籼粳杂种双单倍体的配子选择

对典型的灿与粳稻杂种，窄叶青８号／京系１７Ｆ１花药进行培养获得的１３２个双单倍体的形态特性、同工酶与ＲＦＬＰ标记的分离与重组进行了考察分析，研究是否存在配子选择问题。结果表明：（１）对４个重要数量性状和６个涉及籼、粳特征的形态指数进行考察所获数据均为连续分布，并呈正态曲线；（２）用８种同工酶对５２个ＤＨ系分析结果表明，只有２种同工酶显著偏离期望的１：１比率，而灿与粳的总基因型比率相近；（３）应用１６７个ＲＦＬＰ标记对１３２个ＤＨ系进行的分析发现，有３６％标记发生偏分离，但偏籼与偏粳的比率相近，两个亲本基因组在ＤＨ群体中所占比率相同（各５０％），各种基因组成呈正态分布。综上所述，本研究虽观察到一些轻微偏分离现象，但籼粳基因基本上随机分离与重组，等位基因总频率未偏离１：１比率。

鹅掌楸配子选择与雄性繁殖适合度

在多父本等量花粉混合授粉的交配实验设计基础上,利用SSR分子标记对其子代进行父本分析,研究鹅掌楸的配子选择与雄性繁殖适合度。参试亲本为鹅掌楸2个种的5个单株(鹅掌楸(Liriodendron chinense)2株,即FY和LS;北美鹅掌楸(L.tulipifera)3株,即LYS、MSL和NK)。结果表明:鹅掌楸的配子选择个体间差异较大。作为母本,NK和LYS倾向于选择异种雄配子,而MSL和LS则倾向于选择同种雄配子;在同种雄配子的选择中,NK、LYS和LS倾向于自交,而MSL则倾向于异交。以北美鹅掌楸为母本时,北美鹅掌楸与鹅掌楸的雄性繁殖贡献率分别为45.5%和54.5%,北美鹅掌楸的雄性繁殖适合度为鹅掌楸的0.556倍。以鹅掌楸为母本时,二者的繁殖贡献率分别为15.6%和84.4%,北美鹅掌楸的雄性繁殖适合度为鹅掌楸的0.123倍。总体上看,鹅掌楸的雄性繁殖适合度高于北美鹅掌楸,鹅掌楸与北美鹅掌楸均表现为自交亲和。

雄配子选择：一种有用的育种工具

本文概述了配子体（或花粉）选择的育种策略，对育种中配子体选择的三种途径进行了讨论，包括基因型筛选，配子竞争对后代优势的效应，以及繁殖阶段操作对下代孢子体转移性状的作用；同时对育种中利用配子体选择的优点、缺点和本领域进展以及本方法的展望也一起进行了讨论。

海拔差异对水稻雌配子体基因型选择及其后代表型遗传分化的影响

【目的】分析海拔环境差异对水稻雌配子体基因型选择及其对后代表型遗传分化的影响,为研究植物表型对海拔环境的遗传响应及利用海拔差异进行雌配子体选择育种的方法提供理论参考。【方法】利用2个滇1型细胞质雄性不育系与耐寒粳稻地方老品种杂交,在4个具有明显海拔背景差异的试验点构建并种植了7个水稻F1雌配子体基因型选择群体及其28个F2遗传分离群体,通过估算这些世代群体的形态性状差异来检测不同海拔条件对雌配子体基因型频率变化和后代表型遗传分化的影响。【结果】对F1雌配子体基因型选择群体的形态性状分析发现,在4个不同海拔点都检测到8个性状发生了偏分离,说明海拔背景差异对F1雌配子体基因型具有选择作用,且在2 200和400 m两种海拔环境的影响都大于海拔1 860和1 250 m;产生于海拔1 860 m群体的形态性状多样性指数最大,据此随产生海拔的升高和降低,其多样性指数均减小;差异性比较显示产生于2 200 m高海拔的群体几乎与其他3个海拔产生的群体在所有性状上的差异都达显著水平。对种植于不同海拔环境的28个F2遗传分离群体的形态性状分析,结果显示海拔差异导致的雌配子体基因型选择影响其F2群体的表型遗传分化,且产生海拔差异越大,其后代表型分化就越明显。经2 200和400 m选择过的分离群体,在7个性状上检测出21处差异达显著水平;经1 860和1 250 m选择过的分离群体,仅在3个性状上检测出6处差异达显著水平。总体变化趋势是,经高海拔2 200 m选择的群体,种植在不同海拔表现结实率高、整体生长势较差,而经低海拔400 m选择的群体的性状表现与高海拔的相反,经中海拔1 860和1 250 m选择过的群体表现多居于高、低海拔之间,但群体形态性状多样性指数较大。【结论】海拔环境差异对水稻F1雌配子体基因型具有选择作用,进而影响其后代的表型遗传分化,形成对不同海拔环境条件的生态适应性,这意味着利用海拔背景差异进行雌配子体选择育种的方法是可行的。

