转基因作物对环境影响的讨论

随着转基因作物的不断推广，转基因作物对环境的影响受到越来越多的关注，其中包括转基因作物潜在的侵袭力，基因漂移，对生物多样性的冲击，对农业生产的影响等等。这些议题具有跨学科性和高度的复杂性，要正确评价它们，就必须设定一个合适的标准作为参照。通过传统育种方法培育的新品种对环境的影响成为最合适的参照，这些新品种被广为认可，是现代农业重要的组成部分。在许多实例当中。转基因作物对环境的影响与通过传统育种方式所得到的新品种对环境的影响非常相似。通过比较对转基因作物进行恰当评价，会使植物转基因技术更好的发挥作用。     

The potential use of self-incompatibility for breeding F1 hybrids of naturally self-pollinated vegetable crops

Summary The available evidence indicates that F₁ hybrid varieties of most naturally self-fertilized crops have potentially great economic value. The main deterrent to their wider use is the present high cost of seed production. This can be greatly reduced by breeding into these crops systems for controlled cross-fertilization. In those crops whose flowers lack nectaries (e.g. tomatoes and lettuce), self-incompatibility appears to offer a more efficient cross-fertilizing system than male sterility. Self-incompatibility systems are already available in species of tomatoes, lettuce and beans. The prospect of finding self-incompatibility in other species closely related to the remaining self-fertilized crops appears to be good. Besides introducing self-incompatibility into self-fertilized crops, the breeder also needs to introduce an efficient system of pollen transfer between plants.Paper No. 1574 of the Colorado State University Experiment Station     

Crop sequence,crop protection and fertility management effects on weed cover in an organic/conventional farm management trial

A survey of 128 plots, in 2008, of a trial where the effects of crop protection can be separated from those of fertility management, generated weed cover data within six crops (winter wheat, winter barley, spring barley, potatoes, cabbages and a grass/clover ley). The effects of the 2008 crop types, of the two preceding crops and of organic and conventional crop protection and fertility management, were assessed using mixed-effects models and constrained ordination. Cover data for 22 weed species and for monocotyledon, dicotyledon, annual, perennial and total weed cover were used. Cover of 15 weed species, and of the five weed groups, was significantly affected by 2008 crops, with cover highest in spring beans and cabbage. Nine and four weed species 2008 cover were significantly related to crops grown in 2007 and 2006 respectively, as were dicotyledon, annual and total weed cover, but not monocotyledon or perennial cover. Cover of 15 species, and the five groups, was significantly higher in plots with organic crop protection, but only eight species and annuals were significantly affected by fertility management. Crop:crop protection produced the most significant interactions with most cover in organically managed plots. Five species, perennials and total weed cover produced significant three-factor models. The greatest weed cover was in organic crop protected but conventionally fertilised spring barley and the least in totally conventional winter barley. Other factors such as crop density and mechanical weeding also affected 2008 weed cover. The ordination indicated that most of the 22 species were strongly associated with crops from all three years. The sequence of crops in the rotation had a profound effect on weed cover. Where three spring-sown, difficult to weed, crops were grown in sequence (spring beans, potatoes and vegetables, spring barley) weed cover increased. However, cover was limited in grass/clover and some cereal plots with different preceding crops. Models predicting weed cover may need to take into account crop sequences within crop rotations, as well as the more usual management inputs.     

蓝剑(Echium vulgare)不同部位浸提液对5种常见大田作物种子萌发的化感效应

为探讨蓝剑(Echium vulgare)对本地大田作物是否产生化感效应,本研究以生物测定方法研究蓝剑根、茎、叶3部分的无水乙醇浸提液和水浸提液对玉米、水稻、小麦、花生和大豆5种大田作物种子萌发过程的影响。结果表明:叶的化感作用最为明显,豆科对浸提液的响应比禾本科敏感,无水乙醇浸提液和水浸提液对禾本科影响有差异。综合分析,可以判断外来种蓝剑可与本地大田作物产生较为明显的化感作用,具有一定竞争关系。可初步判断蓝蓟对常见的5种大田作物的竞争力,对大田作物合理的间混套作提供一定的科学依据。     

