2015 Vol. 6, No. 4
2015, 6(4): 353-358.
doi: 10.15886/j.cnki.rdswxb.2015.04.001
Abstract
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Abstract:
Litopenaeus vannamei was treated with dissolved oxygen（ DO） at respective concentrations of 1. 5,3. 0,6. 5 mg·L-1 to study the stress effects of hypoxia on the gill,hepatopancreas and haemolymph of L. vannamei. The results showed that L. vannamei was tissue specific in distribution of activities of alkaline phosphates（ AKP） and acid phosphatase（ ACP） and was obviously different in the AKP and ACP activities among the three tissues（ P ＜ 0. 05）. Of the threes tissues the hepatopancreas contained the highest AKP and ACP activities,while the three tissues contained very low phenoloxidase（ PO） activities without any obvious difference. Under the stress of hypoxia-reoxygenation,the three tissues showed a similar rise-and-decline change in the activities of the three immune-related enzymes which generally recovered to the normal level at 24 h of reoxygenation. When the DO was 3. 0 mg·L-1 ,the gill contained the maximum activities of the three enzymes at 3 h. This indicated that the gill was first to respond to the hypoxic stress and can hence be used as a tissue indicator for hypoxic stress,and that 3 h was a critical time point for hypoxic stress in L. vannamei.
Litopenaeus vannamei was treated with dissolved oxygen（ DO） at respective concentrations of 1. 5,3. 0,6. 5 mg·L-1 to study the stress effects of hypoxia on the gill,hepatopancreas and haemolymph of L. vannamei. The results showed that L. vannamei was tissue specific in distribution of activities of alkaline phosphates（ AKP） and acid phosphatase（ ACP） and was obviously different in the AKP and ACP activities among the three tissues（ P ＜ 0. 05）. Of the threes tissues the hepatopancreas contained the highest AKP and ACP activities,while the three tissues contained very low phenoloxidase（ PO） activities without any obvious difference. Under the stress of hypoxia-reoxygenation,the three tissues showed a similar rise-and-decline change in the activities of the three immune-related enzymes which generally recovered to the normal level at 24 h of reoxygenation. When the DO was 3. 0 mg·L-1 ,the gill contained the maximum activities of the three enzymes at 3 h. This indicated that the gill was first to respond to the hypoxic stress and can hence be used as a tissue indicator for hypoxic stress,and that 3 h was a critical time point for hypoxic stress in L. vannamei.
2015, 6(4): 359-364.
doi: 10.15886/j.cnki.rdswxb.2015.04.002
Abstract:
Six yeast strains were isolated from Litopenaeus vannamei digestive tracts,of which the strains HNC-1,HNC-2 and HNC-6 were observed dominant with the frequencies of the colony forming units being 21. 65%,31. 34% and 22. 89%,respectively. The dominant strain HNC-2 was preliminarily identified as Candida nivariensis according to its morphological,physiological and biochemical characteristics and 26 S r DNA gene sequences. The feeding experiment was conducted to evaluate the effects of the strain HNC-2 on the daily weight gain,digestive tract and survival rate of L. vannamei,and on the population density of total bacteria,yeasts and vibrio in shrimp digestive tracts and shrimp culture water by adding different concentrations of the strain yeast HNC-2 into the feed. The experiment result shows that the strain HNC-2 could improve the survival rate and daily gain of L.vannamei significantly（ P ＜0. 05）,and that the groups treated with the strain at the concentrations from 2. 0×105 to 5. 0×105 cfu·g-1 were obviously different in daily weight gain as compared with the control group（ P ＜0. 05）.Moreover,the 2×105 cfu·g-1 group had the highest survival rate（ 99. 5± 0. 3%）,significantly higher than the control and other groups（ P ＜0. 05）. The quantity of yeast in the digestive tract of shrimp and culture water tended to increase,and was highly significantly different（ P ＜0. 01） between each treatment group and the control group. The quantity of total bacteria and vibrio in digestive tract of shrimp and culture water increased,highly significantly different between the experimental groups and the control group（ P ＞ 0. 05）. The yeast strain HNC-2could promote the growth and improve the survival rate of L. vannamei.
Six yeast strains were isolated from Litopenaeus vannamei digestive tracts,of which the strains HNC-1,HNC-2 and HNC-6 were observed dominant with the frequencies of the colony forming units being 21. 65%,31. 34% and 22. 89%,respectively. The dominant strain HNC-2 was preliminarily identified as Candida nivariensis according to its morphological,physiological and biochemical characteristics and 26 S r DNA gene sequences. The feeding experiment was conducted to evaluate the effects of the strain HNC-2 on the daily weight gain,digestive tract and survival rate of L. vannamei,and on the population density of total bacteria,yeasts and vibrio in shrimp digestive tracts and shrimp culture water by adding different concentrations of the strain yeast HNC-2 into the feed. The experiment result shows that the strain HNC-2 could improve the survival rate and daily gain of L.vannamei significantly（ P ＜0. 05）,and that the groups treated with the strain at the concentrations from 2. 0×105 to 5. 0×105 cfu·g-1 were obviously different in daily weight gain as compared with the control group（ P ＜0. 05）.Moreover,the 2×105 cfu·g-1 group had the highest survival rate（ 99. 5± 0. 3%）,significantly higher than the control and other groups（ P ＜0. 05）. The quantity of yeast in the digestive tract of shrimp and culture water tended to increase,and was highly significantly different（ P ＜0. 01） between each treatment group and the control group. The quantity of total bacteria and vibrio in digestive tract of shrimp and culture water increased,highly significantly different between the experimental groups and the control group（ P ＞ 0. 05）. The yeast strain HNC-2could promote the growth and improve the survival rate of L. vannamei.
