Leaf-color mutations are a widely-observed class of mutations, playing an important role in the study of chlorophyll biosynthesis and plant chloroplast structure, function, genetics and development. A naturally-occurr...Leaf-color mutations are a widely-observed class of mutations, playing an important role in the study of chlorophyll biosynthesis and plant chloroplast structure, function, genetics and development. A naturally-occurring leaf-color rice mutant, Baihuaidao 7, was analyzed. Mutant plants typically exhibited a green-white-green leaf-color progression, but this phenotype was only expressed in the presence of a stress signal induced by mechanical scarification such as transplantation. Prior to the appearance of white ~eaves, mutant plant growth, leaf color, chlorophyll content, and chloroplast ultrastructure appeared to be identical to those of the wild type. After the changeover to white leaf color, an examination of the mutated leaves revealed a decrease in total chlorophyll, chlorophyll a, chlorophyll b, and carotenoid content, a reduction in the number of chloroplast grana lamella and grana, and a gradual degradation of the thylakoid lamellas. At maturity, the mutant plant was etiolated and dwarfed compared with wild-type plants. Genetic analysis indicated that the leaf mutant character is controlled by a recessive nuclear gene. Genetic mapping of the mutant gene was performed using an F2 population derived from a Baihuaidao 7 ~ Jiangxi 1587 cross. The mutant gene was mapped to rice chromosome 11, positioned between InDel markers L59.2-7 and L64.8-11, which are separated by approximately 740.5 kb. The mutant gene is believed to be a new leaf-color mutant gene in rice, and is tentatively designated as gwgl.展开更多
The mechanism of carotenoid degradation and the changes in the activities of related enzymes in flue-cured tobacco at the leaf-drying stage during the bulk-curing process were studied in order to provide theoretical b...The mechanism of carotenoid degradation and the changes in the activities of related enzymes in flue-cured tobacco at the leaf-drying stage during the bulk-curing process were studied in order to provide theoretical basis for optimization of curing technology. The effect of different rising speeds of temperature on the carotenoid degradation and the related enzymes activities at the color-fixing stage during the bulk curing process was studied by using the electric-heated fluecuring barn designed by Henan Agricultural University, China, based on curing technology with yellowing at low temperature and moderate humidity and leaf drying at moderate humidity. The results showed that the carotenoid degradation components （β-carotene, lutein, neoxanthin, and violaxthin） decreased gradually at the color-fixing stage during the bulk curing process. The carotenoid degradation components viz.,β-carotene, lutein, neoxanthin, and violaxthin at the slow heating curing （T1） were relatively higher than the rapid heating curing （T2） accounting for 10, 2, 32 and 32% respectively, but there were no differences among treatments （P〉 0.05）. The effect of different conditions of curing on the activities of enzymes related to carotenoids degradation were significant. The lipoxygenase, phenylalanine ammonialyase, peroxidase, and polyphenol oxidase enzymes had a bidirectional effect on the quality of tobacco leaves and it was beneficial to form more premise matter of aroma based on the higher enzyme activities at the early leaf-drying stage. The slow heating could regulate the change in various enzymes＇ activities reasonably, making cell redox reaction to reach the dynamic balance and make the degradation of carotenoids adequately. Meanwhile, it could avoid the occurrence of browning reaction and provide foundation for improving the quality of tobacco and optimization of technology for bulk curing and further enhancing aroma.展开更多
In order to deeply study the leaf-stripping principle for corn stalk, the hexagon-enveloping leaf-stripping experimental device was designed. To achieve higher leaf-stripping percent and provide important references f...In order to deeply study the leaf-stripping principle for corn stalk, the hexagon-enveloping leaf-stripping experimental device was designed. To achieve higher leaf-stripping percent and provide important references for the separation equipment for corn stalk, it is necessary to fired out the laws of leaf-stripping of such mechanism and to select the main influencing factors of separation performance from a number of factors. Through the study on hexagon-enveloping leaf-stripping mechanism for corn stalks, the leaf- stripping principle of such mechanism was more clear, and the optimization of structural and kinematic parameters achieved by the experiment whose influencing factors were the four selected ones （feeding speed, rotary speed of leaf-stripping roll, clearance and included angle between two leaf-stripping plates） could be directly applied to the development of efficient rind-pith or leaf-stripping separation for corn stalks.展开更多
