Interactions between rodents and weeds in a lowland rice agro‐ecosystem: the need for an integrated approach to management

Rodents and weeds are important pests to rice crops in Southeast Asia. The interaction between these 2 major pests is poorly documented. In temperate cereal systems, seeds of grass weeds can be an important food source for rodents and weed cover along crop margins provides important refuge for rodents. In 2012 and 2013, a replicated study (n = 4) in Bago, Myanmar compared 4 treatments (rodents and weeds; no rodents and weeds; rodents and no weeds; no rodents and no weeds) each of 0.25 ha in transplanted rice. Weeds were managed with hand weeding in the wet season, and hand weeding and herbicides in the dry season. Plastic fences were installed to exclude rodents. We examined the weed cover and relative abundance of weed species, rodent damage, rodent population dynamics and rice yield loss caused by rodents and weeds. The dominant rodent species was Bandicota bengalensis. In the dry season, Cyperus difformis was dominant at the tillering stage and Echinochloa crus‐galli was the dominant weed species at the booting stage. In the wet season E. crus‐galli was a dominant weed throughout the season. Damage by rodents was higher in the dry season. There were larger economic benefits for best weed management and effective rodent control in the dry season (258 US$/ha) than in the wet season (30 US$/ha). Concurrent control of weeds in and around rice fields combined with coordinated community trapping of rodents during the early tillering stage and ripening stage of rice are recommended management options.     

烟草专用液体肥添加黄腐酸对烤烟西柏三烯二醇代谢水平的影响

【目的】 西柏三烯二醇是烤烟香味成分的重要前提物质。本研究探究了黄腐酸对烟草西柏三烯二醇代谢的影响,为提高烤烟品质提供有效方法。 【方法】 以烤烟品种‘豫烟6号’为试材,连续进行了2年的田间试验和1年的盆栽试验。设常规栽培 (FP)、普通烟草专用液体肥料 (DF1) 和含黄腐酸烟草专用液体肥料 (DF2) 3个处理,两种液体肥采用水肥一体化方法施用。观察了不同处理的腺毛形态和密度,测定了不同处理的叶面腺毛分泌物,并利用荧光定量PCR技术比较了不同处理与西柏三烯二醇代谢相关的CYC-1、CYP71D16、DXR、DXS等基因的表达量,对比了不同处理初烤烟叶的茄酮含量并进行了感官质量评价。 【结果】 1) DF2处理的腺毛密度较高且具有较强分泌能力的长柄腺毛较多,叶面腺毛分泌物中西柏三烯二醇的含量也表现为DF2 (65.43 μg/cm2) > FP (46.84 μg/cm 2) > DF1 (39.8 μg/cm 2);2)DF2处理能显著提高烟叶CYC-1、CYP71D16、DXR、DXS基因的表达量,4个基因的表达量分别是FP处理的12.45倍、3.54倍、3.22倍和3.44倍,是DF1处理的4.11倍、5.71倍、2.44倍和2.28倍;3) DF2处理调制后的初烤烟叶茄酮含量明显高于其他处理,可达到112.27 μg/g,分别是FP和DF1处理的2.93倍和1.99倍,且连续2年感官质量评价结果均优于其他处理。 【结论】 肥料中的黄腐酸能促进烤烟西柏三烯二醇代谢相关基因的上调表达,改良烤烟叶面分泌物,提高烟叶茄酮含量,改善抽吸品质。      

Trial grow‐out culture of sea cucumber Holothuria scabra in sea cages and pens

Field trials were conducted to determine the effects of size, grow‐out period and site on the growth and survival of Holothuria scabra. Juveniles were reared in sea cages in two sites for 2 months during two different times of the year. Juveniles from Experiment 1 were subsequently grown in sea pens for 8 months in one site. The significantly lower survival particularly of the small‐sized group (<0.1 g) in Pilar is likely due to reduced water and sediment quality because of proximity to fish‐farming activities. The importance of grow‐out period was evident in the significant differences in weight increments in all size groups and biomass in the small‐sized group (P < 0.10) in Lucero during Experiment 2 when water temperature range and incidence of rainfall were higher. The decrease in the average weight of adults during the second half of the grow‐out period may be due to the interplay of the reduction in salinity, onset of sexual maturity and biomass exceeding carrying capacity in the pens. The estimated biomass threshold in the sea cages and pens in Lucero were 300 g m^?2 and 380 g m^?2 respectively. Implications of the results on the viability of small‐scale pen grow‐out culture are discussed.     

商丘地区畜牧业现状调查

调查以商丘地区的养殖企业为主,旨在了解近年来商丘地区畜牧业发展状况及存在的问题.结果显示:河南省商丘地区的畜牧业因其独到的地理位置,依托资源优势,主要以猪、牛、羊等动物的养殖为主,且有规模不同的饲养方式,养殖数量呈逐年递增趋势(2006,2007,2008年);养殖业存在发展资金不足、品种良种化程度低、饲料资源和种类单一、生态健康养殖理念缺乏等问题,并提出相应的解决方案和措施.     

