油菜菌核病拮抗细菌的筛选和高效菌株的鉴定

从油菜根际和叶围分离得到320个细菌分离物,在马铃薯葡萄糖琼脂培养基上的拮抗实验中,18个分离细菌表现对油菜菌核病菌不同程度的拮抗作用,其中Y1菌株对油菜菌核病菌菌丝的生长具有明显的抑制作用。对Y1进行油菜离体叶片、温室盆栽和田间小区接种实验,该菌均表现对油菜菌核病明显的防病效果;在温室盆栽试验和田间小区试验中,防病效果达到92%。经过鉴定,Y1菌株为枯草芽孢杆菌。

不同粗精比日粮对绵羊小肠中瘤胃微生物蛋白质利用的影响

用4 只装有瘤胃瘘管、十二指肠瘘管和回肠瘘管的去势(公母各半)萨福克羊(体重平均为45.5±5.2 kg),在不同粗精比日粮条件下,研究瘤胃细菌、纤毛虫体蛋白质在小肠内的利用情况。结果表明:到达十二指肠的瘤胃细菌和纤毛虫的量,随日粮中精饲料水平的提高而显著减少(P< 0.05)。与此相反,过瘤胃饲料蛋白质的量则显著增加(P< 0.05)。小肠内的细菌利用率显著受日粮变化的影响,而纤毛虫利用率则不易受日粮影响,且显著地高于细菌的利用率(P<0.05)。小肠内被吸收的细菌和纤毛虫对微生物氮的贡献率在全试验组中分别平均约为50% 。

Monitoring Land Use Dynamics in Chanthaburi Province of Thailand Using Digital Remotely Sensed Images

A comprehensive method of image classification was developed for monitoring land use dynamics in Chanthaburi Province of Tailand. RS (Remote Sensing), GIS (Geographical Information System), GPS (Global Positioning System) and ancillary data were combined by the method which adopts the main idea of classifying images by steps from decision tree method and the hybridized supervised and unsupervised classification. An integration of automatic image interpretation, ancillary materials and expert knowledge was realized. Two subscenes of Landsat 5 Thematic Mapper (TM) images of bands 3, 4 and 5 obtained on December 15, 1992, and January 17, 1999, were used for image processing and spatial data analysis in the study. The overall accuracy of the results of classification reached 90%, which was verified by field check.Results showed that shrimp farm land, urban and traffic land, barren land, bush and agricultural developing area increased in area, mangrove, paddy field, swamp and marsh land, orchard and plantation, and tropical grass land decreased, and the forest land kept almost stable. Ecological analysis on the land use changes showed that more attentions should be paid on the effect of land development on ecological environment in the future land planning and management.

Isolation of a choline monooxygenase cDNA clone from Amaranthus tricolor and its expressions under stress conditions

Plants synthesize the osmoprotectant glycine betaine (GB) via choline→betaine aldehyde→glycine be- taine[1]. Two enzymes are involved in the pathway choline monooxygenase (CMO) and betaine aldehyde dehydrogenase (BADH). A full length CMO cDNA (1,643bp) was cloned from Amaranthus tricolor. The open reading frame encoded a 442-amino acid polypeptide, which showed 69% identity with CMOs in Spina- cia oleracea L. and Beta vulgaris L. DNA gel blot analysis indicated the presence of one copy of CMO gene in the A. tricolor genome. The expressions of CMO and BADH proteins in A.tricolor leaves significantly increased under salinization, drought and heat stress (42℃), as determined by immunoblot analysis, but did not respond to cold stress (4℃), or exogenous ABA application. The increase of GB content in leaves was parallel to CMO and BADH contents.