According to the production index of lint cotton yield over 100kg per mu(1/15ha)and the relationship between the climate factors and the distribution of time and space for cottonboll setting in 1985—1990,we establish...According to the production index of lint cotton yield over 100kg per mu(1/15ha)and the relationship between the climate factors and the distribution of time and space for cottonboll setting in 1985—1990,we established a model of cultural techniques of cotton leaf-age-ad-justing-controlling for enhancing early maturity.By utilizing the principle of leaf-age model andthe principle of regulating nutrient distribution with DPC(Mepiquate chloride),the plants weretreated with DPC in proper time.A new type of population plant patterns was set up.It character-ized by high population density,dwarf,high boll weight,bolls near nodes,high energy and lowconsumption,short distance transport of nutrients,high yield and good quality.We put forward aset of management measures,i.e.adjusting boll setting stage,adjusting and controlling boll set-ting structure,stably applying N,increasing P,supplementing plants with K,increasing irrigationefficiency,techniques were applied and demonstrated in large areas in high yield展开更多
Symbiotic relations are present in the nature and can contribute to the success of the organisms involved. Endophytic fungi live within the leaf tissues without causing any harm to the host plant, and some of them can...Symbiotic relations are present in the nature and can contribute to the success of the organisms involved. Endophytic fungi live within the leaf tissues without causing any harm to the host plant, and some of them can be a defense mechanism against the attack by the leaf-cutting ants. Ants of the genus <em>Atta</em> are known as leaf-cutting ants and have an obligatory association with the fungus <em>Leucoagaricus gongylophorus</em>, cutting pieces of leaves and bringing them back to the colony to the fungus. The present study aimed to find out the endophytic fungi community of an attractive plant (<em>Acalypha wilkesiana</em>) and a less attractive plant (<em>Colocasia esculenta</em>) to the ants <em>Atta sexdens</em>. We found out that the communities are different in quantity and in composition and 73% of the isolated fungi were from <em>A. wilkesiana</em>, which has fungi known as attractive to leaf-cutting ants, such as genus<em> Colletotrichum</em>, <em>Pestalotiopsis</em>, <em>Phomopsis </em>and <em>Xylaria</em>. On the other hand, in <em>C. esculenta</em>, there was found the genus<em> Fusarium</em>, known to be reject by the leaf-cutting ants, and less fungal diversity than in the attractive plant <em>A. wilkesiana</em>. Therefore, our data suggest that attractivity or repelence of a plant to the leaf-cutting ants could be related to presence or ausence of determinated fungi more than the quantity of fungi present in a leaf.展开更多
[ Objectives ] The aim was to optimize the configuration of seedling density and line spacing of forage sweet sorghum （ Sorghum blcolor （ L. ） Moench） and explore its high-yield cultivation techniques. [ Methods] ...[ Objectives ] The aim was to optimize the configuration of seedling density and line spacing of forage sweet sorghum （ Sorghum blcolor （ L. ） Moench） and explore its high-yield cultivation techniques. [ Methods] Effects of such two influencing factors as line spacing and seedling density on the leaf-stem ratio, DW/FW ratio and grass yield of forage sweet sorghum were analyzed by using split-plot experiment design experiment method and LSD method of IBM. SPSS. Statis- tics. v22 stati, stics software. [ Results ~ Seedling density and line spacing had no obvious effect on the leaf-stem ratio and DW/FW ratio of forage sweet sorghum but had obvious influences on the grass yield. Moreover, the optimal combination of seedling density and line spacing for high yield of forage sweet sorghum was A2 B4, that is, seedling density was 225 000 plants/hm2, and line spacing was 40 cm. [ Conclusions] The results provided a theoretical basis and technical support for high-yield cultivation techniques of forage sweet sorghum.展开更多
BACKGROUND： Ginsenoside extracted from the stem and leaf of ginseng （GSL） and choline have both been shown to improve learning and memory functions; however, further studies are needed to understand the synergistic...BACKGROUND： Ginsenoside extracted from the stem and leaf of ginseng （GSL） and choline have both been shown to improve learning and memory functions; however, further studies are needed to understand the synergistic effects of a combination of both. OBJECTIVE： To verify the combined improved synergistic effects of GSL and choline on learning and memory disorders in rats. DESIGN： Control observation. SETTING： Taishan Medical College. MATERIALS： A total of 150 male Kunming mice weighing （204-2） g and 40 healthy male Wistar rats weighing （2204-20） g were provided by the Experimental Animal Department of Jilin University. Animal experimentation received confirmed consent from the local ethic committee. GSL was provided by the Department of Chemistry, Norman Bethune Medical University, and choline was provided by the Third Experiment Factory, Shanghai. METHODS： This study was performed at the Life Science Institute, Taishan Medical College from October 2006 to February 2007. ① Scopolamine-induced learning and memory disorders in rats： Forty rats were randomly divided into control group, model group, combination group （400 mg/kg