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10 July 2010, Volume 24 Issue 4 Previous Issue    Next Issue
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研究报告
综述与专论
实验技术
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研究报告

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Resistance of Antimicrobial Peptide Genes Transgenic Rice to Bacterial Blight WANG Wei,WU Chao,LIU Mei,LIU Xu-ri,HU Guo-cheng, SI Hua-min, SUN Zong-xiu, LIU Wen-zhen,FU Ya-ping 2010, 24(4): 335-340 .  DOI: 10.3969/j.issn.1001-7216.2010.04.001 Abstract ( )   PDF (573KB) ( )   Antimicrobial peptides (AMP) is a polypeptide with antimicrobial activity. The antimicrobial peptide genes np3 and np5 from Chinese shrimp were integrated into Oryza sativa L. subsp. japonica. cv. Aichi ashahi by Agrobacterium mediated transformation system. PCR analysis showed that the positive ratios of np3 and np5 were 36% and 45% in T0 generation，respectively. RTPCR analysis showed that the antimicrobial peptide genes were expressed in T1 generation and there was no obvious difference in agronomic traits between transgenic plants and nontransgenic plants. Four np3 and np5 transgenic lines in T1 generation were inoculated with the strain CR4 of Xanthomonas oryzae pv. oryzae(Xoo), and the results indicated that all the transgenic lines had a significantly enhanced resistance to bacterial blight caused by the Xoo strain CR4. The np5 transgenic lines also conferred higher resistance to bacterial blight caused by the Xoo strains JS972, ZHE173 and OS225. It is suggested that transgenic lines with np5 gene might possess a broad spectrum resistance to rice bacterial blight.

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Pyramiding of Translucent Endosperm Mutant Gene Wx-mq and Rice Stripe Disease Resistance Gene Stv-bi by MarkerAssisted Selection in Rice (Oryza sativa) YAO Shu,CHEN Tao,ZHANG Ya-dong,ZHU Zhen,ZHAO Ling,ZHAO Qing-yong,ZHOU Li-hui,WANG Cai-lin 2010, 24(4): 341-347 .  DOI: 10.3969/j.issn.1001-7216.2010.04.002 Abstract ( )   PDF (996KB) ( )   A high yielding japonica rice variety, Wuyunjing 7, bred in Jiangsu Province, China as female parent was crossed with the Japanese rice variety Kanto 194, which carries the rice stripe disease resistance gene Stvbi and translucent endosperm mutant gene Wxmq. From F2 generations, a SCAR (sequence characterized amplified region) marker tightly linked with Stvbi and a CAPS (cleaved amplified polymorphic sequence) marker for Wxmq were used for markerassisted selection. Finally, a new japonica rice line, Ning 9108, with excellent agronomic traits was bred by multigenerational selection on stripe disease resistance and endosperm appearance. The utilization of the markers from genes related to rice quality and disease resistance was helpful not only for establishing a molecular markerassisted selection system of highquality and disease resistance in rice, but also for providing important intermediate materials and rapid selection method for good quality, disease resistance and high yield in rice breeding.

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Site-Directed Mutagenesis and Functional Analysis of hrcU Gene from Rice Pathogen Xanthomonas oryzae pv. oryzae LIU Xi-ling, ZOU Hua-song,ZOU Li-fang, CHEN Gong-you 2010, 24(4): 348-352 .  DOI: 10.3969/j.issn.1001-7216.2010.04.003 Abstract ( )   PDF (672KB) ( )   The hrp gene cluster is composed of 27 members in rice pathogen Xanthomonas oryzae pv. oryzae(Xoo). To analyze the function of hrcU gene, the hrcU gene was knocked out by allelic exchange. The resulting hrcU mutant lost the pathogenicity in rice and the ability to trigger hypersensitive response in nonhost plant tobacco. The sole hrcU gene fully restored the phenotypic alterations in pathogenicity in rice, hypersensitive response in tobacco, and bacterial growth in rice. Western blot displayed that the typeⅢ secretion system was destroyed in hrcU mutant in which the T3S effectors Hpa1 could not be secreted into extracellular. This indicates that the hrcU gene of Xoo was essential for type Ⅲ secretion system to deliver effectors into plants.

