黄瓜单性结实果实发育与碳氮变化的关系

对黄瓜单性结实品系P 116 8和非单性结实品系UP 3315进行授粉和不授粉处理 ,P 116 8在不授粉的情况下 ,仍具有较好的结实性能 ,其单果质量、果长和果实体积均接近于授粉后生长的果实 ,非单性结实品系UP 3315在不授粉的情况下幼果在花后 3d(天 )就停止发育 ,不能形成产量。随着果实的生长发育 ,果实内碳、氮含量迅速增加 ,花后单果可溶性总糖和蛋白质含量与单果质量呈正相关关系     

Seasonal effects of liming,irrigation, and acid precipitation on microbial biomass N in a spruce (Picea abies L.) forest soil

Summary Seasonal effects of liming, irrigation, and acid precipitation on microbial biomass N and some physicochemical properties of different topsoil horizons in a spruce forest (Picea abies L.) were measured throughout one growing season. The highest biomass N was recorded in autumn and spring in the upper soil horizons, while the lowest values were obtained in summer and in deeper horizons. The clearest differences between the different soil treatments were apparent in autumn and in the upper horizons. Liming increased the microbial biomass N from 1.7% of the total N content to 6.8% (Olf₁ layer) and from 1% to 2% of the total N content in the Of₂ layer. The main inorganic-N fraction in the deeper horizons was NO _inf3 ^sup- . An increase in cation exchange capacity was observed down to the Oh layer, while soil pH was only slightly higher in the Olf₁ and Of₂ layers after liming. The effects of irrigation were less marked. The microbial biomass N increased from 1.7% of total N to 4.8% in the Olf₁ layer and from 1% to 2% of total N in the Of₂ layer. In the Olf₁ layer an increase in C mineralization was observed. Acid precipitation decreased the microbial biomass N in the upper horizons from 4.8% of total N to 1.8% in the Olf₁ layer and from 2% to 0.5% in the Of₂ layer. No significant changes in soil pH were observed, but the decrease in cation exchange capacity may result in a decrease in the proton buffering capacity in the near future.     

南美蟛蜞菊改变资源分配应对CO2升高对其竞争力的负影响

大气二氧化碳(Carbon dioxide,CO2)浓度正随着人类活动向着前所未有的浓度积累.作为光合作用的重要底物,CO2的增加会对植物生长及竞争能力产生影响,因此,研究未来CO2浓度升高背景下植物竞争力的变化对预测未来全球变化背景下植物群落演替及外来植物入侵具有重要意义.本研究以人工气候培养箱控制CO2浓度,探究了...     

略论西北地区渔业发展现状及对策

通过对西北地区渔业现状的分析，从中挖掘出西北地区渔业落后的社会经济原因，并结合当前的社会经济状况和渔业发展形势，总结了西北地区渔业发展的优势所在，以此为基础提出了加强市场宣传和资源开发、引进资金和技术以及政策引导等发展西北渔业的几点建议。     

黄伞菌丝体碳氮源营养的研究

在碳源含量为1%、氮源含量为0.2%的培养基上,采用PDA平板固体培养方法,研究了黄伞对碳源、氮源的利用.试验结果表明,最适宜的碳源为葡萄糖,最适宜的氮源为蛋白胨、牛肉膏.黄伞菌丝营养对双糖、多糖的利用比单糖差,黄伞菌丝营养对有机氮的利用比无机氮强.     

Carbon Dioxide Laser Keratectomy as a Treatment Option for Equine Corneal Stromal Abscessation: A Comparison to Lamellar Keratectomy and Penetrating Keratoplasty

Carbon dioxide (CO₂) laser keratectomy was compared to lamellar keratectomy (LK) and penetrating keratoplasty (PK) as a potential treatment option for equine corneal stromal abscessation. The medical records of 35 client owned horses undergoing surgical management of stromal abscessation were reviewed. Among those 17 underwent LK, 3 PK and 15 CO₂ laser keratectomy. Healing of the stromal abscess was achieved in all treated eyes. Those horses undergoing CO₂ laser keratectomy demonstrated few complications, and the time to healing and cosmetic outcome was comparable to those horses undergoing LK and PK.     