GSL ＋ 200 mg/kg choline）, GSL （400 mg/kg） group, and choline （200 mg/kg） group, 8 rats/group. Rats were perfused and administrated in the morning, once a day for 14 successive days. Rats in the control group and model group were perfused with 20 mL/kg distilled water and underwent Morris water maze spatial resolution test 1 hour after perfusion on the 10m, 11m, and 12m days after administration. Rats also underwent passive step-down avoidance test 1 hour after reperfusion on the 13m and 14m days after administration. Thirty minutes prior to experimentation, rats in the remaining three groups were intraperitoneally （i.p） injected with 2 mg/kg scopolamine, and rats in the control group were i.p. injected with 2 mL/kg saline. ② Scopolamine-induced learning disorder and memory acquired disorder in mice： Fifty mice were randomly divided into control group, model group, combination group （400 mg/kg GSL ＋200 mg/kg choline）, GSL （400 mg/kg） group, and choline （200 mg/kg） group, with 10 mice/group. Mice were perfused and administrated in the morning, once a day for 9 successive days. Mice in the control group and model group were perfused with 20 mL/kg distilled water and underwent passive step down avoidance test 1 hour after reperfusion on the 8th and 9th day after administration. Twenty minutes prior to training, mice in the remaining three groups were i.p. injected with 2 mg/kg scopolamine, and mice in the control group were i.p. injected with 10 mL/kg saline. ③ Sodium nitrite-induced memory consolidation disorder in mice： Grouping, administration, and testing were the same as mentioned above. After training, mice in the remaining three groups were immediately subcutaneously injected with 120 mg/kg sodium nitrite, and mice in the control group were subcutaneously injected with 20 mL/kg saline. ④ Ethanol-induced memory reconsolidation disorder in mice： Grouping, administration, and testing were the same as mentioned above. At 24 hours after training and 20 minutes before retraining, mice in the remaining four groups were perfused with 10 mL/kg ethanol （0.3 volume fraction）, and mice in the control group were perfused with 10 mL/kg saline. MAIN OUTCOME MEASURES： Synergistic effects of GSL and choline on learning and memory deficits induced by scopolamine, sodium nitrite, and ethanol in experimental animals. RESULTS： All 40 rats and 150 mice were included in the final analysis. ① Synergistic effects of GSL and choline on learning and memory disorders induced by scopolamine in rats： During passive step-down avoidance and Morris water maze spatial resolution tests, the number of error responses and length of maze training in the model group were significantly greater than in the control group （P 〈 0.01）; while the number of error responses and length of maze training in the combination group were significantly less than in the model group, GSL group, and choline group （P 〈 0.05-0.01）. The Q value was 〉 1 after combining administration, which suggests that the combination of GSL and choline had synergistic effects. ② Synergistic effects of GSL and choline on learning disorder and memory-acquired disorder induced by scopolamine in mice： During passive step-down avoidance test, the number of error responses in the model group were significantly greater than in the control group （P 〈 0.01 ）; while the number of error responses in the combination group were significantly less than in the model group, GSL group, and choline group （P 〈 0.05-0.01）. The Q value was 〉 1 after combining administration, which suggests GSL and choline had synergistic effects. ③ Synergistic effects of GSL and choline on memory sodium nitrate-induced consolidation disorder in mice： During passive step down avoidance test, the number of error responses in the model group were significantly less than in the control group （P 〈 0.01 ）; while the number of error responses in the combination group were significantly less than in the model group, GSL group, and choline group （P 〈 0.05-0.01）. The Q value was 〉 1 after combined administration, which suggests GSL and choline had synergistic effects. ④ Synergistic effects of GSL and choline on ethanol-induced memory reconsolidation disorder in mice： During passive step down avoidance test, the number of error responses in the model group were significantly greater than in the control group （P 〈 0.01）; while the number of error responses in the combination group were significantly less than in the model group, GSL group, and choline group （P 〈 0.05-0.01）. The Q value was 〉 1 after combined administration, which suggests GSL and choline had synergistic effects. CONCLUSION： GSL and choline have synergistic effects on learning and memory functions.展开更多