2015, 6(4): 365-373.
doi: 10.15886/j.cnki.rdswxb.2015.04.003
Abstract:
MD-2-related lipid-recognition（ ML） superfamily proteins have a single ML domain,which can be bound to specific lipids and play important roles in innate immunity,lipid-recognition and metabolism. The cDNA and gene of a ML protein was identified form Marsupenaeus japonicus,and this ML protein was named as MjML. The full length cDNA of the MjML was 614 bp,with a 453 bp open reading frame that encoded 150 amino acid residues. The MjML gene was 1678 bp in length,and consisted of four exons and three introns. The putative MjML protein contained 6 cysteines which could form 3 pairs of disulfide bonds. Real-time quantitative PCR results showed that MjML mRNA was mainly highly expressed in the hepatopancreas,but very low in other examined tissues. After V. parahaemolyticus was challenged with white spot syndrome virus（ WSSV）,the expression of MjML in hepatopancreas increased gradually and then decreased. At 24 h,the MjML was upregulated and its expression reached the peak. During the early larval development of V. parahaemolyticus,especially after the metamorphosis,the MjML expression had a sharp rise. The MjML expression increased step by step at the post-larvae stage. The results showed that the MjML might play a role in the innate immunity of V. parahaemolyticus. And during the early larval development,the expression of MjML mRNA there might be correlated with the molting and metamorphosis in shrimp larval development.
MD-2-related lipid-recognition（ ML） superfamily proteins have a single ML domain,which can be bound to specific lipids and play important roles in innate immunity,lipid-recognition and metabolism. The cDNA and gene of a ML protein was identified form Marsupenaeus japonicus,and this ML protein was named as MjML. The full length cDNA of the MjML was 614 bp,with a 453 bp open reading frame that encoded 150 amino acid residues. The MjML gene was 1678 bp in length,and consisted of four exons and three introns. The putative MjML protein contained 6 cysteines which could form 3 pairs of disulfide bonds. Real-time quantitative PCR results showed that MjML mRNA was mainly highly expressed in the hepatopancreas,but very low in other examined tissues. After V. parahaemolyticus was challenged with white spot syndrome virus（ WSSV）,the expression of MjML in hepatopancreas increased gradually and then decreased. At 24 h,the MjML was upregulated and its expression reached the peak. During the early larval development of V. parahaemolyticus,especially after the metamorphosis,the MjML expression had a sharp rise. The MjML expression increased step by step at the post-larvae stage. The results showed that the MjML might play a role in the innate immunity of V. parahaemolyticus. And during the early larval development,the expression of MjML mRNA there might be correlated with the molting and metamorphosis in shrimp larval development.
2015, 6(4): 374-380.
doi: 10.15886/j.cnki.rdswxb.2015.04.004
Abstract:
Two strains（ MJBX-1 and MJBX-2） of bacteria were isolated from the hepatopancreas,stomach and intestines of infected Marsupenaeus japonicus,and used for immersion challenge of V. parahaemolyticus to study their infectivity. These isolates induced 100% mortality of V. parahaemolyticus immersion challenged at the concentration of 107 cfu·mL-1,and 90% mortality at 106cfu·mL-1. Subsequent bacterial isolation from the challenged V. parahaemolyticus showed the same bacterial colony type as in the field samples. These isolates were gram-negative,arcshaped,rhabditiform or filamentous,without spore-forming,but mostly with an obvious arc shape. They formed transparent or translucent round colonies on the LB solid medium and green colonies on the TCBS medium. In the meantime,they could grow at the culture medium containing 2%,4%,6% or 8% of Na CL,but not 0% or 10% of Na CL. The isolated strains were preliminarily identified by using the matrix assisted laser desorption/ionization time of flight mass spectrometry（ MALDI-TOF-MS） through comparison of the mass spectrometry between the isolated strains and the standard strain. Moreover,their sequences were analyzed by using the 16 S rRNA to produce phylogenetic tree. The MALDI-TOF-MS and the 16 S rRNA analysis showed that the isolated strains MJBX-1 and MJBX-2 belonged to Vibrio parahaemolyticus. The antibiotic sensitivity test showed that MJBX-1 and MJBX-2 were sensitive to Florfenicol, Norfloxacin, Macrodantin, Gentamicin, Streptomycin and Kanamycin, but not to Amoxicillin and Tetracycline. This study will provide scientific reference for accurate,quick identification and control of the disease of V. parahaemolyticus caused by V. parahaemolyticus.
Two strains（ MJBX-1 and MJBX-2） of bacteria were isolated from the hepatopancreas,stomach and intestines of infected Marsupenaeus japonicus,and used for immersion challenge of V. parahaemolyticus to study their infectivity. These isolates induced 100% mortality of V. parahaemolyticus immersion challenged at the concentration of 107 cfu·mL-1,and 90% mortality at 106cfu·mL-1. Subsequent bacterial isolation from the challenged V. parahaemolyticus showed the same bacterial colony type as in the field samples. These isolates were gram-negative,arcshaped,rhabditiform or filamentous,without spore-forming,but mostly with an obvious arc shape. They formed transparent or translucent round colonies on the LB solid medium and green colonies on the TCBS medium. In the meantime,they could grow at the culture medium containing 2%,4%,6% or 8% of Na CL,but not 0% or 10% of Na CL. The isolated strains were preliminarily identified by using the matrix assisted laser desorption/ionization time of flight mass spectrometry（ MALDI-TOF-MS） through comparison of the mass spectrometry between the isolated strains and the standard strain. Moreover,their sequences were analyzed by using the 16 S rRNA to produce phylogenetic tree. The MALDI-TOF-MS and the 16 S rRNA analysis showed that the isolated strains MJBX-1 and MJBX-2 belonged to Vibrio parahaemolyticus. The antibiotic sensitivity test showed that MJBX-1 and MJBX-2 were sensitive to Florfenicol, Norfloxacin, Macrodantin, Gentamicin, Streptomycin and Kanamycin, but not to Amoxicillin and Tetracycline. This study will provide scientific reference for accurate,quick identification and control of the disease of V. parahaemolyticus caused by V. parahaemolyticus.
2015, 6(4): 381-387.
doi: 10.15886/j.cnki.rdswxb.2015.04.005
Abstract:
The macrobenthos in the Xincun Bay of Lingshui County,Hainan,China were investigated to analyze the relationship between their structure and the seagrass habitats. The result showed that macrobenthos in the Xincun Bay were mainly composed of bivalves,accounting for 43% of the total,followed by gastropods accounting for 26% of the total. The main species did not vary significantly with season,and more species were generally observed in summer and autumn,but less in winter and spring. The dominant species were Batillaris zonalis in spring,Arenicda cristata in summer and autumn,and Dasybranchus caducus in winter. Observation of the biomass variation in the whole year showed that the biomass changed greater in summer and autumn than in spring and winter,and tended to decline from the seagrass region to the outward. The density and biomass of macrobenthos communities in different seagrass habitats were different,and the density,biomass and biodiversity index H’ of Thalassia hemperichii were the highest. Biodiversity and evenness index of macrobenthos in the seagrass habitats were higher in summer and autumn,and lower in spring and winter. Cluster analysis indicated that macrobenthos communities were similar in the habitats of Halodule uninervis,Halophila ovalis and Halophila minor of the sea area under study.
