Alteration of glutathione S-transferase properties during the development of <Emphasis Type="Italic">Micromelalopha troglodyta</Emphasis> larvae (Lepidoptera: Notodontidae)

Micromelalopha troglodyta (Graeser) is an important pest of poplar in China. Glutathione S-transferases (GSTs) are known to be responsible for adaptation mechanisms of M. troglodyta. The activities and kinetic constants of glutathione S-transferases in M. troglodyta were studied. Significant differences in glutathione S-transferase activity and kinetic characteristics were observed among five instars of M. troglodyta larvae. Furthermore, the inhibition of glutathione S-transferase activity in five instars by 24 inhibitors was conducted. The results show the inhibition of GST activity of different instars by 24 inhibitors was different. For GST activity in the 1st instar, chlorpyrifos, lambda-cyhalothrin, endosulfan, abamectin, fipronil and pyridaben were the best inhibitors tested, and for GST activity in the 2nd instar, tannic acid and quercetin were the most potent inhibitors tested, and for GST activity in the 3rd instar, the inhibitory effects of quercetin, chlorpyrifos and lambda-cyhalothrin were the highest, and for GST activity in the 4th instar, quercetin and lambda-cyhalothrin were the best inhibitors, and the inhibitory effect of phoxim was the highest for GST activity in the 5th instar. Our results show that glutathione S-transferases in different instars are qualitatively different in isozyme composition and thus different in sensitivity to inhibitors.     

Cd胁迫对灰木莲幼苗生长及某些生理特性的影响

通过对灰木莲幼苗在重金属镉(Cd)胁迫下生长与生理特征的分析,研究在镉胁迫下生长和生理特征的变化情况.结果表明,灰木莲幼苗的苗高和地径的增长率随着Cd2+浓度的增加而减少,Cd2+对苗高增长的影响较为显著;叶片的保护酶活性在低浓度下升高,在高浓度下保护酶的活性受到抑制;丙二醛浓度、游离脯氨酸含量随着镉胁迫的增加而缓慢上...     

西安市东郊渭河河漫滩沉积与洪水变化

[目的]通过揭示历史时期洪水的演变,科学地预测洪水的发生,以求减少洪水灾害造成的损失。[方法]通过分析西安市东郊水流村剖面106个样品的粒度组成,研究了西安市渭河近230a来的洪水事件。[结果]剖面厚度约5m,沉积物主要由粗粉砂、极细砂、中砂和粗砂组成,在各层中变化明显,能够指示古洪水的变化。粒度成分和粒度参数指示,研究剖面中的洪水沉积可分为21层,表明西安市渭河近230a来至少发生了21次洪水事件,各阶段的洪水动力大小为:第18阶段17阶段15阶段16,19阶段21阶段4,5阶段3阶段1,2阶段6,7阶段10阶段11阶段8,9阶段13,14阶段12阶段20阶段。在研究剖面发生的21次洪水事件中,除第20次洪水外,其余洪水发生时河漫滩上的洪水深度均大于2m,均为大洪水事件。[结论]洪水沉积层的分布和粒度成分指示,第3,5,7,8次大洪水的发生是由于当年降水量的显著增加造成的,其余次洪水的发生可能是当年降水量增加造成的,也可能是当年降水量没有增加而是由于当年降水量集中造成的。     

福建省变性土的性质、形成和肥力

The zonal soils in the south subtropical zone of Fujian are lateritic red soils.A type of dark clayey soils.which was historically defined as lateritic red soils,derived from weathering products of the basalts was indicated by the investigation results to be markedly different from lateritic red soils and could be classified as Typical Hapluderts.They are distributed as complex zones with the lateritic red soils.The vertisols in this region were considered as a type of lithogenic soils and the vertic characteristics delay and inhibit the soils from allitic processes and then formed an independent soil type.The vertisols have higher fertility and better agricultural production characters than the lateritic red soils.The different ways in utilizing and managing these soils according to their properties and fertility are also suggested.     

北京地区常用草坪草的耗水规律及适宜灌溉量研究

研究了在北京地区不同供水条件下，草地早熟禾、高羊茅、多年生黑麦草、野牛草、结缕草和狗牙根整个生长季的蒸散量差异和耗水规律。结果表明，蒸散量主要与草坪草的生物学特性有关，受水分条件影响；冷季型草坪草中多年生黑麦草耗水最少，暖季型草坪草中结缕草耗水最少；通过比较坪草和北方主要农作物的K_C值，得出草坪与大田作物的需水量相当；北京地区常用草坪草整个生长季的适宜灌溉量为：高羊茅(391.8 mm)>草地早熟禾(368.3 mm)>多年生黑麦草(315.1 mm)>狗牙根(300.7 mm)>野牛草(184.0 mm)>结缕草(110.5 mm)。     

硬脂酸-胱氨酸-大豆分离蛋白复合膜的机械特性和吸湿性研究

以硬脂酸作为增塑剂，胱氨酸作为交联剂制备具有一定力学性能和良好抗湿性能的大豆分离蛋白复合膜。将膜放在25℃，相对湿度为50%的干燥器中平衡两天，用质构仪测定膜的抗拉强度(TS),延伸率(E(%))。在水分活度a_w为0.10～0.90的范围内研究了复合膜在25℃的吸湿特性。吸湿速率和吸湿等温线数据分别拟合到Peleg's 方程和GAB(Guggenheim-Anderson-de Boer)模型。结果表明：大豆蛋白复合膜的TS、延伸率E(%)以及吸湿速率随着硬脂酸和胱氨酸的添加比率显著地变化。硬脂酸和胱氨酸的最佳添加比率为40∶60(w/w)(每升蛋白质溶液中加入10 g混合添加剂)，此时，大豆蛋白膜的强度比原来提高2倍，并且有最佳的吸湿速率。吸湿数据和GAB 模型有很高的拟合度，拟合系数最高达0.99。     