籼粳细胞质和海拔差异对水稻F_1配子体基因型的选择效应

为研究籼粳细胞质背景和海拔引起的环境温度变化对水稻F1配子体基因型的选择效应,利用云南海拔2 650 m高寒稻区种植的地方粳稻老品种小麻谷与具有籼稻细胞质背景的改良品系南34为亲本,分析比较了在400、1 860、2 200 m 3个不同海拔下正反交F1的花粉育性和小穗育性,以及在3个不同海拔下产生的F2群体的生物学性状。结果表明:在3个不同海拔、粳稻细胞质背景下的杂种F1的花粉育性和小穗育性均显著高于其在籼稻细胞质背景下的表现,其中花粉育性的差异更为明显。除细胞质外,海拔也同样极显著影响杂种F1的花粉育性,但对其小穗育性影响很小。在不同海拔下产生的F2群体的生物学性状存在显著或极显著差异,同一海拔下产生的正反交F2群体间的生物学性状也存在显著差异。结果表明不同细胞质背景和海拔差异对水稻F1的雄配子基因型具有明显的选择效应,选择压力引起雄配子的败育导致其后代孢子体的基因型发生选择。

温度对水稻雌配子体基因型选择及其后代表型遗传分离的影响

温度对雌配子体选择较困难,研究报道较少。为探究温度对雌配子体基因型的选择作用,分别用高温和低温处理孕穗期和开花期的杂交组合群体(合系41A/‘小麻谷’、合系42A/‘小花谷’),并授予‘南34’花粉,共产生22个F1雌配子体基因型选择群体及其后代F2分离群体。对种植于3个不同海拔环境的这些群体的6个形态性状进行分析,结果显示:温度差异对水稻F1雌配子体基因型具有选择作用,并影响到F2代表型的遗传分离;高温35℃的选择作用大于低温16℃,开花期选择作用大于孕穗期;低温处理的选择群体,种植在海拔2 200 m和1 860 m的结实率高、但整体长势较差,而高温处理的选择群体长势较强、但结实率低。此外,海拔差异对各世代群体的表型有影响,其中1 860 m海拔的影响最小。本研究结果为利用温差对雌配子体选择育种提供一定的参考。

雄配子体选择在遗传偏分离中的效应分析

偏分离是一种广泛存在于生物中的遗传学现象,被认为是一种强有力的进化动力。本文从生殖隔离因子、细胞质效应以及环境因素三个方面分析了雄配子体选择可能导致的遗传偏分离效应。研究证明,位于细胞核基因组上的生殖隔离因子如配子体基因、不育基因等遗传因素导致的雄配子体选择是引起遗传偏分离的主要原因;而细胞质核互作导致的雄性不育产生的雄配子选择同样可导致核基因发生遗传偏分离;非遗传因素如环境温度等引起的雄配子选择也会导致遗传偏分离现象。

雄配子体选择的遗传分化效应及其在植物改良中的应用

在植物世代交替的生活史中,配子体是产生配子和具有单倍数染色体的植物体,并且有自己的遗传表达信息。在配子产生的过程中以及配子结合之前,适者生存的法则对配子发挥着选择作用,只有最适应外界环境条件的配子才能通过竞争性受精并产生合子。雄配子体选择是影响植物遗传分化、演变和遗传多样性的重要因素,被认为是生物进化的有力动力。此外,由于植物基因组中约有2/3的基因表达交错发生在配子体阶段和孢子体阶段,因此雄配子体选择的结果会影响到下一代孢子体的表现型。在育种实践中,利用雄配子体选择对植物进行遗传改良,具有提高选择机率和缩短育种年限等优点。本文主要概述雄配子体选择与孢子体表型的关系、遗传分化效应及其在植物遗传改良中的应用。