The macrobenthos in the Xincun Bay of Lingshui County,Hainan,China were investigated to analyze the relationship between their structure and the seagrass habitats. The result showed that macrobenthos in the Xincun Bay were mainly composed of bivalves,accounting for 43% of the total,followed by gastropods accounting for 26% of the total. The main species did not vary significantly with season,and more species were generally observed in summer and autumn,but less in winter and spring. The dominant species were Batillaris zonalis in spring,Arenicda cristata in summer and autumn,and Dasybranchus caducus in winter. Observation of the biomass variation in the whole year showed that the biomass changed greater in summer and autumn than in spring and winter,and tended to decline from the seagrass region to the outward. The density and biomass of macrobenthos communities in different seagrass habitats were different,and the density,biomass and biodiversity index H’ of Thalassia hemperichii were the highest. Biodiversity and evenness index of macrobenthos in the seagrass habitats were higher in summer and autumn,and lower in spring and winter. Cluster analysis indicated that macrobenthos communities were similar in the habitats of Halodule uninervis,Halophila ovalis and Halophila minor of the sea area under study.
2015, 6(4): 388-396.
doi: 10.15886/j.cnki.rdswxb.2015.04.006
Abstract:
Tidal flooding is one of the most important factors that affect the regional distribution of mangrove plants. The basal stem diameter,height,crown,density and spatial distribution patterns of Ceriops tagal populations in different tidal zones of Dongzhaigang Harbour in Hainan Island were observed and determined for comparative analysis. C. tagal populations among different tidal zones were found different obviously in the population structure,distribution and distribution pattern as the extent of tidal flooding varied. The seedling populations of C. tagal had the highest proportion in all the tidal zones and grew as stable or steady-growing populations,but their densities were highly different: 986 plants/hm2 in the external tidal zone,43873 plants/hm2 in the middle tidal zone,and 141360 plants/hm2 in the inner tidal zone. The basal stem diameter and the crown structure of the C. tagal populations were not obviously different,but the height was obviously different: C. tagal populations tended to grow higher from the inner to the external tide zones. C. tagal populations tended to be distributed randomly and were aggregately distributed in the middle and inner tidal zones. For the dynamics of spatial distribution patterns of the C. tagal populations the seedlings were aggregately distributed while the young and mature trees were scattered randomly in the external tidal zone,but the seedlings and young trees were aggregately distributed and the mature trees randomly distributed in both the middle and inner tidal zones.
Tidal flooding is one of the most important factors that affect the regional distribution of mangrove plants. The basal stem diameter,height,crown,density and spatial distribution patterns of Ceriops tagal populations in different tidal zones of Dongzhaigang Harbour in Hainan Island were observed and determined for comparative analysis. C. tagal populations among different tidal zones were found different obviously in the population structure,distribution and distribution pattern as the extent of tidal flooding varied. The seedling populations of C. tagal had the highest proportion in all the tidal zones and grew as stable or steady-growing populations,but their densities were highly different: 986 plants/hm2 in the external tidal zone,43873 plants/hm2 in the middle tidal zone,and 141360 plants/hm2 in the inner tidal zone. The basal stem diameter and the crown structure of the C. tagal populations were not obviously different,but the height was obviously different: C. tagal populations tended to grow higher from the inner to the external tide zones. C. tagal populations tended to be distributed randomly and were aggregately distributed in the middle and inner tidal zones. For the dynamics of spatial distribution patterns of the C. tagal populations the seedlings were aggregately distributed while the young and mature trees were scattered randomly in the external tidal zone,but the seedlings and young trees were aggregately distributed and the mature trees randomly distributed in both the middle and inner tidal zones.
2015, 6(4): 397-402.
doi: 10.15886/j.cnki.rdswxb.2015.04.007
Abstract:
The soil organic carbon was measured in 6 mangrove communities in Shanwei and Zhushan regions of the Dongzhai Harbor Mangrove Reserve in Hainan Province,China to analyze vertical distribution of the organic carbon content,organic carbon reserve,soil moisture content and soil bulk density in the soil of different mangrove communities,and to compare the organic carbon content and reserve in the mangrove communities in different regions. The results showed that in the soil 0~120 cm deep the organic carbon reserve was 807. 10 t·ha-1 in Shanwei Bruguiera gymnorrhiza community,613. 46 t · hm2 in Shanwei Kandelia candel community,909. 93 t/hm2 in Shanwei Bruguiera marina community,272. 91 t·hm2in Zhushan Bruguiera gymnorrhiza community,286. 50 t·hm2in Zhushan Rhizophora stylosa community,327. 86 t·hm2in Zhushan Bruguiera marina community. The soil organic carbon content and reserve were obviously higher in Shanwei mangrove communities than in the Zhushan,and the organic carbon reserve was still very high in the soil in the depth of 120 cm.
The soil organic carbon was measured in 6 mangrove communities in Shanwei and Zhushan regions of the Dongzhai Harbor Mangrove Reserve in Hainan Province,China to analyze vertical distribution of the organic carbon content,organic carbon reserve,soil moisture content and soil bulk density in the soil of different mangrove communities,and to compare the organic carbon content and reserve in the mangrove communities in different regions. The results showed that in the soil 0~120 cm deep the organic carbon reserve was 807. 10 t·ha-1 in Shanwei Bruguiera gymnorrhiza community,613. 46 t · hm2 in Shanwei Kandelia candel community,909. 93 t/hm2 in Shanwei Bruguiera marina community,272. 91 t·hm2in Zhushan Bruguiera gymnorrhiza community,286. 50 t·hm2in Zhushan Rhizophora stylosa community,327. 86 t·hm2in Zhushan Bruguiera marina community. The soil organic carbon content and reserve were obviously higher in Shanwei mangrove communities than in the Zhushan,and the organic carbon reserve was still very high in the soil in the depth of 120 cm.
