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Table of Content

    10 April 2005, Volume 38 Issue 04
    CROP GENETICS & BREEDING·GERMPLASM RESOURCES
    Genetic Dissection of Early Growth Characteristics in Rice
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    Scientia Agricultura Sinica. 2005, 38(04):  643-649 . 
    Abstract ( 1185 )   PDF (327KB) ( 750 )   Save
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    The aim of the present study is to dissect the genetic factors controlling early growth characteristics of rice (Oryza sativa L.) by QTL analysis. A RIL (recombinant inbred line) population was directly seeded in plastic pots in a randomized complete block. Seedling height (SH) and dry weight (DW) of seedlings were measured at 14, 24, 34 and 44 days after sowing, respectively. Combined with a linkage map based on this population, composite interval mapping was carried out, leading to the identification of 6, 14 and 3 main-effect QTL for DW, SH and 1 000-grain weight (KGW) of the seeds used in the study, respectively. Among these QTL, qGC-3-3 and qGC-5, located within the interval RM148-RM85 of chromosome 3 and the interval RM163-RM161 of chromosome 5, respectively, showed additive effects on multiple measurements of SH and DW in the same direction, but, as the seedlings grew, the magnitude of the effects of QTL qGC-3-3 appeared to have increased while that of QTL qGC-5 seemed to have declined. DW correlated positively with SH (P<0.01), which was genetically explained by the co-locations of some of the QTL for the two traits with effects in the same direction. Both DW and SH correlated positively with KGW, but the correlation degrees became weaker as the seedlings grew, which was also explained well by the coincidence of the QTL for the traits concerned. In addition, comparison of the QTL detected in the current study with those previously identified for yield related traits with the same population revealed that some of the QTL, such as QTL qGC-3-1 and qGC-3-3 on chromosome 3, seem to produce larger effects on late growth of rice so that they show a greater influence on multiple yield traits, while the others, such as QTL GC-5, show larger effects mainly on early growth. From the point of view of breeding, the former could be better to be used as the potential targets to be manipulated in rice breeding program by marker-aided selection.
    Mapping and Analysis of Quantitative Trait Loci Controlling Seed Dormancy in Rice
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    Scientia Agricultura Sinica. 2005, 38(04):  650-656 . 
    Abstract ( 1148 )   PDF (232KB) ( 1077 )   Save
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    Seed dormancy is one of the most important traits related to rice quality and seeds application, because it is associated with pre-harvest sprouting, resulting in a downgrading of quality and severe limitations in end-use application. Recent development of DNA markers and linkage maps of rice has made possible mapping of individual genes associated with complex seed dormancy traits, analyzing the genetics effects of individual genes and genotype-by-environment interactions. Up to now, numerous QTLs associated with seed dormancy in rice have been identified and mapped in the molecular genetic map by different populations. In this review, the genetics bases of seed dormancy in rice are analyzed, the quantitative trait loci (QTL) controlling seed dormancy reported up to now are compared, the expression and stability of QTLs controlling seed dormancy are studied, and the difficulties and new pathways in further research of seed dormancy are discussed.
    Studies on the Rice RVA Profile Characteristics and Its Correlation with the Quality
    Scientia Agricultura Sinica. 2005, 38(04):  657-663 . 
    Abstract ( 1155 )   PDF (231KB) ( 1779 )   Save
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    Rice quality is a key factor and widely concerned by rice breeders and consumers, but it is difficult to evaluate it only through physical and chemical indices. In this study, 114 and 105 varieties including indica, japonica and waxy varieties were employed in two replicates to study the relationship between RVA profile characteristics and rice quality, including the appearance quality, cooking physico-chemical factor and cooking quality. The main results were as follows: (1) RVA profiles characteristics had close relationships with translucency and chalkiness. Rice varieties with higher chalkiness had significant AAC, HPV, CPV, SBV and CSV. (2) RVA profiles characteristics had significant correlation with AAC and GC, but no significant with GT. (3) With the exception to PKV, all the other RVA profiles characteristics correlated significantly with eating quality. These results showed that RVA profiles characteristics could be used as indices to assist in varietal selection for good cooking rice quality.
    Studies on Biochemical Assistant Breeding Technology of Earliness Without Premature Senescence of the Short-Season Upland Cotton
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    Scientia Agricultura Sinica. 2005, 38(04):  664-670 . 
    Abstract ( 1187 )   PDF (266KB) ( 792 )   Save
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    The anti-oxidant enzymes including SOD, POD and CAT and MDA, which is one of the oxidant products, and IAA and ABA, which were relative to earliness but not to decrepitation of the short-season upland cotton (SSC), were studied. The changes and hereditary characters of these biochemical substances at different development stages in different types of short-season upland cottons were studied. CAT activity and ABA content in SSC had significant maternal effect. The activity of SOD, the contents of soluble proteins, IAA and MDA showed significant dominant effect. The activity of POD and the contents of ABA showed significant additive effect. Based on the changes and genetic development, the biochemical assistant breeding technology was established and the relative selective standards, i.e. the selective range, activity of enzymes and time, were determined. Zhongmiansuo 20, 24, 27, 36 and so on were successfully bred by using the biochemical assistant breeding technology.
    Combining Ability and Heterotic Grouping of CIMMYT Subtropical Quality Protein Maize Lines
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    Scientia Agricultura Sinica. 2005, 38(04):  671-676 . 