Plant in vitro organogenesis is well-controlled and thus provides an ideal system for plant propagation and studying mechanisms of plant development. However, the data on systematic in vitro organogenesis from leaf ex...Plant in vitro organogenesis is well-controlled and thus provides an ideal system for plant propagation and studying mechanisms of plant development. However, the data on systematic in vitro organogenesis from leaf explant with various concentrations and combinations of hormones are limited. Arabidopsis is a very useful model plant species for many aspects of plant biological study. Here, we reported a simple, fast and efficient one-step process for evaluating leaf explant-derived in vitro Arabidopsis organogenesis involving the application of various concentrations and combinations of exogenous hormones. The central portion of the fourth rosette leaf was harvested from the 21-days-old seedling and cultured in vitro on the media containing 216 combinations of exogenous hormones. Different types of organs, including roots, shoots, inflorescences, and leaf-like organs were initiated from leaf explants. Several optimal experimental combinations were selected. A hormone combination, 1.00 μM NAA + 10.00 μM ZT, was considered as the most efficient one for adventitious shoot regeneration. And for adventitious root regeneration, six hormone combinations, [(NAA + ZT: 1.00 + 0.10 μM;10.00 + 0.01 μM;20.00 + 0.10 μM;20.00 + 1.00 μM) and (NAA + 6-BA: 10.00 + 0.10 μM;20.00 + 10.00 μM)], were thought to be the best ones. Further, both auxin and cytokinin ratios and concentrations were crucial for efficient in vitro organogenesis. Our study provides the important information for hormone-regulated organogenesis.展开更多
A new kind of ultra wideband antenna,which consists of a leaf-like dipole and a dielectric block,is proposed and analyzed.The dielectric block is attached in parallel with the dipole near its feed point.Thus,the near ...A new kind of ultra wideband antenna,which consists of a leaf-like dipole and a dielectric block,is proposed and analyzed.The dielectric block is attached in parallel with the dipole near its feed point.Thus,the near field is attracted to the side where the dielectric block is located.It leads to a focusing effect of the energy in the far zone.The finite-difference time-domain(FDTD)method combined with the perfectly matched layers(PML)technique is used in the simulation of the antenna radiation characteristics.The research shows that,with proper dielectric loading and 50 Ω feeding line,the bandwidth of the antenna can be up to 6.5 GHz,from 3.5 GHz to 10 GHz with VSWR(voltage standing wave ratio)less than 2.5.展开更多
The biology of a koinobiont parasitoid of leaf-cutting ant larvae, <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>Szelenyiopria talitae<span ...The biology of a koinobiont parasitoid of leaf-cutting ant larvae, <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>Szelenyiopria talitae<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i> (Hymenoptera: Diapriidae), was studied from naturally infested <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>Acromyrmex subterraneus<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i> (Hymenoptera: Formicidae) nests. Nests were collected in the field from the Atlantic rainforest biome in the state of Rio de Janeiro. A total of fifty-three nests were collected from 2015 to 2018. Parasitized nests were only found during the months of September and October. Approximately 22% of the nests collected over a four-year period were found to have been parasitized by <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>S. talitae<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i>. The mean within-nest parasitism rate was<span "=""> 66.3%. This diapriid displayed both solitary (14%) and gregarious parasitism (86%), with up to a maximum of 12 parasitoids developing within a single host. Gregarious parasitism with two (29%) or three (21%) <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>S. talitae<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i></span><i></i> per host was most frequently observed. There was a positive correlation between the number of parasitoids per host and host size (dry weight), indicating that <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>S. talitae<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i> females oviposited a higher number of eggs in larger hosts. There was also a negative correlation between <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>S.</i> <i>talitae<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i> pharate adult size and the number of parasitoids per host, which could have been caused by sibling competition for limited host resources. The high levels of parasitism seen here had a debilitating effect on the colonies. <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>Acromyrmex subterraneus<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i> is a serious pest in Brazil, and these studies lay the foundation for understanding the impact of <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>S. talitae<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i> on ant populations.展开更多
As sessile organisms, plants have to be subjected to insect attack. Over the long course of evolution, plants have produced many mechanisms to resist this biotic stress such as pigment accumulation. Pigment levels det...As sessile organisms, plants have to be subjected to insect attack. Over the long course of evolution, plants have produced many mechanisms to resist this biotic stress such as pigment accumulation. Pigment levels determined depth and distribution of leaf color, thereby indirectly or directly affecting the behavior of insect attack. Therefore, understanding the mechanism of mutual recognition between leaf color and insect will provide important theoretical insight for the cultivation and improvement of new cultivars. This paper outlines leaf-color formation and the effect of pigment on the behavior of insect attack, and explores the challenge of research in the interaction between leaf color and insect, as soon as the potential direction for future development. This will give a broad background for improvements of colored plants with resistance to insect attack.展开更多
