对鸡第三脑室的扫描电镜理察

扫描电镜观察结果表明,鸡第三脑室的室管膜有构造分区。视前隐窝有密集的纤毛和徽绒毛,且呈均匀分布。由第三脑室侧壁的背侧向腹侧过渡,纤毛密度逐渐增加。漏斗隐窝的结构最复杂,是多纤毛区、少纤毛区、无纤毛区和伸张细胞区交错排列形成的嵌合体,并分布有大量的泡状结构。存在于侧壁的室旁器的结构特征为表面分布有大量的室管膜上神经纤维。伸张细胞仅存在于漏斗区,互相排列成蜂窝状,表面分布有少量分泌小泡和微绒毛。在鸡第三脑室的各部均发现了神经元样细胞、神经胶质样细胞和类组织细胞。     

雅安植物线虫初步调查

于１９９３～１９９５年先后用直接剥离法和贝尔曼法对雅安市的３９种农作物、果蔬、花卉及杂草的根和根际土壤,少数植物的茎叶及果实进行了检查。结果发现２４种植物线虫,其中有１０种线虫鉴定到种,其余只鉴定到属;隶属于３目１０科２１属。     

木麻黄木材的化学成分和纤维形态

通过粗杂木麻黄木材的测定和观察，木材试样化学成分和纤维形态的分析，并与其它制浆原料相比较，从而为木麻黄木材用于制浆造纸提供必要的依据．     

草原黄鼠染色体研究

我们采用骨髓细胞直接制备染色体的方法，对草原黄鼠（Ｃｉｔｅｌｌｕｓｄａｕｒｉｃｕｓｐａｌｌａｓ）的染色体进行研究发现，草原黄鼠二倍体体细胞的染色体数除有国内外报道的２ｎ＝３６的个体外；还有２ｎ＝３７的个体；２ｎ＝３８的个体，２ｎ＝３７的个体１条不能配对染色体单体，其形态特殊，按其大小位于在第１３对和第１４对之间；２ｎ＝３８的个体，依据染色体的形态和大小确认为第１０对和第１３对为三体。另外还发现在草原黄鼠１７对染色体的短臂上有髓体清晰可见，而两条染色体上面体大小略有差异，我们的分析研究初步认为草原黄鼠染色体数目和形态的异常是环境诱变所致。     

马尾松种子园及其附近人工林的亲子代群体遗传结构分析

利用同工酶标记对广西覃塘林场马尾松无性系种子园及其附近一人工林的亲子代群体遗传结构进行研究。研究结果表明，不论是种子园还是附近人工林均表现为：亲代群体处于遗传平衡状态，杂合体相对过量，但子代已偏离遗传平衡，杂合体相对不足，亲子代的基因频率变化不大。种子园亲代群体的遗传多样性略高于子代，而附近人工林的亲代群体遗传多样性略低于子代。本文研究的种子园具有较宽的遗传基础，该种子园附近人工林的遗传多样性与种子园接近，但不论是人工林本身还是它的子代其多样性平均水平都较种子园的亲代和子代略低。     

沉水植物化感作用抑制藻类生长的研究进展

根据国内外相关报道,重点对9科15种沉水植物化感作用物质的构成及抑制15种藻类的生长,沉水植物化感作用抑制藻类生长的机理等方面的研究进展进行综合评述。     

承德地区引进食用高粱新品种比较试验

试验对13个引进食用高粱新品种进行比较试验分析,以确定各品种在承德地区的抗病性、丰产性和适应性.结果表明:锦杂108和辽粘3适合承德地区南部无霜期在130 d以上地区大面积推广种植,其它品种可选择种植.     

江汉平原中山杉引种造林试验研究

通过在江汉平原开展中山杉6个品系的引种造林试验。结果表明,引进的6个品系中山杉无严重病虫害发生,各生长指标均大于池杉,11 a生中山杉平均胸径为17.61 cm、树高为11.06 m、材积为0.1297 m^3,表明中山杉在江汉平原的引种试验基本成功,其中中山杉502和中山杉118最为突出,适合在江汉平原推广造林,丰富江汉平原造林树种。     

我国林木生物质发电产业中政府角色与发展模式的思考

我国林木生物质能源十分丰富,适宜发展林木生物质发电产业。但是目前林木生物质发电产业仍处于初级发展阶段,产业发展模式还不够成熟,产业潜力未被充分挖掘。文中基于产业模式相关研究基础,结合我国林木生物质发电产业发展实践,设计了更为全面系统的林木生物质发电产业发展模式,根据政府对产业发展介入力度不同,将产业发展模式分为萌芽期（政府主导型产业发展模式）、成长期（政府引导型产业发展模式）、成熟期（政府规制型产业发展模式）,并从资源、经济、社会、环境、技术5个方面论证林木生物质发电产业发展的可行性、有效性和持续发展的稳定性,以期为国家主管部门制定相关政策提供理论参考。     

Influence of in-house produced biochars on cracks and retained water during drying-wetting cycles: comparison between conventional plant,animal, and nano-biochars

Purpose

Biochars produced from different feedstocks (such as wood, pig manure) possess varying physical and chemical properties, which have influence on crack and evaporation rate of biochar-amended soil (BAS). Furthermore, influence of compaction state and drying-wetting cycles on evaporation rate and cracking of BAS has not been investigated comprehensively. The objective of this study was to investigate the effects of biochar types, compaction state of BAS, and drying-wetting cycles on crack propagation and retained water (or evaporation rate).

Material and methods

An animal and plant feedstock-based biochars were produced in-house from pig manure (PM) and wood (W), respectively. In addition, nano structured chalk and wheat biochar (CWB) were also produced. Soil amended with individual biochars was compacted in petri-glass discs at two densities. Disc specimens were subjected to multiple drying-wetting cycles, and evaporation rate of specimens and crack area were monitored throughout the experimental period (70 days). Images were captured after every 24 h and processed using image processing technique to obtain the crack intensity factor (CIF).

Results and discussion

The results show that plant-based W BAS showed the high water retention, i.e., low evaporation rate and low CIF. Furthermore, the crack potential of CW BAS was seen to be higher. In dense compacted soil, maximum CIF% can be reduced from 3.9 to 0.4% for W BAS, from 3.9 to 1.7% for PM BAS, and from 3.9 to 1.6% for CW BAS.

Conclusion

WB was able to resist cracking more efficiently than other types of biochar. Evaporation was found to be minimal for plant-based W BAS at 10% biochar percentage. Higher biochar content in soil was seen to increase the water retention of BAS significantly. Dense state of BAS at high biochar content (i.e., 10%) was effective in reducing evaporation rate and crack progression.