壳聚糖在农业上的应用研究进展

壳聚糖（Chitosan）是地球上第二大可再生自然资源，属于无毒、无污染的动物源激素物质，可以用作生防农药，对抗病诱导、杀菌杀虫、抵御逆境、种子包衣、果蔬保鲜、农药增效、土壤改良、地膜降解、促进生长、提高产量、改善品质等具有重要的作用，已经在小麦、玉米、水稻、大豆、马铃薯、黄瓜、番茄、芹菜、青椒、白菜、香蕉、芒果、苹果、梨、草莓等多种作物上得到了验证，显示出了广阔的应用前景     

Analysis on a Financing-model of Public Companies in Incomplete Market

It remains intrinsic defect how to explain reasonable financing behaviors in classical theory of capital structure. This paper gives a capital structure decision-making model with asymmetric information and exchange cost in incomplete market, and opens out mechanism of financing-selection base on adverse selection by Chinese public companies, in more we can explain well phenomena about equity over-financing of Chinese public companies.     

Ta6-SFT在烟草中的逆境诱导型表达及抗旱性

分别构建CaMV35S启动子驱动的Ta6-SFT组成型植物表达载体和rd29A启动子驱动的逆境诱导型表达载体。利用农杆菌介导法分别导入烟草中,获得转基因株系,Southern杂交和Northern点杂交确定Ta6-SFT整合进转基因株系基因组中,并正常转录。以非转基因株系作对照,对2种转基因烟草株系进行干旱胁迫处理,采用半定量RT-PCR分析Ta6-SFT在转基因株系中的表达,同时测定胁迫0 d和18 d果聚糖含量及部分农艺性状。结果表明,含有rd29A启动子的逆境诱导型株系中Ta6-SFT相对表达量比在含CaMV35S启动子的组成型株系中高,而且积累更多的果聚糖;从株高、1/2株高处茎粗、叶面积数据来看,逆境诱导型转基因株系的生长势优于组成型株系,对干旱表现强的耐性。因此,在转基因植物中逆境诱导型表达Ta6-SFT基因将发挥更好的抗逆功能。     

Response of beech and oaks to wounds made at different times of the year

Tree care, especially pruning, is still mostly done in the dormant time. Such treatments expose live inner bark, the vascular cambium, and functioning outer sapwood to harsh external influences followed often by infection of pathogens. Investigations about response reactions of beech and oak to wounding made in different times of the year showed that wound closure was significantly slower for December and February wounds than in April and October. The length of discoloured sapwood was in October and December wounds greater than in February and April. Sapwood reaction expressed by the soluble phenol concentration index indicated however no significant differences among wounding dates. Overall, woundings in the vegetation period will be more effectively compartmentalized than in the dormant season. Consequently, tree care like pruning with many woundings should not be done in the winter period.Presented at the 6th ISA European Conference, 9.-12. June 2004, Maastricht, The Netherlands     

Distorted Segregation for Mildew Resistance in Doubled Haploid Lines of Spring Barley

The mildew reactions of the second generation of doubled haploid (DH) plants, derived from anther culture of crosses among three spring barley lines carrying different Mla mildew resistance alleles and the cv. ‘Pallas’, were analyzed by using a set of three European and one Israeli mildew isolate. The results indicated, (1) a significant level of distortion segregation in favour of resistant DH genotypes, which was possibly due to linkage of mildew resistance genes on chromosome 5 with genes for plant regeneration and (2) various degrees of dominance for the different resistance genes studied as well as the possible action of modifier genes.     

富含磁性铁纳米颗粒的生物炭对菌根侵染、植物生长、营养吸收及土壤质量改善的影响

At present, there is little commercial sale of biochar, since farmers find they can not gain a return on their investment in this amendment in the first few years after its application, because of the high cost associated with large application rates. To overcome this constraint, development of artificially aged enriched biochar-mineral complexes (BMCs), having a higher mineral content, surface functionality, exchangeable cations, high concentration of magnetic iron (Fe) nanoparticles, and higher water-extractable organic compounds has been undertaken by a combined team of researchers and a commercial company.~% Two biochars produced under different pyrolysis conditions were activated with a phosphoric acid treatment. A mixture of clay, chicken litter, and minerals were added to the biochar, and then this composite was torrefied at either 180 or 220 $^\circ$C. In this study a pot experiment was carried out in glasshouse conditions to determine the effects of four different BMCs, with different formulations applied at rates of 100 and 200 kg ha$^{-1}$, on the mycorrhizal colonisation, wheat growth and nutrient uptake, and soil quality improvement. It was found that the phosphorus (P) and nitrogen uptake in wheat shoots were significantly greater for a low application rate of BMCs (100 kg ha$^{-1}$).~The present formulation of BMC was effective in enhancing growth of wheat at low application rate (100 kg ha$^{-1}$).~The increase in growth appeared due to an increase in P uptake in the plants that could be partly attributed to an increase in mycorrhizal colonisation and partly due to the properties of the BMC.     

产碱性纤维素酶真菌的筛选鉴定及酶学性质研究

经过初筛和复筛从从碱性土样中分离出的7株产纤维素酶的真菌中获得1株能够产碱性纤维素酶的丝状真菌t42。经18SrRNA基因序列分析和,确定该菌株为镰刀霉菌（Fusarium sp）。酶学性质初步研究显示t42的CMC酶最适作用pH值为7．5,在pH值7．0～8．5的范围内具较高的稳定性：反应温度以50℃左右为宜,且在55℃以下具有较高的温度稳定性;Mg^2＋、Mn^2＋和Zn^2＋对酶反应有促进作用,Pb^2＋和Cu^2＋对酶反应有抑制作用。