低能Ar+注入对玉米花粉萌发及Ca2+浓度分布的影响（英文）

To investigate the effect of low energy ion implantation on maize pollen germination and cytosolic Ca2+ distribution during pollen germination process, the argon ion (Ar+) with energy of 30 keV, dose of 0.78 ×1015-13×1015 ion/cm2 was implanted into maize pollen by irradiation, and the germination of pollen and cytosolic Ca2+ distribution during pollen germination process of the Ar+ implanted pollen were studied. The results showed that when been irradiated with Ar+ with dose of 5.2×1015 ion/cm2, the germination rate of maize pollen increased remarkably, while implantation of ions with dose exceeding 5.2×1015 ion/cm2 sharply decreased the germination rate of maize pollen. Meanwhile, tracing of esterified Ca2+ fluorescence probe fluo-3 AM for intact pollen showed that variation of cytosolic Ca2+ concentration was consistent with the change of pollen fertility. The dynamics of cytosolic Ca2+ concentration caused by low energy ion implantation may be concluded as the initial effects of pollen germination.     

Breeding of Selectable Marker-Free Transgenic Rice Lines Containing AP1 Gene with Enhanced Disease Resistance

In order to obtain marker-free transgenic rice with improved disease resistance, the AP1 gene of Capsicum annuum and hygromycin-resistance gene （HPT） were cloned into the two separate T-DNA regions of the binary vector pSB130, respectively, and introduced into the calli derived from the immature seeds of two elite japonica rice varieties, Guangling Xiangjing and Wuxiangjing 9, mediated by Agrobacterium-mediated transformation. Many cotransgenic rice lines containing both the AP1 gene and the marker gene were regenerated and the integration of both transgenes in the transgenic rice plants was confirmed by either PCR or Southern blotting technique. Several selectable marker-free transgenic rice plants were subsequently obtained from the progeny of the cotransformants, and confirmed by both PCR and Southern blotting analysis. These transgenic rice lines were tested in the field and their resistance to disease was carefully investigated, the results showed that after inoculation the resistance to either bacterial blight or sheath blight of the selected transgenic lines was improved when compared with those of wild type.     

Production of Transgenic Anliucheng Sweet Orange （Citrus sinensis Osbeck） with Xa21 Gene for Potential Canker Resistance

Citrus canker, an epidemic quarantine disease caused by Xanthomonas axonopodis pv. citri, has brought a great damage in citrus production worldwide. Herein, a rice PRR （pattern recognition receptor） gene Xa21 together with GUS reporter gene and hygromycin phosphotransferase gene （HPT） was introduced into Anliucheng sweet orange （Citrus sinensis Osbeck） via Agrobacterium-mediated transformation of embryogenic callus. The transgenic calluses were screened on MT basal medium containing hygromycin （HYG） and detected by histochemical GUS staining. The transgenic plantlets were recovered through somatic embryogenesis pathway. The regenerated plantlets were accustomed to and maintained in the greenhouse. The transgene integration of recovered plantlets was identiifed by PCR and Southern blot hybridization. It showed that all the transgenic plantlets tested had undergone single copy integration, the expression of Xa21 in eight different transgenic lines detected by qRT-PCR can be divided into three grades, high for T5 and T6, middle for T4 and low for the rest. The tolerance to citrus canker disease of the three recovered transgenic lines T2, T4 and T6 was assessed by in vitro pin-puncture inoculation. The results showed that all the three transgenic lines conferred improved resistance to citrus canker bacterium infection and the T4 transgenic line displayed the highest resistance. The mechanism and feasibility of rice Xa21 in triggering innate immunity in citrus was brielfy discussed.     