基金supported by the Natural ScienceFoundation of Jiangsu Province of China (Grant No.SBK2010294)an Open Project Program of Jiangsu Key Laboratory of the Ministry of Education for Plant Functional Genomics (Grant No. K10001)
文摘Leaf-color mutations are a widely-observed class of mutations, playing an important role in the study of chlorophyll biosynthesis and plant chloroplast structure, function, genetics and development. A naturally-occurring leaf-color rice mutant, Baihuaidao 7, was analyzed. Mutant plants typically exhibited a green-white-green leaf-color progression, but this phenotype was only expressed in the presence of a stress signal induced by mechanical scarification such as transplantation. Prior to the appearance of white ~eaves, mutant plant growth, leaf color, chlorophyll content, and chloroplast ultrastructure appeared to be identical to those of the wild type. After the changeover to white leaf color, an examination of the mutated leaves revealed a decrease in total chlorophyll, chlorophyll a, chlorophyll b, and carotenoid content, a reduction in the number of chloroplast grana lamella and grana, and a gradual degradation of the thylakoid lamellas. At maturity, the mutant plant was etiolated and dwarfed compared with wild-type plants. Genetic analysis indicated that the leaf mutant character is controlled by a recessive nuclear gene. Genetic mapping of the mutant gene was performed using an F2 population derived from a Baihuaidao 7 ~ Jiangxi 1587 cross. The mutant gene was mapped to rice chromosome 11, positioned between InDel markers L59.2-7 and L64.8-11, which are separated by approximately 740.5 kb. The mutant gene is believed to be a new leaf-color mutant gene in rice, and is tentatively designated as gwgl.
基金supported by the Key Project of State Tobacco Monoply Administration of China(3300806156)
文摘The mechanism of carotenoid degradation and the changes in the activities of related enzymes in flue-cured tobacco at the leaf-drying stage during the bulk-curing process were studied in order to provide theoretical basis for optimization of curing technology. The effect of different rising speeds of temperature on the carotenoid degradation and the related enzymes activities at the color-fixing stage during the bulk curing process was studied by using the electric-heated fluecuring barn designed by Henan Agricultural University, China, based on curing technology with yellowing at low temperature and moderate humidity and leaf drying at moderate humidity. The results showed that the carotenoid degradation components （β-carotene, lutein, neoxanthin, and violaxthin） decreased gradually at the color-fixing stage during the bulk curing process. The carotenoid degradation components viz.,β-carotene, lutein, neoxanthin, and violaxthin at the slow heating curing （T1） were relatively higher than the rapid heating curing （T2） accounting for 10, 2, 32 and 32% respectively, but there were no differences among treatments （P〉 0.05）. The effect of different conditions of curing on the activities of enzymes related to carotenoids degradation were significant. The lipoxygenase, phenylalanine ammonialyase, peroxidase, and polyphenol oxidase enzymes had a bidirectional effect on the quality of tobacco leaves and it was beneficial to form more premise matter of aroma based on the higher enzyme activities at the early leaf-drying stage. The slow heating could regulate the change in various enzymes＇ activities reasonably, making cell redox reaction to reach the dynamic balance and make the degradation of carotenoids adequately. Meanwhile, it could avoid the occurrence of browning reaction and provide foundation for improving the quality of tobacco and optimization of technology for bulk curing and further enhancing aroma.
基金Supported by the National Science and Technology Support Funded Project(2011BAD20B08)
文摘In order to deeply study the leaf-stripping principle for corn stalk, the hexagon-enveloping leaf-stripping experimental device was designed. To achieve higher leaf-stripping percent and provide important references for the separation equipment for corn stalk, it is necessary to fired out the laws of leaf-stripping of such mechanism and to select the main influencing factors of separation performance from a number of factors. Through the study on hexagon-enveloping leaf-stripping mechanism for corn stalks, the leaf- stripping principle of such mechanism was more clear, and the optimization of structural and kinematic parameters achieved by the experiment whose influencing factors were the four selected ones （feeding speed, rotary speed of leaf-stripping roll, clearance and included angle between two leaf-stripping plates） could be directly applied to the development of efficient rind-pith or leaf-stripping separation for corn stalks.
