The genus Oryza consists of approximately 24 species with 10 recognized genome types (A, B, C, BC, CD, E, F, G, HJ, HK). The species with the CD genome are endemic to the Central and South America and comprise three s...The genus Oryza consists of approximately 24 species with 10 recognized genome types (A, B, C, BC, CD, E, F, G, HJ, HK). The species with the CD genome are endemic to the Central and South America and comprise three species, i.e. O. latifolia Desv., O. alta Swallen and O. grandiglumis (Doell) Prod. Although the three species can be easily distinguished from the species with the other genomes in Oryza by their morphological characteristics, it is very difficult to distinguish them from one another. Recent studies suggested that O. alta and O. grandiglumis should be the same species (O. grandigiumis), whereas O. latifolia retains its taxonomic position unchangeably. In this paper, a total of 77 clones of the nuclear ribosomal internal transcribed spacer (ITS) from 11 samples representing different geographical races were sequenced. Using DNA Strider 1.2 software, the restriction enzyme digestion sites of these clone sequences were analyzed. Based on restriction fragment length polymorphism (RFLP) of ITS sequences, a method to identify the species with CD genome in Oryza was proposed. The method is rapid and convenient and all experimental procedure includes only three steps: (1) to amplify the ITS fragment with the routine primers; (2) to digest PCR products with restriction enzymes Fok I and Dra III or both; (3) to run the digested product on 1% agarose gel and identify the sample based on the restriction profiles.展开更多
[Objective] The aim was to study the relationship between urcrose, zinc and the root system growth in rice. [Method] Changes of root system growth, ROS generation and root system proton export ability were analyzed in...[Objective] The aim was to study the relationship between urcrose, zinc and the root system growth in rice. [Method] Changes of root system growth, ROS generation and root system proton export ability were analyzed in rice (Oryza sativa L. cv Zhonghua No.11) treated with different concentrations of Zn (NO3)3 sucrose, com- bined sucrose and Zn (NO3)3 mannitol as well as mannitol plus Zn (NO3)2. [Result] The results showed that treatment with 1-3 mM Zn(NO3)2 resulted in significant increases in total root length /number and in accumulation of H202 and 02- but decreases in root system proton export ability. With the exception of shoot length, the length of primary, adventitious, and lateral roots, and the number of adventitious, and lateral roots on primary /adventitious roots were all influenced by different concentrations of sucrose. High concentrations of sucrose caused increases in H202 and O2-, starva- tion or high concentrations of sucrose reduced root system proton export ability after treating with or without Zn. However, at the same concentration of sucrose, different changes of these indicators were observed between Zn and non-Zn treatments. The regulation of root system growth induced by sucrose was marked different from that of mannitol at the same concentration of 5%, suggesting that these effects were caused by sugar signal but not by osmotic potential. [Conclusion] This study indicat- ed that both sucrose and Zn play important roles in the regulation of rice root system growth.展开更多
The 1 195 bp 5′ flanking region of rice ( Oryza sativa L.) cytosolic fructose_1, 6_bisphosphatase (cyFBPase) can direct tissue, cell specific expression in transgenic rice. In order to identify sequence elements ...The 1 195 bp 5′ flanking region of rice ( Oryza sativa L.) cytosolic fructose_1, 6_bisphosphatase (cyFBPase) can direct tissue, cell specific expression in transgenic rice. In order to identify sequence elements responsible for the regulation of mesophyll_specific expression, the 5′ flanking regions of -1 195 bp, -1 102 bp, -768 bp, and -644 bp upstream of the translation initiation ATG codon were fused to the reporter gene encoding β_glucuronidase (GUS) and transferred to rice via particle bombardment. Analysis of the 5′ promoter deletions identified that a 93 bp fragment between -1 195 bp and -1 102 bp is essential for directing mesophyll specific expression. High constitutive expression of GUS reporter gene was found in the -768 deletion lines and another two deletion series. These results indicate the great potential utility of the promoter in rice biotechnology.展开更多