2015, 6(4): 403-407.
doi: 10.15886/j.cnki.rdswxb.2015.04.008
Abstract:
Morus alba was pot cultured with 6 treatments with a 10% gradient of soil relative water content（ SRWC） or soil moisture content from 30%- 80% to observe light response parameters,rate of net photosynthesis,and other parameters to explore the combined effects of light intensity and soil moisture on net photosynthesis rate of M. alba leaves by constructing a mathematical model for the rate of net photosynthesis and environmental factors. The observations showed that light intensity gave a significant positive correlation with the rate of net photosynthesis when the soil relative water holding capacity was in the range of 40%- 80%. Both the light intensity and soil moisture had impacts on the rate of photosynthesis,and the impact varied with soil moisture content. Among the soil moisture treatments the rate of photosynthesis tended to show a similar response to light intensity,and the response increased rapidly first with the light intensity,and then slowly concurrent with a light saturation phenomenon. At low soil moisture content,soil moisture had a dominant impact on the rate of net photosynthesis,while at higher soil moisture content,light intensity had a dominant impact on the rate of net photosynthesis.The comprehensive impacts of light intensity and soil moisture on the rate of photosynthesis could be expressed by a exponential mode,and the dominant factor affecting the rate of net photosynthesis was shifted from the soil moisture to the light intensity at a threshold of soil moisture content of 51. 17%.
Morus alba was pot cultured with 6 treatments with a 10% gradient of soil relative water content（ SRWC） or soil moisture content from 30%- 80% to observe light response parameters,rate of net photosynthesis,and other parameters to explore the combined effects of light intensity and soil moisture on net photosynthesis rate of M. alba leaves by constructing a mathematical model for the rate of net photosynthesis and environmental factors. The observations showed that light intensity gave a significant positive correlation with the rate of net photosynthesis when the soil relative water holding capacity was in the range of 40%- 80%. Both the light intensity and soil moisture had impacts on the rate of photosynthesis,and the impact varied with soil moisture content. Among the soil moisture treatments the rate of photosynthesis tended to show a similar response to light intensity,and the response increased rapidly first with the light intensity,and then slowly concurrent with a light saturation phenomenon. At low soil moisture content,soil moisture had a dominant impact on the rate of net photosynthesis,while at higher soil moisture content,light intensity had a dominant impact on the rate of net photosynthesis.The comprehensive impacts of light intensity and soil moisture on the rate of photosynthesis could be expressed by a exponential mode,and the dominant factor affecting the rate of net photosynthesis was shifted from the soil moisture to the light intensity at a threshold of soil moisture content of 51. 17%.
2015, 6(4): 408-419.
doi: 10.15886/j.cnki.rdswxb.2015.04.009
Abstract:
Tobacco leaves were treated with IAA and harpinXoo to observe the interaction between IAA and harpinxoo protein in tobacco leaves,and the oxidative burst in tobacco leaf tissues by quantitative assay and microscopy.The expressions of hypersensitive response marker gene,disease defense genes and auxin related genes were detected by using semi-quantitative PCR.The EF-1α gene was used as an internal control because it is highly conserved and constitutively expressed in eukaryotes.Plant assays showed that 10-4 mol · L-1 IAA inhibited the hypersensitive response induced by harpinxoo protein in tobacco leaves and that the inhibition was weakened when 500μmol · L-1 TIBA was applied at the same time.The analysis of the oxidative burst in tobacco leaf tissue was in accordance with the results of plant assays that IAA could reduce the accumulation of ROS.The semi-quantitative PCR results showed that IAA had different effects on the expressions of hypersensitive response marker gene hsr203 J,disease defense gene chia5 and PR-1b,auxin related genes AUX1,ARF8 and so on.It is concluded that IAA can inhibit the hypersensitive response induced by harpinxoo protein and regulate the oxidative burst in tobacco leaves.
Tobacco leaves were treated with IAA and harpinXoo to observe the interaction between IAA and harpinxoo protein in tobacco leaves,and the oxidative burst in tobacco leaf tissues by quantitative assay and microscopy.The expressions of hypersensitive response marker gene,disease defense genes and auxin related genes were detected by using semi-quantitative PCR.The EF-1α gene was used as an internal control because it is highly conserved and constitutively expressed in eukaryotes.Plant assays showed that 10-4 mol · L-1 IAA inhibited the hypersensitive response induced by harpinxoo protein in tobacco leaves and that the inhibition was weakened when 500μmol · L-1 TIBA was applied at the same time.The analysis of the oxidative burst in tobacco leaf tissue was in accordance with the results of plant assays that IAA could reduce the accumulation of ROS.The semi-quantitative PCR results showed that IAA had different effects on the expressions of hypersensitive response marker gene hsr203 J,disease defense gene chia5 and PR-1b,auxin related genes AUX1,ARF8 and so on.It is concluded that IAA can inhibit the hypersensitive response induced by harpinxoo protein and regulate the oxidative burst in tobacco leaves.
2015, 6(4): 420-425.
doi: 10.15886/j.cnki.rdswxb.2015.04.010
Abstract:
High Performance Liquid Chromatography（ HPLC） was used to analyze the chemical components of 10 ornamental and medical Dendrobium species and hybrids,and the component activity against agricultural pathogenic fungi and in vitro hypoglycemia were assayed by using Filter AGAR diffusion method and α-glucosidase inhibitory assay,respectively. The results showed that these ten Dendrobium species and hybrids had pretty low similarity with the shared characteristic fingerprint,which means there were obvious differences among them.Besides,the Dendrobium hybrid ‘T5’and D. officinale had preferable inhibitory effect on α-glucosidase,and the hybrid ‘920’and D. officinale had the inhibitory activity against 5 species of agricultural pathogenic fungi,especially Colletotrichum gloeosporiodes.