气候变化对中国油料作物的影响研究进展

油料作物是中国重要的粮食作物,对气候变化十分敏感。目前中国食用油自给率较低,存在严重的供需矛盾,油料安全是中国粮食安全中最为薄弱的环节。近年来气候变化也对中国油料作物生产带来了显著影响,因此如何客观准确地评价气候变化对中国油料作物生产的影响,对提高中国食用油自给率、保障粮油安全具有重大意义。综述了气候变化对中国三大主要油料作物（花生、大豆、油菜）影响的相关研究,概括了主要的研究方法和气候变化对油料作物的生长发育及产量、品质以及种植制度的影响,并据此讨论了研究中存在的不足和未来展望。     

利用抗、染根肿病F_2群体构建大白菜AFLP遗传连锁图谱

以易感染根肿病的大白菜(Brassica campestris ssp.pekinensis)自交系94SK和抗根肿病的CR Shinki DH系为亲本,通过杂交获得F1,并选择一株F1植株进行自交,构建了F2作图群体.利用扩增出与根肿病抗性基因CRb连锁标记的17对AFLP引物组合Pst+GNN/Mse+CNN构建大白菜遗传连锁图谱.这些AFLP引物组合共扩增出322个亲本间表现出多态性的AFLP标记.应用其中6个与CRb基因紧密连锁的AFLP标记转化成的SCAR标记和清晰可见的大于100 bp的211个AFLP标记构建了一张包含179个标记位点、10个连锁群、覆盖长度为576 cM,平均图距3.3 cM的遗传图谱.抗根肿病基因CRb定位在第一条连锁群9 cM的范围内.研究表明,利用Pst/Mse Ⅰ和EcoR Ⅰ/Mse Ⅰ引物组合以及其他分子标记类型构建遗传连锁图谱,并有效减少遗传图谱中聚集和间隙现象的产生提供了一定的科学依据.同时,该图谱的构建对在基因组范围内通过分子标记辅助选择选育大白菜根肿病抗性品种奠定了基础.     

Comparison of rye,triticale, durum wheat and bread wheat genotypes for Fusarium head blight resistance and deoxynivalenol contamination

Small-grain winter cereal crops can be infected with Fusarium head blight (FHB) leading to mycotoxin contamination and reduction in grain weight and quality. Although a number of studies have investigated the genetic variation of genotypes within each small-grain cereal, a systematic comparison of the winter crops rye, triticale, durum and bread wheat for their FHB resistance, Fusarium-damaged kernels (FDK) and deoxynivalenol (DON) contamination across species is still missing. We have therefore evaluated twelve genotypes each of four crops widely varying in their FHB resistance under artificial infection with one DON-producing F. culmorum isolate at constant spore concentrations and additionally at crop-specific concentrations in two environments. Rye and triticale were the most resistant crops to FHB followed by bread and durum wheat at constant and crop-specific spore concentrations. On average, rye accumulated the lowest amount of DON (10.08 mg/kg) in the grains, followed by triticale (15.18 mg/kg) and bread wheat (16.59 mg/kg), while durum wheat had the highest amount (30.68 mg/kg). Genotypic variances within crops were significant (p ≤ .001) in most instances. These results underline the differing importance of breeding for FHB resistance in the different crops.     

苜蓿-玉米-小黑麦“草粮兼顾”型种植模式产量及经济效益分析

针对苜蓿生产中存在的问题,为了提高农业产能和经济收益,本研究提出并初步阐述了苜蓿-玉米-小黑麦"草粮兼顾"型种植模式,通过裂区试验设计,以苜蓿种植行数为主处理,以玉米/小黑麦种植行数为副处理,探讨3种作物不同的种植搭配方式对产量和经济收益的影响,并试图通过产量分析简单阐明不同作物的竞争关系。结果表明:苜蓿5行,玉米2行,小黑麦4行的种植模式下3种作物的时空搭配最为合理,利于作物间互相促进,尽量减少种间竞争带来的损失,产量和经济收益最佳。     

Traditional maintenance breeding of landraces: 1. Data by crop

Examples of the methods of traditional maintenance breeding of several crops, cited in literature, are presented. It is concluded that, although crops are grown all over the world, only few examples are sufficiently described. Only for maize some reliable data are available. Three explanations for this small number are 1. the farmers are not aware of their knowledge of growing crops (including traditional maintenance breeding), 2. the interviewers and other scientists are not acquainted with this farmer's knowledge, or 3. most farmers do not actually perform traditional maintenance breeding, as they and their ancestors probably have experienced that traditional maintenance breeding does not result in a better crop. They must have thought that seed replacement was a better method to maintain the yielding capacity of their crops. This revised version was published online in July 2006 with corrections to the Cover Date.     