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Cloning， Expression and Sequence Analysis of G Protein β Subunit Gene of Rice False Smut Pathogen Ustilaginoidea virens LIU Lian-meng,WANG Ling,HUANG Wen-wen,LIU En-yong, HUANG Shi-wen* 2010, 24(4): 353-359 .  DOI: 10.3969/j.issn.1001-7216.2010.04.04 Abstract ( )   PDF (2155KB) ( )   Ustilagionidea virens is a common rice pathogen, which causes rice false smut. G protein may involve in the pathogenicity of U. virens. To study the role of G protein of U. virens in the pathogenicity, a gene that encodes G protein βsubunit had been isolated and characterized. The degenerate primers based on conserved domains of other reported genes were designed to obtain a homologous fragment. Thermal asymmetric interlaced PCR (TAILPCR) was used to isolate flank sequence of the homologous fragment. The gene was obtained by jointing all the fragments and named UvGβ1. Full length of UvGβ1 was 2037 bp, which contained 4 introns, 5 extrons, and an open reading frame (ORF) encoding 359 amino acids. The cDNA sequence containing entire ORF of UvGβ1 was cloned through RTPCR by primers based on the sequence of UvGβ1. The DNA and cDNA sequences of UvGβ1 have been registered in GenBank with accession numbers GU014921 and GU065745. Phylogenetic analysis showed that UvGβ1 had the nearest relationship with the G protein βsubunit gene of Cryphonectria parasitica. The ORF of UvGβ1 was subcloned into pET30a and was expressed in E. coli BL21. The recombinant protein was obtained by IPTG inducing.

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Comparison on Yield Traits of Japonica Hybrid Rice Derived from Different Types of Parents TANG Shu-zhu,ZHANG Hong-gen,KONG Xian-wang,WAN Lin-sheng, ZHU Zheng-bin,YI Chuan-deng,GONG Zhi-yun,GU Ming-hong 2010, 24(4): 360-366 .  DOI: 10.3969/j.issn.1001-7216.2010.04.005 Abstract ( )   PDF (1070KB) ( )   For investigating the effects of parent on yield traits of japonica hybrid rice, 16 BT type cytoplasmicnuclear male sterile lines (A line), and their corresponding maintainer lines (B line) and 16 restorer lines (R line) were used to make 229 hybrids. According to the results of clustering analysis, 229 F1 hybrids were divided into different groups. By comparing the traits of hybrids in different groups, it is concluded that most traits of F1 hybrids derived from different types of A lines and R lines were midtype between their parents. Heading date and plant height of the parents had no obvious effect on panicle number per plant, spikelet number per panicle, filled grain number per panicle, grain yield per plant and total spikelet number per plant of F1 hybrids. But panicle number per plant and spikelet number per panicle of parents had an obvious impact on F1 hybrids. Spikelet number per panicle, total spikelet number per plant and yield potential of the F1 hybrids derived from small panicle type parents (with less grains in a panicle) were less, whereas these of the F1 hybrids derived from largepanicle type parents were more. F1 hybrids derived from small panicle type A lines and largepanicle type R lines had higher yield than others, which could be a better mating type for japonica hybrid rice breeding. F1 hybrids orignated from erect panicle A lines with curved panicle R lines had the most spikelet number per plant, the highest yield potential and best plant type among four mating types.

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Genetic Analysis and Preliminary Mapping of Two Recessive Resistance Genes in Rice to Brown Planthopper, Nilaparvata lugens HOU Li-yuan,YU Ping,XU Qun,YUAN Xiao-ping,YU Han-yong,WANG Yi-ping,WANG Cai-hong,WAN Guo,PENG Suo-tang,WEI Xing-hua 2010, 24(4): 367-371 .  DOI: 10.3969/j.issn.1001-7216.2010.04.006 Abstract ( )   PDF (712KB) ( )   An F2 population was derived from the cross of the brown planthopper resistant line WB01, an introgression line of common wild rice (Oryza rufipogon Griff.) from Hainan Province, China and the susceptible indica cultivar 9311. The population with 303 lines was genotyped using 141 simple sequence repeat (SSR) markers and used for gene mapping. Two softwares, MapMaker/Exp 3.0 and Windows QTL Cartographer 2.0 were applied to detect QTLs. Totally, two QTLs on chromosomes 4 and 8 were detected. Each of these QTLs individually explained 11.3% and 14.9% of the phenotypic variations, respectively.

