尾巨桉不同类型愈伤组织抗性相关酶活性差异与不定芽分化关系研究

本实验以尾巨桉无性系32-29无菌苗的茎段为外植体,应用不同植物生物调节剂处理,诱导愈伤组织形成,分别测量4种类型愈伤组织的蛋白质含量及过氧化物酶(POD)、多酚氧化酶(PPO)、超氧化物歧化酶(SOD)等保护酶的指标活性,比较不同愈伤组织的酶活性强弱与不定芽分化的关系。结果表明:不同处理间愈伤组织诱导率差异达到极显著水平,且不同愈伤组织蛋白质含量及3种酶活力差异明显,POD、SOD活力高的愈伤组织不定芽诱导率也高,而PPO含量高的愈伤组织诱芽率低。     

FX-139发酵液及菌丝体提取物对人参愈伤组织生长及防御酶系的影响

以人参栽培土壤中分离纯化的生防菌株放线菌FX-139的发酵液和菌丝体提取物为供体,研究了其对人参愈伤组织生长的影响,及诱导受体防御酶的能力。结果表明:(1)FX-139发酵液和菌丝体提取物浓度为20 mg/L的处理条件对人参愈伤组织生长促进作用最强,比对照增加了68.96%、51.60%,差异显著。(2)发酵液水饱和正丁醇提取物处理下PAL、POD、PPO酶活峰值分别出现在第21天、第14天、第28天,比CK依次提高了1.29倍、2.5倍、2.12倍。菌丝体丙酮提取物处理下PAL、POD、PPO酶活峰值分别出现在第21天、第14天、第14天,比CK依次提高了1.9倍、2.6倍、1.4倍。(3)通过对人参愈伤组织防御酶活性研究表明,发酵液和菌丝体提取物处理下PAL、POD、PPO酶活性均有明显变化。总体来说,放线菌FX-139发酵液和菌丝体提取物可以诱导人参愈伤组织防御反应的表达,发酵液提取物对POD、PPO有良好的诱导作用,菌丝体提取物对PAL、POD和PPO均有较好的诱导效果。     

黄芩愈伤组织诱导条件的研究

为寻求诱导黄芩愈伤组织的最佳培养条件和激素配比,以黄芩的子叶、真叶和下胚轴为外植体,利用不同激素组合的MS培养基分别在黑暗和光照条件下诱导愈伤组织。结果表明：①在黑暗条件下各激素处理的愈伤组织诱导率和愈伤组织增重均高于光照条件下,而褐化率低于各处理,并且诱导出的愈伤组织较光照下松散,适合于细胞培养;②M6培养基其褐化率为0,诱导率高达100％,愈伤组织增重2．22g,明显优于其它激素配比,是黄芩愈伤组织诱导的最佳激素配比;③各种激素配比处理下,黄芩真叶愈伤组织的愈伤组织增重明显高于子叶和下胚轴。而褐化率却明显低于它们,因此真叶是黄芩诱导愈伤组织的最佳外植体。     

尾叶桉的不同类型愈伤组织芽分化与某些相关生理生化指标的关系

切取8d苗龄的尾叶桉幼苗下胚轴,培养7d后愈伤组织的诱导率达100%。8周后,愈伤组织分化成褐色、白色和浅绿色3种类型。其中只有浅绿色愈伤组织能分化出不定芽,分化率达57%。浅绿色愈伤组织的过氧化物酶（POD）、超氧化物歧化酶（SOD）、过氧化氢酶（CAT）和多酚氧化酶（PPO）的活性最高。除SOD外,浅绿色愈伤组织的POD、CAT和PPO活性与其他两类愈伤组织相比具有显著性差异（P〈0.05）。H2O2和丙二醛含量则是褐色愈伤组织的最高。     