    Abstract ( 1002 )   PDF (245KB) ( 934 )   Save
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    Combining ability and heterotic groups of 22 CIMMYT subtropical quality protein maize (QPM) inbred lines were analyzed based on the data of design II, in which the CIMMYT QPM lines were crossed with 3 QPM testers Qi205, CA375 and CA339 used successfully in China. Field experiments were conducted in two years. The results indicated that a high general combining ability (GCA) of inbred lines CML181, CML182, CML194, CML179 and CML193 was observed and these inbred lines will be used in QPM breeding efforts in China. Inbred lines from populations Pool32, UWO417, WOMTA, CYO and Pool33 were classified into the same heterotic group QA as CA375 and CA339 due to the minor genetic distance among them, while inbred lines from populations Pool34 and UYO showed closer genetic distance with Qi205, and were clustered into the heterotic group QB.
    TILLAGE & CULTIVATION·PHYSIOLOGY & ECOLOGY
    An Ecological Model for Predicting Grain Protein Content in Winter Wheat
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    Scientia Agricultura Sinica. 2005, 38(04):  684-691 . 
    Abstract ( 1066 )   PDF (271KB) ( 766 )   Save
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    Abstract: Based on the experiments conducted at four eco-sites with six wheat genotypes differing in grain protein content, an ecological model for predicting grain protein content in winter wheat was established. Analyses on correlations between grain protein content and climatic factors showed that five factors, i.e. mean temperature (Tmean), difference of diurnal temperature (DT), total rainfall (R), total sunshine (S) and growing degree days (GDD) from anthesis to maturity, determined the variation of grain protein content. By stepwise regression analysis, grain protein contents of high-protein varieties depended on DT under the environment with significant DT variation, but on interaction of Tmean and total sunshine under the environment with DT variation less than 5%. For middle-protein and low-protein varieties, grain protein content depended on the total sunshine, and interaction of Tmean, R and S. In the model, the effectiveness factors of DT and sunshine depended on the linear relationship between grain protein content and DT, total sunshine. The temperature factor was determined by the quadratic relationship between protein content and Tmean. The factor of rainfall linearly changed with total rainfall from anthesis to maturity if R was less than 50mm, whereas quadratic equation was established when R was more than 50mm. The model was tested by the different data from three experiments: the first experiment was conducted under three sowing dates with three varieties, the second at six eco-sites with eight winter varieties, and the third at two sites with forty varieties. The RMSE values of all varieties and eco-sites tested were less than 10%. The results indicate a good fit between the simulated and observed values of grain protein contents, thus a reliable prediction for the grain protein contents of different winter wheats under different environments can be obtained.
    Study on the Sensitivity and Vulnerability of Wheat to Climate Change in China
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    Scientia Agricultura Sinica. 2005, 38(04):  692-696 . 
    Abstract ( 1343 )   PDF (187KB) ( 1075 )   Save
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    By using B2 climate change scenario produced by PRECIS (Providing Regional Climates for Impacts Studies) that developed by the UK Hadley Center and the wheat yield data outputted by CERES-Wheat model, the sensitivity and vulnerability of wheat to future climate change in China were studied based on the yield variation and GIS mapping. Results showed: in 2070s, there will be three negative sensitive areas of rain-fed wheat: northeastern China, the region of the middle and lower reaches of the Yangtze River, and a part of Loess Plateau. For irrigated wheat, most areas of China tend to be sensitive. The distribution tendency of the sensitive areas is similar to that of rain-fed wheat, but the sensitive degree is lighter. Under the consideration of adaptation, rain-fed wheat in most regions of China will not be vulnerable and even has a yield increase. For irrigated wheat, the vulnerable area is bigger, occupying about 2/3 of its total area in China. The highly vulnerable regions will be distributed in northeastern China and northwestern China. And the medium and light vulnerable areas will be distributed along the middle and lower reaches of the Yangtze River, Yunnan and Guizhou Provinces.
    Uptake and Partitioning of Nitrogen in High Oil Corn During
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    Scientia Agricultura Sinica. 2005, 38(04):  697-702 . 
    Abstract ( 948 )   PDF (365KB) ( 831 )   Save
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    The nitrogen uptake and partitioning in high oil corn (HOC) was studied under the growing conditions in field, and compared with normal corn (NC). The nitrogen concentration in grain of HOC was higher than that of NC, but lower in leaves and stalks. At maturity, the distribution of total N to grain in HOC was 6.9% higher than that in NC. As to absorption of N in 100 kg grain yield, there was 0.13 kg in HOC more than that in NC, whereas the nitrogen export rate of vegetable organs was lower. The percentage of N uptake during grain filling period to grain N was 70.05%, that of NC was 40.65%. That to say, the grain nitrogen of HOC was more contributed to N uptake by plant shoots during grain filling period than N translocation from vegetable organs. In conclusion, both the demand and rate of N uptake during grain filling period of HOC are higher. So if HOC achieves the same grain yield as NC, abundant nitrogen fertilization during grain filling period will be very important.
    Physiological Effect of New FA Antitranspirant on Winter Wheat at Ear Filling Stage
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    Scientia Agricultura Sinica. 2005, 38(04):  703-708 . 
