抗旱型稻根系形态与机能的研究

以6个抗旱性不同的栽培稻品种为材料,对其根系形态及解剖学进行研究.结果表明抗旱型稻平均根长、根粗、根系穿透力、不定根伸长速率、不定根中柱及导管面积等显著大于非抗旱型品种;而根干重、不定根数量、根冠比及根系的渗透调节能力等指标,抗旱型与非抗旱型品种间差异不显著.对栽培稻抗旱性的形态指标与抗旱机理进行了探讨.     

Nitrogen forms affect root structure and water uptake in the hybrid poplar

The study analyses the effects of two different forms of nitrogen fertilisation (nitrate and ammonium) on root structure and water uptake of two hybrid poplar (Populus maximowiczii x P. balsamifera) clones in a field experiment. Water uptake was studied using sap flow gauges on individual proximal roots and coarse root structure was examined by excavating 18 whole-root systems. Finer roots were scanned and analyzed for architecture. Nitrogen forms did not affect coarse-root system development, but had a significant effect on fine-root development. Nitrate-treated trees presented higher fine:coarse root ratios and higher specific root lengths than control or ammonium treated trees. These allocation differences affected the water uptake capacity of the plants as reflected by the higher sapflow rate in the nitrate treatment. The diameter of proximal roots at the tree base predicted well the total root biomass and length. The diameter of smaller lateral roots also predicted the lateral root mass, length, surface area and the number of tips. The effect of nitrogen fertilisation on the fine root structure translated into an effect on the functioning of the fine roots forming a link between form (architecture) and function (water uptake).     

节水灌溉对水稻产量形成的影响

从灌溉方式、品种类型、栽插密度和施肥量研究了对水稻汕优63和盐粳2号产量形成的影响.结果表明,库限制型品种盐粳2号,常规灌溉的产量高于节水灌溉;源限制型汕优63,节水灌溉的产量与常规灌溉相近.在中肥条件下,常规灌溉的产量高;在高肥条件下.节水灌溉的产量接近或超过常规灌溉.在节水灌溉时,增加栽插密度有明显的“以密补水”的作用.节水灌溉区每亩穗数、每穗粒数减少,结实率相应提高,但千粒重在两类灌溉方式处理间差异甚小.     

Embryo Production in Superovulated Goats Treated with Insulin Before or After Mating or By Continuous Propylene Glycol Supplementation

Seventeen adult and cyclic Moxoto goats were synchronized using 60 mg MPA vaginal sponge for 11 days and 50 μg cloprostenol, 48 h before sponge removal, and superovulated with 120 mg pFSH i.m. in decreasing doses at 12 h intervals for three consecutive days. In seven goats, 0.2 IU/kg BW/day of long acting insulin was subcutaneously injected at same time as pFSH, and in the other five goats, the same dose of insulin was injected for three consecutive days starting 24 h after mating. Finally, five goats were supplemented with an oral dose of 80 ml/goat/day of propylene glycol continuously during the experiment. The animals were flushed at 7 days after mating and the embryos were classified based on International Embryo Transfer Society criteria. Blood samples were collected every 3 days for insulin assay. Administration of insulin raised the insulin levels of the goats (p < 0.05), whereas in the group treated with propylene glycol, insulin rate was different only between FSH treatment and after mating (p < 0.05). Similar rates of recovery for total (80.05 ± 9.78%) or transferable structures (61.03 ± 15.13%) were obtained. Treatment was not influenced (p > 0.05) by responsiveness to superovulation, which averaged 64%. By contrast, insulin treatments were shown to increase the number of embryos considered excellent with respect to goats supplemented with propylene glycol (p < 0.05). When insulin was given before mating, a strong relationship (r = 0. 90) (p < 0.05) between number of transferable embryo and ovulations was observed in the animals. In conclusion, superovulated goats treated with low doses of exogenous insulin resulted in an enhancement in embryo quality, which was related to changes in circulating insulin concentrations.     

马立克病病毒pp38基因的编码序列及译读框

马立克病病毒(MDV)与致肿瘤相关的38kd磷蛋白(pp38)基因的编码序列是一个不含有内含子的由870个碱基对组成的DNA片断。从对MDVpp38-λgtll Lac Z融合基因的定序及已知Lac Z基因的译读框,直接读出了MDVpp38基因的译读框。根据计算,由该译读框推导出的该基因编码的由290个氨基酸组成的初级多肽分子量约为31kd.     

再生稻根系物质流示踪研究

用~(32)P示踪研究再生稻根系物质流,结果表明,上层根是头季稻灌浆与成熟期的主要功能根系。再生稻苗期主要依靠上、下层根吸收矿质养分(~(32)P),而灌浆至成熟期,则主要依靠再生根,其次是上层根。     

昆虫发育速率与温度关系的正弦模型

提出了昆虫发育速率与温度关系的一个新模型——正弦模型.这个模型适用性强,拟合精度高,计算方便,且能估计发育起点温度.     

抗独特型单克隆抗体在鸡中诱导的抗新城疫病毒保护性免疫——新城疫单克隆抗独特型疫苗研究(Ⅲ)

用AFE_8Id_(16-6)和ALA_(15-6)Id两株新城疫病毒(NDV)的抗独特型单抗(MAb_2)分别免疫接种一组(18只)无HI抗体鸡,并以一组(7只)Lasota苗常规免疫鸡和一组(12只)不免疫的易感鸡分别作为免疫阳性和阴性对照。在两株MAb_2末次免疫后8天,用微量血凝抑制(HI)试验检测了4组鸡的血清中HI抗体水平。结果:两株MAb_2和Lasota苗免疫的鸡全都产生了HI抗体,非免疫鸡均未测到HI抗体。AFE_8Id_(16-6)免疫鸡的HI滴度为1～5log_2;ALA_(15-6)Id免疫鸡的HI滴度为1～4log_2;Lasota苗免疫鸡的HI滴度高达7～10log_2。在HI抗体检测后2天,用100LD_(50)F_(48)E_8株NDV强毒攻击4组鸡,隔离观察10天,AFE_8Id_(16-6)和ALA_(15-6)Id免疫鸡的保护比值分别为17/18和10/18,Lasota苗免疫鸡保护比值达7/7,而非免疫对照鸡在攻毒后6天全部死亡。试验结果证明,上述两株MAb_2是NDV保护性抗原的模拟物,在多次注射后可诱导鸡产生抗NDV的血凝抑制抗体,并能使鸡抵抗NDV强毒的人工感染。因此,这两株抗独特型单抗,尤其AFE_8Id_(16-6)有希望用作新城疫抗独特型疫苗。     

棉纤维细胞壁微晶区的大小和畸变

应用X射线衍射的Hoscmann作图法测得棉纤维细胞壁微晶区的大小为127A(沿纤维轴方向)和66A(垂直于纤维轴方向),徽晶区的畸变为0.69％(沿纤维轴方向)和3.28％(垂直于纤维轴方向)。