五大连池火山山杨叶功能性状的变异特征

  目的  探讨五大连池火山山杨叶功能性状特征，揭示植物对火山生境的适应，以及对不同坡向的生存策略，为特殊生境和微地形生境下植物的适应机制提供参考依据。  方法  以5座火山共有植物山杨为对象，测定叶面积（LS）、叶厚度（LT）、比叶面积（SLA）、叶干物质量（LDMC）、叶碳含量（LCC）、叶氮含量（LNC）、叶磷含量（LPC）和叶氮磷比（LNP）等8种功能性状在坡向间、火山间的变化规律和变异特征，分析叶功能性状间相互关系和主成分。  结果  （1）除LCC外，其他7种功能性状在南北坡向间均具有显著差异，LT、LDMC、LNC、LNP表现为南坡大于北坡，而LS、LCC、LPC表现为南坡小于北坡。（2）山杨SLA、LCC、LPC在新、老期火山间差异显著，但在老期火山间差异不显著。（3）火山南坡、北坡山杨LT与LDMC呈显著负相关，南、北坡向及火山间山杨LNP与LNC均呈极显著正相关、与LPC呈极显著的负相关关系。（4）火山环境中山杨LNP、LPC、LNC和LS在叶功能性状分化中起到主要贡献作用。  结论  五大连池火山山杨叶功能性状的变异与火山喷发的特殊性有关，山杨通过调节自身功能性状形成不同的生存策略来适应南、北坡向和不同火山环境，在生长过程中更容易受到氮元素缺乏的限制。火山森林生态系统是一个特殊环境，研究火山植被演替和植物功能性状等问题需要结合火山喷发的特殊情况深入讨论。      

Revisiting rice breeding methods – evaluating the use of rapid generation advance (RGA) for routine rice breeding

Rice production needs to increase in the future in order to meet increasing demands. The development of new improved and higher yielding varieties more quickly will be needed to meet this demand. However, most rice breeding programmes in the world have not changed in several decades. In this article, we revisit the evidence in favour of using rapid generation advance (RGA) as a routine breeding method. We describe preliminary activities at the International Rice Research Institute (IRRI) to re-establish RGA on a large scale as the main breeding method for irrigated rice breeding. We also describe experiences from the early adoption at the Bangladesh Rice Research Institute. Evaluation of RGA breeding lines at IRRI for yield, flowering time and plant height indicated transgressive segregation for all traits. Some RGA lines were also higher yielding than the check varieties. The cost advantages of using RGA compared to the pedigree method were also empirically determined by performing an economic analysis. This indicated that RGA is several times more cost effective and advantages will be realized after 1 year even if facilities need to be built. Based on our experience, and previous independent research empirically testing the RGA method in rice, we recommend that this method should be implemented for routine rice breeding in order to improve breeding efficiency.     

Drivers of fine-scale avian functional diversity with changing land use: an assessment of the effects of eco-estate housing development and management

Landscape Ecology - The effects of changing land use, and especially urbanisation, on species and functional diversity are of global concern. Eco-estates are a form of urban housing development...     

Long-term study of aerobic bacteria of the genital tract in stud dogs.

The aerobic bacterial flora of the genital tract was characterized in 15 stud dogs in an 18-month study. The dogs represented 4 breeds and were from 3 kennels. Bacterial samples from the prepuce and semen were collected every month, except in connection with matings, when they were collected weekly (464 samples). The dogs that were included all mated at least once during the study. The mean pregnancy rate, litter size, and pup mortality for the bitches with which they had mated were all within normal limits. The most frequent bacteria isolated from the prepuce and semen were Pasteurella multocida, beta-hemolytic streptococci, and Escherichia coli. There was a tendency for breeds to differ in frequency of the most common bacterial species. Bacterial culture yielded no aerobic growth in 14.2% of the preputial samples and 69.8% of the semen samples. Bacteria were transferred between dog and bitch at mating. In this study of healthy breeding dogs, neither the fertility of the dog nor that of the bitch was affected by the bacteria transferred.     

Clinical response of nasal adenocarcinoma to cisplatin chemotherapy in 11 dogs.

