pH值等因素对不同农药悬浮剂稳定性的影响

以实验室自制的30%戊唑醇.甲基硫菌灵和40%戊唑醇.多菌灵悬浮剂为对象,初步研究了pH值、温度、水质、研磨时间对农药悬浮剂粒子大小、粒度分布及悬浮率的影响,其中粒子大小、粒度分布分别以中位径和跨距2个指标来反映。结果表明,以上4种因素的变化对30%戊唑醇.甲基硫菌灵和40%戊唑醇.多菌灵悬浮剂的中位径影响均很小,但粒度分布和悬浮率均受到不同程度的影响。随着pH值的变化,2种体系跨距波动的幅度并不明显,当pH值分别为10、6时,30%戊唑醇.甲基硫菌灵和40%戊唑醇.多菌灵悬浮剂的悬浮率较低;随着贮存温度的升高,2种悬浮剂的跨距均有所增大,悬浮率均降低;随着水质的改变,跨距差异均不大,悬浮率高低呈蒸馏水>超纯水>自来水的趋势,但差异不明显;随着研磨时间的延长,跨距均先显著降低随后趋于平缓,悬浮率则先升高后降低再升高,最后趋于平缓。     

盆钵形状和植株数对盆栽大豆农艺性状的影响

以有限结荚习性的小粒豆材料V97-9003为试材,在固定盆钵容积的情况下,改变盆钵规格(直径和深度),或者在固定盆钵规格的情况下,改变种植株数,考察盆栽大豆农艺性状的变化。结果表明,①在固定盆钵容积的情况下,管径变大(即管高缩短),大豆有效分枝数显著增加;不同管高对有效分枝数的影响不显著,大豆有效分枝数主要受盆径大小(即单株种植面积)的影响。②大豆株高在容积相同的不同盆钵间差异未达到统计显著水平,而在同一管径的盆钵中,盆钵深度增加则株高显著降低,大豆株高主要受盆钵深度影响。③在固定盆钵规格的情况下,株高、无效结荚数和百粒质量对种植密度反应不敏感。其他测定农艺性状对大豆栽植密度反应敏感。以盆栽植株数为自变量(x),拟合的回归方程为结荚高度y=0.852 1 x+7.373 3(r2=0.732 6),主茎节数y=-0.336 4 x+14.88(r2=0.931 5),有效分枝数y=10.889x-0.636 4(r2=0.848 4),单株有效荚数y=270.45x-0.759(r2=0.828 8),单株粒质量y=70.464x-0.798 6(r2=0.863 6),单株根质量y=7.154 9x-0.642 5(r2=0.763 3)。在盆栽株数低于8株或7株时,每盆总粒数、总粒质量和总根质量与盆栽株数的关系可以用直线方程进行拟合,即每盆总粒数y=90.921 x+453(r2=0.798 3),每盆总粒质量y=9.621 4 x+57.804(r2=0.716 5),每盆总根质量y=1.329 6 x+6(r2=0.904 9)。     

Effect of Limestone of Different Sizes on Soil Extractable Phosphorus and Its Concentrations in Grass and Clover Species

Phosphorus (P) is often reported as a nutrient whose availability increases by lime application, although some research suggests a decline in the short-term P availability upon liming. This study addresses the effects of applying different sized limestone (2–4, 0.5–2, 0.25–0.5, and <0.25 mm) on the forms and availability of soil P, P concentrations and extraction by pasture, and yields of plant species. Soil P was partitioned into organic and inorganic forms, using an ignition method. Available P was determined by the Olsen and Mehlich 3 methods. Phosphorus in plants was determined after acid digestion. Most P was present in organic form. One year after sowing, inorganic P increased and organic P decreased. Liming had no significant influences on soil P. Phosphorus extracted by Mehlich 3 explained 40% of the total dry-matter yield in the first harvest. No significant effect of liming on P concentration in plants was observed.     

标本讲解中体态语言的运用

体态语言是人们内心情绪在身体动作上的反映，在标本讲解中正确使用能够感染、激励观众引发共鸣，收到良好的效果。     

关中西部典型人工生态林与经济林林地土壤的剖面特征及土壤粒度组成

对陕西关中西部的苹果人工经济林和槐树人工生态林林地土壤剖面的结构、土壤的粒度组成进行了系统研究。结果表明:(1)人工生态林林地所设的YSL土壤剖面其土壤的碳酸钙淋溶作用较人工经济林林地所设的YSP土壤剖面强;(2)YSP与YSL土壤剖面不同发生层,其土壤粘粒与砂的含量变化差异较粉砂大;(3)YSP土壤剖面的土壤粘粒较YSL土壤剖面的淋失深度浅,但淋溶量大;(4)YSP土壤剖面表层土壤的粘粒含量较YSL土壤剖面高,表明精细的人为管理方式对其林地表层土壤的粘化有显著影响。     

Short-term salinity tolerance of northern pike, Esox lucius, fry, related to temperature and size

