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华北蓝盆花的开花特性及传粉生态学研究 总被引:16,自引:2,他引:16
华北蓝盆花具头状花序 ,花冠蓝紫色 ,1朵花的花期约为 7~ 8d。边缘花比中部花大 ,但二者在花药大小、花丝长度、花柱长度、柱头直径等方面无显著差异。花粉寿命约为 4 d,花柱在花开后逐渐伸长 ,柱头微二裂、干燥型。同一花序内的花朵在 2~ 3d内逐渐开放 ,晚开的花散粉时、早开的花花柱仍未伸长 ,因此 ,花药与柱头之间有空间间隔和时间间隔 ,同一花序内的各花朵间相互传粉的机会很低。按照杂交指数 ,其繁育系统属于异交、部分自交亲和、需要传粉者。依据 P/ O数据 ,其繁育系统属于兼性异交。罩网试验显示 ,华北蓝盆花没有自发的自花传粉现象 ,自然条件下也没有无融合生殖现象 ,没有访花者访问便不能座果。在华北蓝盆花花序上记录到的访花者有 10余种 ,以双翅目、鞘翅目、膜翅目昆虫为主 ,最常见的访花者是雏蜂虻和豆芫菁。开花后不同日期 ,访花者的访花频率有所不同 :开花第 2天到第 7天的花序上 ,访花者的访花频率较高 ;开花第 4天 ,花序上访花者的访花频率最高。同一天内的不同时间 ,访花者的访花频率也有差异 ,一般规律是 :11:0 0~ 15 :0 0之间 ,访花者的访花频率较高。此外 ,气温骤降、阴天及降雨能使访花者的访花频率明显降低。 相似文献
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基因组定点编辑技术是研究基因功能和生物体改造的重要工具。CRISPR-Cas(Clustered regularly interspaced short palindromic repeats and CRISPR-associated proteins)系统是近年来发展的一种新型基因组编辑技术,该技术通过一段向导RNA和配套的核酸酶就可对特定的基因组序列进行定点编辑,具有简单高效、应用广泛的特点,受到了生物学家的广泛关注。本文着重介绍CRISPR-Cas系统在植物中的研究进展,包括CRISPR-Cas9系统在植物中的应用与完善、扩大基因组编辑范围的研究、Cas9切口酶和失活酶的拓展、特异性单碱基突变编辑系统的研究、无外源DNA污染的植物基因编辑技术的发展以及基因组编辑技术在作物育种上的应用等方面。同时也提出了还需解决的问题,并展望了基因组编辑系统在作物育种中的应用前景,为开展这一领域的研究工作提供参考。 相似文献
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Transgressive segregation and heterosis are the reasons that plant breeding works. Molecular explanations for both phenomena have been suggested and play a contributing role. However, it is often overlooked by molecular genetic researchers that transgressive segregation and heterosis are most simply explained by dispersion of favorable alleles. Therefore, advances in molecular biology will deliver the most impact on plant breeding when integrated with sources of heritable trait variation – and this will be best achieved within a quantitative genetics framework. An example of the power of quantitative approaches is the implementation of genomic selection, which has recently revolutionized animal breeding. Genomic selection is now being applied to both hybrid and inbred crops and is likely to be the major source of improvement in plant breeding practice over the next decade. Breeders’ ability to efficiently apply genomic selection methodologies is due to recent technology advances in genotyping and sequencing. Furthermore, targeted integration of additional molecular data (such as gene expression, gene copy number and methylation status) into genomic prediction models may increase their performance. In this review, we discuss and contextualize a suite of established quantitative genetics themes relating to hybrid vigour, transgressive segregation and their central relevance to plant breeding, with the aim of informing crop researchers outside of the quantitative genetics discipline of their relevance and importance to crop improvement. Better understanding between molecular and quantitative disciplines will increase the potential for further improvements in plant breeding methodologies and so help underpin future food security. 相似文献
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《Animal : an international journal of animal bioscience》2016,10(11):1749-1759
Agroecology uses natural processes and local resources rather than chemical inputs to ensure production while limiting the environmental footprint of livestock and crop production systems. Selecting to achieve a maximization of target production criteria has long proved detrimental to fitness traits. However, since the 1990s, developments in animal breeding have also focussed on animal robustness by balancing production and functional traits within overall breeding goals. We discuss here how an agroecological perspective should further shift breeding goals towards functional traits rather than production traits. Breeding for robustness aims to promote individual adaptive capacities by considering diverse selection criteria which include reproduction, animal health and welfare, and adaptation to rough feed resources, a warm climate or fluctuating environmental conditions. It requires the consideration of genotype×environment interactions in the prediction of breeding values. Animal performance must be evaluated in low-input systems in order to select those animals that are adapted to limiting conditions, including feed and water availability, climate variations and diseases. Finally, we argue that there is no single agroecological animal type, but animals with a variety of profiles that can meet the expectations of agroecology. The standardization of both animals and breeding conditions indeed appears contradictory to the agroecological paradigm that calls for an adaptation of animals to local opportunities and constraints in weakly artificialized systems tied to their physical environment. 相似文献
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Abstract Some aspects of the pollination ecology of a wild leek ( Allium tricoccum Ait.) population were studied in Gatineau Park, Southern Québec, Canada. Self-compatibility was determined by a pollinator exclusion experiment. Pollinator limitation of seed production was tested by comparing naturally pollinated plants with hand cross-pollinated plants. The insects observed on the umbels were collected for identification. Wild leek was found to be self-compatible. Seed production does not seem to be limited by pollinator activity. An important year to year variability of pollinator activity was observed according to the flowering intensity within the population. 相似文献
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Kenneth J. Locey 《Journal of Biogeography》2010,37(10):1835-1841
The discovery of biogeographical patterns among microbial communities has led to a focus on the empirical evaluation of the importance of dispersal limitation in microbial biota. As a result, the spatial distribution of microbial diversity has been increasingly studied while the synthesis of biogeographical theory with microbial ecology remains undeveloped. To make biogeographical theory relevant to microbial ecology, microbial traits that potentially affect the distribution of microbial diversity need to be considered. Given that many microorganisms in natural environments are in a state of dormancy and that dormancy is an important microbial fitness trait, I provide a first attempt to account for the effects of dormancy on microbial biogeography by treating dormancy as a fundamental biogeographical response. I discuss the effects of dormancy on the equilibrium theory of island biogeography and on the unified neutral theory of biodiversity and biogeography, and suggest how the equilibrium theory of island biogeography can produce predictions approaching those of the Baas‐Becking hypothesis (i.e. everything is everywhere, but the environment selects). In addition, I present a conceptual model of the unified neutral theory of biodiversity and biogeography, generalized to account for dormancy, from which a full model can be constructed for species with or without dormant life history stages. 相似文献
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银耳是一种经济价值很高的食用菌,又是我国医学中一种久负盛名的药用真菌.我国的银耳研究凝聚着几代菌物学家和科技人员的心血和汗水,在银耳纯菌种的分离培养、生活史、生态系、遗传育种、分子生物学及人工栽培等研究方面,经过艰苦的努力和富于创意的探究,终于取得了诸多颇有分量的科研成果,推动了生产力的大发展,创造了显著的社会效益和经济效益.回顾中国银耳的研究历程,我国的菌物学科研工作者,特别是菌物学的前辈们,在缺资金、缺设备的艰苦条件下,始终坚持科研与生产实际紧密结合,取得了一个又一个辉煌的成果.是我们学习的楷模,将激励着我们在科学发展的道路上锐意进取,开拓创新! 相似文献