Effects of thinning on wind damage in Pinus thunbergii plantation ——Based on theoretlcal derlvation of risk—ratios for assessing wind damage

Based on paper of "Theoretical derivation of risk-ratios for assessing wind damage in coastal forest",wind damage in the pine coasteal forest,which was thinned at four levels in December of 1997,was investigated for four successive growing seasons.Besides wind damage,the wind profiles outside and inside the coastal forest stand and the distributions of optical stratification porosity (OSP) were also observed.Based on these data,risk-ratios of wind damage for both individual trees and stands were estimated according to the methods developed in "Theoretical derivation of risk-ratios for assessing wind damage in a coastal forest".The results showed that risk-ratios of wind damage,which were calculated from the meen height and diameter only and from the combination of wind and stand sructure profiles,accurately predicted wind damage in the plantation.Relationships between different thinning ratios and incidence of wind damage showed that stand stability decreased soon after the thinning.This was due to the immediate effects of thinning on increasing the canopy roughness and wind load,and on decreasing the sheltering effects from surrounding trees.However,thinning strategies could improve the stability by long-term effects on growthand development of trees against extreme wind.Only canopy damage was recorded during the experimental period,no stem damage was found,even though the maximum 10-min wind speed outside the coastal forest attained 30.2m s^-1.The results obtained in this study indicate that thinning is the most effective silvicultural strategy available for managing coastal forest despite the increased probability of wind damage soon after thinning.

Study on intermittent irrigation for Paddy Rice: Ⅱ. Crop Responses

Effect of intermittent irrigation on the production of paddy rice was studied in a well-puddled paddy field with four treatments and 2 replicates: continuous flooding irrigation (CFI), and intermittent irrigation Ⅱ-O, Ⅱ-1 and Ⅱ-2, in which plants were re-irrigated when the soil water potential fell below 0, -10, and -20 kPa, respectively, at soil depth of about 5 cm. Results showed that the reduction in soil water potential to about -10 or -20 kPa did not significantly affect the number of grains and the percentage of ripened grains. While, a lower crop growth rate (CGR) resulted from a decrease in the net assimilation rate (NAR) during intermittent irrigation Ⅱ-1 and Ⅱ-2, and there was also a reduction in the leaf area index (LAI) during intermittent irrigation Ⅱ-2. Senescence of lower leaves on stems was promoted in treatments Ⅱ-1 and Ⅱ-2 at the ripening stage. Early senescence at ripening stage and water stress around midday decreased the rate of photosynthesis in leaves, causing the lower NAR. These physiological responses of the plants were responsible for the reduction in the dry matter production and grain yield in the intermittent irrigation treatments.

Cloning and Expression Analysis of an XET cDNA in the Peel and Pulp of Banana Fruit Ripening and Softening

Xyloglucan endotransglycosylase (XET) is thought to be involved in fruit softening throughdisassembly of xyloglucan, which is the predominant hemicellulose of cell wall. To study the relationshipbetween fruit softening and XET during banana (Musa acuminata Colla cv. Grand Nain) fruit ripening, a fulllength cDNA (1 095 bp) encoding an XET, MA-XET1, was isolated from ripening banana fruit using RT-PCRand RACE-PCR (rapid amplification of cDNA ends) methods. Sequence analysis showed that the cDNAcontains 5' untranslated region of 66 bp, 3' untranslated region of 189 bp and ORF of 840 bp, encoding apredicted polypeptide of 280 amino acids, including DE|DFEFL motif, which is a presumptive catalyticdomain conserved in XETs. DNA gel blot analysis demonstrated that MA-XET1 is encoded by a multi-copyfamily in the banana genome. RNA gel blot analysis revealed that the level of MA-XET1 transcript in thepulp was undetectable, increased and decreased slightly at the preclimacteric, climacteric and postclimactericstages, respectively. In the peel, accumulation of MA-XET1 transcript was low, increased dramatically andthen decreased rapidly, at preclimacteric, climacteric and postclimacteric stages, respectively. Treatmentof fruit with propylene, an analog of ethylene, decreased the firmness and enhanced the accumulation ofMA-XET1 transcript in the peel and pulp. These results suggest that MA-XET1 is involved in softening ofthe peel and pulp during banana fruit ripening and its expression is regulated by ethylene at transcriptionallevel.