低温处理对水稻正反交F_1雄配子基因型频率的影响

利用来自云南海拔2 670 m高寒稻区的地方粳稻品种小麻谷与具有籼稻细胞质背景的籼粳交品系南34进行正反交产生F1,用经14℃和17℃低温离体处理的正反交F1的稻穗与育性稳定的1个滇Ⅰ型细胞质不育系授粉获得3个测交群体。对F1的花粉育性和所获得测交群体的PCR位点进行分析,发现温度及细胞质背景都对F1产生的雄配子基因型发生了选择,导致雄配子基因型的遗传比例偏离孟德尔规律。对这一问题的研究有助于探讨温度对水稻遗传分化的影响,还可探讨通过对雄配子基因型的差异选择提高定向育种效率的育种方法,将有助于探讨全球气候变化对水稻及其他作物的遗传变异将产生的影响。

裙带菜(Undaria pinnatifida)配子体对四种抗生素的敏感性研究

采用显微计数的方法获得潮霉素、氯霉素、卡那霉素、硫酸链霉素等抗生素对裙带菜雌、雄配子体的致死率,通过统计分析研究了雌雄配子体对这些抗生素的敏感性。结果表明,裙带菜雌雄配子体对潮霉素和氯霉素敏感,482.7μg/ml潮霉素分别在第9、10天使雄配子体、雌配子体全部致死;雌雄配子体对氯霉素的敏感性还存在明显的差异,第8天氯霉素对雌雄配子体的半致死剂量分别是218.78μg/ml和371.54μg/ml。配子体对卡那霉素,硫酸链霉素相对不敏感,6000kU/L卡那霉素和800μg/ml的硫酸链霉素作用10天后雌雄配子体均无明显死亡现象。潮霉素和氯霉素可以作为裙带菜配子体的筛选试剂。

论单基因的分离负荷

本文引进两个配子选择系数、三个基因互作系数及互作跃变函数描述分离负荷，统一了近四十年来的理论纷争，得到如下结果：(1）只有当对两个配子的选择系数相等时，种群才能平衡．对平衡种群，以往关于分离负荷的结论是成立的，而且种群的适宜度保持不变；(2）当两配子选择系数不等时，种群不可能平衡，此时选择下分离负荷从Ｆ１代开始逐代减小，种群向杂合子纯合方向进化，从而解释了许多过去不能解释的现象．

不同海拔下水稻正反交F_2群体的孕穗期耐冷性研究

云南高寒稻区的地方粳稻品种小麻谷与籼稻细胞质的改良品系南34的正反交F1分别种植于海拔400,1 860和2 200 m的3个点,对6个F2群体的孕穗期耐冷性进行分析。结果表明小穗育性是对低温最敏感的性状,可用作孕穗期耐冷性的评价指标。F2(小麻谷×南34)群体的平均孕穗期耐冷性均极显著高于同一海拔下产生的反交F2群体的表现(P<0.01)。同一组合在2 200 m海拔产生的F2群体平均孕穗期耐冷性均高于其余两海拔产生的群体,其中显著(P<0.05)或极显著(P<0.01)高于在400 m海拔产生的群体。结果明确了杂种F1在高海拔低温条件下传粉产生的后代更耐低温,其中在粳稻细胞质背景下更为明显。在F2(小麻谷×南34)群体中耐冷性状的分布主要是受耐冷基因的作用,然而在其反交F2群体中耐冷性状的分布除受耐冷基因的作用外,还受到籼稻细胞质背景的影响。

遗传负荷

遗传负荷的一种定义是:一群体的平均值与某一参考基因型的平均值所差异的部份,常用适合度来表示,而用作参考的基因型常常是各种可能有的基因型中适合度最大的基因型。另一个相似的定义是这样的,一个群体中存在某一因子与另一其余都相同但不存在这一因子的群体其平均值进行比较时,即该群体由于存在这一因子平均值发生变化,这一变化的部分就是遗传负荷。