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Comparison of Genetic Linkage Map and QTLs Controlling Flag Leaf Traits Based on F2 and F2:6 Populations Derived from Japonica Rice JIANG Shu-kun,ZHANG Xi-juan,HUANG Cheng,XING Ya-nan,ZHENG Xu,XU Zheng-jin,CHEN Wen-fu 2010, 24(4): 372-378 .  DOI: 10.3969/j.issn.1001-7216.2010.04.007 Abstract ( )   PDF (1033KB) ( )   A comparative analysis was performed on genetic information and QTLs controlling flag leaf traits including length, width and specific leaf weight of flag leaf between two populations (F2 and F2:6) derived from a cross between two japonica rice cultivars, Shennong 265 and Lijiangxintuanheigu(LTH). On the two genetic linkage maps most markers had the same order along chromosomes, but the genetic distance between two markers was different. Thirty and thirteen markers showed genetic distortion significantly and extremely significantly in F2 population, separately. Nineteen and eleven markers deviated toward Shennong 265 and LTH, separately. Sixtytwo and thirtyeight markers showed genetic distortion significantly and extremely significantly in F2:6 population, separately. Fortythree and nineteen markers deviated toward Shennong 265 and LTH, separately. These distortional markers formed ten segregation distortion regions (SDRs). Six of them were detected in both F2 and F2:6 populations. F2:6 population had more powerful detective ability than F2 population in QTL dectection. Seven QTLs controlling flag leaf traits including two controlling leaf length, four controlling leaf width and one controlling specific weight were detected in F2 population. Whereas seventeen QTLs for these traits (seven for leaf length, five for leaf width and five for specific leaf weight) were detected in F2:6 population. Four QTLs were detected in both populations including qFLL9 controlling flag leaf length on chromosome 9, qFLW4 controlling flag leaf width on chromosome 4, qFLW12.1 controlling flag leaf width on chromosome 12 and qSLW6 controlling specific leaf weight on chromosome 6. Among them, qSLW6 (Additive effect was 1.956 mg/cm2) for specific leaf weight has a high research and application value.

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Differences in Amylopectin Structure and Grain Quality of Rice Between Some HighQuality Japonica Cultivars from the Lower Yangtze River Region, China and Koshihikari from Niigata, Japan LEE Jung-ro ,ZHANG Jian-ming,WANG Hui,LI Mao-bai,PIAO Zhong-ze 2010, 24(4): 379-384 .  DOI: 10.3969/j.issn.1001-7216.2010.04.008 Abstract ( )   PDF (1528KB) ( )   Amylopectin chain length distribution, RVA profile value, amylose content, protein content, TOYO palatability and other quality characteristics of rice flour were compared between japonica rice cultivar Koshihikari (produced in Niigata, Japan) and five japonica rice cultivars well known as good eating quality from the Lower Yangtze River Region, China. The Koshihikari rice had no significant difference with japonica rice from the Lower Yangtze River Region in amylopectin chain length distribution and amylose content, whereas the Japanese rice possessed significantly lower proportion of long chain Fb3 \[37≤Degree of polymerization (DP)≤58\] and protein content and a significantly higher ratio of short and long chain(Fa/Fb3) than japonica rice from the Lower Yangtze River Region. Moreover, the Koshihikari rice possessed significantly higher values in Mg and K contents, peak viscosity and breakdown viscosity than those of rice from the Lower Yangtze River Region. There was a significantly positive correlation between the proportion of short chain Fa(5≤DP≤12) and the characteristics of RVA profile, such as peak viscosity and breakdown, and a significantly positive correlation between the ratio of short and long chains(Fa/Fb3) and RVA profile characteristics, such as peak viscosity and breakdown. Therefore, it is concluded that improving structure characteristics of amylopectin in breeding and reducing nitrogen fertilizer in cultivation are the most efficient approach for improving rice palatability in the Lower Yangtze River Region of China.

