底墒差异对夏玉米生理特性及产量的影响

研究了底墒差异对夏玉米生理特性及产量的影响。试验结果表明,在夏玉米生育期间极度干旱的条件下,以冬小麦生育期间灌拔节水和抽穗水(各40mm),夏玉米生育期间灌两水(共计100mm)的处理夏玉米产量最高,达7466.58kg/hm2。而且该处理的叶面积、光合速率、蒸腾速率等生理指标高于其余各处理,气孔阻力和叶温等生理指标则低于其余各处理,以上各生理指标的变化是由于前茬冬小麦不同生育期灌溉而造成的。本试验同时表明,研究作物的水分问题应与特定的种植制度相结合。     

地源热泵水蓄能型植物工厂降温系统夏季运行特性

针对田间环境复杂、秸秆形态多样、秸秆覆盖率判断主观性影响过大、补贴面积测量耗时耗力等问题,该文开展了秸秆覆盖率率自动识别方法研究和监测设备研制。首先,提出利用时频变换进行秸秆识别,设计高通滤波器提取了图像的频域特征进行自适应分割。基于集成分类器利用已有的秸秆识别数据训练支持向量机分类器,对秸秆图像进行再识别和筛选。最后,设计多尺度占比滤波器,对识别图像中的噪声和空洞进行修补,生成适应多种情况的秸秆覆盖率识别算法。与北斗定位模块、无线通讯模块、摄像头、传感器、服务器等设备共同组成秸秆覆盖率识别系统。试验结果表明,设备的秸秆覆盖率识别误差为4.55%,平均单张图像耗时0.05 s。研究结果满足保护性耕作中的自动化监测要求,可为保护性耕作作业质量评测提供有效的技术支持。     

浅析奖励机制在科研成果产出中的导向作用 ——以北京市农林科学院为例

科研成果产出反映了科技创新能力的强弱,成果产出离不开杰出的科研人才和团队.为了提升科技创新能力,有效激发科研人员的主动性和积极性,不断提升科研成果质量,国家、地方、科研单位和高校都制定并出台了相应的科研成果奖励办法.文章以北京市农林科学院为例,对该院科技创新成果奖励的执行情况进行分析,以期总结出科技创新奖励对成果产出的导向作用.     

Factors Affecting Sensory Quality of Cooked japonica Rice

The sensory quality of cooked rice is an important factor in determining its market price, as well as consumer acceptance and breeding efforts aimed at improvement of rice grain quality. In this study,the sensory quality and physicochemical properties of three japonica rice varieties harvested in two different growing locations(Xiangshui and Hangzhou of China) were compared to determine the most important factors affecting the sensory quality. All the three varieties had higher scores for overall sensory quality in Xiangshui than in Hangzhou, indicating that the growing location is a key factor in determining the sensory quality of cooked japonica rice. In addition to growing location, variety(genotype) also had an important effect. Longdao 18 scored the highest for overall sensory quality in the two locations, whereas Longdao 30 had the lowest score in Xiangshui, and both Longdao 20 and Longdao 30 had the lowest scores in Hangzhou. Many physicochemical properties, such as apparent amylose content, protein content, thermal properties and free amino acid contents, showed significant differences between the two locations. Correlation analysis showed that apparent amylose content and protein content had contrasting effects on all the sensory attributes. The overall sensory quality was negatively correlated with protein content(r =-0.89, P 0.01) and positively correlated with gel hardness(r = 0.91, P 0.01),indicating that the protein content and hardness are important physicochemical properties for predicting the sensory quality of japonica rice. These findings will provide guidance for selection from the diverse genotypes available to develop new varieties with the desired eating and cooking quality.     

