New Food Safety Law of China and the special issue on food safety in China

<正>1.Introduction There have been a number of serious incidents of compromised food safety in China in recent years.To list a few,these include:a Salmonella outbreak,the use of horsemeat in burgers,the illegal use of phthalates as a clouding agent,the contamination of formula milk by melamine,the meat scandal of Shanghai Husi Food Company which sold reprocessed stale meat to many fast food chains includ-     

Effect of Long-Term Application of K Fertilizer and Wheat Straw to Soil on Crop Yield and Soil K Under Different Planting Systems

Effect of application of K fertilizer and wheat straw to soil on crop yield and status of soil K in the plough layer under different planting systems was studied. The experiments on long-term application of K fertilizer and wheat straw to soil in Hebei fluvo aquic soil and Shanxi brown soil in northern China were begun in 1992. The results showed that K fertilizer and straw could improve the yields of wheat and maize with the order of NPK ＋ St 〉 NPK 〉 NP ＋ St 〉 NP, and treatment of K fertilizer made a significant difference to NP, and the efficiency of K fertilizer in maize was higher than in wheat under rotation system of Hebei. In contrast with Shanxi, the wastage of soil potassium was a more serious issue in the rotation system in Hebei, only treatment of NPK ＋ St showed a surplus of potassium and the others showed a wane. K fertilizer and straw could improve the content of water-soluble K, nonspecifically adsorbed K, non-exchangeable K, mineral K, and total K in contrast to NP; however, K fertilizer and straw reduce the proportion of mineral K and improve proportion of other forms of potassium in the two locating sites. Compared with the beginning of orientation, temporal variability character of soil K content and proportion showed a difference between the two soil types; furthermore, there was a decrease in the content of mineral K and total K simultaneously in the two locating sites. As a whole, the effect of K fertilizer applied to soil directly excelled to wheat straw to soil. Wheat straw to soil was an effective measure to complement potassium to increase crop yield and retard the decrease of soil K.     

Cell wall degrading isoenzyme profiles of Trichoderma biocontrol strains show correlation with rDNA species

Species of the fungus Trichoderma, a genus of Hyphomycetes, are ubiquitous in the environment, but especially in soil. They have been used in a wide range of commercial applications including the production of hydrolases and in the biological control of plant diseases. A fundamental part of the Trichoderma antifungal system consists of a series of genes coding for a surprising variety of extracellular cell wall degrading enzymes (CWDE). Characterisation and identification of strains at …     

Physiological and Biochemical Characteristics of Lactation in Half-lactating Yak

Yaks of two lactating types, the half-lactating yak and the total lactating yak, were investigated in their milk compositions, milk coagulation properties, and contents of three kinds of hormones, glucose,and protein in plasma. The half-lactating Maiwa yak and Jiulong yak contained significantly higher contents of protein, fat, and activities of alkaline phosphatase and γ-glutamyl transpeptidase in milk than that of the corresponding total-lactating yak breeds, with reduced milk yield and similar lactose level and relative percentages of main milk protein components. The half-lactatin yak resembled yaks in a late stage of lactation in their biochemical composition of milk; however, significant differences were also observed, which indicated that the former was in a special stage of lactation quite different from dairy cows. Milk of the total-lactating or halflactating yaks could be coagulated normally by adding chymosin, with a similar coagulation time. No significant difference was observed between prolactin and progesterone concentrations in plasma of the half-lactating yaks and total-lactating yaks; however, half-lactating yaks had significantly lower level of oestradiol-17 β in plasma than total-lactating yaks.     

A Proposed Batch In vitro Apparatus for Conducting Rumen Fermentation Experiment

This research proposes a batch in vitro rumen apparatus modified from Daisy incubator and procedures of measuring feed digestion by using nylon bag to replace the traditional centrifuging and filtration methods, for the purpose of studying ruminal fermentation. The apparatus consists of 8 sets of airtight reaction vessels which rotated at a speed of 1 r/min and located inside a thermostatic cabin. Optimum procedures was proved to be that the volume of incubation fluid was 400 mL; fineness and size of test feed were 0.125-0.25 mm and 0.4 g, respectively; amount of bags in one vessel was 6; fermentation diet in a single incubation was 4-5 g. Comparing experiments showed that fermentation speed attained with the apparatus was about 15-20% greater than that attained with flask-shaking machine method （revolutionary speed is 100 r/min） and more accurate results could be obtained with the new apparatus. In conclusion, this apparatus could provide an efficient mixing action, and the procedure could allow sensitive detection of differences in ruminal fermentation in a time-saving way.     