Five triterpenoid saponins were isolated from the Chinese traditional medicine Eclipta prostrata L.. On the basis of their chemical properties and spectral data, they were identified as eclalbasaponins II(1), I(2), II...Five triterpenoid saponins were isolated from the Chinese traditional medicine Eclipta prostrata L.. On the basis of their chemical properties and spectral data, they were identified as eclalbasaponins II(1), I(2), III(3), 3-O-[b-D-glucopyranosyl(12)-b-D-glucopyranosyl]-16a-ethoxy-olean-12-ene-28-oic acid-28-O-b-D-glu-copyranoside(4) and 3-O-[(2-O-sulfuryl-b-D-glucopyranosyl)(12)-b-D-glucopyranosyl]-echinocystic acid-28-O-b-D-glucopyranoside(5). Compounds 4 and 5 are new compounds and named eclalbasaponins XI and XII, respectively. Compounds 1 and 5 induced morphological deformation of Pyricularia oryzae mycelia.展开更多
[Objective] This study was aimed at exploring the effect of glucose signal on the zinc-induced growth of root system using rice as the material.[Method] The variation of root system growth,active oxygen production and...[Objective] This study was aimed at exploring the effect of glucose signal on the zinc-induced growth of root system using rice as the material.[Method] The variation of root system growth,active oxygen production and proton secretion of root systems treated with various concentrations of glucose,glucose + Zn(NO3)2,mannitol and Zn(NO3)2 + mannitol were analyzed in rice(Oryza sativa L.cv Zhonghua no.11).[Result] The results showed that the concentrations of glucose had affected the shoot height,primary root length,amount and length of lateral roots on primary roots,adventitious root length and length of lateral roots on adventitious roots in varying degrees,but not the amount of adventitious roots and lateral roots on adventitious roots under Zn+ and Zn-condition.Glucose of high concentrations induced the production of active oxygen,while lacking of glucose would lead to the decrease of proton secretion of root systems.However,there were significant differences in these indexes between under Zn+ and under Zn-condition treated with the same concentrations of glucose.The effects of glucose and mannitol with the same concentration on the growth of root systems were significantly different,indicating that the variation was resulting from sugar signal but not the osmotic potential.[Conclusion] The glucose had played important roles in the growth of rice root system both under normal condition and under Zn+ condition.展开更多
[Objective] The aim was to study the effects of over-expressed sm-Ngt1,a glycosyltransferase gene induced by both methyl jasmonate and salicylic acid from tobacco,on the plant height of rice.[Method] The binary expres...[Objective] The aim was to study the effects of over-expressed sm-Ngt1,a glycosyltransferase gene induced by both methyl jasmonate and salicylic acid from tobacco,on the plant height of rice.[Method] The binary expression vector of the sm-Ngt1 gene was constructed and transferred to matured embryo of indica rice YTB with the method of Agrobacterium infection.The height of the positive transgenic plants was measured.[Result] 117 positive transgenic plants with sm-Ngt1 were obtained.The results showed that the rice plants dwarfed with different degrees after transferring the sm-Ngt1 gene,the height of 37% of transgenic plants is 71.4±9.8 cm,27% is 65.1±4.6 cm,and the average height of YTB(CK) is 130.0±4.3 cm.[Conclusion] These results aid a foundafion for further study on function of sm-Ngt1.展开更多
The utilization of hybrid rice heterosis between subspecies is an important way to prove rice breeding programs, but the low matter conversion rate of inter- subspecific hybrids becomes the bottleneck to get high yiel...The utilization of hybrid rice heterosis between subspecies is an important way to prove rice breeding programs, but the low matter conversion rate of inter- subspecific hybrids becomes the bottleneck to get high yield. To further explore the reasons for the low conversion rate of dry matters, and the coordination mechanism between biological yield's potential and grain yield's potential, we evaluated the correlations of the agronomic characters between the female parent and F1 inter subspecific hybrids, using a male parent R292, three female parents Y58S, Peiai 64S and 83S, and their hybrid combinations Y58S/292, 64S/292 and 83S/292 as experimental materials, Yueyou 9113 as the control. The results indicated that the contents of both soluble sugar and starch of all the experimental materials varied at different growth stages, and the highest starch content appeared at pre-ripening stage while soluble sugar content was the lowest. Notable positive correlations in a- gronomic characteristics were observed between the female parents and their F1 hybrids. The soluble sugar content in stem was the highest, followed by that in panicle, and the soluble sugar content in sheath and flag leaf was lower. The re- sults provide a theoretical basis for the research on heterosis and yield coordination mechanisms of inter-subspecific hybrids of rice.展开更多
