农杆菌──植物间基因转移的分子基础

植物病原细菌多以Ⅲ型分泌系统运送毒性因子或无毒基因产物到植物细胞，但根癌农杆菌利用 ＩＶ型分泌系统转移致瘤基因片断 Ｔ—ＤＮＡ到植物细胞核，并整合到植物基因组，使植物产生肿瘤。作 者将介绍加ｖｉｒ基因的诱导、Ｔ－ＤＮＡ的加工、Ｔ－ＤＮＡ的转移，以及 Ｔ－复合体运输的装备等方面的最 新研究进展，以探讨农杆菌－植物间基因转移的分子基础。研究该系统转移基因的分子基础将有利于开 发和改良植物遗传工程的载体工具；另外，农杆菌－植物作为－种模式植物病害系统，其研究也为植物-病原菌的基础理论研究提供参考。由于有些人体病原细菌也采用ＩＶ型分泌系统运送毒性因子到人体细 胞，研究农杆菌－植物间的基因转移系统也有利于医学研究。

农业植物病理学实验课的双选模式研究型探索

近年来,各高校农学专业逐渐重视对创新型、实用型人才的培养,秉承“以生为本”的教学理念,通过对实验内容和实验方法的改进从而实现“双选模式”教学。同时,在农业植物病理学实验课程当中,还对研究型教学方式进行了探索。结果显示,“双选模式”研究型教学方式在这课程中的应用具有不错的效果。为此,本文对双选模式研究型教学在农业植物病理学实验课的应用以及其成效进行分析。

紫色丘陵区蓑草植物篱的减流减沙效应及其机理

四川盆地紫色丘陵区位于长江上游，是我国土壤侵蚀最重要的地区之一，土壤侵蚀速率高达每平方公里每年3200—7900t。该区域是四川省和重庆市的重要粮食生产基地，人口密集。高垦殖、高复种，高强度的土地利用不仅造成严重的水土流失，而且制约了区域农业和农村经济的可持续发展。应用植物篱农作系统改善土壤抗侵蚀环境，减少水土流失是紫色丘陵高垦殖生态脆弱区生态环境建设的重要内容。蓑草根系发达，地上部生物量大，对土壤的覆盖保护好，且其生长盛期与降雨高蜂同步，具有显著的水土流失防治效果。在120cm×90cm土体内，蓑草根系总长98714．8cm，相当于缠绕整个土体235圈，正是根系的这种缠绕固结作用显著提高了土壤抗侵蚀的能力。蓑草根系平均直径0．20—0．50mm，95％的根系平均直径小于0．40mm，根系总表面积10139．68cm^2．在土壤表层根系表面积高达土体表面积的2～3倍，根系表面对土壤颗粒的巨大吸附作用是蓑草显著提高土壤抗侵蚀能力的另一个重要原因。2003—2004年的监测结果表明，在12度坡度情况下，坡改梯后净作蓑草（PECC）年径流量仅为49．90m^3／hm^2，年土壤流失量为155．78kg／hm^2。而未坡改梯且农作（FNC）情况下，年径流量314．29m^3／hm^2为前者的6．30倍，年土壤流失量3322．50kg／hm^2为前者的21．33倍；在24度坡度情况下，坡改梯后土埂及边坡种植蓑草、坡面农作（PERBC）年径流量248．04m^3／hm^2。年土壤流失量612．00kg／hm^2，坡改梯后净作蓑草（PECC）径流量42．44m3／hm^2，土壤流失量153．75kkg／hm^2，而未坡改梯且农作（FNC）情况下年径流量高达785．73m^3／hm^2，分别为处理1的3．17倍，处理2的18．52倍，年土壤流失t高达37503kg／hm^2。分别为处理1的61．33倍。处理2的244．12倍。