Linking nutrient strategies with plant size along a grazing gradient: Evidence from Leymus chinensis in a natural pasture

St udying the changes in nutrient use strategies induced by grazing can provide insight into the process of grassland degradation and is important for improving grassland quality and enhancing ecosystem function. Dominant species in meadow steppe can optimize their use of limiting resources; however, the regulation of nutrient use strategies across grazing gradients is not fully understood. Therefore, in this study, we report an in situ study in which the impact of grazing rates on nutrient use strategies of Leymus chinensis, the dominant plant species in eastern Eurasian temperate steppes, was investigated. We conducted a large randomized controlled experiment(conducted continuously for five years in grassland plots in a natural pasture in Ha ilar, eastern Mongolia Plateau, China) to assess the effects of grazing rate treatments(0.00, 0.23, 0.34, 0.46, 0.69, and 0.92 adult cattle unit(AU) ha–1) on L. chinensis along a grazing gradient and employed a random sampling approach to compare the accumulation, allocation, and stoichiometry of C, N, and P in leaves and stems. Ou r findings demonstrated the follows:(i) The height of L. chinensis decreased with an increase in the grazing gradient, and the concentrations of C, N, and P significantly increased;(ii) the accumulation of C, N, and P per individual was negatively correlated with the concentration of aboveground tissues, suggesting that there was a tradeoff in L. chinensis between nutrient accumulation and concentration at the individual scale;(iii) the leaf-to-stem ratio of C, N, and P accumulation increased with grazing intensity, indicating a tradeoff in nutrient allocation and plant size at the individual plant level; and(iv) grazing rates were negatively correlated with the ratios of C:N and C:P in the stem; however, these ratios in leaves significantly increased with grazing intensity. Our findings suggest that L. chinensis in meadow steppe adapts to grazing disturbance through tradeoffs between plant size and nutrient use strategies. Moreover, our results imply that grazing produces a compensatory effect on nutrient use efficiency between the stems and leaves of L. chinensis.     

Exogenous Application of Abscisic Acid or Gibberellin Acid Has Different Effects on Starch Granule Size Distribution in Grains of Wheat

Granule size distribution of wheat starch is an important characteristic that can affect its chemical composition and the functionality of wheat products. Two high-yield winter wheat cultivars were used to evaluate the effects of the application of exogenous ABA or GA during the reproductive phase of the initial grain filling on starch granule size distribution and starch components in grains at maturity. The results indicated that a bimodal curve was found in the volume and surface area distribution of grain starch granules, and a unimodal curve was observed for the number distribution under all treatments. The exogenous ABA resulted in a significant increase in the proportions （both by volume and by surface area） of B-type （<9.9 μm in diameter） starch granules, with a reduction in those of A-type （>9.9 μm） starch granules, while, the exogenous GA₃ led to converse effects on size distribution of those starch granules. The exogenous ABA also increased starch, amylose and amylopectin contents at maturity but significantly reduced the ratio of amylose to amylopectin. Application of GA₃ significantly reduced starch content, amylopectin content but increased the ratio of amylose to amylopectin. The ratio of amylose to amylopectin showed a significant and negative relationship with the volume proportion of granules <9.9 μm, but was positively related to the volume proportion of granules 22.8-42.8 μm.     

Application and Development of Biosensors

As a new kind of analytical instrument, the principles, types and characters of biosensors were discussed in this paper. A biosensor is usually composed of a recognition element of biological origin and a physicochemical transducer. The biological element is capable of sensing the presence, activity or concentration of a chemical analyse in solution. The sensing takes place either as a binding event or a biocatalytical event. These interactions produce a measurable change in a solution property, in which the transducer is converted into a quantifiable electrical signal. The principles, types and applications of biosensors in environmental inspection, food production, clinical medicine and military defense were reviewed, and the trends in research were predicated, Furthermore, an attempt had been made to describe the future development directions and prospects.     

A PARTIAL LIST OF THE INSECT PESTS OF THE GENERA ULMUS COLLECTED IN BEIJING, CHINA

<正> There are more than 200 insect pest spcies of Genera Ulmus have been recorded in China. The following is a list of insect species collected on elm tree in some parts of Beijing region in 1980-1981.     

应用型农业科技英语人才培养策略

为培养应用型农业科技英语人才,阐述了依据社会需求培养应用型农业科技英语人才的必要性,并提出农业科技英语人才跨文化交际能力的培养策略,使农业科技英语人才具有国际化视野和理解能力,旨在为与西方发达国家进行农业科技知识合作与交流提供服务。