黑茶茶多酚类物质的提取及其抗氧化性能研究

以湖南安化天尖、茯砖及广西六堡3种黑茶为考察对象,研究黑茶中茶多酚的提取工艺以及抗氧化性能。针对超声波不同提取条件,采用正交试验,确定黑茶中茶多酚的最佳提取工艺条件;采用清除二苯代苦味酰自由基(DPPH)的能力和邻苯三酚自氧化体系来评价其抗氧化活性。结果表明:采用超声波热水复合浸提法提取黑茶中茶多酚的最佳提取条件为超声波提取功率250 W,提取固液比1∶25,提取温度55℃,提取时间45min,茯砖黑茶中茶多酚的提取率5.21%;同时测得茯砖黑茶具有较好的抗氧化能力,对DPPH自由基有较强的清除能力,但与维生素C(VC)相比,其抗氧化能力比VC的能力弱;其清除超氧阴离子自由基能力的IC50为0.507μg/mL。     

谷子秸秆剪切力与其饲料营养特性变化规律及相互关系

为探究谷子秸秆力学性质与其饲料特性的变化规律及相互关系，选用谷物完熟期的谷子秸秆，将其分为5段（近根部、中下部、中部、中上部、上部）并每隔7 d进行秸秆节间、茎节力学性质（剪切、压缩）和饲料特性（形态指标、营养成分）测定。试验结果表明：谷物完熟后，随着时间的推进，秸秆节间、茎节剪切力、抗压强度、干物质含量、纤维素含量、半纤维素含量和木质素含量总体上呈增大趋势，而秸秆含水率、当量直径、横截面积、线性密度和粗蛋白含量总体上呈减小趋势。谷子秸秆单位直径剪切力与含水率和线性密度呈负相关关系（R2≥0.903），与其干物质、纤维素、半纤维素和木质素含量呈正相关关系（R2≥0.845），与其粗蛋白含量无显著相关关系（P>0.05）。采收期内，谷子秸秆基部起秸秆剪切力至顶部逐渐增大，且剪切力与当量直径、横截面积呈正相关关系（R2≥0.916）。试验表明谷子秸秆饲料特性指标验证试验值与预测值相对误差不大于6.48%，预测模型合理。测量秸秆剪切力可用于预测其形态指标参数和营养成分含量，进而一定程度地反映秸秆饲用价值和反刍动物择食趋向。采收期内，谷子中部及以上秸秆单位直径剪切力显著小于其近根部（P<0.05），更适合饲用；且谷物完熟后，及时采收可避免秸秆饲用价值降低。该研究可为高效利用谷子秸秆资源提供参考。     

Genome‐Wide Identification of MicroRNAs Responsive to High Temperature in Rice (Oryza sativa) by High‐Throughput Deep Sequencing

MicroRNAs (miRNAs) are known to play important roles in plant growth and stress response. Heat stress is a severe abiotic stresses by adversely affecting plant growth and yield. To identify heat‐responsive miRNAs at the genome‐wide level in rice (Oryza sativa), we constructed two small RNA libraries from young panicles treated or not with heat conditions. Ion torrent sequencing of the two libraries identified 294 known miRNAs and 539 novel miRNAs. Differential expression analysis showed that 26 miRNAs were downregulated and 21 miRNAs were upregulated in response to heat stress. Among them, five heat‐responsive miRNAs, including miR162b, miR529a‐p5, PC‐5P‐62245‐9, miR171b and miR169n, were validated by quantitative real‐time polymerase chain reaction. A total of 44 target genes of the differentially expressed miRNAs were predicted. These target genes are most significantly overrepresented in the cell growth process. The results demonstrated that rice miRNAs play critical roles in the heat stress response. This study opens up a new avenue for understanding the regulatory mechanisms of miRNAs involvement in the heat stress response in rice.     

锅炉烟气余热用于木材干燥的节能改造

针对广东某胶合板企业2台蒸汽锅炉排烟温度高,不能根据工序用热需求实现能源梯级利用的问题,提出了锅炉烟气余热利用方案。根据干燥窑干燥木材的特点,将蒸汽锅炉的烟气引入干燥窑内的换热器用于干燥木材,每年通过回收利用的锅炉烟气余热折合标煤达439t。     

利用蒸发冷却空调开展控温储粮试验

在拱板式高大平房仓的拱板间安装蒸发冷却空调开展控温储粮技术,解决拱板间的积热,以达到延缓仓内温度和上层粮温上升速度的目的。蒸发冷却空调主要利用水泵抽取水槽内的水,通过分水器均匀分布到特殊纤维制成的湿帘组件上,而大流量轴流风机的转动令仓外空气以极高速度穿过湿帘组件将湿气散发到空间,以增加空气中的湿度,通过正压促使空气流动,从而达到换气降温的效果。试验结果表明,利用低功率蒸发冷却空调,可以有效排除拱板间的积热,实现换气降温、节能、环保、绿色储粮的目的。     