大豆耐低磷胁迫研究进展

磷是作物生长发育不可缺少的营养元素之一,但它在土壤中有效性是非常低的.缺磷是限制目前农业产量的一个重要因子,传统的农业生产主要通过施肥和土壤改良来满足植物对磷的需求,近年来人们开始发掘磷高效利用植物来替代传统方法提高磷的利用效率.在缺磷胁迫下,植物会产生一系列的包括根系形态及生理方面的适应性变化.本文综述了低磷胁迫对大豆根系、光合作用等影响的研究进展,大豆耐低磷胁迫的遗传学研究进展,以及讨论当前大豆磷效率遗传研究中存在的主要问题.     

Proximal optical sensing of cucumber crop N status using chlorophyll fluorescence indices

Sustainable N management of intensive vegetable crops requires accurate and timely on-farm assessment of crop N status. Proximal fluorescence-based sensors are promising tools for monitoring crop N status, by providing non-destructive optical measurements of N-sensitive indicator compounds such as chlorophyll and flavonols. The ability of the Multiplex^® fluorescence sensor to determine crop N status was evaluated in two indeterminate cucumber crops grown in contrasting seasons (autumn and spring). Three fluorescence indices, leaf chlorophyll (SFR) and flavonols (FLAV) contents, and their ratio (Nitrogen Balance Index, NBI) were evaluated, and their consistency between the two crops compared. Actual crop N status was assessed by the Nitrogen Nutrition Index (NNI), calculated as the ratio between the actual and the critical crop N contents (i.e., the minimum N content for maximum growth). There were strong relationships between each of SFR, FLAV and NBI with crop NNI, for most weekly measurements made throughout the two crops. For the three indices, coefficients of determination (R²) were mostly 0.65–0.91 in the autumn crop, and 0.71–0.99 in the spring crop. SFR values were generally comparable between the two crops, which enabled the derivation of common relationships with NNI for individual phenological phases that applied to both cropping seasons. FLAV and NBI values were not comparable between the two crops; FLAV values were appreciably higher throughout the spring crop, which was attributed to the higher solar radiation. Consequently, phenological relationships of FLAV and NBI with NNI were established for each individual cropping season. Our findings suggested that SFR was the most consistent index between cropping seasons, and that NBI was the most sensitive index within each season. Regardless of the index and crops, all fluorescence indices were weakly related to crop NNI during the short vegetative phase while stronger relationships were found in the reproductive and harvest phases. This study also showed that the three fluorescence indices were sensitive to and able to distinguish deficient from optimal crop N status, but that they were insensitive to discriminate optimal from slightly excessive N status. Overall, this study demonstrated that fluorescence indices of chlorophyll content (SFR), flavonols content (FLAV) and nitrogen sufficiency (NBI) can be used as reliable indicators of crop N status in cucumber crops; however, there was variability in FLAV and NBI values between cropping seasons and a lack of sensitivity in the range of optimal to slightly excessive crop N status.     

后基因组时代下作物的SNP分型方法

单核苷酸多态性(single nucleotide polymorphisms,SNPs)是生物体最普遍的一种多态差异,在植物功能基因组研究和作物遗传改良方面有着广泛的应用。利用全基因组水平SNP标记谱进行遗传变异的研究、群体结构分析、关联性分析、作物分子设计育种,以及对大规模SNP数据进行验证、评估等,都迫切需要发展和利用各种不同的SNP分型手段实现。本文综述了目前常用的一些SNP分型方法,简要介绍了检测原理及操作流程,并对后基因组时代下作物的高通量SNP数据的分析进行了讨论。     