The Comparison in Tissue Culture Ability of Mature Embryo in Different Cultivars of Rice

In order to study the regeneration technology of mature embryos in different rice varieties,nine japonica,nine indica and eleven hybrid rice varieties of two line or three line or superiority combinations were selected as explants to study the callus induction,differentiation and regeneration rates on different media.The higher callus induction （61.7-89.2%） was observed in japonica rice,when cytokinin was added at lower concentration （0.3 mg L-1 6-BA） in M8 basal medium,supplemented with 30 g L-1 sucrose,8 g L-1 agar and 2 mg L-1 2,4-D.Further,the addition of two cytokinins （2 mg L-1 6-BA,0.5 mg L-1 KT） and 1 mg L-1 NAA in the M8 basal supplemented medium resulted in 9.1-100% of the callus induction in indica rice.The percent callus induction in hybrid rice varieties was 40-86.3% when addition of 1 mg L-1 6-BA and 1 mg L-1 KT was added,and the cytokinins was required by the japonica and indica rice varieties in the M8 basal supplemented medium.It was observed that when the 0.5 mg L-1 2,4-D and 1 mg L-1 6-BA were added in japonica rice,and 0.2 mg L-1 2,4-D and 0.5 mg L-1 6-BA were added in indica and hybrid rice in the MS different media,the regeneration rates were 9.2-59.5%,3.6-87.5% and 17.2-43.2% for japonica,indica and hybrid rice,respectively.Thus,the regeneration technology with higher output is established in the mature embryos of similar rice varieties.     

Characteristics of Rice Plant with Heavy Panicle

Using 15 indica rice varieties with different panicle weight, some ideal plant type characteristics in heavy panicle type of hybrid rice （HPT） and their relation to yield and its components were studied. Results showed that the leaf area index （LAI） of the HPT varieties was lower than that of medium panicle type （MPT） and light panicle type （LPT） varieties, but its decreasing rate of LAI and efficient LAI after heading was slower and had much higher percentage of efficient LAI, specific leaf weight, and ratio of grain to leaf area （cm^2） in comparison with the MPT and the LPT varieties. The length, width, thickness, and area of top three leaves of the HPT varieties were significantly larger than those of the MPT and the LPT varieties, and these components of top three leaves were significantly and positively correlated with the number of spikelets and filled grains, grain weight per panicle, and grain yield. The flag leaf in HPT varieties was erect with sorrow leaf angle, and their leaf angle of 2nd and 3rd leaf from top increased in sequence. The plant height of the HPT varieties was higher than that of the MPT and the LPT varieties, and their leaf site of top three leaves also increased in sequence. Therefore, HPT varieties as an ideal plant type could increase the utilization efficiency of sunlight energy. The ideal plant type characteristics and their adjuncts for the HPT varieties are proposed in this article.     

Analysis of Indica-Japonica Differentiation in Rice Parents and Derived Lines Using ILP Markers

Revealing the indica-japonica differentiation in parents of hybridization between indica and japonica rice and their derived lines can provide theoretical and practical bases for the breeding of practical inter-subspecific hybrid rice. Using subspeciesspecific molecular markers ILP （intron length polymorphism） and Cheng＇s index, the indica-japonica differentiation was analyzed with special materials including 18 indica-japonica hybrid parents and 39 derived lines, which accumulated different wide compatibility and restoring genes by convergent cross method in 21 years spanning four breeding phases. The indica-japonica differentiation was detected on all tested loci in 57 materials. Among the 18 parental lines, 4 were japonica type, 5 japonicaclinous type, 8 indicaclinous type and one indica type. The japonica proportion indexes in indica restorer lines Minghui 63 and 9308 were 12.50 and 33.33 %, respectively, while that in japonica restorer line C418 was only 31.25%. Among the 39 derived lines from indica-japonica hybridization, one was japonica type, 11 japonicaclinous type, 20 indicaclinous type and 7 indica type. The japonica proportion index in Minghui 502 was only 10.42%. The results of indica and japonica classification by ILP molecular markers and Cheng＇s index were relatively consistent. The correlation coefficient between the japonica proportion index and morphology index was 0.794＊＊, while that between the indica proportion index and morphology index was -0.7662＊＊. ILP markers could be used to accurately detect the proportion of indica/japonica content in the genome of a rice variety. The results of indica-japonica differentiation analysis could make reasonable explanation for that the hybrids obtained from indica-japonica type restorer lines had obvious heterosis. This conclusion would provide important guidance in efficient use of beneficial genes of inter-subspecific hybrid rice.     