基于改进的BP神经网络水果生长气候的数据清洗方法研究

农植物生长环境受多种指标的影响,为了切实地清洗数据和对农植物未来进行准确地预测,必须对数据进行准确的清洗,采用改进Levenberg-Marquardt算法(L-M BP神经网络算法),同时增加用隐节点数优化来改进BP神经网络算法,来减低迭代次数和加快约束速率。本研究采用该算法来建立数据清洗模型,首先对样本进行预处理,对建立的异常数据进行训练和得到的结果反复验证,得到的误差控制在3.0%以内,且模拟的网络值能真实反应的变化趋势。该模型适用对农植物生长气候异常数据清洗数据和预测。

Application of Biological Pesticides in Medicinal Plants

At present, the excessive application of traditional chemical pesticides, serious pesticide residue pollution and destruction of the ecological balance in China have become important factors affecting the quality and safety of medicinal material. Biological pesticides are rapidly developed due to their characteristics of high efficiency, low toxicity and residue. This study aimed to introduce the specific property of biological pesticides, review the classification of biological pesticides and their application in medicinal plants, analyze the problems in the production and utilization process of biological pesticides, and forecast the developmental prospect.

A multi-objective fuzzy optimization model for cropping structure and water resources and its method

Cropping structure has a close relationship with the optimal allocation of agricultural water resources. Based on the analysis of the relationship between agricultural water resources and sustainable development, this paper presents a multi objective fuzzy optimization model for cropping structure and water allocation, which overcomes the shortcoming of current models that only considered the economic objective,and ignored the social and environmental objectives. During the process, a new method named fuzzy deciding weight is developed to decide the objective weight. A case study shows that the model is reliable, the method is simple and objective, and the results are reasonable. This model is useful for agricultural management and sustainable development.

Comparative Study on the Structural and Moisture Characteristics of Leaf from the Plantlets of Three Types of Ornamental Lilium brownii

[ Objective] The study was to compare the structural and moisture characteristics of leaf from the plantlets of three types of omamental lily（ Lilium brownii）. [ Method ] The paraffin sections of leaves of tested lily varieties were prepared and then observed under microscope, and the stomatal characteristics and moisture characteristics of tested lily varieties were measured. I Resaltl All the three ornamental lily varieties show isobilateral leaf, single layer of epicuticula and lower epidermis, and no obvious differentiation of palisade tissue and spongy tissue; their stomata distribute in lower epidermis, and the guard cells are dumbbell-shaped; all of these matedais present high moisture. For the leaf sick- ness, midrib sickness and mesophyll tissue sickness, the order was determined to be oriental lily 〉 Lilium/ongiflorum 〉 Asian lily; of the three types of ornamental lily, Ulium Iongiflorum has the largest stomatai aperture and Asian lily has the smallest; focusing the water potential and moisture, the turn was Asian lily 〉 oriental lily 〉 Lilium Iong＇fflorum. [ Condusion] The study may facilitate the artificial regulation of the growth conditions of the plantlets of ornamental lily.

Agrobacterium-mediated Transformation of Kentucky Bluegrass

Embryogenic calli of Kentucky bluegrass, named Md, were induced from mature seeds and embryos, and proliferated on medium K3 containing 2,4-dichlorophenoxyacetic acid (2,4-D, 10.0 mumol/L), 6-benzylaminopurine (BAR, 0.5 mumol/L) and K5 which was the K3 medium supplemented with cupric sulfa (0.5 mumol/L) under dim-light condition (20-30 mumol.m(-2).s-1, 16 h light) at 24 degreesC. Embryogenic calli were transformed with plasmids pDM805 Carring bar and gus genes, Which was mediated by an Agrobacterium strain AGL1, four transgenic lines were obtained. The important factors that affect the transformation efficiency and obtain desirable number of transgenic plants included: (1) the quality of embryogenic calli; (2) light condition and time of co-cultivation; (3) concentration of antibiotics used for suppressing the overgrowth of Agrobacterium in the course of transformed plant regeneration; (4) selection pressure, etc. The micro nutrient of cupric had significant influence on the quality of embryogenic calli. This presentation is the first successful protocol of Kentucky bluegrass transformation mediated by Agrobacterium.