苗龄、光照强度和施氮量对抗褐飞虱水稻品种主要防御酶活性的影响

为探明苗龄、光照强度和施氮量对水稻主要防御酶活性的影响及其与抗褐飞虱的关系,分别就苗龄、光照强度和施氮量等因子对不同抗褐飞虱水稻品种苯丙氨酸解氨酶(PAL)、多酚氧化酶(PPO)和过氧化物酶(POD)活性的影响进行研究。结果表明:IR56、Ptb33和570011对褐飞虱生物型II的抗性与PAL和PPO活性密切相关,RHT对II型的抗性与PAL、PPO和POD活性密切相关,RP1976-18-6-4-2对II型的抗性与PAL活性密切相关,570011对II型的抗性与PAL和PPO活性密切相关;IR56对褐飞虱孟加拉型的抗性与PAL、PPO和POD活性密切相关,Rathu Heenati(RHT)和RP1976-18-6-4-2对孟加拉型的抗性与与PPO密切相关,570011对孟加拉型的抗性与POD活性密切相关。苗龄、光照强度和施氮量的单独作用或交互作用对不同水稻中防御酶活性有明显影响,但品种不同,其影响程度也不同。苗龄、光照强度和施氮量单独或是交互作用显著影响IR56中PAL和PPO、RHT和RP1976-18-6-4-2中PPO、Ptb33中POD及570011中PAL和POD的活性,苗龄显著影响IR56和RP1976-18-6-4-2中POD的活性,光照强度和施氮量单独或交互作用显著影响RHT和RP1976-18-6-4-2中PAL的活性,施氮量显著影响RHT中POD的活性,光照强度显著影响Ptb33中PAL的活性;苗龄和光照强度单独或交互作用显著影响570011中PPO的活性。     

激素对四裂红景天愈伤组织诱导及其继代培养的影响

以四裂红景天种子和幼茎为材料,应用正交试验进行其愈伤组织诱导及其继代培养的研究.结果表明:种子是诱导四裂红景天愈伤组织的理想外植体;诱导愈伤组织的最佳培养基配方为MS培养基加入6-苄基腺嘌呤(6-BA)3.0 mg/L和α-萘乙酸(NAA)2.0 mg/L和2,4-二硝基苯酸(2,4-D)1.0 mg/L,诱导率为87.1 %.愈伤组织继代培养的最佳培养基配方为MS 6-BA 3.0 mg/L NAA 1.0 mg/L 2,4-D 1.0 mg/L.细胞培养周期为30 d,21 d生物量(干质量)达到最大为13.72 g/L.     

电晕电场对沙生植物愈伤组织诱导及分化的影响

用不同电场剂量处理花棒和杨柴的下胚轴后进行愈伤组织诱导及分化培养,以探讨电晕电场对其愈伤组织诱导与分化的影响.结果表明,电场处理可以显著提高愈伤组织诱导率和分化率,并有效降低愈伤组织的褐化率.花棒在电场强度为5 kV/m下处理60 min时,出愈率可达90.5%,分化率可达88.7%;杨柴在电场强度为3 kV/m下处理100 min时,出愈率可达95.8%,分化率可达78.9%.     

外源激素对四倍体刺槐硬枝扦插生根及其关联酶活性的影响

取四倍体刺槐3年生采穗圃中当年生枝条为插穗,研究了外源激素种类、浓度、处理时间对硬枝插穗生根的影响及生根过程中3种关联酶吲哚乙酸氧化酶(IAAO)、过氧化物酶(POD)和多酚氧化酶(PPO)活性变化规律,以揭示四倍体刺槐插穗生根难的机理.结果显示:(1)四倍体刺槐硬枝插穗生根过程可分愈伤组织诱导期(0～20d)、根源基诱导期(20～30 d)、不定根表达与伸长期(30～45 d)3个阶段.(2)未经外源激素处理的插穗不生根,而激素处理可显著提高插穗生根率,促进根系发育,且IBA处理效果优于GGR6;激素处理浓度与时间无显著互作效应,但插穗生根综合效果随着处理时间和浓度的增加而升高;插穗的平均生根量和生根率在1 000 mg?L-1IBA处理6 h时达到最高,分别为11.74和55.56%.(3)IAAO、PPO是影响四倍体刺槐生根的关键酶,POD影响较小;外源激素处理插穗内IAAO和PPO活性呈先升高后下降的趋势,且均在根源基诱导期达到峰值;对照插穗内IAAO活性峰值出现在愈伤组织诱导期,而其PPO活性一直降低;激素处理和对照插穗内POD活性随着处理时间持续升高.研究表明,外源IBA和GGR6处理均可明显改变与四倍体刺槐插穗生根密切关联的氧化酶IAAO和PPO活性,提高生根率,促进根系发育,且IBA处理效果优于GGR6.     