Differential Proteomic Analysis of Leaf Development at Rice （Oryza sativa） Seedling Stage

To identify the function of differential expression proteins in different leaves of rice seedlings extracted from 2- to 5-leaf stages, the leaf proteins at the seedling stage of hybrid rice Shanyou 63 were studied by using the approach of plant proteomics, and those proteins were separated with two-dimensional electrophoresis （2-DE） and then analyzed with an imagemaster 2D Elite 5.0. The results showed that the 41 protein spots were detected differential expression, of which 17 new protein spots appeared after the 3-leaf stage, including 9 special protein spots, which were only detected at the 3-leaf stage. Thirteen protein spots increased first and then decreased in expression abundance gradually and finally even disappeared. For the other 11 protein spots, 3 protein spots decreased, but 6 protein spots were opposite in expression abundance, however, 2 protein spots expressed in an irregular pattern after the 2-leaf stage. Of the 41 differential leaf proteins, 15 protein spots were identified by ESI-Q MS/MS and categorized into 4 groups of functions. The results indicated that proteins were the carriers of the functions in cells, but were significantly influenced by the changes in cell function or intercellular environment; hence, the reason that caused the proteomic changes as mentioned earlier might be related to the occurrence of tillers at the rice seedling stage after the 3-leaf stage.     

Effect of Nitrogen Applied Before Transplanting on NUE in Rice

Nitrogen （N） application before transplanting, where N fertilizers are applied in seedling-bed and carried to the paddy field with seedlings, is a novel method proposed in this article aiming for improving nitrogen utilization efficiency （NUE） in rice. The effect of this method on mineral N distribution in the rhizosphere soil was investigated in a field experiment with a japonica variety, Ningjing 2, in seasons of 2004 and 2005. There were four levels of N applied 16 h before transplanting： zero N （NO）, 207 kg ha^-1 （NL）, 310.5 kg ha^-1 （NM）, and 414 kg ha^-1 （NH）. The result indicated that N fertilizer before transplantation had positive effect of increasing mineral N content in the rhizosphere soil of rice. Generally, N content in the rhizosphere soil of rice tended to increase with the amount of N fertilizer before transplanting, with the NH treatment having the largest effect. Additionally, N fertilizer before transplanting had significant influence on rice NUE and grain yield. Compared with other treatments, the NM treatment showed the largest influence, with basal-tillering NUE, total NUE, and grain yield being 15%, 12%, and 529.5 kg ha^-1 higher than those of NO treatment. This result indicated that N fertilizer before transplantation had positive effect on mineral N distribution in the rhizosphere soil of rice, thus improving NUE and grain yield.     

Myristic Acid （MA） Promotes Adipogenic Gene Expression and the Differentiation of Porcine Intramuscular Adipocyte Precursor Cells

Intramuscular fat （IMF） content is considered to be a key factor that affects the marbling, tenderness, juiciness and lfavor of pork. To investigate the effects of myristic acid （MA） on the differentiation of porcine intramuscular adipocytes, cells were isolated from longissimus dorsi muscle （LDM） and treated with 0, 10, 50 or 100μmol L-1 MA. The results showed that MA signiifcantly promotes the differentiation of intramuscular adipocytes in a dose-dependent manner. MA also led to a parallel increase in the expression of peroxisome proliferator activated receptor-γ（PPARγ） and adipose-related genes, such as glucose transporter 1 （GLUT1）, lipoprotein lipase （LPL）, adipocyte fatty acid binding protein 4 （FABP4/aP2）, fatty acid translocase （FAT）, acetyl-CoA carboxylaseα（ACCα）, adipose triglyceride lipase （ATGL） and fatty acid synthase （FASN）. However, no signiifcant effects of MA were observed on the expression of CAAT enhancer binding protein-α（C/EBPα） or hormone sensitive lipase （HSL）. The expression of pyruvate dehydrogenase kinase 4 （PDK4） was increased by MA during the early stages of differentiation （day 1-3）. In addition, MA also increased the absolute content of C14 （P〈0.001） and saturated fatty acids （SFA） （P〈0.05） to varying degrees, but no effects were observed on other fatty acids. These results suggest that MA might be able to enhance the IMF content of pork and increase the accumulation of myristic and myristoleic acid in muscle, which might have beneifcial implications for human health.     