    Abstract ( 1010 )   PDF (426KB) ( 934 )   Save
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    The physiological effect of new FA antitranspirant on winter wheat was studied in field trials. The new FA antitranspirant was sprayed at ear filling stage at the concentrations of 0.5, 1.0, 1.5 and 2.0 ml·L-1. The results indicated that new FA antitranspirant increased nitrate reductase activity (NRA), free proline content, chlorophyll content and water content of leaf, thus drought stress can be mitigated. The new FA antitranspirant increased photosynthesis, reduced stomatal opening status and transpiration rate, thus led to growth stimulation and water loss reduction. New FA antitranspirant resulted in an increase of grain yield by 7.2% at the optimal concentration of 1.5 ml·L-1.
    Quantitative Evaluation of Output Efficiency in Different Cropping Patterns
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    Scientia Agricultura Sinica. 2005, 38(04):  709-713 . 
    Abstract ( 1021 )   PDF (183KB) ( 940 )   Save
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    The concept related to yield equivalent and value of output equivalent is proposed. Using various quantitative standards such as land equivalent ratio, yield equivalent, and value of output equivalent, the efficiency of various cropping patterns such as sequential cropping, row cropping, crop rotation was studied. The result showed, comparing with sole cropping, the land use efficiency of sequential cropping, row cropping, crop rotation raised by 62%, 38% and 21%. The unit area yield of sequential cropping, row cropping, crop rotation was 1.63, 1.29 and 1.16 times of sole cropping. The unit area value of double cropping, row cropping was 1.76 and 1.35 times of sole cropping. Through comprehensive analysis, the objective methods for comparison of farm output efficiency are cleared. The paper has provided a theoretical basis for comparison study output efficiency of various cropping patterns in future.
    PLANT PROTECTION
    Degradation Dynamics of Cry1Ac Insecticidal Protein in Leaves of Bt Cotton under Different Environments
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    Scientia Agricultura Sinica. 2005, 38(04):  714-718 . 
    Abstract ( 1081 )   PDF (332KB) ( 786 )   Save
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    The degradation dynamics of Cry1Ac insecticidal protein in the leaves of Bt cotton while exposure to air and soil mediums under different conditions were investigated in both the laboratory and in the field. The results showed that the degradation trends under different situations were different. Bt insecticidal protein in cotton leaves degraded rapidly in first several days, then got slowly and entered a relative stable stage in which Cry1Ac protein content kept at a concentration about 50 ng·g-1. The higher temperature and lower humidity significantly increased degradation speed of the toxin, which shortened the period for the content of the protein to get into stable stage. However, there were no significant difference of the degradation under light or dark treatments. In natural environment, the insecticidal protein in Bt cotton degraded much rapidly in the initial period, it reached 85% in first month, and slowered during winter season, then degraded quickly in next spring until to be undetectable in late April.
    Resistance Selection of Tetranychus cinnabarinus to Fenpropathrin and Genetic Analysis
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    Scientia Agricultura Sinica. 2005, 38(04):  719-724 . 
    Abstract ( 866 )   PDF (322KB) ( 750 )   Save
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    The resistant inheritance mode of Tetranychus cinnabarinus to fenpropathrin were studied based on the resistance selection in laboratory. After 40 generations selection, T. cinnabarinus developed 68.5-fold resistance to fenpropathrin. The methods of cross and back-cross between resistant (R) and sensitive (S) strains were used for exploring the inheritance mode of the resistance of this mite to fenpropathrin. The log (LC)-P equation of F1 got from obverse (SR) and reverse (RS) crosses was intermediate between S and R and inclined to S, the dominant indices DSR and DRS were - 0.83 and - 0.29, respectively, which indicated that the resistance is controlled by the incompletely recessive gene; the 95% confidence limit of this two dominant indices do not superpose showing DSR and DRS have significant difference and the maternal or external karyon effect may be existed in resistance inheritance; the back-cross results of heterozygote F1 with its parents suggested that the separation of progenies F2 (SR♀× S♂ and RS♀× R♂) was consistent with Mendel's single gene inheritance model.
    Resistance of cry1Ac + SCK Transgenic Rice and Its Filial Generation to the Rice Leaf Roller Cnaphalocrocis medinalis
    Scientia Agricultura Sinica. 2005, 38(04):  725-729 . 
    Abstract ( 1256 )   PDF (309KB) ( 949 )   Save
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    Field evaluations were conducted to investigate the resistance of cry1Ac + SCK transgenic rice and its filial generation to the rice leaf roller Cnaphalocrocis medinalis. The results indicated that two transgenic rice lines of MSA and MSB inserted with the combination of cry1Ac and SCK were highly resistant against the rice leaf roller, Cnaphalocrocis medinalis, and the progenies from crosses between cry1Ac and SCK transgenic rice and conventional rice varieties, 21S/MSB and II-32A/MSB showed high resistance to leaf roller C. medinalis. The number, percentage of rolled leaves and leaf-rolled plants as well as plants with C. medinalis of MSA, MSB, 21S/MSB and II-32A/MSB were remarkably lower than those of their conventional control rice varieties, respectively.
    Management of Strawberry (Fragria ananassa Duch) Replanting Problem by Soil Amendments of Medicinal Herbs
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    Scientia Agricultura Sinica. 2005, 38(04):  730-735 . 