日粮钙水平对空怀期云南半细毛羊生长性能及血清生化指标和繁殖相关激素的影响

试验旨在探讨日粮钙水平对空怀期云南半细毛羊生长性能、配种前血清生化指标和繁殖相关激素的影响,为开展空怀期云南半细毛羊营养需要量研究提供参考。选用50只体况良好、体重相近、38月龄的经产2胎空怀云南半细毛羊,随机均分为5组,分别饲喂0.40%(无外源钙)、0.45%、0.53%、0.66%、0.85%5个钙水平的日粮。预试期14d,正试期30d。结果表明:0.53%钙水平组云南半细毛羊的总增重、平均日增重、平均日采食量、耗料增重比等指标相对优于其他组;0.40%钙水平日粮组的血清钙最高,血清碱性磷酸酶、甲状旁腺素、钙、磷组间差异不显著(P>0.05);繁殖相关激素各组间表现不一,0.40%钙水平组雌二醇水平最高(P>0.05)。在日粮磷水平为0.20%水平条件下,0.53%钙水平组的空怀期云南半细毛羊表现出较好的生长性能,可为临配种前生理生化和激素水平提供较好准备;增加日粮钙水平,未见对以上指标有明显的正向增强作用,可能与日粮钙磷比失衡有关。     

人类活动对象山湾滩涂沉积物理化特征的累积效应

[目的]研究人类活动对象山湾滩涂沉积物理化特征的累积效应。[方法]选取象山湾沿岸滩涂沉积物作为供试材料,测定沉积物样品粒度特征、磁化率、总有机碳及硝态氮含量。[结果]象山湾滩涂沉积物粒径组成以粉粒为主,质地较为黏重,可塑性和保水性较好,透气性差,且沉积物粒径组成随深度变化明显;磁性物质的含量随着取样深度的增加而不断减少;有机物质含量较高,且随着取样深度的增加,有机质含量明显下降,但总体维持在较高水平;硝态氮含量随取样深度的增加总体呈上升趋势,波动明显。[结论]人类活动对象山湾滩涂影响较为明显,理化特征的累积效应在剖面上表现显著。     

两种商品木浆的纸浆性能研究

选取市场上具有代表性的两种商品针、阔叶木浆进行PFI打浆处理,研究在不同打浆度下浆料纤维质量、动态滤水性能、Zeta电位、微观结构等方面的变化,并对不同比例配抄条件下的成纸性能进行考察,结果表明:针、阔叶浆的打浆度与打浆转数之间的关系均符合线性分布:y=17.7503+0.0015x,R^2=0.9914(针叶浆);y=8.8986+0.00275x,R^2=0.9734(阔叶浆);经PFI打浆后,两种木浆纤维长度、宽度变化较小,细小组分含量变化明显;随着打浆度的升高,两者的滤水性能下降,Zeta电位先上升然后基本保持不变;初始打浆度下,随着针叶浆比例的减少、阔叶浆比例的增加,成纸的抗张强度先下降再增大,厚度逐渐下降至不变,定量逐渐增加,柔软度逐渐下降;随着打浆度的升高,成纸的抗张强度增大,厚度、定量逐渐下降,针叶浆成纸柔软度逐渐下降,阔叶浆成纸柔软度先升高再逐渐降低。     

毕节市漆树品种产量与树皮性状的灰色关联度分析

为漆树优良品种的选择以及灰色系统理论在林业林木品种评价上的运用提供参考，对毕节市8个漆树品种红漆大木、粉皮大木、灯台大木、红尖大木、肤胭皮、粉红皮、白杨皮、青杠皮等树皮解剖中6个主要性状与产漆量的关系进行灰色关联度分析。结果表明：漆树树皮解剖的单个性状对产漆量有直接影响，其中以漆汁道直径的大小关系最重要，直接关联度达0．7964；其次是活皮漆汁道单位面积与活皮厚度。从树皮解剖的综合性状看，漆树品种最好的依次是红尖大木＞红漆大木＞肤胭皮＞灯台大木＞白杨皮＞粉皮大木＞粉红皮＞青杠皮。分析结果与实际生产基本一致，表明在林业生产中运用灰色关联分析进行综合评价是可行的。     

Effects of spent mushroom substrates and inorganic fertilizer on the characteristics of a calcareous clayey‐loam soil and lettuce production

We evaluated the effects of the addition of two types of spent mushroom substrate (SMS), SMS from an Agaricus bisporus crop (SMS1) and a mixture of SMSs from an A. bisporus crop and a Pleurotus crop (50% v/v each) (SMS2), on the characteristics of a calcareous clayey‐loam soil and the yield and nutritional status of lettuce (Lactuca sativa L.), relative to crops receiving mineral fertilizer (M) and a control (C) without amendment. The application of SMS, especially SMS1, improved soil fertility compared with C and M soils. Moreover, the use of these organic substrates as soil amendments did not harm the plants and gave yields similar to that obtained with mineral fertilizer. The nutritional contents of the lettuce plants were greater than or similar to those of the plants from treatment C or M, except for the plant tissue concentrations of K, Fe and Zn, which were significantly reduced by SMS application. However, this latter fact did not reduce the lettuce yield in the amended soils. Therefore, the use of SMSs as organic amendments contributes to residue utilization, in an environmentally friendly way, and to improved soil fertility and crop yield.