泥胡菜的组织培养及高效无性系建立(英文)

[Objective] The research aimed to study the rapid propagation technology and establish effective clone of Hemistepta lyrata Bunge. [Method] With tender stem of Hemistepta lyrata Bunge as material, the conditions needed in calluses induction and differentiation, adventitious bud differentiation and radication, test tube seedling cutting and transplantation were studied. [Result] The results showed that the optimum medium for granulated calluses induction from tender stem was MS+BA 0.3 mg/L+2,4-D 1-1.5 mg/L, for granulated calluses and adventitious bud differentiation was MS+AgNO3 1.5 mg/L +BA 0.4 mg/L +NAA 0.1 mg/L. 1/2 MS+IAA 0.6 mg/L was suitable for test tube seedling rooting and regeneration, and cinder was used as transplantation and cutting substrate. [Conclusion] This study will provide the scientific reference for choosing the feasible medium in tissue culture of Hemistepta lyrata Bunge.     

Performance of autoregulatory Senescence-inhibition Gene in Rice

The Performance of autoregulatory senescence - inhibition gene PSAG12 - IPT in rice has been investigated in the study. 422 transgenic plants from 134 independent resistant calli were ohmined from 4 rice varieties through Agrobacterium -mediated transformation. Among them, 233 were positive PSAG12 - IPT transgenic plants identified by GUS histochemical assay and PCR analysis.Southern analysis shorted the transgene was randomly integrated into rice genome, of which 42.29% was single copy. Investigations on photmynthesis function and agronomic characters R1 generation shorted that chlorophy Ⅱ content and photmynthesis rate of flag leaves in transgenic plants, were 41.23% and 50.24% higher than the control wild-type rice, respectively. The growth duration and plant height of the transgenic plants were similar to the control. Variations of other characters were dependent on the varieties. For the variety Millin with significant aging phenomenon in China, its total grains per hill, its seed setting rate and 1000-grain wdght were increased by 40.44%, 8.05% and 8.32% respectively. The results indicated that after leaf senesomce of varieties liable to age was delayed, the seed setting rate and the filling degree of seeds were improved, which finally resulted in significantly increased seed yield and biomass per hill. The new variety Wuyujing 2 without serious aging problem, was also increased in the panicles per hill, the totslgrains per hill, the seed yidd per hill and biomass in different degrees.     

Genotypic Difference in the Responses of Seedling Growth and Cd Toxicity in Rice （Oryza sativa L.）

The experiment was carried out to study the genotypic difference in the responses of seed germination, growth and physiological characters of rice seedlings to Cd toxicity. The result showed that the germination was slightly stimulated under low Cd concentration （0.01-1.5 mM Cd）, while severely depressed under higher Cd concentration （2.0 mM）. Rice seedlings exposed to 0.01 mM Cd showed slight increases in plant height, root volume, biomass and chlorophyll concentration. These parameters were significantly reduced when Cd level in the medium was increased to 0.5 mM, and meanwhile corresponding increase in superoxide dismutase （SOD） and peroxidase （POD） activities, and MDA （malondialdehyde） content was observed. However, SOD and POD activities declined when plants were exposed to 1 mM Cd when compared with those under 0.5 mM Cd. Cadmium addition lowered Fe, Cu and Mn concentrations in roots and shoots. There was significant genotypic difference in the response of these parameters to Cd stress. Under Cd stress, Xiushui 110 had the least inhibition of growth and increase in MDA content, higher shoot Cd concentration, and greatest increase in POD and SOD activities, indicating its higher tolerance to Cd toxicity, while Bing 9914 had the greatest reduction of growth, and Zn, Cu, Fe, and Mn contents, but greatest increase in MDA content, and least increase in activities of antioxidative enzymes, indicating its sensitivity to Cd toxicity.     