    Abstract ( 910 )   PDF (296KB) ( 1019 )   Save
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    Replanting problem is serious for the sustainable production of strawberry under continuous cropping. Extracts from 125 species of medicinal plant materials were screened against pathogens of Rhizoctonia solani, Fusarium oxysporum, and Verticillium dahliae that caused strawberry replanting problem in agar plates. Among them, 5 plants of Eugenia caryophyllata, Ligusticum sinence, Stemona japonica, Rhus chinensi and Sophora flavescens significantly inhibited the growth of the pathogens. Single or combinations of these 5 medicinal herds were evaluated for control strawberry replanting problem in pot trials and greenhouse. Results showed that five herbs significantly enhanced strawberry growth, reduced disease index and increased the yield compared with untreated control in pot trial. Four herbs significantly promoted growth of strawberry seedlings, disease index decreased by 13.9-39.5 and death rate of 22.4%-33.2%, increased the yield by 32.6%-33.8% compared with non-herb treatment in greenhouse trials. Based on the cost, disease control efficacy and yield promotion, the equal mixture of Ligusticum sinence and Sophora flavescens was suggested to application in the management of strawberry replanting problem in China.
    SOIL & FERTILIZER·WATER-SAVING IRRIGATION
    The Analysis and Design of Agricultural Sustainability Indicators System
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    Scientia Agricultura Sinica. 2005, 38(04):  736-745 . 
    Abstract ( 916 )   PDF (275KB) ( 1151 )   Save
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    The development and characteristic of agricultural Sustainability Indicators System(SIs), at home and abroad, was reviewed. It was pointed out that the existed domestic methods of sustainability evaluation can not be accepted by foreign scholars, and its scientific basis is inadequate. The experience and shortcomings of previous studies on indicators selection and evaluation methods were analyzed, also with the significance for practice. At the end, a new SIs for agricultural development evaluation was proposed, together with the corresponding calculation and evaluation methods. The Farmer Development Index indicator was proposed to embody the viewpoint that the development of people is the ultimate aim; the dynamic weight calculation method was designed to reflect the different importance of different indicators when their values are changing; and new indicators integrate methods were also explored.
    Dynamics of Ecological Footprint and Ecological Capacity of Shaanxi
    Scientia Agricultura Sinica. 2005, 38(04):  746-753 . 
    Abstract ( 1228 )   PDF (460KB) ( 1053 )   Save
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    The ecological footprint and ecological capacity of Shaanxi Province during 1978 to 2002 was studied, and the forecast model was obtained which shows how the two vary with the time, and the tend of future sustainable development of Shaanxi was forecasted. The results showed that the average personal ecological footprint gradually increased from 0.5508 ha to 1.1059 ha during 1978 to 2002 , whereas, the average personal ecological capacity declined year by year from 0.917 ha to 0.8102 ha. A conclusion could be drawn that the ecological footprint and ecological capacity development just in the opposite direction. In 1978 the ecological surplus was 0.4009 ha, and in 1992 ecological deficit arose, which rose to 0.2958 ha by 2002. The forecast showed that the average ecological footprint would be 1.2013 ha in 2010 and 1.528 ha in 2015, and that the average personal ecological capacity would be 0.7638 ha in 2010 and 0.7198 ha in 2015, and that the average personal ecological deficit would reach to 0.4378 ha in 2010 and 0.5330 ha in 2015. The research indicates that the utilization of natural resource in Shaanxi is increasing year by year, which is beyond the capacity of the natural ecological system, the conflicts between ecological footprint and ecological capacity are going up, the present developing model is not sustainable, the ecological environment is at risk.
    Effects of Fertilization on Wheat Yield, NO3--N Accumulation and Soil Water Content in Semi-Arid Area of China
    Scientia Agricultura Sinica. 2005, 38(04):  754-760 . 
    Abstract ( 1235 )   PDF (285KB) ( 834 )   Save
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    On the basis of long-term experiment at Changwu station on the Loess Plateau, winter wheat yield, nitrogen fertilizer use efficiency, and soil water cycle under continuous wheat cropping system were investigated. For the average of wheat yield over 17 years, CK, M, N, NP, NM, and NPM treatments were 1.5, 2.6, 2.0, 3.3, 3.4, and 4.0 t·ha-1, respectively. For total N uptake by wheat after 17 years, CK, M, N, NP, NM, and NPM treatments were 509.0, 854.6, 781.9, 1 199.8, 1 067.5, and 1 430.9 kg·ha-1, respectively. For NO3--N level in 0-300 cm in 2001, CK, M, N, NP, NM, and NPM treatments were 52.2, 113.1, 1064.8, 254.5, 535.4, and 512.1 kg·ha-1, respectively. Fertilizer N use efficiency ranged from 15% to 36% among fertilizer N treatments. For NO3--N accumulation, N treatment was high in depth of 0-300 cm, NP, NM, and NPM treatments were high in 0-180 cm. Soil water content at harvest follows this order: CK>N>M>NP>NPM. For NP, NPM treatments, subsoil water deficit produced at planting. Fertilization significantly (P<0.05) enhanced crop yield, increased soil productivity led to subsoil water deficit, the soil-water deficit retarded NO3--N movement down and accumulated in the soil profiles. Fertilization is a common drive to increase crop yield, subsoil water deficit and nitrate accumulation in the soil profiles of continuous wheat cropping system on the Loess Plateau.
