A Field Bioassay Approach to Assess the Toxicity of Insecticide Residues on Soil to Collembola

Field bioassays were conducted to assess the toxicity of three insecticides, chlorpyrifos, cypermethrin and pirimicarb, to four species of springtails, Isotoma viridis, Isotomurus palustris, Folsomia candida (Collembola: Isotomidae) and Sminthurus viridis (Collembola: Sminthuridae). Spray residues on two soil types (a sandy clay loam and a sandy soil) were obtained in the field, in the presence and absence of a wheat crop canopy, after spray application by a commercial tractor-mounted sprayer. Collembola were then confined for 24-h periods on the sprayed soils in a constant laboratory environment at 1, 2, 3, 8 and 15 days after treatment. Residual insecticide toxicity was compared between species, insecticides, soils and exposure conditions (crop or no crop) using the age of residue at which median mortality occurred (DAT₅₀). Cypermethrin and pirimicarb residues were of low toxicity, causing less than 10% mortality, whereas residues of chloryprifos were toxic to all four species of Collembola on both soil types and in both exposure treatments. Interspecific differences in collembolan susceptibility to chlorpyrifos residues gave the ranking (from most to least susceptible) S. viridis>F. candida>Isotomurus palustris>Isotoma viridis. Residues on the sandy soil were more toxic than those on the sandy clay loam. These results are discussed in terms of how field bioassay approaches may be used to determine pesticide residual toxicity to microarthropods. We conclude that field bioassays offer a feasible method for evaluating the toxicity of pesticides and the persistence of toxic effects on Collembola. Advantages and disadvantages of this method are considered.     

白马勃液体深层培养工艺条件初探

对白马勃液体深层培养的工艺条件进行探索,得出其最佳摇瓶条件为:温度24～28℃,种龄4 d,接种量10%,振荡转速为150 r·min-1,培养时间为6 d,在最佳工艺条件下菌丝体干重可达11.7 g·L-1.     

生物、物理吸附与光解处理硝基苯污水的特性比较研究

分别选取产朊假丝酵母、活性炭和紫外光照三种不同方式对不同浓度的含硝基苯污水进行处理,探索其去除规律.实验结果表明：三种处理方式对水体中硝基苯均有去除作用;从去除效率角度考查,活性炭吸附适于硝基苯浓度较高的前期处理,中等浓度水体则应采用酵母生物吸附,当浓度较低时应用紫外光解效率最高.     

葱莲的同工酶和染色体核型分析

本文报道了对葱莲[Zephyranthes candida(Lindl.)Herb.]的过氧化物酶,酯酶,乙醇脱氢酶和6-磷酸-葡萄糖脱氢酶等同工酶的研究和对葱莲的体细胞染色体数目及其核型所进行的分析。结果表明,葱莲的过氧化物酶同工酶呈现出6条分子量相对较大的谱带;酯酶同工酶可划分成2个活性区,共10条酶带;乙醇脱氢酶同工酶只有1条酶带;6-磷酸-葡萄糖脱氢酶同工酶有4条酶带,可划分成3个活性区。该种核型为2n=28=20m+2m(SAT)+6sm,核型的不对称性为 Stebbins 核型分类的2B 型,具有核型的杂合性。染色体数目为2n=28,与前人报道不一致。     

Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modelling

We have studied the effect of anaerobically digested (ADMSW) and composted municipal solid waste (CMSW) on mineralization and foodweb dynamics to verify the hypothesis that ADMSW would immobilize N right after addition to soil in contrast to addition with CMSW. Another hypothesis was that the mesofauna (enchytraeids and microarthropods) would stimulate N release from the decomposer community. We measured excretion of -N and urea-N from the mesofauna and hypothesized that enchytraeids would release urea. ADMSW and CMSW were amended to pots with sandy loam and barley. The pots were divided into treatments with or without mesofauna. Mesofauna, plant N and biomass, soil N and ergosterol (fungal biomass) were measured over a 113-day period of four equidistant samplings. Soil respiration, N mineralization and N release by the mesofauna were modelled from concurrent studies. ADMSW- and CMSW-treated soils initially (<20 days) immobilized N. The amendments did not increase plant growth substantially, and this was probably due to N-limitation in the early stages of plant growth. Enchytraeid abundance was about three times higher in ADMSW- than CMSW-treated soils, indicating that ADMSW contained more labile compounds, bacteria, and microfauna. The mesofauna did not affect N-content, but the cumulated -N excreted by the mesofauna was estimated to be substantial and about one-fifth of total plant N in ADMSW. An explanation for this discrepancy might be that in the absence of the mesofauna, other members of the detrivore and microbivore community performed the mesofauna’s function. Neither enchytraeids nor microarthropods excreted urea.     

