Participation of Opioid Peptides in Sucking‐induced Oxytocin and Prolactin Secretions in Lactating Goats

The role of opioid peptides in the secretion of oxytocin (OT) and prolactin (PRL) induced by sucking was studied in goats. Seven goats were isolated with their kids (four singletons and three twins) in individual corrals 3–4 weeks after parturition. On day 1 of the experiment, the kids were separated from the does for 7 h and were weighed before and 15 min after being reunited with their mothers to assess the amount of milk obtained by sucking. The does were blood‐sampled 10 min before and at the end of the sucking period. On day 2, a similar protocol was followed, but naloxone was given immediately after the first blood sample. On day 3, the protocol was repeated but saline vehicle was injected instead of naloxone. On day 5, the naloxone experiment was repeated as on day 2. Milk ejection was evaluated as the difference in the weight of the kids before and after sucking for 15 min, and the maternal serum levels of OT and PRL were measured by radioimmunoassay. A significant decrease in the weight gain of the kids was obtained when the mothers were treated with naloxone on day 2. Consistently, serum levels of OT and PRL induced by sucking were significantly reduced; indicating that sucking‐induced OT secretion for milk ejection in lactating goats is facilitated by opioid peptides. In a second experiment performed in the same animals 10 days later, the administration of OT, immediately after naloxone administration, prevented the decrease in the weight gain induced by naloxone, suggesting that the effect of the opioid antagonist on milk ejection in goats is a result of a reduced OT secretion. The results of this study confirm the importance of sucking‐induced OT secretion for milk ejection in lactating goats, and indicate that OT and PRL secretion are regulated by opioid peptides in this species.     

大额牛群体遗传多样性的微卫星标记分析

 利用26对黄牛微卫星引物,对分别来自云南省泸水县凤凰山大额牛保种区和贡山县独龙野牛种源保护基地的2个大额牛群体进行遗传变异分析,研究其群体内的遗传变异和群体间的遗传分化。结果共检测到105个等位基因,每个座位的等位基因数从2~6不等,所有座位平均等位基因数、平均有效等位基因数、平均期望杂合度、平均多态信息含量分别为4.0385±0.9999,3.1393±0.9507,0.6490±0.1246和0.5904±0.1334,表明大额牛群遗传多样性比较丰富。F统计量、基因流、Nei氏遗传距离和遗传相似系数等值反映出两个群体遗传差异较小,遗传分化不明显,遗传一致性较大。     

Influence of host plant species of Bemisia tabaci (Genn.) (Hom., Aleyrodidae) on some of the biological and ecological characteristics of the entomophagous Serangium parcesetosum Sicard (Col., Coccinellidae)

The entomophagous Serangium parcesetosum Sicard (Col., Coccinellidae) is an effective predator of some whitefly species. However, information on the influence of the preys host plant species on its biological and ecological characteristics is still lacking in the literature. Therefore, the current study focuses on the possible influence of three greenhouse and two field host plant species of Bemisia tabaci (Genn.) (Hom., Aleyrodidae) on the number of eggs laid by S. parcesetosum. In addition, because of the economic importance and widespread planting of cucumber in greenhouses and cotton in the field, these plants were selected for further investigation into the development, mortality, longevity and reproduction of S. parcesetosum at a high temperature in the laboratory. Results showed that S. parcesetosum was able to lay eggs on all five host plant species of B. tabaci, whether greenhouse or field plants. However, among the three greenhouse plant species studied, S. parcesetosum females laid the highest number of eggs on cucumber followed by tomato and then sweet pepper. Of the two field plant species, significantly higher numbers of eggs were laid on tobacco than on cotton. S. parcesetosum could develop either on cucumber or on cotton as preferable host plant species for B. tabaci. There were significant differences in mean developmental duration of larval instars of the same sex between both host plant species; the duration was significantly shorter on cucumber than on cotton. There were no significant differences for mean total developmental duration from egg to adult emergence between both host plant species within the same sex; females showed a mean of 15.9 days and males of 15.1 days on cucumber, while on cotton the means were 17.2 days for females and 16.2 days for males. Total mortality percentage of S. parcesetosum during development from egg to adult stage was lower on cucumber than on cotton, 20.6 and 23.8%, respectively. Longevity of S. parcesetosum varied according to host plant species and sex with a mean of 63.4 days for females and 50.3 days for males on cucumber, and 92.4 days for females and 52.5 days for males on cotton. On cucumber, mean period of oviposition of S. parcesetosum was significantly longer than on cotton. Mean total fecundity was significantly higher on cucumber than on cotton, with means of 97.7 and 31.0 eggs/female, respectively.     