    Effect of Different Irrigation and Fertilization Strategies on Yield, Fiber Quality and Nitrogen Balance of High-Yield Cotton System
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    Scientia Agricultura Sinica. 2005, 38(04):  761-769 . 
    Abstract ( 971 )   PDF (356KB) ( 698 )   Save
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    The effect of different water and nitrogen management strategies on cotton was studied at two sites(Cele and Yuli) at the edge of Tarim basin of south Xinjiang. The result showed that the optimized irrigation and fertilization strategy based on soil nitrate quick testing and soil moisture measurement can dramatically reduce N fertilizer application rate from 432 kg?ha-1 to 256 kg?ha-1 at Cele and 310 kg?ha-1 to 137 kg?ha-1 at Yuli site. Meanwhile, irrigation water can be decreased from 660 mm to 427 mm at Cele and 600 mm to 402 mm at Yuli. The cotton yield, cotton fiber quality and N uptake of the optimized management strategies were similar to the conventional one, but significantly higher than the no N fertilization treatment at both experimental sites. The optimized strategies can dramatically increase N recovery and water use efficiency, and significantly reduce soil residual Nmin and apparent N losses.
    HORTICULTURE
    The Evaluating Criteria of Some Botanical Quantitative Characters of Peach Genetic Resources
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    Scientia Agricultura Sinica. 2005, 38(04):  770-776 . 
    Abstract ( 1280 )   PDF (319KB) ( 994 )   Save
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    There were two peach descriptions, one from IPRGI in 1980, another from China in 1990. Yet the former only has referenced cultivars without quantity grades, the latter only has some characteristics list. Both of them make breeders difficult to share genetic resource information. In order to descript the main quantitative characteristics, a new system was established. 10 kinds characteristics of 346-476 peach cultivars were investigated from 1986 to 2002 in National Peach Genetic Collection of Zhengzhou City in China. These characters and their coefficients of variation were flower diameter19.55%, length diameter of fruit 14.24%, cheek diameter of fruit 10.36%, suture diameter of fruit 11.44%, stone length 19.04%, stone width 10.86%, stone thickness 11.19%, leaf length 7.9%, leaf width 10.55 and leaf stalk length 19.03%, respectively. Grade index and reference cultivars were given by statistical data for peach description. These grade indexes were recorded on 1-5 scales, and the third grade as a middle one occupied 39% or more distribution . In general, two reference cultivars for each grade were given, one is USA cultivar, another is Chinese cultivar. The authors try to use these as the reference cultivars, which are planted or used by breeders widely in China.
    Regeneration Mechanism of Fragaria×ananassa Duch. cv. Toyonoka Under Different Color Plastic Films
    Yonghua Qin,
    Scientia Agricultura Sinica. 2005, 38(04):  777-783 . 
    Abstract ( 1131 )   PDF (467KB) ( 879 )   Save
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    The effect of different color plastic films on the shoot regeneration and its mechanism from the leaf discs of Fragaria×ananassa Duch. cv. Toyonoka were studied in an experiment using an optimized MS medium (1.5 mg·L-1 TDZ and 0.4 mg·L-1 IBA). Color films had significant effects on shoot regeneration of strawberry. The highest percentage of shoot regeneration (> 95%) and maximum number of shoots per explant (>25) were observed under red and green films. Different spectrum ranges of the color films were 300 to 700 nm. Light intensity under red and green films was weaker than fluorescent light and yellow, blue films. Red and green films induced a higher level of chlorophyll and lower chlorophyll a/b in tissue culture of strawberry. Antioxidant enzyme (SOD, CAT and POD) activities were the highest under red films, followed by green and the lowest was under yellow ones. Antioxidant activities had positive correlation with the shoot regeneration while malondialdehyde (MDA) was negative. After 15 days in culture, GA3 content was higher under fluorescent light, red and green films, respectively. Zeatin (ZT) and gibberellic acid (GA3) contents were the highest under red and green films after 45 days, however, indole-3-acetic acid (IAA) accumulation in the tissues was higher under yellow and blue films.
    Direct Adventitious Bud Induction and Plant Regeneration of Rosa hybrida cv. Samantha
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    Scientia Agricultura Sinica. 2005, 38(04):  784-788 . 
    Abstract ( 917 )   PDF (504KB) ( 602 )   Save
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    Effect of explant, site of leaflet, induction period in the dark and combinations of plant growth regulators on adventitious bud induction and plant regeneration of Rosa hybrida cv. Samantha was investigated. The results showed that after 8 days of induction on MS medium with 1.5mg·L-1 TDZ and 0.05mg·L-1 NAA in the dark and a subculture on MS medium with 0.5mg·L-1 BA and 0.01mg·L-1 NAA under light, the best plant regeneration was obtained and the regeneration frequencies of leaflets and petioles were 51.8% and 10%, respectively. There was no significant difference in regeneration ability between leaflets at different sites of the leaves. Longer time of induction in the dark caused callus formation and the regeneration frequency was significantly reduced. High concentration of auxin resulted in callus growth which was disadvantageous to shoot regeneration.