Abstract  The short-term tolerances of northern pike, Esox lucius L., fry reared in a freshwater hatchery, to salinity were examined in the laboratory. Survival of two size groups of pike fry (mean length 21 ± 2 mm SD and 37 ± 4 mm SD) was examined over 72- to 96-h periods at 9–14 ppt salinity in combination with temperatures of 10, 14 and 18 °C. A parametric survival model found a significant correlation between survival of pike fry and temperature and salinity, respectively. L _C50 values after 72 h were between 11.2 and 12.2 ppt, being lowest at 10 °C. Pike fry did not survive more than 13 ppt. Mortality at 12 ppt was significantly faster at 18 °C than 10 or 14 °C. Moreover, mortality was higher and faster for large than for small pike fry at 12 ppt and 14 °C. These results imply that pike raised in fresh water can survive stocking into brackish waters below 11 ppt at least for a short time.     

Reproductive biology of Venus clam Gafrarium tumidum (Roding, 1798) from Southeast coast of India

The reproductive biology of tumid venus clam Gafrarium tumidum (Roding) was studied in detail from the Southeast coast of India. Sample size ranged from 10.3 to 41.3 mm. Sexes are separate but not differentiated externally. Annual sex ratio male:female (M:F) deviated significantly from the 1:1 ratio with females dominating. Based on ova diameter progression of gonad smear and histology, four and two maturity stages of gonads were differentiated in female and male clams, respectively. Peak spawning was observed during November and a minor one in April. The monthly average condition index based on wet/dry flesh weight ranged from 7.24 (November) and 14.14 (September) and 8.82 (October) and 14.38 (August), respectively. The condition index observed by both the methods is comparable and corresponds with the spawning season. Water content observed for male and female clams varied negligibly and showed positive correlation with spawning period. Size at first maturity was estimated to be 22.3 mm.     

柳厚壁叶蜂幼虫生长发育与虫瘿增长的相关性

柳厚壁叶蜂（Pontania dolichura）是一种危害垂柳的食叶类害虫，严重影响柳树的景观绿化效果。为了研究柳厚壁叶蜂不同发育时期虫瘿大小与幼虫形态的相关性，了解柳厚壁叶蜂的发生发育规律及成瘿机制，系统测量了55组不同调查时期柳厚壁叶蜂的虫瘿长、虫瘿宽、虫瘿厚、虫瘿壁厚和幼虫的体长、体宽、头长、头宽共8个形态特征的数据。对测得的形态特征数据进行主成分分析和去除趋势对应分析，并对虫瘿形态指标之间、幼虫形态指标之间以及虫瘿与幼虫形态指标之间进行线性回归分析。结果表明，柳厚壁叶蜂幼虫的生长呈现明显的梯度变化，且虫瘿各形态指标之间、幼虫各形态指标之间分别存在显著线性关系（P<0000 1）；但虫瘿厚与幼虫体长的线性关系为条件函数，即当幼虫体长小于等于6.90 mm时，存在显著线性关系，线性方程为y=1.771x+0.653 (R2=0.920，P<0.000 1)。因此，实践中可以根据柳厚壁叶蜂的幼虫形态与其虫瘿之间的线性关系，用虫瘿的长、宽、厚和壁厚等易测量指标来判断虫瘿内柳厚壁叶蜂幼虫的生长发育状况，确定幼虫的生长发育规律，为柳厚壁叶蜂的生长发育提供科学的评判标准，为其科学防治提供理论依据。     

传统社会孝·家庭规模与人口数量分析

介绍了中国传统社会父母生育子女数量的影响因素及传统社会家庭子女的回报函数,运用博弈论对中国传统社会父母与子女的博弈以及子女合理反哺的比例问题进行了分析,研究了传统社会子女数量的弹性与约束条件。结果表明：生育子女数量多且父慈子孝时,传统社会总效用达到最大 （Br-C,-Br）是子女合理反哺博弈模型的均衡解 传统社会孝道与人口增长显著正相关。     

Genetic basis of phenotypic differences between transplanted stocks of brown trout

Abstract– We present results from an experiment testing for the existence of genetically based phenotypic differences among populations of brown trout ( Salmo trutta L.) born and raised under entirely natural environmental conditions. Genetically tagged individuals from two stocks (A and B) were introduced into a drainage system in Sweden previously void of brown trout, and the first generation (F₁) progeny were sampled from two lakes during nine consecutive years. Phenotypic differences among groups of progeny (A, B, and the AB hybrid) are expected to reflect genetically determined dissimilarities between the introduced stocks. Phenotypic differences among progeny groups were observed for age at maturity and for migratory and reproductive behavior, and these characters are apparently determined by genetic factors to an extent that permit their detection even in the presence of confounding and naturally occurring sources of variation such as lake, age, cohort and year of sampling. There was also significant variation among offspring groups with respect to body size (length), but only a small proportion of the total variation in size could be attributed to stock differences. These genetically based stock characteristics may represent local adaptations, and the fishery management implications of these findings are discussed.