Chromium(VI) Reduction in Wheat Rhizosphere

Reduction of Cr(VI) to Cr(III) were studied in a fresh wheat rhizosphere soil (Kuroboku, high humic andosol) pretreated with a basal fertilizer consisting of (NH4)2SO4, P2O5 and KH2PO4 and with K2Cr2O7 by using a rhizobox system. It was found that rhizosphere exerted a positive effect on Cr(VI) reduction. Part of the reason was the decrease of pH in the rhizosphere due to application of (NH4)2SO4, implying that application of physiologically acid fertilizers would reduce Cr(VI) toxicity to plants.

Collapse-type shrinkage characteristics in plantation-grown eucalypts： I . Correlations of basic density and some structural indices with shrinkage and collapse properties

Collapse-type shrinkage is one of highly refractory drying defects in low-medium density plantation-grown eucalypt wood used as solid wood products. Basic density (BD), microfibril angle (MFA), double fibre cell wall thickness (DWT), proportion of ray parenchyma (RP), unit cell wall shrinkage, total shrinkage and residual collapse, which are associated with collapse-type shrinkage characteristics, were investigated by using simple regression method for three species of collapse-susceptible Eucalyptus urophyll, E. grandis and E.urophyllaxE.grandis, planted at Dong-Men Forest Farm in Guangxi autonomous region, China. The results indicated that : unit cell wall shrinkage had a extremely strong positive correlation with BD, moderately strong positive correlation with DWT, and a weakly or moderately negative correlation with RP and MFA; total shrinkage was positively correlated with BD, DWT and RP and negatively related to MFA, but not able to be predicted ideally by any examined factors alone owing to lower R^2 value (R^2≤0.5712); residual collapse was negatively correlated with BD and DWT, linearly positively correlated with MFA, and had strongly positive linear correlation with RP. It is concluded that BD can be used as single factor (R^2≥0.9412) to predicate unit cell wall shrinkage and RP is the relatively sound indicator for predicting residual

Propylene Effects on Ethylene Biosynthesis in Relation to Gene Expression of ACS,ACO in Persimmon Fruit

Influences of propylene treatment on fruit softening and ethylene biosynthesis of persimmon genotype, 'Hiratanenashi' were investigated. The treatment with propylene could accelerate the softening and enhance ethylene biosynthesis, with higher sensitivity of immature fruit to the propylene was consistent with mRNA increase derived from transcription of ACS and ACO genes. Furthermore, ethylene synthesis increase in immature fruits was controlled and regulated mainly by DK-ACS1, DK-ACS2, DK-ACO1 and DK-ACO2, but regulated only by DK-ACS1 and DK-ACO1 in mature fruits.

Impact of light intensity on flowering time and plant quality of Antirrhinum majus L. cultivar Chimes White

Shades of different light intensities (29%, 43%, 54%,60% or 68%) along with control (no shade) were studied to observe their effects on the flowering time and plant quality. A hyperbolic relationship was observed between different light intensities under shade,and time to flowering.The total number of flower buds showed a curvilinear relationship with light intensities. Growth parameters related to the plant characteristics such as plant height,leaf area and plant fresh weight were improved under shading treatments at the expense of flowering time and number of flower buds.However,both linear and polynomial models applied assumed that cultivar Chimes White was equally sensitive to light intensity throughout development.