High Performance Liquid Chromatography（ HPLC） was used to analyze the chemical components of 10 ornamental and medical Dendrobium species and hybrids,and the component activity against agricultural pathogenic fungi and in vitro hypoglycemia were assayed by using Filter AGAR diffusion method and α-glucosidase inhibitory assay,respectively. The results showed that these ten Dendrobium species and hybrids had pretty low similarity with the shared characteristic fingerprint,which means there were obvious differences among them.Besides,the Dendrobium hybrid ‘T5’and D. officinale had preferable inhibitory effect on α-glucosidase,and the hybrid ‘920’and D. officinale had the inhibitory activity against 5 species of agricultural pathogenic fungi,especially Colletotrichum gloeosporiodes.
2015, 6(4): 426-431.
doi: 10.15886/j.cnki.rdswxb.2015.04.011
Abstract:
To elucidate the nitrogen use efficiency of different cassava varieties,soil pot culture was conducted to differentiate three main cultivars: NZ199,KU50 and SC8 in China. The three cassava varieties subjected to nitrogen treatments at 4 gradient concentrations from low to normal. The results showed that one month after cultivation the cassava leaf colors are obviously different among the same variety under different nitrogen levels or different varieties under the same nitrogen level. Nitrogen levels have significant impact on cassava plant height,and the ratio of plant height under low nitrogen to that under normal nitrogen can be used as the nitrogen use efficiency coefficient to differentiate nitrogen utilization ability of cassava varieties. Further fertilizer response function was obtained by using nitrogen levels and plant height,and the coefficient of this function shows that these cassava varieties are tolerant to low nitrogen in the order of NZ199＞ KU50＞ SC8.
To elucidate the nitrogen use efficiency of different cassava varieties,soil pot culture was conducted to differentiate three main cultivars: NZ199,KU50 and SC8 in China. The three cassava varieties subjected to nitrogen treatments at 4 gradient concentrations from low to normal. The results showed that one month after cultivation the cassava leaf colors are obviously different among the same variety under different nitrogen levels or different varieties under the same nitrogen level. Nitrogen levels have significant impact on cassava plant height,and the ratio of plant height under low nitrogen to that under normal nitrogen can be used as the nitrogen use efficiency coefficient to differentiate nitrogen utilization ability of cassava varieties. Further fertilizer response function was obtained by using nitrogen levels and plant height,and the coefficient of this function shows that these cassava varieties are tolerant to low nitrogen in the order of NZ199＞ KU50＞ SC8.
2015, 6(4): 432-437.
doi: 10.15886/j.cnki.rdswxb.2015.04.012
Abstract:
Cassava Witches’ Broom and Frog Skin diseases are worldwide important diseases caused by phytoplasma,which could induce serious loss of yield and poor quality of root tubers of cassava（ Manihot esculenta Crantz）. In order to ensure the sustainable development of the cassava industry in China,these two diseases were put for risk analysis. The related progress at home and abroad and cassava disease survey results in China were retrieved from the literature,and the distribution of these two diseases and their potential economic damage as well as the economic importance of the infected host plants were described. The risk of the infection of the two diseases was evaluated by using the available software Pest Risk Analysis（ PRA） developed for evaluation of alien species. The risk values of these two diseases were given accordingly and input into the PRA program to evaluate the risk of the diseases. The PRA evaluation showed that the overall risk R values of cassava Witches’ Broom and Frog Skin diseases were 2. 19 and 2. 31,which indicated these two diseases were pests with high risk and had to be listed for quarantine inspection.
Cassava Witches’ Broom and Frog Skin diseases are worldwide important diseases caused by phytoplasma,which could induce serious loss of yield and poor quality of root tubers of cassava（ Manihot esculenta Crantz）. In order to ensure the sustainable development of the cassava industry in China,these two diseases were put for risk analysis. The related progress at home and abroad and cassava disease survey results in China were retrieved from the literature,and the distribution of these two diseases and their potential economic damage as well as the economic importance of the infected host plants were described. The risk of the infection of the two diseases was evaluated by using the available software Pest Risk Analysis（ PRA） developed for evaluation of alien species. The risk values of these two diseases were given accordingly and input into the PRA program to evaluate the risk of the diseases. The PRA evaluation showed that the overall risk R values of cassava Witches’ Broom and Frog Skin diseases were 2. 19 and 2. 31,which indicated these two diseases were pests with high risk and had to be listed for quarantine inspection.
2015, 6(4): 438-443.
doi: 10.15886/j.cnki.rdswxb.2015.04.013
Abstract:
Aqueous extracts from different parts of 20 plants were used to inhibit the growth of the strain Fusarium oxysporum f. sp. cubense based on the methods of mycelial growth and spore germination. Of the 20 plants Chinese leek,sunflower and lettuce exhibited the best antifungal effect on mycelial growth of the strain at an extract concentration of 200 m L·L-1. Among these three plants,for the whole plant extract Chinese leek exhibited the best antifungal effect with an inhibition rate of 93. 6%,followed by the sunflower and the lettuce; for the root extract the sunflower exhibited the best antifungal effect with an inhibition rate of 88. 5%,followed by the lettuce and the Chinese leek; for the leaf and pseudostem extract these three plants had a poor inhibitory activity with an inhibition rate of less than 56%. Ten plants with the extract from the whole plant were all found to show inhibitory effect on conidial germination of F. oxysporum f. sp. cubense. When the extracts were mixed with spore suspension at an equal volume,Chinese leek with aqueous extract had best inhibitation against conidial germination of F. oxysporum f. sp. cubense,followed by the sunflower and lettuce,but no significant difference were observed in conidial inhibition between the Chinese leek and sunflowers.
Aqueous extracts from different parts of 20 plants were used to inhibit the growth of the strain Fusarium oxysporum f. sp. cubense based on the methods of mycelial growth and spore germination. Of the 20 plants Chinese leek,sunflower and lettuce exhibited the best antifungal effect on mycelial growth of the strain at an extract concentration of 200 m L·L-1. Among these three plants,for the whole plant extract Chinese leek exhibited the best antifungal effect with an inhibition rate of 93. 6%,followed by the sunflower and the lettuce; for the root extract the sunflower exhibited the best antifungal effect with an inhibition rate of 88. 5%,followed by the lettuce and the Chinese leek; for the leaf and pseudostem extract these three plants had a poor inhibitory activity with an inhibition rate of less than 56%. Ten plants with the extract from the whole plant were all found to show inhibitory effect on conidial germination of F. oxysporum f. sp. cubense. When the extracts were mixed with spore suspension at an equal volume,Chinese leek with aqueous extract had best inhibitation against conidial germination of F. oxysporum f. sp. cubense,followed by the sunflower and lettuce,but no significant difference were observed in conidial inhibition between the Chinese leek and sunflowers.