Little information is available on the interactive effects of inorganic and organic pollutants on carbon utilization by soil microorganisms.This study examined the effects of two common soil pollutants,lead(Pb) and be...Little information is available on the interactive effects of inorganic and organic pollutants on carbon utilization by soil microorganisms.This study examined the effects of two common soil pollutants,lead(Pb) and bensulfuron-methyl herbicide(BSM),on decomposition of an adscititious carbon source(14C-glucose).Two contrasting paddy soils,a silty clay soil and a clay loam soil,were incubated with different concentrations and combinations of pollutants for 60 days.Orthogonal rotatable central composite design was adopted to design the combinations of the pollutant concentrations so that rate response curves could be derived.Rapid decomposition of 14C-glucose occurred in the first three days for both soils where no Pb or BSM was added(control).Overall,63%-64% of the added 14C-glucose was decomposed in the control over the 60-day incubation.The addition of Pb or BSM significantly decreased the decomposition of 14C-glucose during the first week but increased the decomposition thereafter;as a result,the percentages of 14C-glucose decomposed(57%-77%) over the 60-day period were similar to or higher than those of the control.Application of the pollutants in combination did not further inhibit decomposition compared with the control.Overall,decomposition rates were lower in the silty clay soil than in the clay loam soil,which was related to the soil texture,cation exchange capacity,and pH.The relationship between the decomposition rates and the pollutants could be well characterized by the quadratic regression orthogonal rotation model.The initial antagonistic effects of the pollutants followed by the synergistic effects on microbial activity might result from changes of the concentrations of the pollutants.展开更多
Plastids of nongreen tissues import carbon as a source of biosynthetic pathways and energy, and glucose 6 phosphate is the preferred hexose phosphate taken up by nongreen plastids. A cDNA clone encoding glucose 6 ph...Plastids of nongreen tissues import carbon as a source of biosynthetic pathways and energy, and glucose 6 phosphate is the preferred hexose phosphate taken up by nongreen plastids. A cDNA clone encoding glucose 6 phosphate/phosphate translocator ( GPT ) was isolated from a cDNA library of immature seeds of rice and named as OsGPT . The cDNA has one uninterrupted open reading frame encoding a 42 kDa polypeptide possessing transit peptide consisting of 70 amino acid residues. The OsGPT gene maps on chromosome 8 of rice and is linked to the quantitative trait locus for 1000 grain weight. The expression of OsGPT is mainly restricted to heterotrophic tissues. These results suggest that glucose 6 phosphate imported via GPT can be used for starch biosynthesis in rice nongreen plastids.展开更多
In this paper, processes for producing a food-grade glucose solution through enzymatic hydrolysis of celluloserich solids obtained from rice straws are presented. The rice straws were pretreated by acid-catalyzed stea...In this paper, processes for producing a food-grade glucose solution through enzymatic hydrolysis of celluloserich solids obtained from rice straws are presented. The rice straws were pretreated by acid-catalyzed steam explosion, and the reaction efficiency, toxicity control, and process economic feasibility were studied. Mass transfer resistance to the hydrolysis reaction was reduced by grinding with glass beads. A higher glucose concentration could be obtained by feeding more cellulose in the hydrolysis reaction; however, this also resulted in the production of undesired byproducts. Thus, a soaking process for the cellulose solids in water was developed to effectively reduce the generation of byproducts in the hydrolysis reaction. The resulting food-grade glucose solution can provide 414 kilocalories per liter, and could be used during a food-shortage crisis in the future.The current production cost is estimated to be 0.82 USD·L^(-1).展开更多