我国渔药剂型使用现状及其在渔药安全使用技术中的价值

从渔药安全使用的角度,对我国渔药剂型的现状和存在的问题进行了分析。通过总结渔药剂型在提高生物利用度、降低毒副作用、延长作用时间和提高稳定性等方面的作用,阐述了渔药剂型在降低水产品药物残留风险方面的潜在应用价值,期望为我国渔药剂型在渔药安全使用中提供参考。     

Serological survey of Encephalitozoon cuniculi in farm rabbits in Italy

Rabbit sera (n = 1600) from 40 commercial farms were submitted to a serological screening for Encephalitozoon cuniculi by an enzyme-linked immunosorbent assay (ELISA) and a carbon immunoassay (CIA test). Antibodies anti-Encephalitozoon cuniculi were found in 505/1600 (31.6%) sera analysed, and all the farms (100%) resulted positive. Rabbits older than 4 months showed a significantly higher seropositivity for E. cuniculi (chi-squared test: p < 0.0001) than rabbits under 4 months, E. cuniculi sero-prevalence showed an increasing trend in rabbits within the farm along with the increase in the “number of rabbits on the farm”; however, this trend was not significant (Spearman’s correlation: p = 0.073).The findings of the present study confirm that rabbit is the main reservoir of E. cuniculi; they are of epidemiological relevance and immediate public health importance because of the recognized infectivity in humans by the microsporidium.     

草地生态系统碳循环研究进展

随着全球气候变化和陆地生态系统碳循环研究的发展,碳循环正成为草地生态系统研究的热点.本文在介绍其研究发展过程、主体内容和方向的同时,对目前的研究动态和研究方法进行系统的概述,重点分析了目前国内外草地生态系统碳循环过程研究、机制研究、研究方法及模型的发展动态,并对今后草地生态系统碳循环和相关研究提出了建议.     

Growth and physiological responses of growing pigs to wheat–corn distillers dried grains with solubles

Gaining a detailed knowledge on the impact of a feedstuff on pig growth and physiological responses is critical for its effective utilization. Thus, the purpose of this study was to investigate the effect of distillers dried grains with solubles derived from co‐fermentation of wheat and corn (wcDDGS) on performance, carcass and visceral organ weights, whole‐body O₂ consumption and heat production (HP) in growing barrows. The experimental diets were as follows: corn–soybean meal diet (Control), Control + 15% wcDDGS and Control + 30% wcDDGS. In Exp. 1, 48 pair‐housed pigs of average BW 18.6 ± 1.5 kg (mean ± SD) were allotted to the 3 diets (n = 8). Pigs had free access to water and feed for a 28‐day period during which ADG and ADFI were calculated weekly. Thereafter, 1 pig/pen was killed to measure carcass and visceral organ weights. Overall, wcDDGS linearly decreased (p < 0.05) ADFI and ADG but had no effect on G:F (p > 0.10). The ADFI was 1.55, 1.45 and 1.36 kg/day for diets containing 0, 15 and 30% wcDDGS respectively; corresponding values for ADG were 0.79, 0.75 and 0.67 kg/day respectively. A linear decline (p = 0.01) in eviscerated hot carcass weight was observed as dietary wcDDGS increased. In Exp. 2, 18 pigs of average BW 20.4 ± 2.4 kg (mean ± SD) were individually housed in metabolism crates and fed the 3 diets (n = 6) at 550 kcal ME kg BW^?0.60day for a 16‐day period followed by measurement of O₂ consumption using an indirect calorimeter. Diet had no effect (p > 0.10) on whole‐body O₂ consumption and HP. In conclusion, increasing wcDDGS content in growing pig diets linearly reduced ADFI, ADG and eviscerated hot carcass weight but had no effect on G:F, visceral organ weights or HP.