The Levels of Genetic Differentiation of Small-Tailed Han Sheep and Tan Sheep Populations Using Structural Loci

Using the method of ＂random sampling in typical colonies of the central area of the habitat＂ and several electrophoresis techniques, the variations of 17 structural loci encoding blood proteins in 60 Small-Tailed Han sheep and 73 Tan sheep were examined and compared with those of 14 other sheep populations in China and other countries to investigate their levels of genetic differentiation. The average heterozygosities of Small-Tailed Han sheep and Tan sheep were 0.2360 and 0.2587, respectively. The average polymorphic information content values were 0.1974 and 0.2102, respectively. The average effective numbers of alleles were 1.5723 and 1.5751, respectively. The coefficients of gene differentiation in the four groups （including 4, 6, 13, and 16 sheep populations, respectively） were 0.049323, 0.059987, 0.1728, and 0.201256, respectively, indicating that the degree of gene differentiation at the structural loci was the least in Hu sheep, Tong sheep, Small-Tailed Hart sheep, and Tan sheep; followed by the above-mentioned four sheep populations and two Mongolian sheep populations; and was the highest in sheep populations belonging to the Mongolian sheep group, South Asian sheep, and European sheep. The earlier researchers＇ conclusions that both Small-Tailed Han sheep and Tan sheep evolved from Mongolian sheep were further verified by the results of this study. Hu sheep, Tong sheep, Small-Tailed Han sheep, and Tan sheep were decreasingly affected by the bloodline of Mongolian sheep to different degrees. The relationships among sheep populations were not closely related to the geographical distances among sheep populations.     

Genotypic variations in nitrogen use efficiency of rice cultivars at various levels of nitrogen under subtropical environment

Insufficient N supply is an important constraint to productivity of lowland rice. Studies on N nutrition of rice cultivars with different durations representing the north western part of Indo-Gangetic Plains are scanty. A field experiment was conducted during kharif seasons of 2006 and 2007 at PAU, Ludhiana to assess the differences in grain yield and N utilization of three popular rice cultivars at varying N doses. Significant differences among genotypes were observed in grain yield, N uptake, N use efficiency and N utilization efficiency. The cultivar PAU-201 was found to be superior among all the tested genotypes. Total N uptake and grain N uptake was highest in cultivar PAU-201 followed by cultivars PR-115 and PR-113. On an average, the response to applied N for grain yield was observed upto 90 kg N ha1. Grain yield increased significantly up to 90 kg N hal in cultivars PR-115 and PAU-201 and up to 120 kg N ha1 in PR-113. Apparent recovery efficiency （ARE） and Partial factor productivity （PFPN） of N was significantly reduced at higher level of N （150 kg N hal）. It was concluded that N uptake is predominant factor in grain yield formation and cultivars differ in NUE suggesting that it may be possible to develop cultivars that are efficient at low nutrient level or are capable of using N more efficiently when applied as fertilizer.     