芒不同基因型愈伤组织诱导及分化的差异

芒(Miscanthus sinensis)具较高的生物学产量, 是一种极具发展前景的纤维素类能源植物。以芒的8种不同基因型幼穗为外植体, 进行了组织培养研究。结果表明, 不同基因型芒在愈伤组织诱导率、胚性愈伤组织诱导率和胚性愈伤组织分化率等方面均存在显著差异。W89和W70均具较高的愈伤组织诱导率, 分别为91.7%和89.1%; W69的外植体几乎全部褐化, 且未能诱导出愈伤组织。W89、W70和W17的胚性愈伤组织分化率较高, 达50%以上。另外, 发现愈伤组织诱导率与细胞壁木质素含量间呈显著的负相关。该研究建立了稳定且有效的再生体系, 并初步确定W89和W70可作为芒组织培养的理想材料, 为芒的遗传转化、定向改良和良种快繁提供了技术支持。     

不同激素对青钱柳外植体和愈伤组织褐化的影响

以青钱柳(Cyclocarya paliurus)叶片为研究材料, 采用单因素完全随机试验法比较不同激素(6-BA、GA₃和NAA)浓度组合对叶片外植体褐化的影响; 在此基础上, 分别采用二因素、单因素完全随机试验法比较6-BA+NAA不同浓度组合、不同基本培养基对愈伤组织褐化的影响。结果表明, 改良MS+1.0 mg∙L ^-1 6-BA+1.0 mg∙L ^-1 GA₃+0.3 mg∙L ^-1 NAA是抑制青钱柳叶片外植体褐化的最佳培养基, 其褐化率为0, 愈伤组织诱导率100%; 改良MS+0.5 mg∙L ^-1 6-BA+0.2 mg∙L ^-1 NAA是抑制愈伤组织褐化的最佳培养基, 其褐化率为0, 愈伤组织增殖倍数达4.80倍, 愈伤组织呈黄绿色或黄色, 颗粒状, 颗粒小而紧密、质硬且表面干燥。该方法有效解决了青钱柳叶片外植体和愈伤组织褐化问题, 为青钱柳组织培养褐化控制提供了一条简单高效的离体培养途径, 也为青钱柳叶片离体再生体系的建立奠定基础。     

Time dependency of molecular rate estimates and systematic overestimation of recent divergence times

Studies of molecular evolutionary rates have yielded a wide range of rate estimates for various genes and taxa. Recent studies based on population-level and pedigree data have produced remarkably high estimates of mutation rate, which strongly contrast with substitution rates inferred in phylogenetic (species-level) studies. Using Bayesian analysis with a relaxed-clock model, we estimated rates for three groups of mitochondrial data: avian protein-coding genes, primate protein-coding genes, and primate d-loop sequences. In all three cases, we found a measurable transition between the high, short-term (< 1-2 Myr) mutation rate and the low, long-term substitution rate. The relationship between the age of the calibration and the rate of change can be described by a vertically translated exponential decay curve, which may be used for correcting molecular date estimates. The phylogenetic substitution rates in mitochondria are approximately 0.5% per million years for avian protein-coding sequences and 1.5% per million years for primate protein-coding and d-loop sequences. Further analyses showed that purifying selection offers the most convincing explanation for the observed relationship between the estimated rate and the depth of the calibration. We rule out the possibility that it is a spurious result arising from sequence errors, and find it unlikely that the apparent decline in rates over time is caused by mutational saturation. Using a rate curve estimated from the d-loop data, several dates for last common ancestors were calculated: modern humans and Neandertals (354 ka; 222-705 ka), Neandertals (108 ka; 70-156 ka), and modern humans (76 ka; 47-110 ka). If the rate curve for a particular taxonomic group can be accurately estimated, it can be a useful tool for correcting divergence date estimates by taking the rate decay into account. Our results show that it is invalid to extrapolate molecular rates of change across different evolutionary timescales, which has important consequences for studies of populations, domestication, conservation genetics, and human evolution.     

Predation rate and numerical response of Aphidoletes aphidimyza feeding on different densities of Aphis craccivora

Predation rate and numerical response are basic to any investigation of predator–prey relationships and key components in the selection of predators for biological control. The density-dependent predation rate and numerical response of Aphidoletes aphidimyza (Rondani) (Diptera: Cecidomyiidae) to varying densities (5, 10, 20, 40, 60 and 80) of third-instar Aphis craccivora (Koch) (Hemiptera: Aphididae), were studied in laboratory conditions [23±1°C, 70 ± 5% relative humidity (RH), and a photoperiod of 16:8 h L:D. Predation rate data were analysed using the age-stage, two-sex consumption rate software. Net consumption rate (C₀) increased by increasing prey density. The lowest and highest net consumption rates were 20.75 and 190.8 prey nymphs at densities of 5 and 80 A. craccivora. The transformation rate from prey population to predator offspring (Q_p) increased by increasing prey density. The reproductive numerical response, in terms of eggs laid, increased curvilinearly with increasing prey density. Females laid 121.375 ± 4.301 eggs when exposed to the highest prey density (80) and 52.5 ± 1.544 eggs at lowest prey density (5). It can be concluded that different densities of A. craccivora influenced the reproductive performance of A. aphidimyza in terms of predation rate and numerical response.     

