野生稻与栽培稻的杂种后代对褐稻虱的抗性机制初探

为了开拓抗虫基因源,培育抗性稳定的水稻抗虫品种,采用感虫的栽培稻雄性不育株为母本,以高抗褐稻虱的野生稻为父本进行有性杂交。通过用改良的苗期群体筛选法,对其后代进行抗性鉴定,证实其抗性可以遗传,已成功地获得了抗褐稻虱的杂种后代。并根据飞虱在抗虫植株上的生存率、群体建立、蜜露量和稻株的受害级别等指标与感虫对照种TN1上的差异显著性作比较,综合评定杂种后代对褐稻虱的抗性机制。结果表明,测试的N482(A)/101392组合的F_5、F_6、F_7和H_4等几个后代对褐稻虱的抗性机制均为抗生性。     

菜心对邻苯二甲酸酯(PAEs)吸收途径的初步研究

采用玻璃室处理和污染土壤覆盖原土壤来控制PAEs来源进行盆栽试验，应用GC/MS联机检测技术初步研究了菜心对PAEs的吸收途径。结果表明：污染土壤处理与污染土壤上覆盖原土壤处理相比，前者菜心茎叶中DBP和DEHP的含量均高于后者，但相差不大，表明菜心茎叶可以吸收污染土壤中挥发出来的DBP和DEHP，而根系吸收运移是菜心茎叶中DBP和DEHP的主要来源途径。玻璃室处理增加了菜心茎叶和根系中DBP的含量，而对DEHP的影响趋势不明显。DBP与DEHP相比，前者更易被菜心根系吸收并向地上部(茎叶)运移，后者主要滞留在根部。     

作物连作障碍的产生及防治

阐述作物连作障碍的定义,总结了作物连作障碍的发生原因和防治措施,并展望了今后的研究方向。     

优质高产玉米新品种郑农7278综合分析

玉米是河南省重要的粮、饲、经及加工原料作物,以掖单13、农大108、豫玉22为代表的第五次玉米新品种的更新换代对河南省玉米生产起到了积极     

小麦黑胚病抗性遗传研究进展

小麦黑胚病病因复杂,链格孢（Alternaria alternata）、麦根腐平脐蠕孢（Bipolaris Sorokiniana）、层出镰刀菌（Fusarium proliferatum）等多种真菌是引起小麦黑胚病的主要病原。有限的研究报告显示,小麦对黑胚病的抗性具有数量性状特征,QTL定位研究尚处于初级阶段。目前报道的小麦抗黑胚病QTLs位于1D、2A、2B、2D、3D、4A、5A、7A等多条染色体上。小麦第2部分同源群携带了较多抗病QTLs,与这些QTLs连锁的分子标记有gwm319(2B)、gwm341(3DS)和wmc048(4AS)等,但是还没有见到这些标记在抗小麦黑胚病新品种培育中应用的报道。综上所述,针对目前小麦黑胚病抗性遗传研究中缺乏准确的抗性鉴定方法和病原不清导致的QTL定位结果不可靠的问题,应在明确病原菌的情况下,采取可靠的接菌鉴定方法进行QTL定位研究并开发分子标记,以期辅助抗黑胚病株系的选择。     

Arbuscular mycorrhizal-like fungi and glomalin-related soil protein drive the distributions of carbon and nitrogen in a large scale

Purpose

Arbuscular mycorrhizal-like fungi (AM-like fungi) are crucial for ecosystem functioning and soil organic matter (SOM) is an indicator of soil quality. However, the spatial distribution of arbuscular mycorrhizal-like fungi, glomalin-related soil protein (GRSP) and SOM in a large scale is still unclear. The objectives of this study were to investigate the spatial distribution of SOM, arbuscular mycorrhizal-like fungi and GRSP, and reveal the potential relationship among them in a large scale across China.

Materials and methods

Soil samples (different in vegetation type, climate, and soil variables) were collected from 26 sites in a large scale across China. The soil properties including pH, total carbon (TC), total nitrogen (TN), and SOM were determined. Quantitative PCR amplification of the 18S rRNA gene was conducted to evaluate the abundance of arbuscular mycorrhizal-like fungi. The contents of easily extractable GRSP (EE-GRSP), difficultly extractable GRSP (DE-GRSP), and total GRSP (T-GRSP) were measured.

Results and discussion

Arbuscular mycorrhizal-like fungi abundance was significantly affected by the vegetation type and dramatically correlated with the soil TN and mean annual precipitation (MAP). EE-GRSP and DE-GRSP were more associated with the TC and TN content, respectively. The abundance of arbuscular mycorrhizal-like fungi significantly but weakly correlated with the T-GRSP and EE-GRSP. The SOM content positively correlated with the DE-GRSP and T-GRSP. Those results suggested that the arbuscular mycorrhizal-like fungi are a larger contributor to regulating the content of GRSP, which is an important indicator of the soil organic carbon pool.

Conclusions

Our results indicated that arbuscular mycorrhizal-like fungi abundance has a greater contribution to driving the distribution of soil C and N in a large scale by affecting the content of glomalin-related soil protein.

     

湖南省普通高校生均成本的探讨Ⅰ.生均成本现状的调查与分析

为了解湖南省高等教育经费投入与高校生均支出成本之间的关系,对1985,1993,1994和1995年4个年度湖南省属8所高等学校的生均支出成本和办学条件等基本情况进行了调查和分析.结果表明,在1985～1994年年间,湖南省高等学校得到了较快发展,规模效益也有了明显提高.但是,由于政府对高等教育的投入不能满足办学的需要,加之本科办学规模扩大过快,导致了本科院校办学条件的逐年下降.     