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Estimating Rice Yield by HJ-1A Satellite Images LI Wei-guo, LI Hua, 2010, 24(4): 385-390 .  DOI: 10.3969/j.issn.1001-7216.2010.04.009 Abstract ( )   PDF (1005KB) ( )   With Xuyi County, Jinhu County and Hongze County in Jiangsu Province, China as examples, monitoring and forecasting of rice production were carried out by using HJ1A satellite remote sensing images. The handhold GPS machines were used to measure the geographical position and some other information of these samples such as areas shapes. The GPS data and the interpretation mark were used to correct HJ1 image, assist humancomputer interactive interpretation, and other operations. The test data had been participated in the whole classification process. The accuracy of interpreted information on rice planting area was more than 90%. By using the leaf area index got from the normalized difference vegetation index inversion, and the biomass got from the ratio vegetation index inversion, combined with the rice yield estimation model, the rice yield was estimated. Further the thematic map of rice production classification was made based on the rice yield data. According to the comparison results between measured and fitted values of the yields and areas of sample sites, the accuracy of the yield estimation was more than 85%. The results suggest that HJ1A/B images could basically meet the demand of rice growth monitoring and yield forecasting, and could be widely applied to rice production monitoring.

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Effect of H2O2 Pretreatment on Cd Tolerance of Different Rice Cultivars BAI Xiao-juan,LIU Li-juan,ZHANG Chun-hua,GE Ying,CHENG Wang-da 2010, 24(4): 391-397 .  DOI: 10.3969/j.issn.1001-7216.2010.04.010 Abstract ( )   PDF (701KB) ( )   The effect of H2O2 pretreatment on Cd tolerance and translocation in rice seedlings was studied by using two rice cultivars (N076 and N0763) differing in Cd tolerance. The contents of malondialdehyde(MDA), reduced glutathione (GSH), nonprotein thiols (NPT), phytochelatins(PCs) and the activity of glutathione Stransferase (GST) were compared between the two cultivars exposed to various treatments. The results showed that 50 μmol/L Cd exposure significantly inhibited rice growth, enhanced the production of GSH, NPT, PCs, MDA and the activity of GST, and there were significant differences between the two cultivars. More Cd was transported into the shoot in N076. The H2O2 pretreatment alleviated Cd toxcity by further increasing GSH, NPT and PCs contents, as well as the root GST activities. The larger increase in N0763 than in N076 suggests that the tolerance of N0763 was enhanced more significantly than N076. H2O2 pretreatment reduced Cd translocation to rice shoots but affected the Cd concentration in roots differently. From the above results, it may be speculated that there were clear differences in the Cd detoxification and response to the H2O2 pretreatment between the two cultivars.

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Effects of High Temperature on Key Enzyme Activities of Nitrogen Metabolism and Protein Content During Rice Grain Filling LIANG Cheng-gang, CHEN Li-ping,WANG Yan,LIU Jia,XU Guang-li,LI Tian* 2010, 24(4): 398-402 .  DOI: 10.3969/j.issn.1001-7216.2010.04.011 Abstract ( )   PDF (1363KB) ( )   The japonica rice variety Koshihikari and indica rice variety IR72 were used to research the effects of high temperature on the activities of glutamine synthetase(GS), glutamate synthase(GOGAT), glutamic oxaloacetic transaminase(GOT), glutamate pyruvate transaminase(GPT), and the contents of protein and amino acids in grains during rice grain filling. The average activities of GOGAT, GOT and GPT in grains significantly increased under high temperature during rice grain filling, while the activity of GS significantly decreased. And the contents of protein and amino acids constituents in grains significantly increased. The significant decrease of GS activity in grains under high temperature did not influence the synthesis of protein, so it is presumed that GS in rice grains was not the key enzyme to restrain the synthesis of protein.

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Effects of Different Nitrogen Forms and Water Stress on the Growth and Osmotic Adjustment of Rice Seedlings LI Hai-jun,LI Yong,YANG Xiu-xia,SHEN Qi-rong,GUO Shi-wei* 2010, 24(4): 403-409 .  DOI: 10.3969/j.issn.1001-7216.2010.04.012 Abstract ( )   PDF (979KB) ( )   The responses of indica and japonica rice seedlings to water stress were studied by supplying with different nitrogen forms under 100 g/L PEG6000 simulated water stress. The results showed that compared with ammonium nutrition, water stress significantly decreased shoot growth and photosynthesis of nitrate supplied indica and japonica rice seedlings with a more severe inhibition on japonica rice seedlings; under water stress, ammonium supplied rice plants could sufficiently accumulate and transfer amino acids and potassium, which led to relative higher amino acids and potassium contents in xylem and phloem sap; when leaf water potential decreased under water stress, ammonium supplied rice plants could enhance or maintain relative higher leaf water content through osmotic regulation. Therefore, when leaf water potential was decreased under water stress, the maintenance of leaf water content in ammonium supplied rice plants ensured relative higher photosynthesis, which subsequently enhanced the tolerance of rice plants to water stress.