    A Simple Method to Evaluate the Drought Tolerance of Ground-Cover Chrysanthemum(Dentranthema×grandiflorum)Rooted Cuttings
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    Scientia Agricultura Sinica. 2005, 38(04):  789-796 . 
    Abstract ( 962 )   PDF (589KB) ( 896 )   Save
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    This experiment was conducted with rooted cuttings of ground-cover chrysanthemum, Dentranthema×grandiflorum White Snow. The 10-leaf cuttings were exposed to dehydrations in air and osmotic adjustments of PEG, respectively. With the prerequisite of determination of wilting index (WI), fresh weight retention rate (FWRR), leaf water potential (LWP), leaf solute osmotic potential (LSOP), malondialdehyde (MDA) content, the activities of superoxide dismutase (SOD) and catalase (CAT) were measured. The main morphological characteristics to describe WI differed in both treatments. When the duration of dehydrations in air was less than 8 h, the cuttings could be recovered in 1/2 Hoagland and Arnon solutions, during which, the changes of FWRR, LWP, MDA content, SOD and CAT activity were related to drought tolerance of the cuttings. With 20% PEG treatment, the cuttings could be recovered normally in the recovery solution within 4 h stress, and the changes of FWRR, LSOP, MDA content, and SOD activity were related to drought tolerance. The above results suggested that both dehydrations in air and osmotic adjustments of PEG could be used to evaluate simply the drought tolerance of White Snow, and it differed in their available indices of water relations and physiology.
    Study on the Parameter of Ice-Temperature Storage in Litch(Litchi chinensis Sonn.)
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    Scientia Agricultura Sinica. 2005, 38(04):  797-802 . 
    Abstract ( 1110 )   PDF (281KB) ( 1299 )   Save
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    Eight litchi cultivars from China and one from Thailand were used as materials to measure the freezing point and supercool point of fruit, and some physiological and biochemical changes of litchi fruits stored at -1℃ were also investigated. The results showed that the freezing point of the 9 cultivars ranged from -2.14 to -2.87℃. The freezing points had a positive correlation with total soluble substance of fruit but no correlation was found with single fruit weight. Ice-temperature storage combined with pericarp color retention technology made litchi fruit safe over 60 days at -1℃. The rates of respiration and ethylene releasing maintained at very lower level during storage period at -1℃, and the activities of polyphenol(PPO), peroxidase(POD) and anthocyanase were significantly inhibited, thus greatly retarding pulp senescene and pericarp browning.
    ANIMAL SCIENCE·VETERINARY SCIENCERE·SOURCE INSECT
    Effect of Betaine and Yeast Chromium on Carcass Quality and Lipid Metabolism in 4-7-week-old Broiler Chickens
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    Scientia Agricultura Sinica. 2005, 38(04):  803-812 . 
    Abstract ( 1045 )   PDF (336KB) ( 1012 )   Save
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    An experiment was conducted using a total of 288 three-week-old AA broiler chickens to investigate the effects of adding yeast chromium (0, 400, 600 μg·kg-1 respectively) and betaine (0, 800, 1 000 mg·kg-1 respectively) to corn soybean diets on carcass quality and lipid metabolism in broiler chickens and their interaction. Chickens were randomly divided into 9 treatments (32 for each treatment, 8 for each replicate). A 3×3 (chromium×betaine) experiment with replicates was designed. The basal diet was used as control group, and the experiment lasted for four weeks. The result showed:(1) There were significant effects of interaction between betaine and chromium on slaughter rate, abdomininal fat rate, the rate of the whole pure thorax, (P<0.01) and no significant interactive effects on half pure thorax rate (P>0.05).(2) Betaine and chromium on the content of cholesterol (TC) and triglycerides (TG) in liver and muscle of chest and leg had interactive effects (P<0.01). Analysis showed that, it was better for the test group to add 1 000 mg·kg-1 betaine and 400μg·kg-1 chromium at the same time.(3) At the end of 7 weeks, betaine and chromium significantly increased the concentrations of serum total protein (TP), albumin (ALB), free fatty acid (FFA), high density lipid protein chloesterol(HDL-C) in serum compared with control group (P<0.01) and significantly reduced the concentrations of cholesterol (TC), uric acid (UA), low density lipid protein chloesterol (LDL-C), triglycerides (TG), and glucose (Glu).
    Effects of Compound Polysaccharide Extracted from Traditional Chinese Medical Herbs on the Immunity Function in Chickens
    Scientia Agricultura Sinica. 2005, 38(04):  813-820 . 