2015, 6(4): 444-448.
doi: 10.15886/j.cnki.rdswxb.2015.04.014
Abstract:
Leaf premature senescence phenomenon is proved to have obvious effect on the quality and yield of banana fruit. So,unveiling of the mechanism of leaf senescence would have a profound significance on the theory and practice for improving the quantity and quality of banana. The third leaves were detached and collected from tissue cultured banana plants of 3 months old. They were treated in light,dark,6-BA + light,or 6-BA + dark with 3 replications and collected at different hours after treatment for RNA extraction. Expressions of genes related to invertase and leaf senescence in the leaves treated were determined by using the real-time fluorescence quantitative PCR approach（ RT-PCR）,and their changes were analyzed in leaf senescence.. In the darkness treatment to induce senescence of the detached banana leaves the sucrose concentration declined,leading to sucrose starvation and high expression of senescence-associated genes（ SAG） after the cell wall invertase genes（ INCWs） were highly expressed. This experiment gives a molecular support to the conclusion of the leaf senescence initiation reported at physiological and biochemical levels: that leaves were induced by sucrose starvation to start their senescence process.
Leaf premature senescence phenomenon is proved to have obvious effect on the quality and yield of banana fruit. So,unveiling of the mechanism of leaf senescence would have a profound significance on the theory and practice for improving the quantity and quality of banana. The third leaves were detached and collected from tissue cultured banana plants of 3 months old. They were treated in light,dark,6-BA + light,or 6-BA + dark with 3 replications and collected at different hours after treatment for RNA extraction. Expressions of genes related to invertase and leaf senescence in the leaves treated were determined by using the real-time fluorescence quantitative PCR approach（ RT-PCR）,and their changes were analyzed in leaf senescence.. In the darkness treatment to induce senescence of the detached banana leaves the sucrose concentration declined,leading to sucrose starvation and high expression of senescence-associated genes（ SAG） after the cell wall invertase genes（ INCWs） were highly expressed. This experiment gives a molecular support to the conclusion of the leaf senescence initiation reported at physiological and biochemical levels: that leaves were induced by sucrose starvation to start their senescence process.
2015, 6(4): 449-459.
doi: 10.15886/j.cnki.rdswxb.2015.04.015
Abstract:
HpaXm,cloned and identified from Xanthomonas citri subsp. malvacearum,is a new class of harpin proteins. Tobacco（ Nicotiana tobacum‘Xanthi nc’） was transformed with HpaXm through Agrobacterium-mediation,and the resultant transgenic tobacco plants were subjected to molecular identification and protein activity assay to study the effect of the endogenous expression of hpaXm in the transgenic tobacco. The target gene and the 35 S promoter sequences were detected by PCR,and the target genes sequences were detected by Southern Blot hybridization in the genome from the T1 line positive transgenic plants,indicating that the hpaXm gene had already been integrated into the recipient genomes. Reverse transcriptase PCR indicated that the transferred genes were expressed normally in the transgenic plants. Soluble proteins extracted from plants which had been transformed with hpaXm could stimulate hypersensitive response on tobacco leaves,indicating that hpaXm expressed in transgenic tobacco plants are bioactive. Although the endogenous expression of hpaXm failed to make a large area visible necrotic spots,but the phenomenon of micro-allergic reactions was observed after trypan blue staining. Constitutive expression of hpaXm in transgenic tobaccos conferred defense responses to TMV. The study would provide a scientific basis to explore the biological characteristics of transgenic plants induced by hpaXm.
HpaXm,cloned and identified from Xanthomonas citri subsp. malvacearum,is a new class of harpin proteins. Tobacco（ Nicotiana tobacum‘Xanthi nc’） was transformed with HpaXm through Agrobacterium-mediation,and the resultant transgenic tobacco plants were subjected to molecular identification and protein activity assay to study the effect of the endogenous expression of hpaXm in the transgenic tobacco. The target gene and the 35 S promoter sequences were detected by PCR,and the target genes sequences were detected by Southern Blot hybridization in the genome from the T1 line positive transgenic plants,indicating that the hpaXm gene had already been integrated into the recipient genomes. Reverse transcriptase PCR indicated that the transferred genes were expressed normally in the transgenic plants. Soluble proteins extracted from plants which had been transformed with hpaXm could stimulate hypersensitive response on tobacco leaves,indicating that hpaXm expressed in transgenic tobacco plants are bioactive. Although the endogenous expression of hpaXm failed to make a large area visible necrotic spots,but the phenomenon of micro-allergic reactions was observed after trypan blue staining. Constitutive expression of hpaXm in transgenic tobaccos conferred defense responses to TMV. The study would provide a scientific basis to explore the biological characteristics of transgenic plants induced by hpaXm.
2015, 6(4): 460-466.
doi: 10.15886/j.cnki.rdswxb.2015.04.016
Abstract:
Kongjac glucomannan（ KGM） was blended with pullulan（ PULL） by using a single factor experiment to determine the effect of KGM concentration,PULL concentration,swelling temperature and swelling time on the swelling properties of the KGM/PULL blend system,and a three factorial and three level response surface design was optimized by using the Box-Behnken design with the conditions determined of significant effect as the factors and the viscosity of the blend sol solution as the response value,and a mathematical model was established for statistical analysis by using the software Design-Expert V8. 0. 6 to fit the surface response values to the regression curve of variables. The KGM concentration,PULL concentration and swelling time were determined as most important factors affecting the viscosity of the blend sol solution; the interaction between the KGM concentration and the swelling time gave a significant impact on the viscosity of the blend sol solution; when the KGM concentration,PULL concentration and swelling time were set at 0. 28%,0. 55% and 1. 9 h,respectively,the model predicted the optimal viscosity of the blend sol solution be 19. 2371 Pa·s,which fell within 1% of the error in the experiment,indicating this result had a high level of fitness and confidence.