Removal of short‐range‐order minerals prior to grain‐size analysis of volcanic ash soils

Incomplete dispersion of aggregates is a well‐known difficulty when analyzing soil texture of Andosols, particularly if no fresh soil material is available. To facilitate such investigations, several dispersion procedures were carried out on air‐dried samples rich in short‐range‐order minerals, originating from selected Andosol profiles (S Mexico). As a result, we propose an improved method based on a sequential chemical treatment with K oxalate, NH₄ oxalate, and oxalic acid that reliably removes cementing agents and allows for a stable dispersion of soil particles after addition of Na pyrophosphate. This method was proved to be well reproducible and highly reliable for routine grain‐size determinations. The potential error caused by the inherent risk of dissolving primary minerals or fresh volcanic glass remains far beyond the analytical error resulting from the incomplete and irreproducible dispersion of highly resistant aggregates by other commonly used techniques.     

不同遮光率对香水花扦插苗生长的影响

本文探讨了4种不同遮光率对香水花(Heliotropium arborescens)扦插苗生长的影响,结果表明不同光照条件对香水花植株在新增株高、萎焉发生、植株分枝、开花和生长量等方面有着十分重要的影响,在4个处理中,处理3遮光70%处理植株的生长状况最好,处理4遮光90%处理属于遮光过度,造成植株徒长,处理2遮光50%处理属于遮光不够,而处理1全光照处理很容易造成植株发生萎焉情况。     

三七根系分泌物的化学成分研究

研究三七根系分泌物中的疏水性物质,利用D101大孔吸附树脂柱层析,硅胶柱进行化合物的分离纯化,根据其理化性质和光谱数据进行结构鉴定,从三七根系分泌物中的疏水性物质部分分离鉴定出6个化合物,分别为原人参三醇（protopanaxatriol）、人参皂苷Rh1（ginsenoside Rh1）、韩国人参皂苷R1（Korgoginsenoside R1）、羽扇豆-20-烯-3β,16β-二醇-3-阿魏酸酯（Lup-20-ene-3β,16β-diol-3-ferulate）、β-谷甾醇（β-sitostero）、胡萝卜苷（daucosterol）。     

全球变暖情景下新疆降水的变化

基于有关水文气象测站的观测资料,对全球变暖背景下新疆降水的时空分布特征、演变趋势与变化原因进行了分析。结果表明:近40年来新疆年降水量总体上呈增加的趋势,并且不同地区降水的区域性差异十分明显。从年代际变化来看,新疆降水从上世纪60年代到80年代中期处于振荡减少阶段,80年中后期以后降水呈振荡增加趋势,且1987年为一个降水突变的拐点;新疆年平均降水量的增加主要应归因于全球变暖所带来的境外输入水汽量的增加。     

有效微生物群对仔猪生产性能的影响初探

对产后母猪和断奶仔猪饲喂有效微生物菌群(EM),研究其对仔猪生产性能的影响。从产前7d开始给母猪基础饲料中添加5mL/kg的EM菌液,选产仔数不少于8头的3头母猪及其仔猪连续饲喂EM菌28d,仔猪进行断奶,统计母猪的增重、仔猪初生重、断奶重,仔猪成活率等,分析添加EM菌后对母猪生产性能的影响。在这24头断奶仔猪饲料中添加EM菌的饲料,饲喂至60日龄,统计仔猪的增重、采食量、料重比、发病数等,分析EM菌断奶仔猪生产性能的影响。另外选取3头同品种、同批次生产、产仔数相同的母猪及其仔猪饲料中不添加EM菌作为对照。结果表明,母猪产后日均采食量较对照组提高12.07%,仔猪的初生重较对照组提高15.90%,产活仔数提高了12.09%,断奶重增加9.09%,断奶头数增多20.99%,断奶成活率提高8.81%。断奶后仔猪试验组的平均采食量较对照组提高10.26%,料重比降低了7.14%,发病率下降了50.03%。说明EM菌对母猪和仔猪的生产性能均有提高作用,研究结果为EM菌在生猪养殖中的应用提供了基础资料。     

黏土和沙壤土对烟叶发育过程中栅栏细胞超微结构的影响

采用大田试验,比较研究了黏土和沙壤土烟叶发育过程中栅栏细胞超微结构变化,结果表明:1)叶长5 cm之前,黏土和沙壤土烟叶细胞超微结构变化差异不大.2) 5 cm之后沙壤土烟叶细胞发育较为迅速,叶长10～15 cm时叶绿体开始贴壁排列,功能开始全面发挥,叶长20 cm时基粒垛叠明显增厚,叶长30 cm时液泡发育成熟,叶绿体进入旺盛功能期;而黏土烟叶细胞发育相对迟缓,叶长20 cm时叶绿体功能才开始全面发挥,叶长40~50 cm时进入旺盛功能期.3)定长时黏土烟叶细胞内叶绿体积累的淀粉粒和嗜锇颗粒不及沙壤土烟叶充实.