Effect of montmorillonite on hydrate-based methane separation from mine gas

Three types of mine gas samples were used in the solutions of tetrahydrofuran(THF),sodium dodecyl sulfate(SDS)and THF-SDS with/without MMT respectively to investigate the effect of montmorillonite(MMT)on separation characteristics of methane recovered from mine gas based on hydrate method.The partition coefficient,separation factor and recovery rate were used to evaluate the effects of MMT,and the selection factor was primarily proposed to define the selectivity of mine gas hydrate in the relative target gases.The experimental results indicate that MMT could improve the following factors including hydration separation factor,the selection factor,the partition coefficient,and the recovery rate.Furthermore,the effect of SDS on the function of MMT is analyzed in the process of hydration separation.Finally,due to the results of the experiment,it is concluded that MMT hydration mechanism explores the effect of MMT enrichment methane from mine gas.

Lipase-catalyzed Synthesis of Caffeic Acid Phenethyl Ester in Ionic Liquids： Effect of Specific Ions and Reaction Parameters

Caffeic acid phenethyl ester(CAPE)is a rare,naturally occurring phenolic food additive.This work systematically reported fundamental data on conversion of caffeic acid(CA),yield of CAPE,and reactive selectivity during the lipase-catalyzed esterification process of CA and phenylethanol(PE)in ionic liquids(ILs).Sixteen ILs were selected as the reaction media,and the relative lipase-catalyzed synthesis properties of CAPE were measured in an effort to enhance the yield of CAPE with high selectivity.The results indicated that ILs containing weakly coordinating anions and cations with adequate alkyl chain length improved the synthesis of CAPE.[Emim][Tf2N]was selected as the optimal reaction media.The optimal parameters were as follows by response surface methodology(RSM):reaction temperature,84.0°C;mass ratio of Novozym 435 to CA,14︰1;and molar ratio of PE to CA,16︰1.The highest reactive selectivity of CAPE catalyzed by Novozym 435 in[Emim][Tf2N]reached 64.55%(CA conversion 98.76%and CAPE yield 63.75%,respectively).Thus,lipase-catalyzed esterification in ILs is a promising method suitable for CAPE production.

Optimization of maintenance strategy for high-speed railwaycatenary system based on multistate model

A multi-objective optimization model considering both reliability and maintenance cost is proposed to solve the contradiction between reliability and maintenance cost in high-speed railway catenary system maintenance activities.The non-dominated sorting genetic algorithm 2(NSGA2)is applied to multi-objective optimization,and the optimization result is a set of Pareto solutions.Firstly,multistate failure mode analysis is conducted for the main devices leading to the failure of catenary,and then the reliability and failure mode of the whole catenary system is analyzed.The mathematical relationship between system reliability and maintenance cost is derived considering the existing catenary preventive maintenance mode to improve the reliability of the system.Secondly,an improved NSGA2(INSGA2)is proposed,which strengths population diversity by improving selection operator,and introduces local search strategy to ensure that population distribution is more uniform.The comparison results of the two algorithms before and after improvement on the zero-ductility transition(ZDT)series functions show that the population diversity is better and the solution is more uniform using INSGA2.Finally,the INSGA2 is applied to multi-objective optimization of system reliability and maintenance cost in different maintenance periods.The decision-makers can choose the reasonable solutions as the maintenance plans in the optimization results by weighing the relationship between the system reliability and the maintenance cost.The selected maintenance plans can ensure the lowest maintenance cost while the system reliability is as high as possible.

Partial characterization of the N-linked oligosaccharide structures on P-selectin glycoprotein ligand-1 (PSGL-1)

PSGL-1, a specific ligand for P-, E- and L-selectin, was isolated from in vivo [3H]-glucosamine labeled HL- 60 cells by a combination of wheat germ agglutinin-agarose and P- or E-selectin-agarose chromatography. N- linked oligosaccharides were released from the purified, denatured ligand molecule by peptide: N-glycosidase F treatment and, following separation by Sephacryl S-200 chromatography, partially characterized using lectin, ion-exchange and size-exclusion chromatography in combination with glycosidase digestions. The data obtained suggest that the N-glycans on PSGL-1 are predominantly core-fucosylated, multiatennary complex type structures with extended, poly- N- acetyllactosamine contaniing outer chains. A portion of the outer chains appears to be substituted with fucose indicating that the N-glycans, in addition to the O-glycans on PSGL-1, may be involved in selectin binding.