文摘According to the production index of lint cotton yield over 100kg per mu(1/15ha)and the relationship between the climate factors and the distribution of time and space for cottonboll setting in 1985—1990,we established a model of cultural techniques of cotton leaf-age-ad-justing-controlling for enhancing early maturity.By utilizing the principle of leaf-age model andthe principle of regulating nutrient distribution with DPC(Mepiquate chloride),the plants weretreated with DPC in proper time.A new type of population plant patterns was set up.It character-ized by high population density,dwarf,high boll weight,bolls near nodes,high energy and lowconsumption,short distance transport of nutrients,high yield and good quality.We put forward aset of management measures,i.e.adjusting boll setting stage,adjusting and controlling boll set-ting structure,stably applying N,increasing P,supplementing plants with K,increasing irrigationefficiency,techniques were applied and demonstrated in large areas in high yield
文摘Symbiotic relations are present in the nature and can contribute to the success of the organisms involved. Endophytic fungi live within the leaf tissues without causing any harm to the host plant, and some of them can be a defense mechanism against the attack by the leaf-cutting ants. Ants of the genus <em>Atta</em> are known as leaf-cutting ants and have an obligatory association with the fungus <em>Leucoagaricus gongylophorus</em>, cutting pieces of leaves and bringing them back to the colony to the fungus. The present study aimed to find out the endophytic fungi community of an attractive plant (<em>Acalypha wilkesiana</em>) and a less attractive plant (<em>Colocasia esculenta</em>) to the ants <em>Atta sexdens</em>. We found out that the communities are different in quantity and in composition and 73% of the isolated fungi were from <em>A. wilkesiana</em>, which has fungi known as attractive to leaf-cutting ants, such as genus<em> Colletotrichum</em>, <em>Pestalotiopsis</em>, <em>Phomopsis </em>and <em>Xylaria</em>. On the other hand, in <em>C. esculenta</em>, there was found the genus<em> Fusarium</em>, known to be reject by the leaf-cutting ants, and less fungal diversity than in the attractive plant <em>A. wilkesiana</em>. Therefore, our data suggest that attractivity or repelence of a plant to the leaf-cutting ants could be related to presence or ausence of determinated fungi more than the quantity of fungi present in a leaf.
基金Supported by Special Fund for Agro-scientific Research in the Public Interest(20120304201)
文摘[ Objectives ] The aim was to optimize the configuration of seedling density and line spacing of forage sweet sorghum （ Sorghum blcolor （ L. ） Moench） and explore its high-yield cultivation techniques. [ Methods] Effects of such two influencing factors as line spacing and seedling density on the leaf-stem ratio, DW/FW ratio and grass yield of forage sweet sorghum were analyzed by using split-plot experiment design experiment method and LSD method of IBM. SPSS. Statis- tics. v22 stati, stics software. [ Results ~ Seedling density and line spacing had no obvious effect on the leaf-stem ratio and DW/FW ratio of forage sweet sorghum but had obvious influences on the grass yield. Moreover, the optimal combination of seedling density and line spacing for high yield of forage sweet sorghum was A2 B4, that is, seedling density was 225 000 plants/hm2, and line spacing was 40 cm. [ Conclusions] The results provided a theoretical basis and technical support for high-yield cultivation techniques of forage sweet sorghum.
