过湿条件下大豆不定根的发生及其生理作用研究

大豆是实行水旱轮作的重要作物之一,在缺乏良好排水条件的水田中实行水旱轮作时,长期涝渍所致的伤害成为大豆生长不良及产量低的重要原因.通过盆栽和大田试验在大豆生育初期进行过湿处理,调查培土或无培土条件下不定根的发生情况,揭示不定根对伤流速度,氮素的吸收运转等的影响,讨论了不定根与大豆耐湿性的关系.淹水条件下培土对不定根及根瘤的发生产生较大的影响,淹水条件下发生的不定根的量占总根重的43.1%,这些不定根提供了81.4%的伤流速度.不定根的呼吸速度为2.61 mg CO2g-1h-1,是初生根的近3倍.淹水导致全叶位叶片的叶色变淡,不定根的发生改变了伤流液中不同形态氮素的组成和全氮含量,可使下位叶的叶色维持较高水平.淹水条件下大豆的冠根比比对照小.不定根取代了受涝渍伤害而失去功能的初生根的作用,积极地进行养分和水的吸收,确保了涝渍逆境下物质生产的顺利进行.     

Erythropoietin-producing cells in the liver of ICR-derived glomerulonephritis (ICGN) mice

The ICR-derived glomerulonephritis (ICGN) mouse is an appropriate model for anemia associated with chronic renal disorder (CRD). Insufficient renal production of erythropoietin (EPO) induces the anemia associated with CRD. EPO mRNA is expressed in both kidneys and liver of progressing-stage ICGN mice. Hypoxic stimulation induced the EPO mRNA expression in the liver as well as in the kidneys of ICGN mice. The localization of EPO-producing cells in the liver remains controversial. Present study using an amplified in situ hybridization technique identified that nonparenchymal cells were the source of hepatic EPO production in ICGN mice under both normoxia and hypoxia.     

Experimental evidence for the influence of cumulus-oocyte-complexes on sperm release from the porcine oviductal sperm reservoir

In the pig, a temporal relationship is suggested between sperm release from the sperm reservoir (SR) and ovulation, but the mechanism(s) is still under discussion. In two experiments, the influence of transferred ova on the release of SR-spermatozoa at ovulation and the effect of supplementation with non-sulfated glycosaminoglycan hyaluronan (HA) on embryo development and the number of accessory spermatozoa, respectively, were examined. PMSG/hCG primed ovectomized gilts that had previously received endoscopic low-dose insemination into the cranial uterine horn were used as an experimental model. After salpingectomy, tubal segments (ampulla, cranial, and caudal isthmus) were flushed and sperm numbers or respective accessory spermatozoa were counted. In Experiment 1, the distribution of the sperm population was altered in the presence of cumulus-oocyte-complexes (COCs). A higher proportion of spermatozoa was found after transfer of COCs into one oviduct in the ampulla and cranial isthmus segments compared with the controls (17.5 vs. 4.9%, p<0.05). In Experiment 2, the quality of the transferred ova and treatment influenced the presence of accessory spermatozoa. Transfer of COCs together with HA increased (p<0.05) the number of accessory spermatozoa compared with the other treatment groups and was similar to those in the "undisturbed" controls. No modifications were obtained regarding mean blastomere numbers (2.6 +/- 0.2 to 3.1 +/- 0.2). In summary, this study was demonstrated that cumulus-oocyte-complexes may be involved in triggering sperm release from the pig oviductal SR and that HA might be related to sperm release.     

Genetic characteristics of inbred Wuzhishan miniature pigs, a native Chinese breed

The Wuzhishan miniature pig originates from Hainan Island, P. R. China, and is considered useful for medical and veterinary research due to its small size; a mature adult weights less than 25 kg. To reveal the genetic characteristics of this breed, the genetic polymorphism in 4 inbred strains was estimated using 30 microsatellite genes, multiplex polymerase chain reaction, and gene scanning. The average number of alleles at the 30 marker loci was 8.300, 4.533, 6.700, and 7.433, respectively. The polymorphism information content was 0.632, 0.507, 0.653, and 0.691, respectively. The average homozygosity in these strains was 0.537, 0.546, 0.549, and 0.520, respectively. These results indicate a relatively high degree of heterozygosity, perhaps becaquse these strains were inbred for 3 generations. Therefore, a long-term inbred breeding program should be conducted for Wuzhishan pigs to establish an experimental model.     

