小麦的分类、起源与进化

小麦是世界历史上最古老的作物之一,约在一万年以前,在西南亚,人类首先成功地将小麦进行栽培生产粮食,因此小麦栽培历史和人类开化有着密切的相互关系。在现代世界农业中,小麦也是最重要的作物之一。它分布面积很广,从北纬67°的挪威、芬兰和苏联到南纬45°的阿根庭都有栽培。世界生产小麦的地区有苏联南部、美国中部平原和加拿大相邻地区、地中海地区、中国、印度、阿根廷北部和澳大利亚的西南部。这类作物在比较宽的环境 范围内都能获得高产。据统计,全世界有1/3的人口以小麦为主要粮食.消费的小麦食物卡值占全世界的20%以上。     

高寒地区豆秸裁培香菇

香菇在世界菇类产量中居第 2位 ,是仅次于双孢菇的食用蕈菌 ,香菇的人工栽培 ,也是我国最早 ,距今已有 80 0多年的历史。 80年代后逐渐以袋料栽培为主 ,所用原料以阔叶木屑、棉籽壳居多 ,寒地利用粉碎豆秸栽培香菇的报道甚少。黑龙江省龙门农场地处北纬 48 5°～49 0 2° ,东经 1 2 6°～ 1 2 7° ,海拔 42 5米 ,年平均气温 - 0 9℃ ,属我省第四积温带 ,是大豆主产区之一 ,随着农业产业结构调整木屑代料香菇生产已迅速发展起来 ,但林木资源的紧缺制约了香菇产业的发展 ,而这里每年大量的豆秸作为废弃物在地里堆放燃烧 ,不但是一种浪费 ,还…     

水稻进化的“路线图”

与其他几大作物(如小麦、玉米、大麦、大豆和棉花等)相比,目前人类对水稻起源的认识仍十分肤浅,这和水稻世界第一大作物的地位是不相称的。     

小麦染色体组的起源与进化

小麦是世界上最重要也是最古老的作物之一,同时它还是典型的多倍体植物,关于它的起源与进化至今还是１个未彻底揭开的谜。长期以来各国学者在这方面进行了大量研究。１小麦属的分类小麦属禾本科（Ｃｒａｍｉｎｅａｅ）、小麦族（Ｔｒｉｔ－ｉｃｅａｅ）、小麦亚族（Ｔｒ...     

黄淮海平原高产田作物群体结构特征

本文利用实测资料分析了高产田作物群体结构特征。精播高产栽培麦田春季最大蘖数12×10~6/ha,群体最大叶面积指数5.5—6.0,成穗4.5—5.25×10~6/ha。传统高产栽培麦田春季最大蘖数15—18×10~6/ha,群体最大叶面积指数6.0—6.5,成穗6.0—7.5×10~6/ha。小麦营养生长与生殖生长期叶日积比,精播高产栽培麦田是1∶0.89,传统高产栽培麦田为1∶0.73。夏玉米种植密度主要受叶倾角的影响。紧凑型玉米品种的叶倾角大于65°,种植密度7.5—8.25×10~4/ha;平展型玉米品种的叶倾角小于50°,种植密度5.25—6.0×10~4/ha。     

北疆普通甜菜象虫(Bothynoderes punctiventris Germ.)发生消长和防治试验

一、分布与发生地理特点 我国主耍的甜菜栽培区,自宁夏以西,内蒙、甘肃、经河西走廊至新疆乌伊公路以西地区,均有普通甜菜象虫分布。在北疆常受为害的地区有乌鲁木齐、昌吉、呼图壁、玛纳斯、沙湾和乌苏等地(N42°—46°)。这些地区,3月份平均气温为-2.4—-3.7℃,与苏联东     

纬度变化对不同冬小麦品种蛋白质组分的影响

选用6个有代表性的冬小麦品种在河南省5个不同纬度试验点（32°—36°N）进行种植,研究纬度变化对冬小麦蛋白质组分含量的影响.结果表明：纬度变化对冬小麦清蛋白、麦谷蛋白含量和谷/醇比值有显著影响,而基因型差异对蛋白质组分的影响不显著.随着纬度的升高,清蛋白和醇溶蛋白含量呈降低趋势,而麦谷蛋白含量、谷/醇比值、蛋白质组分之和及小麦产量呈递增趋势.与其他试验点相比,信阳种植的6个小麦品种的清蛋白含量相对较高,驻马店和许昌的醇溶蛋白含量较高,而武陟和汤阴的麦谷蛋白含量较高.5月份平均气温、总日照时数和降雨量与小麦蛋白质组分地点间变化关系密切.因此,生产上选择适宜的小麦种植区,同时可在5月份采取改善光合作用、延长灌浆时间等栽培措施,以提高小麦籽粒品质.     