文摘BACKGROUND： Ginsenoside extracted from the stem and leaf of ginseng （GSL） and choline have both been shown to improve learning and memory functions; however, further studies are needed to understand the synergistic effects of a combination of both. OBJECTIVE： To verify the combined improved synergistic effects of GSL and choline on learning and memory disorders in rats. DESIGN： Control observation. SETTING： Taishan Medical College. MATERIALS： A total of 150 male Kunming mice weighing （204-2） g and 40 healthy male Wistar rats weighing （2204-20） g were provided by the Experimental Animal Department of Jilin University. Animal experimentation received confirmed consent from the local ethic committee. GSL was provided by the Department of Chemistry, Norman Bethune Medical University, and choline was provided by the Third Experiment Factory, Shanghai. METHODS： This study was performed at the Life Science Institute, Taishan Medical College from October 2006 to February 2007. ① Scopolamine-induced learning and memory disorders in rats： Forty rats were randomly divided into control group, model group, combination group （400 mg/kg GSL ＋ 200 mg/kg choline）, GSL （400 mg/kg） group, and choline （200 mg/kg） group, 8 rats/group. Rats were perfused and administrated in the morning, once a day for 14 successive days. Rats in the control group and model group were perfused with 20 mL/kg distilled water and underwent Morris water maze spatial resolution test 1 hour after perfusion on the 10m, 11m, and 12m days after administration. Rats also underwent passive step-down avoidance test 1 hour after reperfusion on the 13m and 14m days after administration. Thirty minutes prior to experimentation, rats in the remaining three groups were intraperitoneally （i.p） injected with 2 mg/kg scopolamine, and rats in the control group were i.p. injected with 2 mL/kg saline. ② Scopolamine-induced learning disorder and memory acquired disorder in mice： Fifty mice were randomly divided into control group, model group, combination group （400 mg/kg GSL ＋200 mg/kg choline）, GSL （400 mg/kg） group, and choline （200 mg/kg） group, with 10 mice/group. Mice were perfused and administrated in the morning, once a day for 9 successive days. Mice in the control group and model group were perfused with 20 mL/kg distilled water and underwent passive step down avoidance test 1 hour after reperfusion on the 8th and 9th day after administration. Twenty minutes prior to training, mice in the remaining three groups were i.p. injected with 2 mg/kg scopolamine, and mice in the control group were i.p. injected with 10 mL/kg saline. ③ Sodium nitrite-induced memory consolidation disorder in mice： Grouping, administration, and testing were the same as mentioned above. After training, mice in the remaining three groups were immediately subcutaneously injected with 120 mg/kg sodium nitrite, and mice in the control group were subcutaneously injected with 20 mL/kg saline. ④ Ethanol-induced memory reconsolidation disorder in mice： Grouping, administration, and testing were the same as mentioned above. At 24 hours after training and 20 minutes before retraining, mice in the remaining four groups were perfused with 10 mL/kg ethanol （0.3 volume fraction）, and mice in the control group were perfused with 10 mL/kg saline. MAIN OUTCOME MEASURES： Synergistic effects of GSL and choline on learning and memory deficits induced by scopolamine, sodium nitrite, and ethanol in experimental animals. RESULTS： All 40 rats and 150 mice were included in the final analysis. ① Synergistic effects of GSL and choline on learning and memory disorders induced by scopolamine in rats： During passive step-down avoidance and Morris water maze spatial resolution tests, the number of error responses and length of maze training in the model group were significantly greater than in the control group （P 〈 0.01）; while the number of error responses and length of maze training in the combination group were significantly less than in the model group, GSL group, and choline group （P 〈 0.05-0.01）. The Q value was 〉 1 after combining administration, which suggests that the combination of GSL and choline had synergistic effects. ② Synergistic effects of GSL and choline on learning disorder and memory-acquired disorder induced by scopolamine in mice： During passive step-down avoidance test, the number of error responses in the model group were significantly greater than in the control group （P 〈 0.01 ）; while the number of error responses in the combination group were significantly less than in the model group, GSL group, and choline group （P 〈 0.05-0.01）. The Q value was 〉 1 after combining administration, which suggests GSL and choline had synergistic effects. ③ Synergistic effects of GSL and choline on memory sodium nitrate-induced consolidation disorder in mice： During passive step down avoidance test, the number of error responses in the model group were significantly less than in the control group （P 〈 0.01 ）; while the number of error responses in the combination group were significantly less than in the model group, GSL group, and choline group （P 〈 0.05-0.01）. The Q value was 〉 1 after combined administration, which suggests GSL and choline had synergistic effects. ④ Synergistic effects of GSL and choline on ethanol-induced memory reconsolidation disorder in mice： During passive step down avoidance test, the number of error responses in the model group were significantly greater than in the control group （P 〈 0.01）; while the number of error responses in the combination group were significantly less than in the model group, GSL group, and choline group （P 〈 0.05-0.01）. The Q value was 〉 1 after combined administration, which suggests GSL and choline had synergistic effects. CONCLUSION： GSL and choline have synergistic effects on learning and memory functions.