Effects of Film－Degraded Rice Controlled Release Fertilizer on the Nitrogen Uptake and Yield of the Hybrid Rice

Field experiment was carded out to nitrogen release characteristics of rice controlled release fertilizer (RCRF) coated with natural and half natural high molecular materials, and to thereof effects on the nitrogen uptake and yield of early and late hybrid rice from 1999 to 2000, with urea as control.In experimental fields regardless of early and late seasons, the amount of N in the plants increased exponentially at the early growth stage (y=ab^x) and nonlinearly at the middle and late growth stages(y=a bx cx^2).Rice controlled release fertilizer lengthened the exponential phase and increased the parameter -b/c during the nonlinear phase. Although the N amount of plants was less in rice controlled release fertilizer plots than in urea plots within 20 days after transplanting, at the heading and maturity stages, the N amount of plants in rice controlled release fertilizer plots was above two times greater than in the urea plots due to the higher N recovery, and the high absorption density of N in the nonlinear phase. Tillers pattern and achievement of the maximum filleting stage varied with fertilizer types. The maximum tillering stage in the urea plots occurred a week earlier than in the rice controlled release fertilizer plots. Yield sink size and potential sink size of the plants reflected the N absorption pattern and the amount of N in the plants. The yields of early and late rice with 90 kg N ha^-1 of rice controlled release fertilizer were respectively increased by 832.7 kg ha-1 and 412.8 kg ha-1 than those with 90 kg N ha^-1 of urea, almost equivalent to the yield of early and late hybrid rice with 180 kg N ha^-1 of urea.     

Determination of Amylose Content and Its Relationship with RVA Profile Within Genetically Similar Cultivars of Rice （Oryza safiva L. ssp. japonica）

Anther culture pure lines with antisense Wx gene were generated by Agrobacterium tumefaciens-mediated co-transformation followed by anther culture in transgenic rice （Oryza sativa L. ssp. japonica）. The antisense Wx transgenic pure lines were used to analyze the differences and the relationship between RVA eigenvalues among the lines with different amylose contents. 77 pure lines of anther culture having antisense Wx gene were studied for the amylose content of its offspring cultivar, Wuyunjing 7. It was found that levels ofamylose content were similar to the control in 19 lines （16.0%）; 1-5% lower than control in 50 lines, of which, within 11.0-13.9% in 40 lines; and 3.1-4.0% in 8 lines. The effect of the amylose content on RVA eigenvalue was analyzed through the RVA profile graphic comparison and test of significance for RVA eigenvalues. The analysis of RVA profiles with different amylose contents indicated that there were two kinds of RVA profiles within genetically similar cultivars. The lines with 3.1-4.0% of amylose content were distinctly different from other lines and conventional glutinous rice. The comparison of the similarity curve of RVA profile of the lines with different amylose contents showed that the lines with lower amylose content had a distinguished RVA profile with the curve increasing gradually, but not exceeding the first apex. The test of significance for eigenvalues of the RVA profile in the lines with different amylose contents indicated that there were five eigenvalues remarkably different among the lines with 3.1-4.0% of amylose content compared with other two groups. Further, there were three eigenvalues remarkably different among the lines with 11.0-13.5% of amylose content compared with control group. An optimized mathematical model, which characterizes the relationships between the amylose content and RVA eigenvalue, has been established in this study. From this model, it was clearly indicated that the parameters PeT and SBV were more related to amylose content. It was concluded that the differences in amylose content not only affected the eigenvalues of RVA but also caused different RVA profiles within genetically similar cultivars. The introduction of antisense Wx gene could lead to reduce the amylose content and lay theoretical foundation for quality improvement in rice breeding programs.     

A Novel Three-Dimensional Mouse Embryonic Implantation Model In Vitro

To regenerate three-dimensional endometrium in vitro as a novel model for studying the mechanism of implantation of embryos, the luminal epithelial cells and stromal cells of the rabbit uterus were separated and cultured in vitro. The type Ⅰ mouse tail collagen was used as scaffolding material. The stromal cells were inoculated in the type I mouse tail collagen, and the luminal epithelial cells were inoculated on the type i mouse tall collagen to regenerate the endometrium in vitro. The regenerated endometrium was cultured in DMEM-F/12 media containing 100 nmol L^-1 progesterone, 10 nM β-estradiol, and 10% fetal bovine serum （FBS） for 3 d. The media were then replaced with CZB containing 100 nM progesterone, 10 nmol L-1 β-estradiol, and 10% FBS, and the mouse blastulas were co-cultured with it. The results of scanning electronic micrography showed that the epithelial cells on the surface of the reconstructed endometrium were covered with numerous slender microvilli and some epithelial cells protruded pinopodes. After culturing for 12 h with the mouse blastula, the shedding, attachment, and implantation of the blastula were observed. The blastula can escape from zona pellucida and attach to the three-dimensional endometrium and is then implanted into it. This study showed that the reconstructed three-dimensional endometrium can serve as a robust embryo implantation model in vitro.     