亚麻籽胶对面团流变性质的影响及其在面条加工中的应用

该文重点研究了添加亚麻籽胶对面粉的粉质特性、面团的流变性质以及面条品质的影响。粉质特性的结果表明，添加亚麻籽胶使面团的吸水率增加，面团的形成时间和稳定时间延长，弱化度降低，使面团的稳定性更好。动态流变性质和超微结构的显微观察表明，添加亚麻籽胶后，亚麻籽胶的网络结构加固了面筋蛋白的网络结构，因而面团的稳定时间和粘弹性均能提高。质构分析的结果表明，添加亚麻籽胶使面条烹煮后的硬度和咀嚼度提高，并具有较好的弹性和拉伸性能，面条的烹煮损失和面汤浊度降低，因而亚麻籽胶可用于面制品中以改善其食用品质。     

Analysis of indigenous production methods and farm-based biodiversity of amochi (<Emphasis Type="Italic">Arisaema schimperianum</Emphasis> Schott) in two sub-zones of Southern Ethiopia

For the first time we report that diverse types of Arisaema schimperianum Schott locally called amochi, are grown and managed as an off-season food crop in Southern Ethiopia. Participatory Rural Appraisal (PRA) and formal survey studies on 204 households were conducted over two consecutive years (2003–2004) in Chencha and Dita sub zones of Southern Ethiopia, to identify indigenous production methods and farm based biodiversity of amochi. Amochi is propagated from seed tubers and tuber parts left in the soil from the preceding harvest and grow during the dry season, February to June. Average share of proportion in the annual household consumption from amochi tubers was 9% and 4% for Chencha and Dita respectively. Uncooked amochi is irritating in contact to skin and mouth. Fifteen amochi types were identified in Dita and 12 in Chencha. They differ in the level of irritation, maturity and yield. Rich farmers with large family size as a working force, large farm size to support larger number of livestock that is source of farmyard manure, have farms with larger diversity of amochi than their poor counterparts, suggesting that its diversity is influenced by house hold characteristics and favoured under relatively fertile soil conditions. In both sub zones women had better experience in identifying amochi types than men. Further study is needed to identify chemical contents; and genetic variation using morphologic and molecular traits, in order to develop a strategy to assess and utilise the existing genetic diversity.     

光辐射强度对侧柏油松幼苗光合特性与水分利用效率的影响

 探讨不同土壤水分条件下光辐射强度对侧柏和油松苗木光合特性与水分利用效率的影响规律,可为林木栽培和管理提供科学依据。在黄土半干旱区,采用人工控制土壤水分的方法,利用模拟光源研究了侧柏和油松苗木的净光合速率、蒸腾速率、水分利用效率和胞间CO2浓度随模拟光辐射增强的变化规律。结果表明:在模拟光辐射为0～2200μmol/（m2.s）的范围内,侧柏和油松叶片的净光合速率、蒸腾速率和水分利用效率均随光辐射强度的增强而增大,但光辐射强度进一步增强,侧柏和油松净光合速率和水分利用效率呈下降趋势;在同样土壤水分条件下,侧柏净光合速率、蒸腾速率和水分利用效率高于油松,侧柏光饱和点高于油松,而侧柏光补偿点低于油松,侧柏光能利用率高于油松;随着土壤水分的增加,侧柏与油松净光合速率、蒸腾速率和胞间CO2浓度升高,而水分利用效率降低。在土壤含水量为7.90%、13.00%和19.99%条件下,侧柏光饱和点分别为1275、1 450和1 675μmol/（m2.s）,光补偿点分别为4225和13μmol/（m2.s）,由光饱和点对应最大净光合速率分别为3.04、4.06和5.53μmol/（m2.s）;在土壤含水量为7.83%1、3.04%与20.15%条件下,油松光饱和点分别为11001、325和1500μmol/（m2.s）,光补偿点分别为60.30和23μmol/（m2.s）,由光饱和点对应最大净光合速率分别为1.08、3.35和4.36μmol/（m2.s）。     

灌区土壤盐分空间变异及多因素响应关系

[目的]研究土壤含盐量空间特征和分布格局,分析土壤盐分空间格局与地下水、土壤物理特性参数间的空间响应关系,为灌区盐渍化防控提供理论依据。[方法]以黄河南岸灌区吉格斯太灌域为例,网格化布点,分层采样测定土壤含盐量、表层土壤含水量、颗粒组成、干容重并换算热容量及导热率,同步监测地下水埋深及含盐量,采用经典统计方法和地统计方法分析土壤含盐量空间分布特征及其与物理特性和地下水等因素间的空间相关性。[结果]灌域处于非盐化—轻度盐化状态,土壤含盐量呈中等空间变异程度,总体呈现相对独立的随机分布,空间结构特征可以用高斯模型和指数模型描述。土壤含盐量与地下水埋深呈显著负相关,与地下水含盐量呈显著正相关,地下水埋深1.6 m区域发生轻度盐渍化风险较高。0—20 cm土壤含盐量与黏粒含量、容重、含水量、导热率及热容量显著空间正相关,相关范围约2～6 km;与砂粒含量呈显著空间负相关,相关范围约2～4 km。20—60 cm土壤盐分与0—20 cm土壤黏粒、砂粒含量、导热率、热容量及含水量呈显著相关,相关范围与土壤表层略有差异。[结论]黏粒含量较高,含水率较大,地下水埋深1.6 m的区域是灌域盐渍化防控的重点区域。