关于红草细长锥螺发生危害的专题报告及防治探讨

红草细长锥螺Dbeasgracile在汕头、潮州等地区大面积发生,对红绿草这种园林植物造成严重危害。文章综合分析探讨了红绿草细长锥螺分类地位、分布和寄主、形态特征、生物学特性、危害情况和防治方法。     

饲料中添加核苷酸混合物对凡纳滨对虾幼虾非特异性免疫和抗氧化指标的影响

本试验旨在研究外源核苷酸混合物对凡纳滨对虾(Litopenaeus vannamei)幼虾非特异性免疫和抗氧化指标的影响.选取960尾初始体重为(0.43±0.01)g的凡纳滨对虾,随机分为8组(每组设3个重复,每个重复40尾虾),分别投喂在基础饲料中添加0(对照)、0.1、0.2、0.4、0.6、0.8、1.0和1....     

噪声应激对蛋鸡血液生化指标的影响

500日龄海兰褐商品蛋鸡120只,随机分为3组,每组4个重复,每个重复10只鸡。研究噪声应激对蛋鸡血液生化指标的影响。结果表明,噪声对甘油三酯、葡萄糖、钙、磷及总胆固醇含量及肌酸激酶、乳酸脱氢酶、碱性磷酸酶、丙氨酸氨基转移酶活性影响差异不显著（P〉0.05）。日粮中添加60IU/kg的维生素E对缓解应激起到一定作用（P〉0.05）。     

不同基质配方对辣椒穴盘育苗质量的影响

在温室条件下,以泥炭土和珍珠岩为主要原料,按照不同的比例配合,对不同基质配方对辣椒幼苗生长发育的影响进行了研究。结果表明:辣椒幼苗在珍珠岩含量为25%的复合基质(泥炭土:珍珠岩=3:1)中表现最好,幼苗生长简单指标和复合指标均高于用其它3种配方;珍珠岩含量为50%的复合基质(泥炭土:珍珠岩=1:1)对辣椒幼苗生长有明显的抑制作用;综合分析表明,泥炭土与珍珠岩按照3:1配比作为辣椒穴盘育苗基质效果最佳。     

Effect of short term exposure of fenvalerate on biochemical and haematological responses in Labeo rohita (Hamilton) fingerlings

Experiment was carried out to determine the median lethal concentration (LC₅₀) of fenvalerate to Labeo rohita fingerlings. After determining the LC₅₀ value of fenvalerate, a sub-lethal concentration (1/3rd of LC₅₀) of fenvalerate was exposed for 15 days. Significant alterations in SOD (P < 0.05) activity of liver and gill was observed due to fenvalerate. Catalase activity in gills of fishes was also affected significantly (P < 0.05). WBC, NBT and Hct values were reduced significantly in fenvalerate exposed fishes as compared to control group, whereas blood glucose level showed higher values in fenvalerate exposed group. Serum total protein and albumin were also reduced significantly as a result of fenvalerate exposure. Significant increase in the serum GOT, serum GPT, creatinine, triglyceride and serum ACP was noticed after 15 days of fenvalerate exposure. Results indicated that short term exposure of fenvalerate can induce biochemical and haematological alterations causing stress to L. rohita fingerlings.     

Effects of diazinon on biochemical parameters of blood in rainbow trout (Oncorhynchus mykiss)

Existence of diazinon, an organophosphorous pesticide, in river waters of Iran near rice paddy fields has been reported by some authors. The present research aimed to determine the acute toxicity and evaluate the effect of sub-lethal concentrations of diazinon on some biochemical parameters of rainbow trout, Oncorhynchus mykiss after 7, 14 and 28 days. No significant differences were observed in the plasma levels of creatinine among the treatment groups at different sampling intervals. Acetylcholinesterase activity and the levels of total protein, albumin as well as globulin in plasma were significantly reduced at both concentrations tested (p < 0.05). Lactate dehydrogenase activity was only decreased on 7th day in 0.1 mg/L diazinon treatment (p < 0.05). Creatine kinase activity was significantly lower in 0.1 mg/L diazinon group at 14th and 28th sampling periods, whereas its activity significantly increased in fishes exposed to 0.2 mf/L diazinon only on 7th day (p < 0.05). Aspartate aminotransferase, alanine aminotransferase activities and glucose levels in diazinon treated groups were significantly higher than the controlled group at experimental periods (p < 0.05). In conclusion, long-term exposure to diazinon at sub-lethal concentrations induced biochemical alterations in rainbow trout, and offers a simply tool to evaluate toxicity-derived alterations.     