利用杀配子染色体2C诱导大麦染色体产生结构变异

Introgression of agronomically important traits from barley to wheat is important for the improvement of wheat. Also, knowledge about precise location of genes in barley chromosomes is a prerequisite for map based gene isolation. The isolated genes would be introduced into wheat by crop transformation and consequently improve wheat. Many attempts have been conducted to achieve chromosome mediated introgressions from barley to wheat and to construct chromosome maps of barley showing physical locations of genes in the past. In the present study I have developed an alternative chromosome mutation inducing system capable of producing barley/wheat translocations and deletions in barley chromosome. The following is the summary. 1)In the attempt to induce breakage in barley chromosomes, I introduced a gametocidal chromosome 2C into six wheat barley addition lines. Chromosome 2C, from Aegilops cylindrica, which is a related species of wheat, has a gametocidal action causing chromosome breakage in the progeny of the monosomic 2C addition line of Chinese Spring wheat. The critical plants (21″+H″+2C′), disomic for each of barley chromosomes and monosomic for the 2C chromosome, were obtained. 2)The six critical lines were either selfed or backcrossed with the respective wheat barley addition lines. The selfed and backcrossed progeny of these lines were cytologically investigated by N banding and FISH using the barley probe HvT01 that is specific to the subterminal repeats of barley chromosomes. Various types of structural aberrations, most of which were deletions and translocations, were detected for all barley chromosomes with frequencies ranging from 10.8% to 27.9%. 3)Chromosome 7H was chosen to investigate the distribution of the breakpoints in the aberrations. Reciprocal crosses were made between the mutation inducing common wheat line (or critical lines) (21″+7H″+2C′) and the 7H addition line of common wheat (21″+7H″) to obtain more 7H deletions and 7H/wheat translocations. There were various types of aberrations as observed in the previous study. The breakpoints of these deletions and translocations appeared to distribute along the entire length of chromosome 7H.

Adsorption of Acrylonitrile on Some Soils and Minerals from Aqueous Solutions

Equilibrium and kinetic studies have been made on the adsorption of acrylonitrile(CH2=CHCN) on three soils and four minerals from aqueous solutions.It was shown that the organic matter was the major factor affecting the adsorption process in the soils.The conformity of the equilibrium data to linear type(one soil) and Langmuir type(two soils) isotherms indicated that different mechanisms were involved in the adsorption.This behavior appears bo be related to the hydrophobicity of soil organic matter due to their composition and E4/E6 ratio of humic acids.The adsorption kinetics were also different among the soils,indicating the difference in porosity of organic matter among the soils,and the kinetics strongly affected the adsorption capacity of soils for acrylonitrile.Acrylonitrile was slightly adsorbed from aqueous solutions on pyrophyllite with electrically neutral and hydrophobic nature,and practically not on montmorillonite and kaolinite saturated with Ca.However,much higher adsorption occurred on the zeolitized coal ash,probably caused by high organic carbon content(107g/kg).

Green Rice Leafhopper Resistance Gene Transferring Through Backcrossing and CAPS Marker Assisted Selection

Grh2, a green rice leafhopper resistant gene from an indica cultivar DV85, was located on chromosome 11, and two RFLP markers C189 and G1465 were found to be linked to this gene. In order to transfer Grh2 into Taichung65, a japonica cultivar with elite characters, backcross method with Taichung65 as the recurrent parent was used and the two RFLP markers were converted into CAPS markers for marker assisted selection (MAS). In the BC6F3 population, both phenotypic evaluation and MAS were conducted to screen the resistant plants with Taichung65 background. The linkage distance between CAPS markers and Grh2 was calculated and the efficiency of MAS was analyzed.

Micronutrient dynamics in some wetland soils of south-eastern Nigeria

The inventory of profile distribution of total iron (Fe), zinc(Zn), manganese(Mn) and copper(Cu) were determined in three different soil horizons each of the wetland soils selected form Mbiabet(MB), Nkari(NK) and Nkana(NA) in Ini Local Government Area of Akwa Ibom State. Total Fe ranged between 3 25 and 4 15 ppm. The average contents were 3 72, 3 91 and 3 62 ppm in Mbiabet(MB), Nkari(NK) and Nkana(NA) soils respectively. The total value of Zn also ranged between 2 4 and 4 9 ppm with the average content in each soil being 28.27, 17 73 and 36 53 ppm respectively. The amount of Fe and Zn in these soil profiles were strongly correlated with the clay content and high levels of organic matter of 3 70%, 2 47% and 2 5% respectively. The content clearly reflected a poor drainage conditions.In all the soil profiles Mn and Cu were detected in at least one of the soil horizons. However, Mn and Cu were not detected in the soil horizons at Nkari.Generally, the relative inventory of these micronutrients appeared to be influenced by pH, drainage pattern, organic matter and clay contents of these soils.The inventory of total values of the wetland soils considered are assessed in the light of establishing a baseline information.