Prevention and Utilization of Invasive Plants of Agriculture and Forestry in Guangdong Province

Guangdong has become a major＂window＂ for invasive plants, and the largest zone, where cross-border and intercontinental migration frequencies reach the peak. The invasive plants in Guangdong are dominated by Mikania micrantha, Eichhornia crassipes, Alternanthera philoxeroides, Eupatorium odoratum, and Wedelia trilobata. It is an important way for treating the invasive plants by exploring the prevention methods and making ful use of the characteristics of the invasive plants, and it is of great significance to prevent and utilize alien species in a scientific and effective way in order to control the invasive plants with minimal cost.

Comparison on Methods.for Extracting DNA from Pteridophyta

[ Objective] The aim was to study method for extracting DNA from pteridophyta and provide basis for further study on genetic diversity and taxonomy. [ Method] By changing the dosage of reagent and operating method, CTAB method for extracting DNA was improved. [ Result] The results showed that the improved CTAB method could extract high-quality DNA from pteridophyta. [ Conclusion] The study improved method for extracting DNA from pteridophyta.

Flora and ecological characteristics of rare plant communities on the southern slope of Shennongjia Mountain

According to the investigation of sampling area of 6800 m2 on the south slope of Shennongjia Mountain, there were 126 vascular plant species, belonging to 108 genera and 64 families, in the investigated rare plant communities, of which 9 rare plant species were recorded, accounting for 27.3% of the total rare plants. The communities were about 30 m in height and were divided into three layers as tree layer, shrub layer, and herb layer. The flora of the communities had obvious temperate character. Phanerophytes (accounted for 65.9%), Mesophyllous (62.7%), Papyraceous (84.1%), simple leaf (83.3%), un-entire leaf (69.8%) were dominant in life form, leaf size class, leaf texture, leaf form, and leaf margin respectively. According to important value of species, the communities were divided into three types as Davidia involucrata + Litsea pungens community, Cercidiphyllum japanicum + Padus wilsonii community, and Padus wilsonii + Acer mono community. The indexes of species diversity of tree layer had little difference among communities and evenness was high. The results indicated that the communities had complex structure and relative stability.

Agroinoculation as a Simple Way to Deliver a Tobacco Mosaic Virus- Based Expression Vector

烟草花叶病毒(TMV)表达载体30B是一个目前广泛应用的植物病毒表达载体,但用其生产外源蛋白时,必须先将它体外转录成RNA,才能被用来接种宿主植物。由于RNA体外转录费用昂贵、操作复杂,因此限制了30B表达载体的进一步应用。针对这一不足,我们用农杆菌接种法(agroinoculation)接种该病毒载体,即将30B cDNA置于花椰菜花叶病毒(CaMV)的35S启动子和终止子之间,再将整个表达框架插入到农杆菌T-DNA的左边界和右边界之内,构建成质粒p35S-30B,将转入该质粒的农杆菌注射到植物的叶片中,30B cDNA随T-DNA进入植物细胞后,被转录成可自我复制的RNA形式,进而发生系统侵染。为了检测此接种方式的可行性,绿色荧光蛋白(GFP)报告基因被克隆到p35S-30B中,构建成p35S-30B∶∶GFP,用含有该质粒的农杆菌进行注射操作。证实该病毒载体可通过简便的农杆菌接种法侵染Nicotiana benthamiana,在被接种植物的系统叶中,GFP的表达量可占植物总可溶蛋白的5.2％。

养犬狩猎亦时尚

兔多犬旺,这是生态平衡的自然规律.野兔的大量繁殖,已成为农植物的一大祸害.养猎犬追捕野兔,在一些地区,已悄然成为部分农民闲暇时的一种时尚.

