗电位CM与CAP重叠；而脉冲短声诱发耳蜗电位的CM与CAP分离。并对频谱复合音的振幅与微音电位(CM)、听神经复合电位(NI，N2)的关系进行了深入探讨，发现刺激频率的振幅Amp是负值时听神经复合电位Nl与N2随Amp的增加而降低。     

樟子松天然母树林疏伐强度与种子产量的关系

通过对樟子松天然母树林的４种不同疏伐强度标准地的林木开花结实与气象因子观测，进行了疏伐强度对母树林种子产量影响的研究。结果表明：（１）疏伐可有效的促进母树林的开花结实；（２）疏伐强度与母树林单位面积产种量相关密切；（３）疏伐促进林木结实其主要影响因素是光照，地面温度等气象因子；（４）樟子松天然母树林定株疏伐的最佳密度为１９０株ｈｍ＾２。     

A new device for monitoring the activity of freely swimming flatfish, Japanese flounder Paralichthys olivaceus

ABSTRACT:   The tail beat and activity behavior of four captive Japanese flounder Paralichthys olivaceus , were monitored with acceleration data-loggers while the fish swam in an aquarium. Depth, swimming speeds and two-axis acceleration data were collected continuously for approximately 20 h per fish. Simultaneously, the swimming behaviors of the fish were filmed at different angles. Using the specific characteristic of the acceleration profiles, in tandem with other types of data (e.g. speed and depth), four behavioral patterns could be distinguished: (i) 'active' swimming; (ii) burying patterns; (iii) 'inactive' gliding; and (iv) lying on the bottom. Tail beat frequency ranged from 1.65 ± 0.47 to 2.04 ± 0.25 Hz (mean ± SD; n  = 4). Using the relationship between tail beat frequency and swimming speed, the 'preferred' swimming speed of the fish was estimated to be between 0.6 and 1.2 body lengths (BL)/s. Additionally, fish rarely swam faster than 1.2 BL/s. This study shows that the acceleration data-loggers represent a useful and reliable system for accurately recording the tail beat of free-ranging fish and estimating flatfish behavior.