世行贷款FRDPP项目毛竹示范林效益初步分析

通过对宜丰县云峰尖林场毛竹示范林的经营状况进行调查，分析了其经济效益、社会效益、生态效益。     

酿酒山葡萄引种的试验研究

2001~2005年,引种8个山葡萄种内和种间杂交品种的试验结果表明:筛选出适宜当地气候和土壤条件、抗寒、产量高、可酿造干红葡萄酒左优红、加工果汁饮料的哈桑、用于调色和调酸的双优和双红,为当地主栽和推广品种。     

不同基因型烤烟叶片光合作用对光和CO2的响应研究

为揭示不同基因型烤烟的光合特性,通过大田试验,利用LI-6400XT光合测定系统测定了毕节烟区4种主栽品种上部叶片的光、CO2的响应曲线,分别利用Farquhar模型和直角双曲线模型拟合光、CO2曲线,阐述了4个品种光响应和CO2响应特征及其主要参数.结果表明,4个品种响应曲线规律基本一致,响应特征参数差异明显.云烟97对高光照的适应能力相对最强、碳同化能力也表现较好;K326则表现出对弱光和低摩尔分数CO2的利用效率,对环境适应能力较强;毕纳1号饱和CO2速率明显高于其余品种,具有一定的高产潜力;红花大金元的优势体现在自身碳同化过程中的羧化效率.高海拔区域,选择种植云烟97能发挥其适应高光照的优势;中低海拔区域,K326和毕纳1号适应性较好,且能更好地发挥其生产潜力.     

甘南高原独一味间作栽培藏木香对独一味生长的影响

采用田间随机区组法研究甘南高原独一味间作栽培藏木香对独一味出苗率、成活率、叶长、叶宽和株高的影响。结果表明,独一味间作栽培藏木香时,当年生独一味的出苗率、成活率比单作极显著提高;两年生独一味的叶长、叶宽和株高的生长变化也比单作显著加快。该研究攻克了独一味大田栽培中成活率低的技术难关,对独一味的人工栽培有一定的指导意义。     

Dynamical Instabilities and the Formation of Extrasolar Planetary Systems

The existence of a dominant massive planet, Jupiter, in our solar system, although perhaps essential for long-term dynamical stability and the development of life, may not be typical of planetary systems that form around other stars. In a system containing two Jupiter-like planets, the possibility exists that a dynamical instability will develop. Computer simulations suggest that in many cases this instability leads to the ejection of one planet while the other is left in a smaller, eccentric orbit. In extreme cases, the eccentric orbit has a small enough periastron distance that it may circularize at an orbital period as short as a few days through tidal dissipation. This may explain the recently detected Jupiter-mass planets in very tight circular orbits and wider eccentric orbits around nearby stars.     

红莲型细胞质雄性不育恢复系特青和珍汕97的恢复性遗传分析

以花粉育性和小穗育性为指标 ,对红莲型细胞质雄性不育系丛广 4 1 A、恢复系特青以及丛广 4 1 A/特青的 F1 、F2 ,丛广 4 1 A∥丛广 4 1 B/特青的三交 F1 等亲本和杂种群体的育性调查分析结果表明 :特青具有 1个主效的显性恢复基因 ,该基因暂命名为 Rf-5(t) ;对红莲型细胞质雄性不育系丛广 4 1 A、恢复系珍汕 97以及丛广 4 1 A/珍汕 97的 F1 、F2 ,丛广 4 1 A∥丛广 4 1 B/珍汕 97的三交 F1 等亲本和杂种群体的育性调查分析结果表明 :在红莲型细胞质雄性不育和恢复性上 ,这 2个亲本之间可能有两类基因 ,其中一类控制着圆败型花粉 ,另一类控制着典败型花粉 ;对丛广 4 1 A∥珍汕 97/特青三交 F1 的育性调查分析结果表明 :珍汕 97具有一个与 Rf-5(t)等位的恢复基因