Screening for resistance to black rot in a Spanish collection of Brassica rapa

Productivity and quality of crops of Brassica rapa L. in north‐western of Spain are highly affected by black rot, caused by the bacterium Xanthomonas campestris pv. campestris (Pammel) Dowson (Xcc). Several races of Xcc have been described in this area, being the race 6 the most frequent in B. rapa crops and races 1 and 4 the most frequent in B. oleracea crops. The control of the disease can be aided by the employment of resistant varieties. The aim of this work was to find sources of resistance to Xcc in a collection of open‐pollinated varieties of B. rapa from north‐western Spain. Resistance was evaluated in 191 landraces. Partial resistance to races 6, 1 and 4 and complete resistance to race 4 were identified in several landraces. Several accessions exhibited partial resistance to the three races. Sources of resistance were identified in landraces of different crops of the species (turnips, turnip greens and turnip tops). These landraces could be grown after selection for resistance or they can be donors of resistance genes in breeding programmes.     

作物对干旱胁迫的响应机制及提高作物抗旱能力的调控措施研究进展

干旱是影响作物生长发育和产量的最主要非生物胁迫之一,在气候变化背景下,作物遭受干旱胁迫的风险越来越大。为了应对干旱,作物表现出一系列的抵御机制,包括形态特征和生理生化（抗氧化酶、渗透调节物质、内源激素）特性改变。本研究从上述2个方面总结了作物对干旱胁迫的响应机制,并对提高作物抗旱能力的调控措施进行了论述,主要包括：（1）筛选抗旱性品种,促进对深层土壤贮水的吸收利用;（2）地面覆盖,有利于降低土壤蒸发,增加土壤含水量;（3）节水灌溉技术,如微喷灌、滴灌等灌溉方式能实现少量多次灌溉,根区局部灌溉有利于调节气孔关闭,减少奢侈蒸腾,降低土壤蒸发;（4）抗蒸腾剂,在作物枝干及叶面表层形成超薄透光的保护膜,抑制作物水分过度蒸腾;（5）植物生长调节剂,调控植物生理代谢,增强抗旱性;（6）纳米肥料,改变作物生理生化反应,促进植株生长发育;（7）生物炭,有利于土壤通气保水,改善土壤的物理性质和土壤的持水能力。本研究系统地对以上7种措施提高作物抗旱能力的作用机理、应用前景及存在问题进行了论述,以期为应对干旱胁迫提供理论依据和技术参考。     

Light competition for invasive species control: A model of cover crop–weed competition and implications for Phalaris arundinacea control in sedge meadow wetlands

Summary Since resource competition plays a critical role in many plant invasions, controlling invasive vegetation may require managing the supply of limiting resources. For example, lowering light availability with a cover crop might prevent invasions during community establishment in light-limited restored ecosystems. However, most cover crops evaluated for invasive species control either do not adequately suppress invasives or equally suppress desired species. To improve our ability to predict cover crop effectiveness, we use a theoretical model of plant competition to identify potential mechanisms by which cover crops might favor desired species over invasives. In addition, we consider the model's implications for controlling an invasive forage, Phalaris arundinacea, in restored sedge meadows. The model suggests that cover crops will improve the outcome of competition between desired and invasive species only when (1) desired species have lower minimum light requirements than invasive species and (2) invasive species dominance results from rapid establishment and resource preemption. Cover crops in the model favor desired species over faster-growing invasives because faster-growing invasives are positioned higher in the canopy. Invasive species higher in the canopy shade desired species more than desired species shade invasives. Consequently, by reducing invasive species biomass, cover crops give desired species a competitive advantage. The simple requirements for cover crop success in the model suggest that cover crops may be effective for invasive species control in light-limited restored ecosystems. The available information on P. arundinacea responses to shade suggests, however, that cover crops are unlikely to favor sedge meadow species over P. arundinacea.     