文摘Plant in vitro organogenesis is well-controlled and thus provides an ideal system for plant propagation and studying mechanisms of plant development. However, the data on systematic in vitro organogenesis from leaf explant with various concentrations and combinations of hormones are limited. Arabidopsis is a very useful model plant species for many aspects of plant biological study. Here, we reported a simple, fast and efficient one-step process for evaluating leaf explant-derived in vitro Arabidopsis organogenesis involving the application of various concentrations and combinations of exogenous hormones. The central portion of the fourth rosette leaf was harvested from the 21-days-old seedling and cultured in vitro on the media containing 216 combinations of exogenous hormones. Different types of organs, including roots, shoots, inflorescences, and leaf-like organs were initiated from leaf explants. Several optimal experimental combinations were selected. A hormone combination, 1.00 μM NAA + 10.00 μM ZT, was considered as the most efficient one for adventitious shoot regeneration. And for adventitious root regeneration, six hormone combinations, [(NAA + ZT: 1.00 + 0.10 μM;10.00 + 0.01 μM;20.00 + 0.10 μM;20.00 + 1.00 μM) and (NAA + 6-BA: 10.00 + 0.10 μM;20.00 + 10.00 μM)], were thought to be the best ones. Further, both auxin and cytokinin ratios and concentrations were crucial for efficient in vitro organogenesis. Our study provides the important information for hormone-regulated organogenesis.
基金Sponsored by National Nature Science Foundation of China(60471053)the Program for New Century Excellent Talents in University of MOE,China
文摘A new kind of ultra wideband antenna,which consists of a leaf-like dipole and a dielectric block,is proposed and analyzed.The dielectric block is attached in parallel with the dipole near its feed point.Thus,the near field is attracted to the side where the dielectric block is located.It leads to a focusing effect of the energy in the far zone.The finite-difference time-domain(FDTD)method combined with the perfectly matched layers(PML)technique is used in the simulation of the antenna radiation characteristics.The research shows that,with proper dielectric loading and 50 Ω feeding line,the bandwidth of the antenna can be up to 6.5 GHz,from 3.5 GHz to 10 GHz with VSWR(voltage standing wave ratio)less than 2.5.
文摘The biology of a koinobiont parasitoid of leaf-cutting ant larvae, <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>Szelenyiopria talitae<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i> (Hymenoptera: Diapriidae), was studied from naturally infested <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>Acromyrmex subterraneus<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i> (Hymenoptera: Formicidae) nests. Nests were collected in the field from the Atlantic rainforest biome in the state of Rio de Janeiro. A total of fifty-three nests were collected from 2015 to 2018. Parasitized nests were only found during the months of September and October. Approximately 22% of the nests collected over a four-year period were found to have been parasitized by <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>S. talitae<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i>. The mean within-nest parasitism rate was<span "=""> 66.3%. This diapriid displayed both solitary (14%) and gregarious parasitism (86%), with up to a maximum of 12 parasitoids developing within a single host. Gregarious parasitism with two (29%) or three (21%) <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>S. talitae<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i></span><i></i> per host was most frequently observed. There was a positive correlation between the number of parasitoids per host and host size (dry weight), indicating that <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>S. talitae<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i> females oviposited a higher number of eggs in larger hosts. There was also a negative correlation between <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>S.</i> <i>talitae<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i> pharate adult size and the number of parasitoids per host, which could have been caused by sibling competition for limited host resources. The high levels of parasitism seen here had a debilitating effect on the colonies. <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>Acromyrmex subterraneus<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i> is a serious pest in Brazil, and these studies lay the foundation for understanding the impact of <span style="color:#4D5156;background-color:#FFFFFF;"><i></i></span><i><i>S. talitae<span style="color:#4D5156;background-color:#FFFFFF;"></span></i></i> on ant populations.
文摘As sessile organisms, plants have to be subjected to insect attack. Over the long course of evolution, plants have produced many mechanisms to resist this biotic stress such as pigment accumulation. Pigment levels determined depth and distribution of leaf color, thereby indirectly or directly affecting the behavior of insect attack. Therefore, understanding the mechanism of mutual recognition between leaf color and insect will provide important theoretical insight for the cultivation and improvement of new cultivars. This paper outlines leaf-color formation and the effect of pigment on the behavior of insect attack, and explores the challenge of research in the interaction between leaf color and insect, as soon as the potential direction for future development. This will give a broad background for improvements of colored plants with resistance to insect attack.