Study of the Protective Effects in PEPC Transgenic Rice

The diurnal course of chlorophyll fluorescence parameter and active oxygen metabolism of flag leaves in PEPC transgenic and untransformed rice Kitaake were studied. The results showed that the photosynthetic rate under high light intensity has been increased by 50% and photoinhibition of photosynthesis in PEPC transgenic was alleviated after the introduction of PEPC gene from maize into rice. It was demonstrated that the increment of photosynthesis in PEPC transgenic was related to the introduction of PEPC gene using specific inhibitor of PEPC. Photoinhibition of photosynthesis in different genotypes exists at noon under natural condition. PEPC transgenic rice exhibited a less decrease in Fv/Fm, a less photoinhibition and a higher efficiency of light energy conversion to chemical energy and lower thermal energy dissipation.These results provided the physiological basis on the mechanism of tolerance to photoinhibition and rice breeding with high photosynthetic efficiency.     

The Susceptibilities of Oxya chinensis （Orthoptera： Acridoidea） to Malathion and Comparison of the Esterase Properties from Three Collected Populations in Tianjin Area,China

The susceptibilities of Oxya chinensis to malathion were studied in three populations collected from outskirt of Tianjin, China, using bioassays and biochemical analysis. Populations were chosen to represent different exposure to insecticides： BDG （Beidagang; low exposure）, BD （Baodi; high exposure previously but low exposure now）, and JN （Jinnan; high exposure）. The results showed that the LD50 values of BD and JN populations were 3.95- and 12.02-fold and 3.64- and 10.07- fold higher than that of BDG population in females and males, respectively. The LD50 values in females were higher than those in males. The results of biochemical analysis indicated that the esterase （EST） activities in JN population were higher than those in BD and BDG populations. They showed that when α-NA, α-NB, and α-NA were used as substrates, females＇ EST activities of JN population were 1.11-, 1.30-, and 1.14-fold and 1.39-, 1.59-, and 1.54-fold higher than those of BD and BDG populations, respectively. When α-NA, α-NB, and β-NA were used as substrates, males＇ EST activities of JN population were 1.13-, 1.12-, and 1,00-fold and 1.20-, 1.14-, and 1.07-fold higher than those of BD and BDG populations, respectively. The results also showed that the specific activities of the females were higher than those of the males in the BD and JN populations, whereas the specific activities of the males were higher than those of the females in the BDG population. The results of bioassay were consistent with those of biochemical analysis. Thus, it was inferred that the elevated ESTs activities might play an important role in conferring the differences of susceptibility of O. chinensis to malathion in the three collected populations. Enzyme kinetic studies indicated that the Km and Vmax values were different among the three collected populations and between the females and the males. The observed changes in the kinetic parameters might be explained by differential expression patterns of isozymes so that the insect esterases have different affinities and maximum velocities toward the same substrate.     

Study on the Optimum Moisture Amount Added to Brown Rice once during the Wet Conditioning

In the experiment, the brown rice whose moisture content was 12.5% was used as raw material. The brown rice was grouped, then moisturized differently and milled. While milling, the energy consumption, the rate of broken rice and the crack rate were tested. It is confirmed that the stress crack owing to the moisture added to the brown rice can be avoided when the moisture amount added once is limited to no more than 1.5%. It is also proved that the energy consumption can be reduced, the yielding rate of rice can be increased and that the quality of rice can be imoroved.