综述与专论

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A Review on Detection Technologies for Exogenous Proteins in Transgenic Rice HUANG Guo-ping,WANG Lin,CHEN Ke-ping 2010, 24(4): 410-416 .  DOI: 10.3969/j.issn.1001-7216.2010.04.013 Abstract ( )   PDF (458KB) ( )   With the development of transgenic rice research and industrialization, it becomes a hot research area to detect exogenous proteins in transgenic rice (EPTR). Here, current detection technologies used for detecting EPTR and other potential protein detections were described, and the problems for these technologies were preliminarily analyzed. In the end, trends of detection technologies for EPTR were predicted.

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Progress in Research on Patterns and Systematic Theories of SuperHighYielding Cultivation in Rice GONG Jin-long,ZHANG Hong-cheng,LI Jie,DAI Qi-gen,HUO Zhong-yang,XU Ke, ,LI De-jian,HUA Zheng-xiong,SHA An-Qin,ZHOU You-yan,LUO Xue-chao, LIU Guo-lin 2010, 24(4): 417-424 .  DOI: 10.3969/j.issn.1001-7216.2010.04.014 Abstract ( )   PDF (564KB) ( )   The development of the patterns of superhighyielding cultivation in rice was reviewed. Several new patterns of superhighyielding cultivation in rice were highlighted and the systematic theories and approaches of the formation of superhighyielding were analyzed. Moreover, the problems existed in the course of largescale extension and production of superhighyielding were discussed and the solutions were then put forward. Finally, the development of superhighyielding cultivation pattern in the future was forecasted.

实验技术

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Preliminary Report on the Transmission of Rice BlackStreaked Dwarf Virus from Frozen Infected Leaves to Rice by Insect Vector Small Brown Planthopper (Laodelphax striatellus） ZHOU Tong#,WU Li-juan#,WANG Ying,CHENG Zhao-bang,JI Ying-hua,FAN Yong-jian,ZHOU Yi-jun* 2010, 24(4): 425-428 .  DOI: 10.3969/j.issn.1001-7216.2010.04.015 Abstract ( )   PDF (601KB) ( )   In order to preserve virus for identifying resistant rice varieties against rice blackstreaked dwarf disease, a simple and reliable method was developed by which virusfree small brown planthopper(SBPH) acquired rice blackstreaked dwarf virus（RBSDV） from frozen infected leaves and transmitted the virus to healthy rice plants. RBSDV acquired from infected leaves frozen at -70℃ by SBPH was transmitted to a susceptible rice variety. The experimental result showed that the SBPH could acquire the virus from frozen infected leaves and transmit it to the susceptible rice variety. For the ability of obtaining and transmitting the virus by SBPH, there was no significant difference between frozen infected leaves and fresh infected leaves. The novel method could be applied to the resistance identification of rice varieties to rice blackstreaked dwarf disease and it would facilitate the breeding process for rice blackstreaked dwarf disease resistance.

研究简报

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Genetic Analysis and Molecular Mapping of a PhotoperiodThermoSensitive Genic Male Sterile Gene (PTGMS2-1) in Rice Line Guangzhan 63S WANG Bao-he,XU Jian-jun,WU Yin-hui,ZHU Jin-yan,LI Sheng-qiang,ZHOU Yong,CHENG Xiao-tao,LIANG Guo-hua 2010, 24(4): 429-432 .  DOI: 10.3969/j.issn.1001-7216.2010.04.016 Abstract ( )   PDF (566KB) ( )   Guangzhan 63S, a photoperiodthermosensitive genic male sterile (PTGMS) line, was one of the most widely used PTGMS lines in twoline indica hybrid rice breeding system in China. Genetic analysis indicated that the sterility of Guangzhan 63S was controlled by a single recessive gene using the F2 population derived from a cross between the Guangzhan 63S and Han 1587. Molecular mapping was performed on the F2 mapping population using SSR and InDel markers and bulkedsegregant analysis(BSA). The PTGMS21 was restricted to a 390kb region on chromosome 2 between the markers S24 and S227, at genetic distances of 0.5 cM and 1.1 cM, respectively, and cosegregated with S224.