In order to study osmotic adjustment and accumulation of anions and cations in rice (Oryza sativa L.) seedlings under NaCl stress, a greenhouse experiment was conducted using two rice cultivars including IR651 (tol...In order to study osmotic adjustment and accumulation of anions and cations in rice (Oryza sativa L.) seedlings under NaCl stress, a greenhouse experiment was conducted using two rice cultivars including IR651 (tolerant) and IR29 (sensitive). Seedlings were grown in Youshida nutrient solution. Salinity treatments were imposed 21 days after sowing with 0 and 100 mM NaCI and seedlings were harvested 0, 72, 120 and 240 hour after salinization. Water (ψw) and osmotic (ψs) potentials, total soluble sugars and inorganic ions (Na+. K+, Cl-, Ca2+ and Mg2+) concentrations and osmotic adjustment were determined in sixth (youngest) leaf. Salinity caused a substantial biomass reduction in rice seedlings, ψs reduction in IR29 was occurred more than IR651. Water potential decreased in both the cultivars under stress conditions, but IR651 was able to maintain higher ψw and kept better growth till the end of the experiment. Osmotic adjustment was observed in IR651 was about 10 times more than in IR29. K+ accumulation decreased in both cultivars under stress condition while Na+ accumulation increased in both the cultivars with higher increase in IR29 seedlings. CI concentration increased in youngest leaf of both IR29 and IR651. Our results showed that tolerant cultivar was able to make osmotic adjustment faster than the sensitive cultivar using high accumulation of solutes especially total soluble sugars.展开更多
This research was to examine if rice (Oryza sativa L.), a monocotyledon of angiosperm, was able to synthesize chlorophyll (Chl) in complete darkness. Five-cm-tall etiolated seedlings of rice were used as starting mate...This research was to examine if rice (Oryza sativa L.), a monocotyledon of angiosperm, was able to synthesize chlorophyll (Chl) in complete darkness. Five-cm-tall etiolated seedlings of rice were used as starting materials and treated with or without various concentrations of glucose and/or δ-aminolevulinic acid (ALA) in the dark. Leaves harvested at the indicated time were determined for their contents of Chl, protoporphyrin Ⅸ (Proto), Mg-protoporphyrin Ⅸ (Mg-Proto) and protochlorophyllide (Pchlide). The mole percentage of porphyrin was calculated. The Chl content in the etiolated rice seedlings slightly increased from about 2.5 μg/g to 7.5 μg/g within 12 d in the dark, but the total Chl of dark-grown rice increased from 0.36 μg/g to 3.6 μg/g. While the mole percentages of Proto, Mg-Proto and Pchlide in the dark-grown seedlings without any treatment were about 65%, 27.5% and 7.5% at the beginning, respectively, those in the light-grown seedlings were about 42.5%, 35% and 22.5%, respectively. The mole percentage of porphyrin of etiolated seedlings resumed its normal ratio within 2 d after treatment with glucose. While the Chl content of etiolated seedlings grown in culture solution with 3% and 6% glucose increased 2.5 and 4.0 folds, respectively, those with 3% and 6% glucose and 1 mmol/L ALA increased 22 and 24 folds, respectively. It is concluded that angiosperm might be able to synthesize a small amount of Chl in complete darkness, that either glucose or ALA could stimulate dark Chl synthesis in angiosperm, and that a combination of glucose and ALA exhibited an additional effect. It is still unknown and remains to be further explored what is the mechanism of the effect of glucose and ALA on the Chl synthesis of rice in the dark.展开更多
文摘The genus Oryza consists of approximately 24 species with 10 recognized genome types (A, B, C, BC, CD, E, F, G, HJ, HK). The species with the CD genome are endemic to the Central and South America and comprise three species, i.e. O. latifolia Desv., O. alta Swallen and O. grandiglumis (Doell) Prod. Although the three species can be easily distinguished from the species with the other genomes in Oryza by their morphological characteristics, it is very difficult to distinguish them from one another. Recent studies suggested that O. alta and O. grandiglumis should be the same species (O. grandigiumis), whereas O. latifolia retains its taxonomic position unchangeably. In this paper, a total of 77 clones of the nuclear ribosomal internal transcribed spacer (ITS) from 11 samples representing different geographical races were sequenced. Using DNA Strider 1.2 software, the restriction enzyme digestion sites of these clone sequences were analyzed. Based on restriction fragment length polymorphism (RFLP) of ITS sequences, a method to identify the species with CD genome in Oryza was proposed. The method is rapid and convenient and all experimental procedure includes only three steps: (1) to amplify the ITS fragment with the routine primers; (2) to digest PCR products with restriction enzymes Fok I and Dra III or both; (3) to run the digested product on 1% agarose gel and identify the sample based on the restriction profiles.