    Abstract ( 1252 )   PDF (359KB) ( 922 )   Save
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    Four hundred and eighty 7-day-old chickens(Roman) were randomly divided into four groups and with 120 chidkens for each. Eight-day-old chickens were vaccined with the Chinese herbal medicine compound polysaccharide plus cyclophosphamide, the Chinese herbal medicine compound polysaccharide, cyclophosphamide, physiologic saline. All chickens (15 in each group)were bled and smeared before injection, and on the 8th, 17th, 21st, 29th, 37th day post-vaccination, the percentage of lymphocyte and ANAE+ were determined. All chickens (12 in each group) were bled before using medicine and after stopping use medicine, the phagocytosis ability of neutrophil exythrocyte were determined. At 18-, 25- and 32-day-old of age chickens' (12 in each group) phagocytosis function of the abdominal cavity macrophage was determined. At 7th, 14th, 21st day post the frist immunization and at 7th, 14th, 28th day post the second immunization of ND Ⅱ vaccine, all chickens (15 in each group) were bled and serum was sampled, ND-HI antibody titers were determined. At 4-, 6- and 9-week-old of age chickens'(12 in each group)weight of bursa F, thymas and spleen were determined. All chickens (15 in each group) were bled before using medicine, and 4, 8 days after stopping use medicine, immunity function of red blood cell were determined. The results showed that the Chinese herbal medicine compound polysaccharide increased the percentage of lymphocyte transformations and ANAE+, the phagocytosis rate and index of neutrophil erythrocyte, the phagocytosis rate and index of the abdominal cavity macrophage, ND-HI antibody titers after the first and the second immunization, weight of bursa F, thymas and spleen, RBC-C3b rosette rate and RBC-IC rosette rate. Nevertheless, cyclophosphamide decreased all of these values. Significant differences between the group treated with the Chinese herbal medicine compound polysaccharide plus cyclophosphamide and the group treated with cyclophosphamide in these values. The values of group treated with the Chinese herbal medicine compound polysaccharide plus cyclophosphamide were higher than the control group.
    Fusion of Microvascular Endothelial Cells Induced by Muramidase-Released Protein of Streptococcus suis Type 2
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    Scientia Agricultura Sinica. 2005, 38(04):  821-825 . 
    Abstract ( 1199 )   PDF (254KB) ( 849 )   Save
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    Streptococcus suis type 2 (SS2) mainly causes meningitis of human and pigs. Muramidase-released protein (MRP) is one of the key virulence factors of SS2. However,the pathogenic effects of MRP on microvascular endothelial cells (MEC) which makes up of brain blood barrier (BBB) is unknown to date. So the spleen microvascular endothelial cells (SMEC) from neonatal rabbit were isolated, purified, immortalized by SV40-T antigen, and used as cell model in present study. After co-incubation with electrophoretically purified MRP, two principal morphologic changes of SMEC confluent layer were revealed by light microscopy. Firstly, the confluent cell layer turned into a riddle-like structure full of giant hole. Secondly, cells were fused into syncytia which scattered in the hole, containing 10~30 nuclei. The nuclei were then released from the syncytia after an extreme condensation. And finally, the syncytia disappeared. Results of present study suggest that MRP alone is sufficient to destroy the brain blood barrier.
    Multiplex PCR Detection of Allele on Benzimidazole-Resistance or -Susceptibity in Natural Populations of Haemonchus contortus
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    Scientia Agricultura Sinica. 2005, 38(04):  826-830 . 
    Abstract ( 1170 )   PDF (377KB) ( 712 )   Save
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    A multiplex PCR was developed to detect benzimidazole-resistance (BZ-R) or -susceptibility (BZ-S) in Haemonchus contortus by amplification with 4 primers of a sequence of the GRU-1 gene of β-tubulin of H. contortus making use of sequence information available in Genbank. The method was based on two allele-non-specific primers and two allele-specific primers. F1 (264 bp) and F3 (799 bp) should be produced in BZ-R,F2 (585 bp) and F3 in BZ-S. With this method, it was found that H. contortus BZ-R strain from Australia showed F1 and F3, and the worm BZ-S strain from Shanghai did F2 and F3. Sequences analysis of the isotype 1 gene of β-tubulin of BZ-R from Australia and BZ-S from Shanghai showed the code in residue 200 of the gene was respectively TAC and TTC. The LD50 of Albendazole of the Australian BZ-R strain was 0.54 μg·ml-1, the Shanghai BZ-S train was only 0.0023 μg·ml-1 by EHA (Egg Hatch Assay). The multiplex PCR could determinate the genotype of single adult worm or several third stage larvae and was performed on at least 50 ng of genomic DNA. BZ-R H. contortus were not detected in Shihezi and Yining of Xinjiang Region, Wuhe of Anhui Province, Nanjing and Xuzhou of Jiangsu Province. The LD50 of the H. contortus from these locations to Albendazole as determined by EHA varied between 0.0023-0.0032 μg·ml-1. The result indicated that the multiplex PCR could be used to differentiate BZ-R and BZ-S of H. contortus and that the BZ-R situation of H. contortus was not serious in China.
    RESEARCH NOTES
    Evaluation of Blast Resistance and Restoring or Remaining Characteristics of Rice Germplasm Resources
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    Scientia Agricultura Sinica. 2005, 38(04):  831-836 . 
    Abstract ( 903 )   PDF (187KB) ( 810 )   Save
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    Screening and utilization of rice blast resistant germplasm resources are the important foundation for breeding resistance varieties. The blast resistance and main agronomic traits and restoring or remaining characteristics of 97 rice germplasm resources were evaluated systematically. The results showed that these 97 rice germplasm resources had high or middle resistance to blast and their main agronomic traits were significantly different with the period of 99-132 d from sowing to heading,89.6-149.2 cm in plant height,4.0-13.1 effective panicles per plant, 18.50-42.50 g per 1000-grain weight, 97-268 spikelets per panicle, 45.83%-93.90% of seed setting percentage, 15.28-32.58 g grain yield per plant. This indicated that they had highly genetic diversity. Among them, 37 germplasm resources had restoring character to male-infertile lines and 9 germplasm resources had maintaining character to male-infertile lines. It had an important value for breeding new restorer lines resistant to blast and new male-infertile lines resistant to blast and new high-yield hybrid rice combinations resistant to blast.