尼日利亚Akwa Ibom洲Uyo市郊传媒蚊虫的繁殖和流行区的确定

蚊虫是寄生虫病的主要传播者.为确定传病媒介蚊虫在Uyo郊区的繁殖和流行地,从1999年5月到2000年1月在208个繁殖地进行了取样,从144个地点用滤网取到了5 844只蚊虫幼体.采集到的4种蚊虫是致倦库蚊(Culex quinquefasciatus) 成虫604只 (43.5%),冈比亚按蚊(Anopheles gambiae)357 只(26.1%), 一种按蚊(Aedes uegypti) 208只 (25.5%)和非洲曼蚊(Mansonia africana)101只(7.4%).监测了蚊虫种群的时间变化,发现5月份～10月份的丰度高于11月份～1月份,幼体表明了同样的趋势,但比成体提前1～2个月.卡方检验表明,除了非洲曼蚊以外,其它3种蚊虫数量与混凝土水槽、土坑和居民区/公共环境之间的相关显著[动物学报 49(3):522～524,2003].

A Method for Accuracy of Genetic Evaluation by Utilization of Canadian Genetic Evaluation Information to Improve Heilongjiang Holstein Herds

The objectives of this study were to set up a new genetic evaluation procedure to predict the breeding values of Holstein herds in Heilongjiang Province of China for milk and fat production by utilizing Canadian pedigree and genetic evaluation information and to compare the breeding values of the sires from different countries. The data used for evaluating young sires for the Chinese Holstein population consisted of records selected from 21 herds in Heilongjiang Province. The first lactation records of 2 496 daughters collected in 1989 and 2000 were analyzed. A single-trait animal model including a fixed herd-year effect, random animal and residual effects was used by utilizing Canadian pedigree and genetic evaluation information of 5 126 sires released from the Canadian Dairy Network in August 2000. The BLUP procedure was used to evaluate all cattle in this study and the Estimated Breeding Values (EBV)for milk and fat production of 6 697 cattle (including 673 sires and 6 024 cows) were predicted. The genetic levels of the top 100 sires originated from different countries were compared. Unlike the BLUP procedure that is being used in conjunction with the single-trait sire model in Heilongjiang Province of China now, the genetic evaluation procedure used in this study not only can be used simultaneously to evaluate sires and cows but also increase the accuracy of evaluation due to using the relationships and genetic values of the Canadian evaluated sires with more daughters. The results showed that the new procedure was useful for genetic evaluation of dairy herds and the comparison of the breeding values of these sires imported from different countries showed that a significant genetic improvement has been achieved for milk production of the Heilongjiang Holstein dairy population by importing sires from foreign countries, especially from the United States due to the higher breeding values.

Analysis of QTL for Seed Dormancy and Their Response to Dry Heat Treatment in Rice (Oryza sativa L.)

Quantitative trait loci (QTL) controlling seed dormancy in rice were identified usingrecombinant inbred lines (RILs) population derived from the cross between a japonicavariety Kinmaze and an indica variety DV85. Seeds of two parental cultivars and each RILwere harvested in 35d after heading. The germination percentage of these seeds at 30℃for 7 days were measured as the degree of seed dormancy. QTL analysis was performed withWindows QTL Cartographer 1.13a program by composite interval mapping. A total of four QTLfor seed dormancy were detected on chromosome 2 (two regions), 5 and 11, respectively.Phenotypic variation explained by each QTL ranged from 8.37 to 17.40%. Responses of suchloci to a dormancy-breaking treatment with dry heat were further detected. The resultsshowed that two alleles of qDOR-2-1 and qDOR-5 from DV85 as well as the allele of qDOR-11 from Kinmaze increased the seed dormancy, which seemed to be easily broken by dry heattreatment. Such loci of seed dormancy may be applied to rice genetic improvement. Theallele of qDOR-2-2 from DV85 increased the seed dormancy, which could not be broken bydry heat treatment.