In 11 dogs with nasal adenocarcinoma, IV treatment with 2 to 8 cycles of cisplatin at a dosage of 60 mg/m2 of body surface, given at 3-week intervals, resulted in a survival time of 8 to 128 weeks (mean, 32.7 weeks; median, 20 weeks). Radiography revealed complete remission in 2 dogs and partial remission in 1 dog, for an overall response rate of 27%. Clinical problems such as nasal discharge (n = 11), sneezing (n = 6), and epistaxis (n = 4) resolved in 1 to 2 weeks in all dogs after beginning chemotherapy.     

Effect of a supply of raw or extruded rapeseeds on digestion in dairy cows.

The influence of extruded oilseeds on total tract digestibility and ruminal digestion in dairy cows was studied in three cows fed a hay-concentrate (60.5/39.5; 3.7% fatty acids in diet on DM basis) control diet (C) or the same diet supplemented with raw (R) or extruded (ER) rapeseeds (8.0% fatty acids in diet DM). The experimental design was a 3 x 3 Latin square design. Compared with diet C, diets containing rapeseed decreased ruminal OM digestibility (9.5%, P less than .10) and increased (P less than .05) the proportion of propionate in ruminal fluid VFA. Extrusion had no effect on DM and OM total tract digestibilities and increased (P less than .10) N digestion. Microbial N flow at the duodenum was calculated taking into account solid-adherent bacteria (SAB) and liquid-associated bacteria (LAB). Duodenal flows of total, SAB, and LAB of OM and N did not change with diet. Extrusion of the rapeseeds did not modify (P less than .10) the proportion of bacterial N at the duodenum and had no effect on crude fiber digestibility. This trial demonstrates that rapeseeds in hay-based diets can be fed at levels of up to 14% of the diet without adversely affecting crude fiber digestibility.     

Consistency of results from the Vettest 8008 clinical biochemistry analyser.

Findings are presented on the precision of a clinical biochemistry analyser designed specifically for veterinary use. Twenty biochemical analytes have been examined in detail for variation within and between runs. The results indicate that the analyser can provide high precision for all the analytes with the possible exception of calcium, and suggest that the instrument can be used with confidence in the practice laboratory to aid diagnosis and to monitor biochemical changes in animals receiving treatment.     

Immunologic responses in healthy random-source cats fed N,N-dimethylglycine-supplemented diets.

The immunomodulatory capacities of N,N-dimethylglycine (DMG) were examined in random-source cats. Blood mononuclear leukocytes of healthy adult cats that had negative results to tests for FeLV and feline immunodeficiency virus were exposed in vitro to various concentrations of DMG (10 to 1,000 micrograms/ml) and were evaluated for proliferative responses to T- or B-cell phytomitogens. Although increased, mean lymphocyte blastogenic responses to phytolectins in DMG-treated cultures did not differ significantly from responses of untreated cultures. For in vivo studies, cats were given a solution containing either 100 mg of DMG or a control solution without DMG orally at 8 AM and 6 PM for 40 consecutive days. On post-treatment day 24 and 25, mean blastogenic responses to phytolectins in DMG-treated and control cats inoculated 10 days earlier with an inactivated feline virus vaccine were similar. Cats given DMG and inoculated twice in a 3-week interval with a commercial vaccine containing inactivated feline herpesvirus-1 and feline calicivirus had significantly (P = 0.045) lower virus neutralizing serum antibody titers against feline herpesvirus-1, compared with titers of control cats, whereas feline calicivirus titers were similar in both groups. On day 25, mean serum interferon activity, induced after IV inoculation of Newcastle disease virus, was significantly (P = 0.021) lower in the DMG-treated cats. Results of this study of DMG in healthy cats failed to demonstrate enhancement of either specific or nonspecific immunity.     

Blindness associated with toxoplasmosis in canaries.

Seven of 30 canaries in an aviary in New Zealand developed ophthalmic problems. Clinically, 5 birds had unilateral and 2 birds had bilateral lesions characterized by conjunctivitis, crusty exudates on eyelids, and collapse of the eyeball. Microscopic lesions in 12 of 14 eyes examined included inflammation of the choroid and retina, with osseous replacement of the globe in some. Numerous Toxoplasma gondii tachyzoites were seen in the detached retina and vitreous humor of acutely affected birds. The diagnosis of toxoplasmosis was confirmed by immunohistochemical staining with T gondii antiserum. Affected birds had encephalitis, and T gondii was localized in the brains of these by immunohistochemical examination and by use of bioassays in mice. Toxoplasmosis should be considered in differential diagnosis of ophthalmitis in canaries.