基金Supported by the National Natural Science Foundation of China(30671126)the Science and Technology Development Planning Project of Zibo City(2009)~~
文摘[Objective] The aim was to study the relationship between urcrose, zinc and the root system growth in rice. [Method] Changes of root system growth, ROS generation and root system proton export ability were analyzed in rice (Oryza sativa L. cv Zhonghua No.11) treated with different concentrations of Zn (NO3)3 sucrose, com- bined sucrose and Zn (NO3)3 mannitol as well as mannitol plus Zn (NO3)2. [Result] The results showed that treatment with 1-3 mM Zn(NO3)2 resulted in significant increases in total root length /number and in accumulation of H202 and 02- but decreases in root system proton export ability. With the exception of shoot length, the length of primary, adventitious, and lateral roots, and the number of adventitious, and lateral roots on primary /adventitious roots were all influenced by different concentrations of sucrose. High concentrations of sucrose caused increases in H202 and O2-, starva- tion or high concentrations of sucrose reduced root system proton export ability after treating with or without Zn. However, at the same concentration of sucrose, different changes of these indicators were observed between Zn and non-Zn treatments. The regulation of root system growth induced by sucrose was marked different from that of mannitol at the same concentration of 5%, suggesting that these effects were caused by sugar signal but not by osmotic potential. [Conclusion] This study indicat- ed that both sucrose and Zn play important roles in the regulation of rice root system growth.
文摘The 1 195 bp 5′ flanking region of rice ( Oryza sativa L.) cytosolic fructose_1, 6_bisphosphatase (cyFBPase) can direct tissue, cell specific expression in transgenic rice. In order to identify sequence elements responsible for the regulation of mesophyll_specific expression, the 5′ flanking regions of -1 195 bp, -1 102 bp, -768 bp, and -644 bp upstream of the translation initiation ATG codon were fused to the reporter gene encoding β_glucuronidase (GUS) and transferred to rice via particle bombardment. Analysis of the 5′ promoter deletions identified that a 93 bp fragment between -1 195 bp and -1 102 bp is essential for directing mesophyll specific expression. High constitutive expression of GUS reporter gene was found in the -768 deletion lines and another two deletion series. These results indicate the great potential utility of the promoter in rice biotechnology.
文摘Five triterpenoid saponins were isolated from the Chinese traditional medicine Eclipta prostrata L.. On the basis of their chemical properties and spectral data, they were identified as eclalbasaponins II(1), I(2), III(3), 3-O-[b-D-glucopyranosyl(12)-b-D-glucopyranosyl]-16a-ethoxy-olean-12-ene-28-oic acid-28-O-b-D-glu-copyranoside(4) and 3-O-[(2-O-sulfuryl-b-D-glucopyranosyl)(12)-b-D-glucopyranosyl]-echinocystic acid-28-O-b-D-glucopyranoside(5). Compounds 4 and 5 are new compounds and named eclalbasaponins XI and XII, respectively. Compounds 1 and 5 induced morphological deformation of Pyricularia oryzae mycelia.
基金Supported by National Natural Science Foundation of China(No.30671126)Technology Development Program of Zibo City(2009)~~
文摘[Objective] This study was aimed at exploring the effect of glucose signal on the zinc-induced growth of root system using rice as the material.[Method] The variation of root system growth,active oxygen production and proton secretion of root systems treated with various concentrations of glucose,glucose + Zn(NO3)2,mannitol and Zn(NO3)2 + mannitol were analyzed in rice(Oryza sativa L.cv Zhonghua no.11).[Result] The results showed that the concentrations of glucose had affected the shoot height,primary root length,amount and length of lateral roots on primary roots,adventitious root length and length of lateral roots on adventitious roots in varying degrees,but not the amount of adventitious roots and lateral roots on adventitious roots under Zn+ and Zn-condition.Glucose of high concentrations induced the production of active oxygen,while lacking of glucose would lead to the decrease of proton secretion of root systems.However,there were significant differences in these indexes between under Zn+ and under Zn-condition treated with the same concentrations of glucose.The effects of glucose and mannitol with the same concentration on the growth of root systems were significantly different,indicating that the variation was resulting from sugar signal but not the osmotic potential.[Conclusion] The glucose had played important roles in the growth of rice root system both under normal condition and under Zn+ condition.