Trichostatin A and nuclear reprogramming of cloned rabbit embryos

To investigate the influence of histone deacetylases on nuclear reprogramming after nuclear transfer, we treated the cloned embryos with a histone deacetylase inhibitor, Trichostatin A (TSA). In the present study, global changes in acetylation of histone H3-lysine 14, histone H4-lysine 12, and histone H4-lysine 5 were studied in rabbit in vivo fertilized embryos, somatic cell nuclear transfer (SCNT) embryos, and TSA-treated SCNT embryos. From the pronuclear to the morula stage, the deacetylation-reacetylation changes in acetylation of histone H3-lysine 14 and histone H4-lysine 12 occurred in both fertilized embryos and TSA-treated cloned embryos; however, the distribution pattern in untreated cloned embryos failed to display such changes. More interesting, the signal of acetylation of histone H4-lysine 12 in cloned embryos was detected in both the inner cell mass and the trophectoderm, whereas TSA-treated cloned embryos showed the same staining pattern as fertilized embryos and the staining was limited to the inner cell mass. The histone acetylation pattern of TSA-treated SCNT embryos appeared to be more similar to that of normal embryos, indicating that TSA could improve nuclear reprogramming after nuclear transfer.     

松针多糖对肉鸡生产性能和免疫功能的影响

本研究旨在探讨松针多糖对肉鸡生长性能和免疫功能的影响。选取240只1日龄的815肉鸡,随机分为4个处理,每个处理4个重复,每个重复15只鸡,分别在基础饲粮中添加0(对照)、0.05%、0.10%和0.15%的松针多糖提取物。试验期为42d,测定处理组生长性能、免疫器官指标、血清免疫指标。结果显示,在生长前期(1-21d),松针多糖对肉鸡的生产性能没有影响(P0.05),0.05%多糖组白细胞介素2的浓度极显著高于对照组(P0.01),对肿瘤坏死因子、胸腺素及免疫器官指标影响不显著(P0.05)。在生长后期(22-42d),0.10%多糖组平均日增重显著高于对照组(P0.05),对平均体重及料重比无显著影响(P0.05),0.05%多糖组肿瘤坏死因子浓度显著高于对照组(P0.05),而对白细胞介素2、胸腺素及免疫器官指标影响不显著(P0.05)。结果表明,饲粮中添加适量的松针多糖在一定程度上可以提高肉鸡的免疫功能和生产性能,0.10%的松针多糖添加量较为适宜。     

叶用银杏栽培密度及采叶方式的综合分析

本文对幼龄叶用银杏从不同密度、不同采叶方式,综合产叶量和黄酮含量两方面因素,对其药用价值进行了分析评价,结果表明：３ 年生幼龄叶用银杏种植密度以 ７．５ 万株／ｈｍ ２ 为佳,７．５～１１ 万株／ｈｍ ２ 均宜,年２ 次采叶包括 １／２ 采、全采和 １ 次性采叶对照 ３ 种采叶方式无显著性差异,以 １ 次性采叶为宜。     

阿月浑子花芽分化的初步研究

本文对阿月浑子雌雄株的花序分化进行了观察研究,花序的分化各阶段牟形态特征基本一致,只是在分化的时间上有些差异,整个花序分化初步五个时期为制定丰产栽培技术措施,提供了科学依据。     

用主成分分析法研究西葫芦早熟性及品种分类

通过观察与分析５２个西葫芦品种的１１个性状,利用主成分分析法确定出５个主要分量性状,其中第一、第二主分量性状的累积贡献率为６５．０６％．根据其主分量的大小选出了综合性状优良的早熟西葫芦材料,并利用主成分分析法将５２份西葫芦材料分为６类。     

恩诺沙星对人工诱发的鸡大肠杆菌病的疗效

应用氟喹诺酮类抗菌动物专用药恩诺沙星水溶性粉剂对人工感染大肠杆菌病的雏鸡进行了治疗研究,用环丙沙星、阳性空白对照、阴性空白对照进行了比较。结果表明,６０,３０,１０ｍｇ·Ｌ－１浓度的恩诺沙星可溶性粉剂的保护率分别为８５．７％,７７．１％,２８．６％;环丙沙星２０ｍｇ·Ｌ－１的保护率为７４．３％,阳性对照组为１１．４％,阴性对照组为１００％．说明恩诺沙星对鸡大肠杆菌病有较好的疗效。