中国的痲類植物

麻是我国重要的纖维作物之一,它的地位仅次於棉花。像苧麻是我国特产,世界的苧麻市场,差不多完全由我国供给。在抗日战争以前,我国的大麻和(?)麻也運销国外。解放以後,为了解决运输的包装材料,大规模的发展黄麻、洋麻和亚麻等作物。四年来,已获得了很大的成绩,不但已经满足了国内的需要;同时还可以销到苏联和新民主主義的兄弟国家等。随着祖国工业化的发展,麻的需要量也一定会增加起来,因此,麻类作物在工业原料上,在国民经济上占有相当重要的地位.从历史上看,我国种麻是世界上最古的国家。大麻,苧麻在我国栽培至少有三、四千年。从目前看来,我国麻的栽培情况,种类之多,分佈之广,可说是世界第一.这里介绍的是我国几种重要麻类作物的一般情形。     

西藏栽培大麦的遗传多样性中心

 以西藏3 204份栽培大麦(Hordeum vulgare)地方品种为材料,运用群体遗传学的原理与方法,研究了西藏栽培大麦遗传资源的数量、遗传多样性指数和综合变异系数及其生态地理分布特征。结果表明：1) 28°～30° N×88°～94° E的藏中地区栽培大麦资源分布广泛,遗传多样性丰富,综合变异系数高;2) 30°～31° N×96°～98° E的藏东横断山脉地区栽培大麦资源、遗传多样性和综合变异系数次之。并据此提出西藏栽培大麦的遗传多样性中心及其多样性扩散方式。     

小麦,玉米轮作田蜘蛛群落结构及多样性研究

一、研究方法本项工作于1988—1990年在青州市南郊农田进行。位于东经118°17′,北纬36°27′,年平均气温9℃,年降雨量860mm以上,无霜期180天左右。调查了不同作物类型的地块,包括玉米间作(大豆)田、净玉米田、有水浇条件的麦田、旱麦田和田埂杂草五种生境。其中小麦、玉米轮作田各3块,每块面积0.2ha以     

蛋白质定向进化的研究进展

在工业生物催化过程和生物细胞工厂构建方面,蛋白质定向进化被广泛地应用于酶的分子改造.蛋白质定向进化不仅可以针对某一目的蛋白进行改造,还可以改善代谢途径、优化代谢网络、获得期望表型细胞.为了获得更高效的突变效率,快捷、高通量的筛选方法,提高蛋白质定向进化的效果,研究者不断开发蛋白质体内、体外进化方法,取得了新的进展和应用.本文介绍了最近发展的蛋白质定向进化技术的原理、方法及特点,总结了突变文库的筛选方法和蛋白质定向进化的最新应用,最后讨论了蛋白质定向进化存在的挑战和未来发展方向.     

Systems for in vivo hypermutation: a quest for scale and depth in directed evolution

Traditional approaches to the directed evolution of genes of interest (GOIs) place constraints on the scale of experimentation and depth of evolutionary search reasonably achieved. Engineered genetic systems that dramatically elevate the mutation of target GOIs in vivo relieve these constraints by enabling continuous evolution, affording new strategies in the exploration of sequence space and fitness landscapes for GOIs. We describe various in vivo hypermutation systems for continuous evolution, discuss how different architectures for in vivo hypermutation facilitate evolutionary search scale and depth in their application to problems in protein evolution and engineering, and outline future opportunities for the field.     

Strong links between genomic and anatomical diversity in both mammalian olfactory chemosensory systems

Mammalian olfaction comprises two chemosensory systems: the odorant-detecting main olfactory system (MOS) and the pheromone-detecting vomeronasal system (VNS). Mammals are diverse in their anatomical and genomic emphases on olfactory chemosensation, including the loss or reduction of these systems in some orders. Despite qualitative evidence linking the genomic evolution of the olfactory systems to specific functions and phenotypes, little work has quantitatively tested whether the genomic aspects of the mammalian olfactory chemosensory systems are correlated to anatomical diversity. We show that the genomic and anatomical variation in these systems is tightly linked in both the VNS and the MOS, though the signature of selection is different in each system. Specifically, the MOS appears to vary based on absolute organ and gene family size while the VNS appears to vary according to the relative proportion of functional genes and relative anatomical size and complexity. Furthermore, there is little evidence that these two systems are evolving in a linked fashion. The relationships between genomic and anatomical diversity strongly support a role for natural selection in shaping both the anatomical and genomic evolution of the olfactory chemosensory systems in mammals.     

发育重演律与生物进化

发育重演律是生物个体发育的一般规律,该规律认为生物个体的发育是类囊胚不断形成和演化的过程,并认为生物进化亦是类囊胚不断形成和演化的过程.因类囊胚层级不断增加而导致的生物体结构复杂程度提高的演化为纵向进化,而不能提高生物体复杂程度的演化为横向演化,生物的纵向进化具有周期性.生物种系进化与个体发育之间具有严格的对应关系,一个物种经历的纵向进化的周期数与该物种所属个体完成发育所经历的细胞分化的周期数相等.     