On-station comparative analysis of reproductive and survival performance between Red Maasai,Dorper, and Merino sheep breeds

The reproductive performance of ewes and the survivability of lambs to weaning have a critical economic impact on sheep farming worldwide. Further, knowledge of major mortality causes allows an opportunity for improved flock management to evade financial losses. The maximum likelihood estimates for generalised linear mixed models and chi-square test methods were used to examine 971 mating records, 839 and 763 lambs born and weaned (singles or twins) from the Naivasha Sheep and Goats station in Kenya for the years 2011 to 2020 consisting of Dorper, Red Maasai (RedM), and Merino breeds. The RedM (P < 0.05) outperformed Dorper and Merino in weaning rate, whereas reproductive performance between the three breeds was not significantly different (P > 0.05) in litter size and multiple lambings per ewe lambing. On the one hand, Dorper significantly (P < 0.05) outperformed the other two breeds only in weaning weight per lamb born. In addition, among all the major causes of death, pneumonia appeared to be the one to which Dorper breeds were most susceptible (chi-square test, P < 0.05). According to the findings of this study, neither the Dorper nor the Merino sheep breeds were reproductively superior to the RedM in an extensive semi-arid production environment. In addition, Dorper's susceptibility to the leading causes of mortality, particularly pneumonia and sheep pox, were relatively high compared to other breeds and could be a precursor to massive economic losses for Dorper sheep producers. In contrast to the indigenous RedM breed, imported sheep breeds appeared to be more susceptible to major mortality-related under an extensive production system. Therefore, regardless of weaning weight, RedM breed production appears to be a more viable investment for small-scale farmers, particularly in semi-arid regions.     

光周期和温度对虎斑蝶卵、幼虫及蛹存活的影响

通过在人工气候箱内设定不同光周期和温度梯度单虫饲养观察个体发育史,研究了光周期和温度对虎斑蝶Danaus genutia幼期存活的影响,研究结果可为该高观赏价值蝶种的规模化养殖提供依据。结果表明,在长光照(L∶D=15∶9)条件下,17.5、20.0、22.5、25.0、27.5、30.0℃时虎斑蝶卵的孵化率分别为63.72%、71.67%、65.75%、75.00%、67.12%、59.56%,幼虫的存活率分别为85.67%、85.96%、91.19%、89.20%、80.86%、68.78%,蛹的存活率分别为82.76%、100.00%、96.00%、97.06%、100.00%、100.00%;在短光照(L∶D=9∶15)条件下,17.5、20.0、25.0、30.0℃时虎斑蝶卵的孵化率分别为86.36%、67.06%、75.00%、77.50%,幼虫的存活率分别为85.05%、84.59%、85.74%、80.78%,蛹的存活率分别为93.30%、94.12%、100.00%、100.00%。结果表明,17.5℃和30.0℃均不利于虎斑蝶幼期的存活,20.0～27.5℃是其幼期生长发育适宜的温度范围。长光照利于幼虫的存活,短光照利于卵的孵化和蛹的羽化;在17.5～30.0℃内,较高的温度利于蛹的羽化,而较低的温度利于卵的孵化和幼虫的存活;温度对虎斑蝶卵的孵化、幼虫的存活及蛹的羽化影响大于光周期;在养殖生产上,建议将幼期养殖温度控制在20.0～27.5℃,幼虫期饲养在长光照下为宜,卵和蛹期置于短光照下为宜。     

吉粳88高效再生体系的建立

以吉粳88为材料,通过对不同培养基和激素的筛选,确定最佳的再生体系。结果表明:NMB培养基为吉粳88最适的愈伤组织诱导培养基。通过L₉(3³)正交实验研究最适激素浓度配比,筛选出吉粳88愈伤组织诱导的最佳激素配比为2.0 mg/L 2,4-D+0.2 mg/L 6-BA+0.10 mg/L NAA。在添加2.0 mg/L 6-BA+0.5 mg/L NAA的NMB基本培养基条件下,吉粳88的分化率最高,成培苗率也最高。     

Optimising a clearance index based on neutral red as an indicator of physiological stress for bivalves