Follicular turnover and hormonal association in postpartum goats during early and late lactation

To clarify the effect of lactation period on ovarian follicular activity and associated hormonal levels in goats, six goats were monitored daily by ultrasonographic examination with blood sampling during early (Days 5 to 25; Day 0 was the day of kidding) and late (Days 40 to 60) lactation. While the presence of a corpus luteum of pregnancy retarded follicular growth in the ipsilateral ovary until Days 11-13 postpartum, the total follicular number (TFN) and area (TFA) increased during late lactation due to the significant increase in the number of medium- and large-sized follicles and decrease in the number of small follicles. Four goats showed a similar pattern of follicular development during the period studied characterized by the emergence of five and six waves during the early and late lactation, respectively. The largest follicle diameter of the first three waves monitored during early lactation was significantly smaller as compared with the diameter of those existing during late lactation. TFN showed a positive correlation with FSH but showed a negative correlation with immunoreactive (ir-) inhibin and estradiol during the postpartum period. TFA was positively correlated with ir-inhibin, estradiol and PRL and negatively correlated with FSH during the monitored periods. The plasma levels of ir-inhibin and progesterone were significantly higher during late lactation compared with the levels recorded during early lactation. Ir-inhibin levels showed a significant positive correlation with LH and estradiol during early and late lactation but showed a negative correlation with FSH during the whole lactation period. LH was positively correlated with estradiol and PRL during early and late lactation, respectively. These results suggest that the lactation period has a detrimental effect on ovarian activity during the early postpartum period in goats.     

Retinal ganglion cell (RGC) death in glaucomatous beagles is not associated with mutations in p53 and NTF4 genes

Background Glaucoma in humans is a second leading cause of irreversible vision loss in the world and can affect all age groups as well as all populations. The precise mechanism of retinal ganglion cell (RGC) death and progressive degeneration of optic nerve in glaucoma is not understood. It has been suggested that apoptosis is the common pathway that leads to the death of RGCs in glaucoma and that neurotrophin 4 (NTF4) protein plays a role in the protection of RGCs by activating tyrosine kinase receptors. Additionally, one previous study suggested that p53 codon 72 polymorphism (R72P) might have a greater susceptibility to apoptosis in some ethnic population. Glaucoma also occurs in dogs, and the primary glaucoma in beagles is inherited as an autosomal recessive trait. Although recently a candidate gene has been isolated, the mechanism underlying RGC death is not understood. Method To understand whether the same p53 and NTF4 pathway mechanism is involved in a beagle model of glaucoma, we have isolated NTF4 gene from dog and analyzed both p53 and NTF4 genes for mutations in glaucomatous animals. Results Our analyses failed to identify any disease-causing mutations in both genes with the exception of two polymorphisms in NTF4 gene. However, these are not pathogenic changes because they are also present in normal animals and are not segregated with the disease. Conclusion These results suggest that impaired neurotrophin signaling or compromised trophic support to the retina and p53-mediated apoptosis may not be the underlying mechanism of RGCs death in a beagle model of glaucoma.     

Addition of ginkgo fruit to cattle feces and slurry suppresses methane production by altering the microbial community structure

The effect of ginkgo fruit addition on methane production potential of cattle feces and slurry was assessed in relation to other fermentation products and the microbial community. Holstein cattle fresh feces and slurry were left at 30°C for 0, 30, 60, 90, and 180 days with/without ginkgo fruit to monitor the effect on fermentation potential. With the addition of ginkgo fruit, methane production potential of feces was reduced on Day 30 and thereafter, and that of slurry was consistently reduced over the experimental period. As a general trend, ginkgo fruit addition resulted in decreased acetate and increased propionate in feces and acetate accumulation in slurry. With ginkgo fruit addition, MiSeq analyses indicated decreases in methanogen (in particular Methanocorpusculum), Ruminococcaceae, and Clostridiaceae populations and increases in Bacteroidaceae and Porphyromonadaceae populations, which essentially agreed with quantitative real-time polymerase chain reaction (qPCR) assay results. These data indicate that direct addition of ginkgo fruit to cattle excreta is useful for reducing methane emissions by altering the microbial community structure. The application of ginkgo fruit to lower methane emissions from cattle excreta is, therefore, useful in cases in which the excreta is left without special management for a long period of time.     

精细农业机械化作物生产计算机集成技术(英)

介绍了一项适用于精细农业机械化的新技术：计算机集成作物生产技术（CCP）。该技术融合信息采集、网络通讯、数据处理、过程决策、自动执行等功能，能有效地完成作物生产的精确机械化作业。计算机集成作物生产技术的3个主要功能是先根据需要实时采集传感数据，然后根据传感信息构建合理的行动决策，最后将传递上述决策并付诸实施。为了说明CCP的工作原理和结构设计，介绍了由伊利诺依大学机械电子系统实验室设计开发的CCP技术系统的关键功能。研究结果表明，在车辆自动导航，主从机械控制，在线式变量作业等利用农业机械实施田间作物生产作业的领域，有必要在农业机械上集成CCP技术，使机械自动地完成各项最优化项目作业。最后，根据以往工作中的经验，简要讨论了目前CPP技术发展所面临的问题和挑战。