基金Supported by National Science Foundation of China(30871318)Key Research Project of Ministry of Education,PRC(210265)~~
文摘[Objective] The aim was to study the effects of over-expressed sm-Ngt1,a glycosyltransferase gene induced by both methyl jasmonate and salicylic acid from tobacco,on the plant height of rice.[Method] The binary expression vector of the sm-Ngt1 gene was constructed and transferred to matured embryo of indica rice YTB with the method of Agrobacterium infection.The height of the positive transgenic plants was measured.[Result] 117 positive transgenic plants with sm-Ngt1 were obtained.The results showed that the rice plants dwarfed with different degrees after transferring the sm-Ngt1 gene,the height of 37% of transgenic plants is 71.4±9.8 cm,27% is 65.1±4.6 cm,and the average height of YTB(CK) is 130.0±4.3 cm.[Conclusion] These results aid a foundafion for further study on function of sm-Ngt1.
文摘The utilization of hybrid rice heterosis between subspecies is an important way to prove rice breeding programs, but the low matter conversion rate of inter- subspecific hybrids becomes the bottleneck to get high yield. To further explore the reasons for the low conversion rate of dry matters, and the coordination mechanism between biological yield's potential and grain yield's potential, we evaluated the correlations of the agronomic characters between the female parent and F1 inter subspecific hybrids, using a male parent R292, three female parents Y58S, Peiai 64S and 83S, and their hybrid combinations Y58S/292, 64S/292 and 83S/292 as experimental materials, Yueyou 9113 as the control. The results indicated that the contents of both soluble sugar and starch of all the experimental materials varied at different growth stages, and the highest starch content appeared at pre-ripening stage while soluble sugar content was the lowest. Notable positive correlations in a- gronomic characteristics were observed between the female parents and their F1 hybrids. The soluble sugar content in stem was the highest, followed by that in panicle, and the soluble sugar content in sheath and flag leaf was lower. The re- sults provide a theoretical basis for the research on heterosis and yield coordination mechanisms of inter-subspecific hybrids of rice.
基金supported by the National Natural Science Foundation of China (No.40371062)the National Natural Science Foundation for Distinguished Young Scholars of China (No.40425007)the Science and Technology Program of Zhejiang Province,China (No.2006C12027)
文摘Little information is available on the interactive effects of inorganic and organic pollutants on carbon utilization by soil microorganisms.This study examined the effects of two common soil pollutants,lead(Pb) and bensulfuron-methyl herbicide(BSM),on decomposition of an adscititious carbon source(14C-glucose).Two contrasting paddy soils,a silty clay soil and a clay loam soil,were incubated with different concentrations and combinations of pollutants for 60 days.Orthogonal rotatable central composite design was adopted to design the combinations of the pollutant concentrations so that rate response curves could be derived.Rapid decomposition of 14C-glucose occurred in the first three days for both soils where no Pb or BSM was added(control).Overall,63%-64% of the added 14C-glucose was decomposed in the control over the 60-day incubation.The addition of Pb or BSM significantly decreased the decomposition of 14C-glucose during the first week but increased the decomposition thereafter;as a result,the percentages of 14C-glucose decomposed(57%-77%) over the 60-day period were similar to or higher than those of the control.Application of the pollutants in combination did not further inhibit decomposition compared with the control.Overall,decomposition rates were lower in the silty clay soil than in the clay loam soil,which was related to the soil texture,cation exchange capacity,and pH.The relationship between the decomposition rates and the pollutants could be well characterized by the quadratic regression orthogonal rotation model.The initial antagonistic effects of the pollutants followed by the synergistic effects on microbial activity might result from changes of the concentrations of the pollutants.
文摘Plastids of nongreen tissues import carbon as a source of biosynthetic pathways and energy, and glucose 6 phosphate is the preferred hexose phosphate taken up by nongreen plastids. A cDNA clone encoding glucose 6 phosphate/phosphate translocator ( GPT ) was isolated from a cDNA library of immature seeds of rice and named as OsGPT . The cDNA has one uninterrupted open reading frame encoding a 42 kDa polypeptide possessing transit peptide consisting of 70 amino acid residues. The OsGPT gene maps on chromosome 8 of rice and is linked to the quantitative trait locus for 1000 grain weight. The expression of OsGPT is mainly restricted to heterotrophic tissues. These results suggest that glucose 6 phosphate imported via GPT can be used for starch biosynthesis in rice nongreen plastids.