玉米与旱地作物间作套种研究进展

玉米是重要的谷类作物之一,其丰产与否将对中国的粮食安全起着举足轻重的作用。实践证明,作物合理的间作套种具有充分利用资源和大幅度增加产量的特点。本文总结了旱地种植玉米与豆科作物、小麦、蔬菜以及其他一些旱地作物的间作套种的研究进展及一些实施成效。通过文献综合分析得出,玉米与旱地作物间作或套种的生产模式与单作栽培模式相比,不仅有利于提高作物产量与品质,而且有利于提高资源利用率。提出如何拓展与深化系统研究,着力构建技术体系与栽培标准,无疑是至关重要的,并且认为要将研究成果转化为能够应用于大面积实际生产的技术规范和栽培方法,服务于当今现代旱地农业生产是必要的也是亟待要探讨的。     

Analysis of Water Supply of Plants Under Saline Soil Conditions and Conclusions for Research on Crop Salt Tolerance

Abstract In the dry areas of the world there is an increasing pressure to apply low quality brackish waters for plant irrigation (agriculture, horticulture, landscape greening). Consequently there is a demand to improve salt tolerance of conventional crops and to develop adequate irrigation techniques too. The efforts in the past decades to approach the understanding of salt stress mechanism by focusing on biochemical and physiological research were disappointing with respect to progress for crop growth and yields under saline soil conditions. However, it is generally agreed by all disciplines involved in research for crop salt tolerance that under saline soils conditions the reduced water supply of crops is the most critical growth factor. The paper presents some model calculations and field investigations that demonstrate the effect of root water uptake on the salinity of the root surrounding soil fraction (rhizospheric soil). It is shown that root hair length and rhizospheric soil volumes are factors most relevant for understanding crop salt tolerance, when growing in soils. It is postulated that short root hairs contribute to a lower salt tolerance (onions), whereas long root hairs enhance water uptake from saline soils and crop salt tolerance (rape). As interactions between roots and soil contribute to the salt tolerance of crops under field conditions, it is doubtful that selection for salt tolerant varieties and breeding for salt tolerance under conditions of water and flow culture experiments is very efficient. Breeding for more salt-tolerant crops and brackish irrigation techniques should consider root morphology and soil/root contact zone.     

转BADH基因苜蓿T-DNA侧翼序列分析及转化事件特异性分析

为了从分子水平上鉴别不同的转基因株系,以转BADH基因苜蓿的T₀代基因组DNA为模版,采用热不对称交错PCR(TAIL-PCR)方法分离其外源基因插入位点的侧翼序列,获得了B127株系的左翼序列和右翼序列,以及B125、B138、B295和B196株系的左翼序列。侧翼序列特征分析表明,有的T-DNA边界序列被删除,有的边界序列被保留,并填充了一段未知来源的核苷酸序列。根据侧翼序列中插入载体序列和紧邻插入序列的基因组序列特征,分别设计PCR扩增的上、下游引物,并对获得的42个转BADH株系分别进行左、右翼序列的扩增,结果表明,转基因植株B106、B125、B138、B157、B158、B289、B295、B305和B127具有相同的扩增条带,B203、B220、B223和B196具有相同的扩增条带,说明这些株系可能仅来源于2个转化事件。本研究建立的事件特异性检测方法可以准确地将不同的转化株系区别开来。     

Study on Absorption Distribution of Rare Earth Elements in Crops With Rare Earth Fertilizer

The absorption and content distribution of 5REs (La,Ce,Nd,Y and Gd) in 3species of crops (corn,paddy and soybean )have been studied. The results show that there exists the positive relationship between capability of rare earth elements being absorbed by crops and available rare earth elements in soil. Generally,content distribution of rare earth elements in crops are root >leaf >stem >fruit. Distribution of unitary rare earth elements in root is La>Ce>Nd>Y>Gd,and in leaf ,stem and fruit is Ce>La>Nd>Y>Gd. It is proved that light rare earth elements absorbed are easier than heavy rare earth elements. In addition ,capability of rare earth elements absorbed in crops growing is seedling >ramification >maturity . In a word,the data of pot experiment show that most of bioaccumulation in root . Thus, it is helpful to agricultural application of rare earths.     

基因组编辑技术在作物育种中的应用及监管现状

随着基因组编辑技术的迅猛发展,CRISPR/Cas9 系统已经成为农作物改良的最主要手段之一。为给中国未来可能出现的,商业化应用的基因编辑作物的监管工作提供参考,本文简要归纳了目前运用CRISPR/Cas9 技术培育农作物的现状,总结了基因编辑技术在作物改良中的典型成功事例,分析了各国政府对于基因编辑作物的监管态度,并指出中国科学家应在此次革命中迎头赶上。