Neutral red is a weakly cationic dye that is soluble in water, has a low toxicity for almost all classes of organisms, and has been used as a histological and vital stain since the early twentieth century. Estimating the volume of water cleared of indicator material by suspension feeding bivalves (clearance or filtration rate) was one of the earliest applications of neutral red; however, less than thirty studies have applied this methodology since it was first described in 1954. The feeding/clearance rate is used as a sensitive indicator of physiological stress and is therefore an early-warning tool that is suitable for monitoring the ecological status of water bodies. The aim of our study was to optimise a clearance index based on neutral red solution by addressing the effect of i) the acidifying pH; ii) the holding temperature before spectrophotometric reading; and the time iii) before and iv) after the acidification of solutions of neutral red used to carry out clearance assays. Furthermore, as a case study we fine-tuned the clearance assay for the edible estuarine bivalve, Cerastoderma edule. The results showed that there were no statistical differences as regards the absorbance of neutral red solutions holding at 4 or 20 °C or a solution acidified between the ranges of pH 4–5. However, the absorbance significantly decreased as the pH increased to pH 6. The time before acidification had no significant effect on absorbance. Once the neutral red solution is acidified, the absorbance decreases over time, signifying that the absorbance should be read in the first 24 h. The concentration of neutral red used in the experiences should be sufficient to allow final concentrations of over 0.5 mg/L after the clearance period, since we observed that the sensitivity of this protocol decreased at low concentrations. In the case of C. edule, the optimum clearance conditions per individual were found to be 100 ml of 4 mg/L of neutral red dye during a 30 min period in dark conditions. A bioassay using a clearance index of C. edule based on this simple colorimetric technique would appear to be a potential tool for implementation in environmental monitoring programmes for water quality assessment in accordance with European directives. We trust that the new harmonised protocol will become a widely used and cost-effective means to monitor the clearance index as an indicator of physiological stress for bivalves.     

On the interpretation of some planktonology equations

Summary The concept of the mean value of a function is used to interpret some population-dynamics equations. The well-known formula for the per capita growth rate r gives a precise mean value for any (not only exponentially growing) populations. This result is used to derive the birth and death rate equations of Paloheimo (1974) with minimal initial limitations.Abbreviations t time - N number of animals - E number of eggs - r specific (i.e. per capita) population growth rate - b specific birth rate - d specific death rate - D duration of embryonic development     

Ingestion Rates of Some Daphnia Species in a Shallow Lake (Lake Balaton,Hungary)

Filtering rates of three species of Daphnia were studied in situ by the ¹⁴C technique during the summer in a lake with a water temperature of 20-25°C (Lake Balaton, Hungary). The renewal time of gut contents proved to be 3-5 min in each of the three species whether fed on natural or artificial food. From May to September, filtering rates of D. cucullata, D. hyalina and D. galeata averaged 7.8, 10.3 and 9.2 ml ind.⁻¹ day⁻¹, respectively. Identically long individuals of all three species had almost the same filtering rates in spring, whereas in summer animals of identical weights had similar filtering rates regardless of species because of the length variability of the helmets. The grazing rate of adult filter-feeding crustaceans is suggested to be approximately 7 % per day.     

转基因鱼构建模式的研究II.构建转基因鱼的几个影响因素(英文)

ＳｔｕｄｉｅｓｏｎＰａｔｅｒｎｏｆＰｒｏｄｕｃｉｎｇＴｒａｎｓｇｅｎｉｃＦｉｓｈＩ．ＳｅｖｅｒａｌＥｌｅｍｅｎｔｓＲｅｌａｔｅｄｔｏｔｈｅＥｓｔａｂｌｉｓｈｍｅｎｔｏｆＴｒａｎｓｇｅｎｉｃＦｉｓｈＬＩＵＣｈｕｎｑｉａｏ,ＺＨＡＮＧＹｏｎｇｚｈｏｎ...     

光合单位的周转率与叶片光合速率的关系

利用闪光技术,测得若干高等植物叶片的光合单位为 1450～2050 Chl/CO_2。在含O_2 2％及CO_2浓度和光通量密度都饱和的条件下,测得叶片的连续光合速率为25～70μmol CO_2 m~(-2) s~(-1)。从上述数据及叶片叶绿素含量计算,得叶片光合单位的周转率已达80～160次/s。这样的周转速率与Emerson当初用改变闪光间暗间隔而测到的光合单位周转时间相似(即<10 ms/次,或>100次/s),从而证实了光合单位的周转与光合速率直接有关。这样的速率可称之为叶片光合的理论速率。