Kongjac glucomannan（ KGM） was blended with pullulan（ PULL） by using a single factor experiment to determine the effect of KGM concentration,PULL concentration,swelling temperature and swelling time on the swelling properties of the KGM/PULL blend system,and a three factorial and three level response surface design was optimized by using the Box-Behnken design with the conditions determined of significant effect as the factors and the viscosity of the blend sol solution as the response value,and a mathematical model was established for statistical analysis by using the software Design-Expert V8. 0. 6 to fit the surface response values to the regression curve of variables. The KGM concentration,PULL concentration and swelling time were determined as most important factors affecting the viscosity of the blend sol solution; the interaction between the KGM concentration and the swelling time gave a significant impact on the viscosity of the blend sol solution; when the KGM concentration,PULL concentration and swelling time were set at 0. 28%,0. 55% and 1. 9 h,respectively,the model predicted the optimal viscosity of the blend sol solution be 19. 2371 Pa·s,which fell within 1% of the error in the experiment,indicating this result had a high level of fitness and confidence.
2015, 6(4): 467-473.
doi: 10.15886/j.cnki.rdswxb.2015.04.017
Abstract:
Typhoon Ramasun slashed Hainan Island on July 18,2014 in Hainan,China. A survey of wind damages to rubber plantations in Hainan,China was made twice in July and August 2014 in the aftermath of the attack of the typhoon to study the relationship of different topographical factors with the wind damages to the rubber plantations in Hainan. The wind damages to the rubber plantations were found to be related with wind forces and also with the site environment of the rubber plantations. The severity of the wind damages to the rubber plantations was in the order of the top ＞ the bottom ＞ the middle of slope,or of the windward ＞ the crosswind ＞ the leeward slope. However,if there were other topographical factors affecting the wind damage to the rubber plantations,no obvious difference of the wind damage rate was observed between slope position and aspect. The wind damage rate increased with the slope degree,and it was obviously less in the rubber plantations with shelter belts than in those without shelter belts. The wind damage rate in special landforms was related to the location of the rubber plantation.
Typhoon Ramasun slashed Hainan Island on July 18,2014 in Hainan,China. A survey of wind damages to rubber plantations in Hainan,China was made twice in July and August 2014 in the aftermath of the attack of the typhoon to study the relationship of different topographical factors with the wind damages to the rubber plantations in Hainan. The wind damages to the rubber plantations were found to be related with wind forces and also with the site environment of the rubber plantations. The severity of the wind damages to the rubber plantations was in the order of the top ＞ the bottom ＞ the middle of slope,or of the windward ＞ the crosswind ＞ the leeward slope. However,if there were other topographical factors affecting the wind damage to the rubber plantations,no obvious difference of the wind damage rate was observed between slope position and aspect. The wind damage rate increased with the slope degree,and it was obviously less in the rubber plantations with shelter belts than in those without shelter belts. The wind damage rate in special landforms was related to the location of the rubber plantation.
2015, 6(4): 474-477.
doi: 10.15886/j.cnki.rdswxb.2015.04.018
Abstract:
Eligible Sprague Dawley（ SD） male rats were chosen to make chronic constriction injury（ CCI） model of the rat sciatic nerve,and CCI mechanical pain thresholds in different positions of the hind paw of rats were measured and compared to determine the best position for measurement. No significant difference was found in pain threshold among Positions 1,2 and 3 before CCI surgery（ P ＞0. 05）,whereas highly significant difference were observed between the Positions 1 or 2 and Position 3 after surgery of hind paw（ P ＜0. 001） and no significant difference was between Positions 1 and 2（ P ＞0. 05）. For the hind paw prior to surgery no significant difference was observed in pain threshold between the Positions 1 or 3 and the Position 2 in the hind paw,but significant difference were found between the Positions 1 and 2（ P ＜0. 05）. The Position 2 is the best place for measurement of mechanical pain threshold in CCI rats.
Eligible Sprague Dawley（ SD） male rats were chosen to make chronic constriction injury（ CCI） model of the rat sciatic nerve,and CCI mechanical pain thresholds in different positions of the hind paw of rats were measured and compared to determine the best position for measurement. No significant difference was found in pain threshold among Positions 1,2 and 3 before CCI surgery（ P ＞0. 05）,whereas highly significant difference were observed between the Positions 1 or 2 and Position 3 after surgery of hind paw（ P ＜0. 001） and no significant difference was between Positions 1 and 2（ P ＞0. 05）. For the hind paw prior to surgery no significant difference was observed in pain threshold between the Positions 1 or 3 and the Position 2 in the hind paw,but significant difference were found between the Positions 1 and 2（ P ＜0. 05）. The Position 2 is the best place for measurement of mechanical pain threshold in CCI rats.
2015, 6(4): 478-484.
doi: 10.15886/j.cnki.rdswxb.2015.04.019
Abstract:
Genomic DNA of Jatropha curcas was extracted by improved CTAB method from J. curcas leaves,and detected through agarose gel electrophoresis and SSR-PCR amplification. The results showed that genomic DNA of J. curcas extracted by the modified CTAB method had good integrity,high purity,and hence could be used as a template of SSR markers. At the same time,4 factors influencing PCR amplification: d NTPs,Taq DNA polymerase,primers and Mg2+concentration were optimized to obtain a reaction system most suitable for SSR-PCR amplification and SSR-PCR amplification procedure for J. curcas. In this optimal reaction system with a total volume of 20μL the template DNA was 100 ng,d NTPs 0. 2 mmol·L-1,Taq DNA polymerase 100 U·m L-1,primer 0. 6μmol·L-1 and Mg2+1. 5 mmol·L-1,and the suitable amplification program included 94℃ pre degeneration for 3min at 94℃,denaturation for 1 min at 94℃,annealing for 1 min at 51- 53℃（ annealing temperature changed with primers）,extension for 2 min at 72℃,35 cycles,extension for 10 min at 72℃.