Genome architecture drives protein evolution in ciliates

Studies of microbial eukaryotes have been pivotal in the discovery of biological phenomena, including RNA editing, self-splicing RNA, and telomere addition. Here we extend this list by demonstrating that genome architecture, namely the extensive processing of somatic (macronuclear) genomes in some ciliate lineages, is associated with elevated rates of protein evolution. Using newly developed likelihood-based procedures for studying molecular evolution, we investigate 6 genes to compare 1) ciliate protein evolution to that of 3 other clades of eukaryotes (plants, animals, and fungi) and 2) protein evolution in ciliates with extensively processed macronuclear genomes to that of other ciliate lineages. In 5 of the 6 genes, ciliates are estimated to have a higher ratio of nonsynonymous/synonymous substitution rates, consistent with an increase in the rate of protein diversification in ciliates relative to other eukaryotes. Even more striking, there is a significant effect of genome architecture within ciliates as the most divergent proteins are consistently found in those lineages with the most highly processed macronuclear genomes. We propose a model whereby genome architecture-specifically chromosomal processing, amitosis within macronuclei, and epigenetics-allows ciliates to explore protein space in a novel manner. Further, we predict that examination of diverse eukaryotes will reveal additional evidence of the impact of genome architecture on molecular evolution.     

Reversal of evolutionary downsizing caused by selective harvest of large fish

Evolutionary responses to the long-term exploitation of individuals from a population may include reduced growth rate, age at maturation, body size and productivity. Theoretical models suggest that these genetic changes may be slow or impossible to reverse but rigorous empirical evidence is lacking. Here, we provide the first empirical demonstration of a genetically based reversal of fishing-induced evolution. We subjected six populations of silverside fish (Menidia menidia) to three forms of size-selective fishing for five generations, thereby generating twofold differences among populations in mean weight and yield (biomass) at harvest. This was followed by an additional five generations during which size-selective harvest was halted. We found that evolutionary changes were reversible. Populations evolving smaller body size when subjected to size-selective fishing displayed a slow but significant increase in size when fishing ceased. Neither phenotypic variance in size nor juvenile survival was reduced by the initial period of selective fishing, suggesting that sufficient genetic variation remained to allow recovery. By linear extrapolation, we predict full recovery in about 12 generations, although the rate of recovery may taper off near convergence. The recovery rate in any given wild population will also depend on other agents of selection determined by the specifics of life history and environment. By contrast, populations that in the first five generations evolved larger size and yield showed little evidence of reversal. These results show that populations have an intrinsic capacity to recover genetically from harmful evolutionary changes caused by fishing, even without extrinsic factors that reverse the selection gradient. However, harvested species typically have generation times of 3–7 years, so recovery may take decades. Hence, the need to account for evolution in managing fisheries remains.     

Molecular Evolutionary Dynamics of Energy Limited Microorganisms

Microorganisms have the unique ability to survive extended periods of time in environments with extremely low levels of exploitable energy. To determine the extent that energy limitation affects microbial evolution, we examined the molecular evolutionary dynamics of a phylogenetically diverse set of taxa over the course of 1,000 days. We found that periodic exposure to energy limitation affected the rate of molecular evolution, the accumulation of genetic diversity, and the rate of extinction. We then determined the degree that energy limitation affected the spectrum of mutations as well as the direction of evolution at the gene level. Our results suggest that the initial depletion of energy altered the direction and rate of molecular evolution within each taxon, though after the initial depletion the rate and direction did not substantially change. However, this consistent pattern became diminished when comparisons were performed across phylogenetically distant taxa, suggesting that although the dynamics of molecular evolution under energy limitation are highly generalizable across the microbial tree of life, the targets of adaptation are specific to a given taxon.     

Higher rates of sex evolve under K‐selection

The geographical distribution of sexual and related asexual species has been suggested to correlate with habitat stability; sexual species tend to be in stable habitats (K‐selection), whereas related asexual taxa tend to be in unstable habitats (r‐selection). We test whether this broad‐scale pattern can be re‐created at a microevolutionary scale by experimentally evolving populations of facultatively sexual rotifers under different ecological conditions. Consistent with the pattern in nature, we find that the rate of sex evolves to lower levels in the r‐selected than in K‐selection environments. We consider several different explanations for these results.     

Feedback selection and the evolution of modifiers

The problem of modifier evolution was examined with regard to the idea that modifier evolution can be considered as a result of selection for adaptation speed in populations far from equilibrium. This kind of selection was called feedback selection in order to emphasize the difference to theories which consider modifier evolution near the equilibrium. The basic principles of this kind of selection are derived for asexual populations and the problem of dominance is discussed in the light of this concept. In general the results support the view, that the genetic properties of a character are selected along with the character itself.This work was supported by the Austrian Fonds zur Förderung der Wissenschaftlichen Forschung (Proj. Nr. 3502).