Potentialities of Maize on the Removal of Organochlorine Pesticides from Contaminated Soils

In this paper, glasshouse experiments were conducted to determine the accumulation, distribution and transformation of DDTs and HCHs by maize under pot culture conditions. The culture soil was spiked with the organic pollutants and samples were collected in different durations. Analysis of the plants at harvest showed that the selected plant varied widely in their ability to remove and translo- cate DDTs and HCHs from the soil, the bioconcentration factor ranged from 0.004 to 0.027 for the shoot and from 0.036 to 0.097 for the roots, and the translocation factors were lower than 0.1 with variation between DDTs and HCHs, but no signifi- cant differences were observed. DDTs appeared to have accumulated by both pas- sive adsorption and active absorption, p,p＇-DDT and p,p＇-DDE were the major metabolite and the transformation was mediated by reductive dehalogenation, the affinity of the OCPs for lipids is one of the major factors affecting their uptake and translocation within the plants.

Genomic selection methods for crop improvement:Current status and prospects

With marker and phenotype information from observed populations, genomic selection （GS） can be used to establish associations between markers and phenotypes. It aims to use genome-wide markers to estimate the effects of all loci and thereby predict the genetic values of untested populations, so as to achieve more comprehensive and reliable selection and to accelerate genetic progress in crop breeding. GS models usually face the problem that the number of markers is much higher than the number of phenotypic observations. To overcome this issue and improve prediction accuracy, many models and algorithms, including GBLUP, Bayes, and machine learning have been employed for GS. As hot issues in GS research, the estimation of non-additive genetic effects and the combined analysis of multiple traits or multiple environments are also important for improving the accuracy of prediction. In recent years, crop breeding has taken advantage of the development of GS. The principles and characteristics of current popular GS methods and research progress in hese methods for crop improvement are reviewed in this paper.

A Sand Control and Development Model in Sandy Land Based on Mixed Experiments of Arsenic Sandstone and Sand: A Case Study in Mu Us Sandy Land in China

Serious desertification caused by human activity and climate change,in addition to water loss and soil erosion related to arsenic sandstone in the Mu Us Sandy Land,lead to severe scarcity of soil and water resources,which causes worse local agricultural conditions accordingly.Many physical properties of arsenic sandstone is complementary with that of sand,arsenic sandstone is therefore supposed to be blended to enhance water productivity and arability of sandy land.Container experiments are carried out to study the enhancement of water holding capacity of the mixture,the blending ratio of arsenic sandstone and sand,and the proper size of the arsenic sandstone particles,respectively.The results of the experiments show that particle size of 4 cm with a ratio of 1∶2 between arsenic sandstone and sand are the proper parameters on blending.Both water content and fertility increase after blending.Water use efficiency in the mixture is 2.7 times higher than that in sand by the water release curves from experiments.Therefore,a new sand control and development model,including arsenic sandstone blending with sand,efficient water irrigation management and reasonable farming system,is put forward to control and develop sandy land so that water-saving agriculture could be developed.Demonstration of potato planting about 153.1 ha in area in the Mu Us Sandy Land in China indicates that water consumption is 3018 m3/ha in the whole growth period.It means that about 61%of irrigation water can be saved compared with water use in coarse sand without treatment.Recycle economic mode and positive feedback of sand resource-crop planting-soil resource are constructed,which changes sand into arable soil and make it possible to develop water-saving agriculture on it.The proposed model will be helpful for soil-water resources utilization and management in the Mu Us Sandy Land.

Synergism Among VA Mycorrhiza, Phosphate Solubilizing Bacteria and Rhizobium for Symbiosis with Blackgram (Vigna mungo L.) Under Field Conditions