Genomic DNA of Jatropha curcas was extracted by improved CTAB method from J. curcas leaves,and detected through agarose gel electrophoresis and SSR-PCR amplification. The results showed that genomic DNA of J. curcas extracted by the modified CTAB method had good integrity,high purity,and hence could be used as a template of SSR markers. At the same time,4 factors influencing PCR amplification: d NTPs,Taq DNA polymerase,primers and Mg2+concentration were optimized to obtain a reaction system most suitable for SSR-PCR amplification and SSR-PCR amplification procedure for J. curcas. In this optimal reaction system with a total volume of 20μL the template DNA was 100 ng,d NTPs 0. 2 mmol·L-1,Taq DNA polymerase 100 U·m L-1,primer 0. 6μmol·L-1 and Mg2+1. 5 mmol·L-1,and the suitable amplification program included 94℃ pre degeneration for 3min at 94℃,denaturation for 1 min at 94℃,annealing for 1 min at 51- 53℃（ annealing temperature changed with primers）,extension for 2 min at 72℃,35 cycles,extension for 10 min at 72℃.
2015, 6(4): 485-490.
doi: 10.15886/j.cnki.rdswxb.2015.04.020
Abstract:
The strain S1 was separated from the roots of Dendrobium sinense,its mycelial morphology was observed under the microscope,and the ITS-5. 8S rDNA sequences of the strains were cloned,sequenced and analyzed by using BLAST. The strain isolated was cultured in PDB and DE liquid culture media,and plant free amino acids were detected by using high performance liquid chromatography（ HPLC）. The strain S1 isolated from the roots of D. sinense was identified as Tulasnella sp. of the family Tulasnellaceae,and detected to contain 17 essential amino acids in both PDB and DE fermentation broths,of which 3 amino acids,Pro,Cys and Lys,were much higher than the other amino acids.
The strain S1 was separated from the roots of Dendrobium sinense,its mycelial morphology was observed under the microscope,and the ITS-5. 8S rDNA sequences of the strains were cloned,sequenced and analyzed by using BLAST. The strain isolated was cultured in PDB and DE liquid culture media,and plant free amino acids were detected by using high performance liquid chromatography（ HPLC）. The strain S1 isolated from the roots of D. sinense was identified as Tulasnella sp. of the family Tulasnellaceae,and detected to contain 17 essential amino acids in both PDB and DE fermentation broths,of which 3 amino acids,Pro,Cys and Lys,were much higher than the other amino acids.
2015, 6(4): 491-496.
doi: 10.15886/j.cnki.rdswxb.2015.04.021
Abstract:
Crude arginine deiminase（ ADI） enzyme was extracted from Pseudomonas alcaligenes,purified by using ammonium sulfate graded precipitation,and then further separated and purified by using DEAE-Sephadex A-50 and Sephadex G-100 column chromatography to produce purified ADI. The purity of the purified ADI was determined by SDS-PAGE electrophoresis. The total enzyme activity of the ADI crude enzyme was detected to be 424. 43 U with a specific enzyme activity of 0. 42 U; the enzyme purified via salting out and dialysis had a total activity of 222. 10 U with a specific enzyme activity of 2. 05 U·mg-1; the enzyme purified by ion exchange analysis showed a total activity of 105. 83 U at the active site and its specific enzyme activity was 5. 61 U·mg-1; the enzyme purified through gel permeation chromatography had a total activity of 17. 94 U at the active site and its specific enzyme activity was 11. 80 U·mg-1. The purified ADI had a relative purity of 96%,which can be used for electrophoresis. It is concluded that this method can be used to produce ADI with higher purity and activity.
Crude arginine deiminase（ ADI） enzyme was extracted from Pseudomonas alcaligenes,purified by using ammonium sulfate graded precipitation,and then further separated and purified by using DEAE-Sephadex A-50 and Sephadex G-100 column chromatography to produce purified ADI. The purity of the purified ADI was determined by SDS-PAGE electrophoresis. The total enzyme activity of the ADI crude enzyme was detected to be 424. 43 U with a specific enzyme activity of 0. 42 U; the enzyme purified via salting out and dialysis had a total activity of 222. 10 U with a specific enzyme activity of 2. 05 U·mg-1; the enzyme purified by ion exchange analysis showed a total activity of 105. 83 U at the active site and its specific enzyme activity was 5. 61 U·mg-1; the enzyme purified through gel permeation chromatography had a total activity of 17. 94 U at the active site and its specific enzyme activity was 11. 80 U·mg-1. The purified ADI had a relative purity of 96%,which can be used for electrophoresis. It is concluded that this method can be used to produce ADI with higher purity and activity.
2015, 6(4): 497-503.
doi: 10.15886/j.cnki.rdswxb.2015.04.022
Abstract:
Transgenic Bt crops producing insecticidal crystalline proteins from Bacillus thuringiensis,so-called Cry toxins,have been proved useful in controlling insect pests. However,evolution of insect resistance threatens the continued success of the transgenic crops. Understanding how insects become resistant will provide the basis for insect resistance management. Here we review possible pest resistance mechanisms against transgenic Bt crops and different strategies to cope with resistance,such as high dose-refugee strategy,pyramiding or Cry gene stacking which express several toxins with different modes of action in the same plant,Bt plants with novel Cry toxins,and so on. These approaches should be proposed to deal with resistance in the field to assure successful use of Bt crops for an extended period of time.
Transgenic Bt crops producing insecticidal crystalline proteins from Bacillus thuringiensis,so-called Cry toxins,have been proved useful in controlling insect pests. However,evolution of insect resistance threatens the continued success of the transgenic crops. Understanding how insects become resistant will provide the basis for insect resistance management. Here we review possible pest resistance mechanisms against transgenic Bt crops and different strategies to cope with resistance,such as high dose-refugee strategy,pyramiding or Cry gene stacking which express several toxins with different modes of action in the same plant,Bt plants with novel Cry toxins,and so on. These approaches should be proposed to deal with resistance in the field to assure successful use of Bt crops for an extended period of time.
2015, 6(4): 504-511.
doi: 10.15886/j.cnki.rdswxb.2015.04.023
Abstract:
This review focuses on the anthranilate synthase（ AS）-associated pathway,the properties of AS α and β subunits,the regulatory mechanism of gene expression and the application of AS in improving plant nutritional quality. And the future emphasis on plant AS research is proposed.
This review focuses on the anthranilate synthase（ AS）-associated pathway,the properties of AS α and β subunits,the regulatory mechanism of gene expression and the application of AS in improving plant nutritional quality. And the future emphasis on plant AS research is proposed.
2015, 6(4): 513-518.
Abstract:
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