半干旱黄土丘陵沟壑区人工混交林土壤抗蚀性研究初报

半干旱黄土丘陵沟壑区, 在同一条件下, 0～100cm土层内, 有机质和水稳性团粒抗蚀性指标, 混交林较纯林分别高38%和23%; 分散率和分散系数抗蚀性指标, 混交构较纯林分别低3.5%和3.9%。经差异显著性检验, 有机质和水稳性团粒抗蚀性指标, 以99%概率保证, 差异极显著, 分散率和分散系数抗蚀指标, 以95%概率保证, 差异显著。但分层指标不规律。     

川西北退化草地土壤微生物生化活性的初步研究

通过对川西北三种不同退化程度的几种土壤的生化活性大小及其相关性进行研究，结果表明，草地退化后其土壤生化活性受到不同程度的影响，其影响明显地与退化程度有关；土壤生化活性大小有随退化程度增高而减小的趋势，但差异并非都达到统计学上的显著性，而土壤生化活性间地的相关性则显著地与草地退经程度有关，说明退化草地其土壤微生物间的协同作用受到显著影响，从而影响其土壤碳氮循环代途径，降低土壤肥力水平。     

免耕法对土壤微生物和生物活性的影响

本文比较常耕和免耕法对土壤微生物和生物学活性的影响.结果表明,连续免耕6-7年的砂壤土中微生物的数量较集中分布于上表层,常耕处理则相对均匀地分布于经常翻动的土层中.0-7cm表层土壤中微生物的优势种群在两种耕法中有一定差异,特别是霉菌.免耕处理0-7cm土壤培养1天的呼吸活性是常耕处理的2.1倍,尿酶活性是常耕处理的1.6倍.但随着土层的加深,免耕处理的呼吸活性、尿酶活性下降很快,至7-14cm处分别下降56%、71%.培养40天时0-7cm土壤无机氮释放量免耕和常耕处理分别为48.1、34.5mgN/kg,而7-14cm土层则分别为21.5、29.1mgN/kg.不加碳源只加入硫铵培养3天土壤中无机氮的减少在10%左右,免耕上表层0-7cm土壤减少较多,反映土壤微生物对无机氮的固定作用.长期免耕使具有高生物学活性的土层变得浅薄,而常耕处理则较为深厚.     

Predicting N transformations from organic inputs in soil in relation to incubation time and biochemical composition

Seventeen different added organic materials (AOM) in a sandy soil were incubated under controlled laboratory conditions (28 °C, 75% WHC), and examined for C and N mineralisation. The transformation of added organics (TAO) model has been presented in previous work for predicting C mineralisation. The two variables (very labile and stable fractions of AOM) used in TAO have been related to the biochemical characteristics of the AOM. The transformed added organic N fraction (TAONF) was estimated from the remaining C_AOM and N_AOM linked by the C-to-N ratios. TAONF was split (P_im parameter) into immobilised N (imN) and inorganic N (inorgN). When necessary, an additional N mineralisation of imN was predicted by first order kinetics (constant k_remin). The TAO version with the two parameters P_im and k_remin allowed us to predict very different dynamics of N mineralisation and N immobilisation from the AOM. In a few cases, another first order kinetic law (constant k_v) was used to predict N volatilisation from inorgN.Biochemical characteristics of AOM were used for predicting N transformations. First, at each incubation date, inorgN was approximated to inorgNa=α(N-to-C_AOM)+β by linear regression. The α, β and −β/α (C-to-N_AOM threshold for mineralisation/immobilisation) were related to time. The TAO expression (1−P_im)TAONF was then replaced by the proposed approximation inorgNa as a function of incubation time and C-to-N_AOM. Secondly, significant relationships were computed between k_remin and organic fibre content of AOM. Finally, a TAO approximation was proposed for predicting the simultaneous transformations of C and N, only using biochemical data (plus the k_v parameter in a few cases of N volatilisation). For all AOMs, the validity of the approximation and its borderline cases were examined by comparing the two TAO versions.