基金the Ministry of Science and Technology of Taiwan for financially supporting this research under Contract No.NSC-1022623-E-002-012-ET
文摘In this paper, processes for producing a food-grade glucose solution through enzymatic hydrolysis of celluloserich solids obtained from rice straws are presented. The rice straws were pretreated by acid-catalyzed steam explosion, and the reaction efficiency, toxicity control, and process economic feasibility were studied. Mass transfer resistance to the hydrolysis reaction was reduced by grinding with glass beads. A higher glucose concentration could be obtained by feeding more cellulose in the hydrolysis reaction; however, this also resulted in the production of undesired byproducts. Thus, a soaking process for the cellulose solids in water was developed to effectively reduce the generation of byproducts in the hydrolysis reaction. The resulting food-grade glucose solution can provide 414 kilocalories per liter, and could be used during a food-shortage crisis in the future.The current production cost is estimated to be 0.82 USD·L^(-1).
文摘In order to study osmotic adjustment and accumulation of anions and cations in rice (Oryza sativa L.) seedlings under NaCl stress, a greenhouse experiment was conducted using two rice cultivars including IR651 (tolerant) and IR29 (sensitive). Seedlings were grown in Youshida nutrient solution. Salinity treatments were imposed 21 days after sowing with 0 and 100 mM NaCI and seedlings were harvested 0, 72, 120 and 240 hour after salinization. Water (ψw) and osmotic (ψs) potentials, total soluble sugars and inorganic ions (Na+. K+, Cl-, Ca2+ and Mg2+) concentrations and osmotic adjustment were determined in sixth (youngest) leaf. Salinity caused a substantial biomass reduction in rice seedlings, ψs reduction in IR29 was occurred more than IR651. Water potential decreased in both the cultivars under stress conditions, but IR651 was able to maintain higher ψw and kept better growth till the end of the experiment. Osmotic adjustment was observed in IR651 was about 10 times more than in IR29. K+ accumulation decreased in both cultivars under stress condition while Na+ accumulation increased in both the cultivars with higher increase in IR29 seedlings. CI concentration increased in youngest leaf of both IR29 and IR651. Our results showed that tolerant cultivar was able to make osmotic adjustment faster than the sensitive cultivar using high accumulation of solutes especially total soluble sugars.
文摘This research was to examine if rice (Oryza sativa L.), a monocotyledon of angiosperm, was able to synthesize chlorophyll (Chl) in complete darkness. Five-cm-tall etiolated seedlings of rice were used as starting materials and treated with or without various concentrations of glucose and/or δ-aminolevulinic acid (ALA) in the dark. Leaves harvested at the indicated time were determined for their contents of Chl, protoporphyrin Ⅸ (Proto), Mg-protoporphyrin Ⅸ (Mg-Proto) and protochlorophyllide (Pchlide). The mole percentage of porphyrin was calculated. The Chl content in the etiolated rice seedlings slightly increased from about 2.5 μg/g to 7.5 μg/g within 12 d in the dark, but the total Chl of dark-grown rice increased from 0.36 μg/g to 3.6 μg/g. While the mole percentages of Proto, Mg-Proto and Pchlide in the dark-grown seedlings without any treatment were about 65%, 27.5% and 7.5% at the beginning, respectively, those in the light-grown seedlings were about 42.5%, 35% and 22.5%, respectively. The mole percentage of porphyrin of etiolated seedlings resumed its normal ratio within 2 d after treatment with glucose. While the Chl content of etiolated seedlings grown in culture solution with 3% and 6% glucose increased 2.5 and 4.0 folds, respectively, those with 3% and 6% glucose and 1 mmol/L ALA increased 22 and 24 folds, respectively. It is concluded that angiosperm might be able to synthesize a small amount of Chl in complete darkness, that either glucose or ALA could stimulate dark Chl synthesis in angiosperm, and that a combination of glucose and ALA exhibited an additional effect. It is still unknown and remains to be further explored what is the mechanism of the effect of glucose and ALA on the Chl synthesis of rice in the dark.