CO_(2) reduction reaction pathways on single‐atom Co sites:Impacts of local coordination environment

Single‐atom catalysts have been proposed as promising electrocatalysts for CO_(2) reduction reactions(CO_(2)RR).Co‐N_(4) active sites have attracted wide attention owing to their excellent CO selectivity and activity.However,the effect of the local coordination environment of Co sites on CO_(2) reduction reaction pathways is still unclear.In this study,we investigated the CO_(2) reduction reaction pathways on Co‐N_(4) sites supported on conjugated N_(4)‐macrocyclic ligands with 1,10‐phenanthroline subunits(Co‐N_(4)‐CPY)by density functional theory calculations.The local coordination environment of single‐atom Co sites with N substituted by O(Co‐N_(3)O‐CPY)and C(Co‐N_(3)C‐CPY)was studied for comparison.The calculation results revealed that both C and O coordination break the symmetry of the primary CoN_(4) ligand field and induce charge redistribution of the Co atom.For Co‐N_(4)‐CPY,CO was confirmed to be the main product of CO_(2)RR.HCOOH is the primary product of Co‐N_(3)O‐CPY because of the greatly increased energy barrier of CO_(2) to*COOH.Although the energy barrier of CO_(2) to*COOH is reduced on Co‐N_(3)C‐CPY,the desorption process of*CO becomes more difficult.CH3OH(or CH_(4))are obtained by further*CO hydrogenation reduction when using Co‐N_(3)C‐CPY.This work provides new insight into the effect of the local coordination environment of single‐atom sites on CO_(2) reduction reaction pathways.

Effects of nitrogen form on growth,CO_2 assimilation,chlorophyll fluorescence,and photosynthetic electron allocation in cucumber and rice plants

Cucumber and rice plants with varying ammonium (NH4+) sensitivities were used to examine the effects of different nitrogen (N) sources on gas exchange, chlorophyll (Chl) fluorescence quenching, and photosynthetic electron allocation. Compared to nitrate (NO3-)-grown plants, cucumber plants grown under NH4+-nutrition showed decreased plant growth, net photosynthetic rate, stomatal conductance, intercellular carbon dioxide (CO2) level, transpiration rate, maximum photochemical efficiency of photosystem II, and O2-independent alternative electron flux, and increased O2-dependent alternative electron flux. However, the N source had little effect on gas exchange, Chl a fluorescence parameters, and photosynthetic electron allocation in rice plants, except that NH4+-grown plants had a higher O2-independent alternative electron flux than NO3--grown plants. NO3- reduction activity was rarely detected in leaves of NH4+-grown cucumber plants, but was high in NH4+-grown rice plants. These results demonstrate that significant amounts of photosynthetic electron transport were coupled to NO3- assimilation, an effect more significant in NO3-- grown plants than in NH4+-grown plants. Meanwhile, NH4+-tolerant plants exhibited a higher demand for the reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) for NO3- reduction, regardless of the N form supplied, while NH4+-sensitive plants had a high water-water cycle activity when NH4+ was supplied as the sole N source.

Reviewing guppy color vision： integrating the molecular and physiological variation in visual tuning of a classic system for sensory drive

Sensory drive predicts coevolution of mate choice signals with the sensory systems detecting those sig nals. Guppies are a classic model for sensory drive as mate preferences based on coloration differ across individuals and populations. A large body of work has identified variation in color vision, yet we lack a dir ect tie between how such variation in color vision influences variation in color preference. Here we bring together studies that have investigated guppy vision over the past 40years to： （1） highlight our current understanding of where variation occurs in the guppy color vision pathway and （2） suggest future ave nues of research into sources of visual system variation that could influence guppy color preference. This will allow researchers to design careful studies that couple measures of color preference with measures of visual system variation from the same individual or population. Such studies will finally provide im portant answers as to what sets the direction and speed of mate preference evolution via sensory drive.