    Mating Type and Fertility of the Rice Blast Fungus Population Derived from Guangdong Province, China
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    Scientia Agricultura Sinica. 2005, 38(04):  837-842 . 
    Abstract ( 932 )   PDF (247KB) ( 652 )   Save
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    Mating type and fertility of rice blast fungus population, which consists of 141 isolates collected from Guangdong (GD) Province, China, were characterized by using A and B sets of standard isolates originated from barley and rice, respectively. As for fertility, the frequencies of fertile isolates were 97.7%, 74.2% and 85.5%, respectively, in North, Middle and South GD regions. As for rice-growing season, the frequencies of fertile isolates were 82.8% and 89.6% in early and late seasons respectively. As for mating type, GD population was predominated of MAT1-2. That is, the proportion of MAT1-2 isolates in the fertile part was 98.3%. As for the sexes of isolates, all the fertile isolates were male isolates. In other words, there is no any female and hermaphroditic isolate in the GD population. In regard to the two sets of standard isolates, the frequencies of mating type identified were 86.5% and 4.3% in the GD population by A and B sets, respectively, suggesting that the differentiating capacities of A and B sets of standard isolates are quite different. This result further suggests the genetic background and/or combining ability of standard isolates are important factors in determining mating types and fertilities of heterothalic isolates.
    Alleviatory Effects of Phosphorus on Growth Inhibition of Seawater-Stressed Aloe Seedlings
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    Scientia Agricultura Sinica. 2005, 38(04):  843-848 . 
    Abstract ( 946 )   PDF (333KB) ( 728 )   Save
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    Effects of different P levels on dry matter accumulation, leaf elongation rate, chlorophyll content, root vigor, K+, Na+, Ca2+, Mg2+, Cl- contents of aloe seedings under 30% concentration of seawater were studied. The results showed that addition of P increased significantly plant dry weight, promoted markedly leaf elongation rate, chlorophyll contents and root vigor, decreased the electrolytic leakage of leaves. Addition of P also decreased significantly Na+, Cl- contents, promoted K+, Ca2+ transport to shoot, maintained high K+/ Na+ ,Ca2+/ Na+ and SK,Na in aloe leaves, improved ion homeostasis in leaves, this was one of the main causes of the alleviatory effects of P on growth inhibition of seawater-stressed aloe seedlings.
    Study on Technique of Fast Microbial Retting of Fla
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    Scientia Agricultura Sinica. 2005, 38(04):  849-853 . 
    Abstract ( 1486 )   PDF (236KB) ( 1000 )   Save
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    A scale production trial of fast microbial retting of flax under industrial conditions was conducted. The results indicated that the best cultivating condition for rapid retting strain Ym68ˊ(E. herbicoli) was 35℃, stirring, pH 6.5-7.5, aerate 0.02m3·m-3water·min-1 and maintained for 5-6 h. Compared with traditional method, the retting time decreased by 70%, long fiber production increased by 31%, the fiber quality upgraded by 25.9%, the total effuluent discharge of BOD5 and SS reduced by 33% and 89%, respectively.
    Study on in vitro Growth and Development of Bovine Small Preantral Follicles
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    Scientia Agricultura Sinica. 2005, 38(04):  854-858 . 
    Abstract ( 1072 )   PDF (307KB) ( 725 )   Save
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    Bovine small preantral follicles whose diameter <100 μm (61-70 μm in average) were chosen to culture in vitro. EGF, bFGF and hydrocortione were added to α-MEM medium containing ITS, Sodium Pyruvate, and L-Glutamine, hypoxanthine, serum, FSH, LH, E2. The first experiment result showed that the follicles were cultured for 7 days in vitro when the concentration of FSH, LH, E2 were 0.25 μg·ml-1, 5 iu·ml-1, 0.5 μg·ml-1. The development of the follicles when using both EGF and bFGF was better than with EGF or bFGF individually. When the dose of bFGF(25 ng or 50 ng)was kept invariable, the development of the follicles would be inhibited with the increase of the concentration of EGF . If the dose of bFGF was increased, there would be a good development. The second experiment: the concentrations of FSH, LH and E2 were adjusted into 4 μg·ml-1, 10 iu·ml-1, 0.1 μg·ml-1 and hydrocortione (40 ng·ml-1) was added to α-MEM medium. After being cultured for 13 days in vitro, the developmental rates and the average increasement diameter of follicles in both the test group 3 (EGF 25 ng ) and the test group 4 (EGF 25 ng+bFGF 50 ng) were significantly better than test group 1 (without EGF, bFGF, hydrocortione ) and test group 2 (only added with hydrocortisone). At the 20 day in vitro culture, in both the test group 3 and the test group 4, the ratio of development follicles were 15.79% and 25.58%, and the maximum increase diameter of follicles were 300 μm and 320 μm, and small antrum of follicles came into being (the rates of antrum formation were 7.69 % and 17.65 %, respectively). While in the test group 1 and test group 2, the developmental rate of the follicles was 0. The results showed that when the follicles were cultured in vitro, the variety of culture system had an important influence on the development of preantral follicles, and the components of medium influenced each other.