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Effects of Gibberellic Acid 3 and Abscisic Acid on Growth, Physiological Characteristics and Gene Expression of GA20ox2 and GA3ox2 in Different Rice Cultivars YANG Yan-hua,ZHANG Ya-dong,ZHU Zhen,ZHAO Ling,CHEN Tao,ZHAO Qing-yong,WANG Cai-lin* 2010, 24(4): 433-437 .  DOI: 10.3969/j.issn.1001-7216.2010.04.017 Abstract ( )   PDF (1106KB) ( )   Effects of exogenous gibberellic acid 3 (GA3) and abscisic acid (ABA) on the growth, physiological characteristics and gene expression of GA20ox2 and GA3ox2 were studied at fourleaf stage with five rice cultivars. Results showed that 1 μmol/L GA3 could promote seedling height, restrain root elongation, and increase the contents of chlorophyll and soluble protein, and permeability of cell membrane. However, 10 mg/L ABA could inhibit the seed germination heavily and also retard seedling height and decrease the contents of chlorophyll and soluble protein, and permeability of cell membrane. RTPCR detection showed that the expression of GA20ox2 was obviously upregulated under the GA3 treatment, except for Nipponbare. On the contrary, ABA restrained the expression of GA20ox2. In the three rice cultivars, Nanjing 44, Kanto 194 and Nipponbare, GA3 induced the expression of GA3ox2 and ABA inhibited the expression of GA3ox2.

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Relations Between Changes in Contents of Phenolic Acids and Phenolic Polymers and Induced Resistance to Bacterial Blight in Rice under Nickel Treatment TAN Xin-zhong,PENG Xi-xu,HU Yao-jun,TANG Xin-ke,ZHOU Ping-lan,DENG Xiao-bo,WANG Hai-hua* 2010, 24(4): 438-442 .  DOI: 10.3969/j.issn.1001-7216.2010.04.018 Abstract ( )   PDF (869KB) ( )   Changes in accumulation of total phenolics, phenolic acids, phenolic polymers and activity of cell wall bound peroxidase (POD) were investigated in leaves of rice exposed to nickel treatment. Ten soluble phenolic acids and seven bound phenolic acids were detected. The levels of soluble chlorogenic acid and salicylic acid were significantly promoted by nickel treatment, whereas the contents of their bound forms remained unchanged. Nickel treatment evidently increased the concentrations of both soluble and bound ferulic acid. However, nickel treatment led to a significant decrease in the contents of soluble syringic acid and pcoumaric acid but an increase in those of their bound forms. Moreover, the pronounced accumulation of phenolic polymers and enhancement in activities of cell wall bound POD, either with ferulic acid or syringaldazine as its substrate, were registered in rice leaves following nickel treatment. The present results combined with the previous study suggest that the accumulation of phenolic acids and phenolic polymers are involved in the establishment of nickelinduced resistance against bacterial blight in rice.

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Effects of Temperature on Resistance of Rice to Brown Planthopper, Nilaparvata lugens WANG Bao-ju,XU Hong-xing,ZHENG Xu-song,FU Qiang,LU Zhong-xian 2010, 24(4): 443-446 .  DOI: 10.3969/j.issn.1001-7216.2010.04.019 Abstract ( )   PDF (836KB) ( )   To investigate effect of temperature on the resistance characteristics of rice varieties with different resistance genes to rice brown planthopper (BPH), Nilaparvata lugens (Stl), the resistances of IR26(Bph1) and IR36 (bph2) to Hangzhou population of BPH were monitored in greenhouse during 2007 and 2008 by using the Standard Seedling Screening Techniques (SSST) developed by the International Rice Research Institute (IRRI). The changes in resistances of IR26 and IR36 to BPH, soluble sugar and oxalic acid contents in 25dayold rice plants of susceptible variety TN1 and resistant varieties IR26 and IR36 were detected at five temperatures (22℃, 25℃, 28℃, 31℃ and 34℃). The results showed that IR26 completely lost its resistance both at natural temperatures and at the five tested constant temperatures, IR36 still had medium level resistance under natural temperature. IR26 and IR36 showed a decreased trend in the resistance from 25℃ to 34℃, and they fully lost the resistance at 31℃ and 34℃. The highest resistance duration for both of IR26 and IR36 was recorded at 25℃. The soluble sugar contents in plants of the three tested rice varieties increased with the increasing temperature, and the oxalic acid content decreased at the temperatures higher than 25℃. Twoway ANOVA indicated the significant effects of temperature and rice variety on contents of soluble sugar and oxalic acid in rice plant.