产朊假丝酵母改善麻疯树提油饼粕营养效价的研究

利用产朊假丝酵母作为发酵菌株,采用固态发酵方式改善麻疯树提油饼粕的营养效价。试验结果表明,控制培养基湿度为100%(w/w)条件下恒温发酵4d,麻疯树提油饼粕中的粗蛋白含量达到最大值。统计分析结果表明,向培养基中添加碳源后,发酵饼粕的粗蛋白增长率、粗蛋白体外消化率、氨基氮含量和蛋白酶活力都比未添加碳源组有显著提高(P<0.05)。与未发酵麻疯树提油饼粕相比,添加10%(w/w)葡萄糖的发酵饼粕中粗蛋白含量、粗蛋白体外消化率和氨基氮含量分别提高了0.48、15.6和37倍,蛋白酶活力达到2100U/g,其营养效价得到明显提高。     

ABSTRACT of the Articles Printed in Journal of the Science of Soil and Manure,Japan

Changes in soil moisture determine the reproductive, respiratory, and metabolic activities of soil microorganisms and hence the rate of microbial nitrogen (N) mineralization. Soil moisture also affects the feeding activity and movement of soil invertebrates. Bacterial and fungal grazing by soil invertebrates such as Collembola and nematodes is known to increase N mineralization by increasing the reproductive, respiratory, and metabolic activities of microorganisms. Therefore, to assess the effect of soil moisture on N mineralization, faunal responses need to be considered. We used microcosms to investigate the effect of soil moisture on N mineralization mediated by a species of Collembola, Folsomia candida Willem. We used four moisture levels corresponding to matric potentials of ?42.5, ?11.8, ?0.8, and ?0.5 kPa and investigated the effects of these on Collembola with respect to feeding activity, growth, and contribution to N mineralization. The microbial biomass and ratio of bacterial to fungal biomass tended to increase with increasing soil moisture. Collembola feeding activity and growth increased with increasing soil moisture conditions. Collembola significantly enhanced N mineralization in soil at water potentials of ?11.8 and ?0.5?kPa. The greatest relative increase in N mineralization attributed to Collembola occurred in the ?11.8?kPa treatment. The change in contribution of the Collembola to N mineralization with soil moisture was most likely induced by changes in Collembola feeding activity and microbial community structure. The growth in body length of the Collembola was significantly greater at higher moisture conditions than at the lowest moisture condition, indicating that increases in both metabolic activity and biomass of the Collembola population contributed to the enhanced N mineralization.     

葱兰叶枯病研究初报

葱兰叶枯病是葱兰上一种病害。其症状是在线形叶上产生红褐色病斑或段斑，最后呈红褐色卷曲状枯死。经分离培养和接种确认由炭疽菌引起。病害在土壤瘠薄、排水不良及管理粗放的情况下往往发生较重。     

复合发酵对棉籽饼混合底物中FG和BG含量的影响

试验通过测定棉籽饼混合底物在微生物固体发酵过程中棉酚含量的变化,以研究复合发酵对棉籽饼混合底物中棉酚含量的影响。试验采用添加不同比例的ZD-3与ZD-5和ZD-3与ZD-8对棉籽饼混合底物进行二元复合发酵,然后测定发酵产物中TG、FG、BG含量。试验结果表明:棉籽饼混合底物经复合发酵处理后,均可极显著降低发酵底物中TGF、G和BG含量(P<0.01),并且FG和BG的减少部分均被降解消除;同时发现,ZD-3与ZD-5的复合发酵效果优于ZD-3与ZD-8的发酵效果,并且菌种比例对发酵结果有显著影响。当ZD-3与ZD-5的比例为3:1时,脱毒效果最好,脱毒率可达90.82%。