Identification and mapping of a novel Turnip mosaic virus resistance gene TuRBCS01 in Chinese cabbage (Brassica rapa L.)

We aimed to identify Turnip mosaic virus (TuMV) resistance genes in Chinese cabbage by analysing the TuMV resistance of 43 P₁ (resistant), 88 P₂ (susceptible), 26 F₁, 104 B₁ (F₁ × P₁), 108 B₂ (F₁ × P₂) and 509 F₂ individuals. All parents and progeny populations were mechanically inoculated with TuMV‐C4. Both F₁ and B₁ populations showed TuMV resistance. Resistant: susceptible ratios in the B₂ and F₂ populations were 1 : 1 and 3 : 1, respectively. TuMV resistance in P₁ was controlled by a dominant gene, TuRBCS01. Bulked segregation analysis was performed to identify simple sequence repeat or insertion or deletion markers linked to TuRBCS01. Data from 108 B₂ individuals with resistant or susceptible phenotypes were analysed using mapmake r/exp 3.0. Polymorphic marker sequences were blast searched on http://brassicadb.org/brad/ . TuRBCS01 was found to be linked to eight markers: SAAS_mDN192117a_159 (3.3 cM), SAAS_mDN192117b_196 (4.0 cM), SAAS_mDN192403_148 (13.0 cM), SAAS_mGT084561_233 (6.8 cM), BrID10723 (3.3 cM), mBr4041 (3.3 cM), SAAS_mBr4055_194 (2.6 cM) and mBr4068 (4.0 cM). Further, TuRBCS01 was mapped to a 1.98‐Mb region on chromosome A04 between markers BrID10723 and SAAS_mBr4055_194.     

Composition and transformation of 1.4 nm minerals in cutan and matrix of alfisols in central China

Background, Aims, and Scope  Hydroxy interlayered vermiculite (HIV) and vermiculite are commonly referred to as 1.4 nm minerals. In the subtropical soils of central China, the concentration of vermiculites decreased while that of HIVs increased gradually from north to south as the intensity of soil formation or eluviation increases in the same direction. The cutans in these soils closely interact with air, roots, microbes, water and dissolved ions in soils. Cutans may therefore be expected to exert an important influence on the formation of 1.4 nm minerals relative to the matrix soils. However, little is known about the transformation of 1.4 nm minerals in Alfisols in central China. Here, we investigate the compositional differences of 1.4 nm minerals in cutans and matrix soils, and the probable transformation of vermiculite to HIV or vice versa when sodium citrate and sodium acetate are added to matrix Alfisols. Methods  Cutans and matrix soils were separated from three soils in the northern subtropical zone in China. The samples were analyzed for Fe, Mn, exchangeable cations, organic matter(O.M.), pH, and clay minerals. To 10 mL of matrix soil, suspensions containing about 250 mg (oven-dry weight) of clay was added with 5 mL of 0.4 mol/dm³ or 2 mol/dm³ of sodium citrate or sodium acetate solution and 5 mL of 0.2 mol/dm³ mixed solutions of CaCl₂, Mg(NO₃)₂ and KCl. After its pH was adjusted to 6.0, the mixture was ‘incubated’ for 120 or 210 days (more than one season or half a year) during which period it was shaken for 1 hour every day. The clay mineral composition of the samples was determined after incubation. Results  Both vermiculites and HIVs were present in matrix soils, but only vermiculties were detected in cutans. The addition of organic ligands (citrate and acetate) promoted the transformation of HIV to vermiculite. This transformation was obvious for the matrix soils that had been incubated with 0.5 mol/dm³ sodium citrate for 210 days while sodium acetate was less effective in this regard. The promoting effect of organic ligands is dependent on type and concentration as well as incubation time. This would suggest the reverse transformation occurred in the formation of cutans compared with a vermiculite-to-HIV transformation in the subtropical soils of central China from north to south. Discussion  The position and environment of cutans in the B horizon together with the pH, organic matter and exchangeable base status in cutans seem conducive to the co-existence of vermiculite and HIV in the soils, but only vermiculite is found in cutans. The transformation of HIV to vermiculite in incubation experiments could be divided into two steps: 1) Cheluviation of organic matter to the interlayer hydroxy-aluminums from HIVs. 2) Rebasification of hydrated cations into the interlayers of vermiculites. Conclusions  The clay minerals in cutans can interact with organic ligands and nutrient elements excreted by roots. Under conditions of frequent wetting and drying and high pH, and when the concentrations of exchangeable bases, iron-manganese oxides, clays, and organic matter are high, the exchangeable cations can be incorporated into the interlayers of HIV, thereby promoting the partial transformation of HIV to vermiculite in rhizosphere soils. Recommendations and Perspectives  Cutan is at the interface of material and energy exchange involved in physical, chemical and biochemical reactions in the rhizosphere. These factors strongly affect the compositions of cutans. HIVs in (upper or adjacent) matrix soils may transform to vermiculites during cutan formation in these special soil environments. ESS-Submission Editor: Jizheng (Jim) He (jzhe@rcees.ac.cn)     

郑单22玉米不同种植密度对产量的影响

通过不同种植密度对郑单22生长发育及产量影响的研究,郑单22单株叶面积和单株干物质积累量随密度增大而减小。群体叶面积系数和干物质积累量随密度增大而增加,达到一定种植密度后而下降,产量随密度加大而增加,结果表明,郑单22的适宜种植密度为45000~52500株/hm2。