A field experiment was conducted at the G.B. Pant University Research Station, Ujhani (U.P.) in rainy (Kharif) season of the year 1994-1995 to study the effect of Rhizobium, VAM (vesicular arbuscular myc- orrhiza) and PSB (phosphate solubilizing bacteria) inoculation, with and without P, on blackgram (Vigna mungo L.) seed yield. Phosphorus application in soil with medium P content (5.4 mg kg～1) increased nodu- lation, grain yield, N and P in plant and grain over no phosphorus control. Forty kilograms of P-2O-5 each hactare recorded an increase of 20.6 % in nodule dry weight, significant increases of 0.35 g kg～(-1) in N con- centration and 1.28 g kg～(-1) in P concentration of plant over 20 kg P-2O-5 ha～(-1). Similar significant increases of 0.59 g kg～(-l) in grain yield and 0.54 and 0.23 g kg～(-1) in N and P concentrations of the grain, respectively, over 20 kg P-2O-5 ha～(-1) were also obtained with higher dose. Inoculation of Rhizobium ＋ VAM ＋ PSB at all the stages of plant growth recorded maximum increases in all the parameters studied. Dual inoculation of Rhizobium with either VAM or PSB was generally significant in the effect and better than that of VAM ＋ PSB, however, P accumulation in plant and grain was more with VAM ＋ PSB. Among single inocula tions, Rhizobium gave highest and 21.0 % more nodule number, 34.7 % more nodule dry mass, 0.73 g kg～(-1) more N in grain and 4.2 % higher grain yield over PSB. PSB, however, registered significant increases in P concentration in plant and grain over VAM and Rhizobium.

Bio-Economic Strategy to Combat Non-Point Pollution in China

While non-point pollution from agriculture has become an increasingly serious problem in China, some progress has been made in studying the causal biophysical processes. However, few studies have assessed the economic consequences of non-point pollution in China or the policy options that could be employed to combat it. In this work a sustainable strategy to control non-point pollution from crop production, which involved taxing excessive inputs of irrigation water and fertilizer, was proposed. The approach taken to assess these measures combined biophysical and economic models,having a trade-off between economic returns and an improved environment. A proven and practical spatially referenced water and nutrient management model was used to determine the quantities of excessive irrigation water and fertilizer for specific soil and land use. Also, a set of indicators were proposed for evaluating the effects of agricultural economic output and agricultural practices on the environment.

Applications of Trichoderma formulations in crop protection

The choice of active Trichoderma strains is important in designing effective and safe biocontrol applications. Many species of Trichoderma have multiple strategies for fungal antagonism and indirect effects on plant health, such as growth promotion, systemic resistance induction and fertility improvements. Some strains are powerful antibiotic producers, and their suitability for use in biocontrol systems must be carefully assessed. However, many other active strains have no antibiotic capacity, and these are likely to be more useful in food production systems since they have not adverse effects on important groups of beneficial soil organisms. We have assessed the performance of selected naturally occurring Trichoderma strains (singly and in combination) and developed TUSAL, a mixture of Trichoderma harzianum and T. viride that has demonstrated to be effective against major pathogens in sugar beet and horticulture. TUSAL, has been bulked up and tested under field conditions, showing positive effects on precocity and root development, and increasing the crop production in field trials carried out in different pathosystems. The environmental impact of TUSAL strains on beneficial organisms in the environment were assessed before release, and molecular detection methods were developed to monitor the presence and performance of strains in the field. In addition, Trichoderma protein extracts with high glucanase and chitinase activities, have also been obtained from wild type strains and their effectiveness as biofungicides was tested in laboratory and field conditions, defining the concentration of protein necessary to produce fungicide effects. The genes coding for protein production were introduced into suitable organisms for large-scale production in the laboratory, never released to the environment. The effect of these novel biofungicide proteins was studied separately and synergistically with Trichoderma conidia, and with minimal doses of chemical fungicides. Suitable active Trichoderma strains are being registered in the EU by the company NBT. Both Trichoderma strains and proteins are included in formulations patented as biocontrol agents.

Development and Utilization of Botanical Pesticide Resources in Changbai Mountain

From the viewpoint of characteristics of botanical pesticides, the development and market prospect of botanical pesticides in China were analyzed, and the resources of botanical pesticides in Changbai Mountain, as well as corresponding for their development and utilization were summed up in this paper.