2019 Vol. 10, No. 4
2019, 10(4): 307-313.
doi: 10.15886/j.cnki.rdswxb.2019.04.001
Abstract
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Abstract:
To explain the molecular mechanisms of interaction between β4 nAChR subunit and ligand（agonist ACh and inhibitor α-CTx RegIIA）, a mutant of β4 nAChR subunit was constructed by substituting 168 th Ile（I） with Ser（S） in the Loop F of N-terminal ligand-binding region, by using the method of site-directed mutagenesis that PCR mediated. The results showed that the inward current of oocytes injected with cRNA of α3β4[S168 I] nAChR could be recorded by two-electrode voltage clamp. The mutant receptor had 1.4 times lower sensitivity to α-CTx RegIIA with a higher IC50 of 170 nmol·L-1, compared with the wild-type α3β4 nAChR.
To explain the molecular mechanisms of interaction between β4 nAChR subunit and ligand（agonist ACh and inhibitor α-CTx RegIIA）, a mutant of β4 nAChR subunit was constructed by substituting 168 th Ile（I） with Ser（S） in the Loop F of N-terminal ligand-binding region, by using the method of site-directed mutagenesis that PCR mediated. The results showed that the inward current of oocytes injected with cRNA of α3β4[S168 I] nAChR could be recorded by two-electrode voltage clamp. The mutant receptor had 1.4 times lower sensitivity to α-CTx RegIIA with a higher IC50 of 170 nmol·L-1, compared with the wild-type α3β4 nAChR.
2019, 10(4): 314-318.
doi: 10.15886/j.cnki.rdswxb.2019.04.002
Abstract:
In order to clarify the occurrence of sugarcane ratoon stunting disease（RSD） in sugarcane plantations in China, 598 sugarcane leaf samples were collected from 12 sugarcane plantations in the main sugarcane producing areas like Guangxi, Yunnan, Guangdong and Hainan in China, and the pathogen of RSD was identified by using specific primers through polymerase chain reaction（PCR）. The results showed that 99 out of 598 sugarcane samples were detected to contain bacteria of RSD, with an average detection rate of 16.56%. RSD detection rates varied in 12 sugarcane plantations, the highest in Lincang sugarcane plantations（27.78%） and the lowest in Nanning sugarcane plantations（4.88%）. RSD was detected in 15 main sugarcane cultivars, with positive detection rates ranging from 15.38% to 44.44%. Among the sugarcane cultivars, sugarcane cultivar ROC 22 was most seriously infected with RSD, and its RSD positive detection rate was 44.44%, while sugarcane cultivar Haitang 22 was less infected with RSD and its RSD positive detection rate was 15.38%. It can be seen that sugarcane ratoon stunting disease is common in sugarcane cultivars in China.
In order to clarify the occurrence of sugarcane ratoon stunting disease（RSD） in sugarcane plantations in China, 598 sugarcane leaf samples were collected from 12 sugarcane plantations in the main sugarcane producing areas like Guangxi, Yunnan, Guangdong and Hainan in China, and the pathogen of RSD was identified by using specific primers through polymerase chain reaction（PCR）. The results showed that 99 out of 598 sugarcane samples were detected to contain bacteria of RSD, with an average detection rate of 16.56%. RSD detection rates varied in 12 sugarcane plantations, the highest in Lincang sugarcane plantations（27.78%） and the lowest in Nanning sugarcane plantations（4.88%）. RSD was detected in 15 main sugarcane cultivars, with positive detection rates ranging from 15.38% to 44.44%. Among the sugarcane cultivars, sugarcane cultivar ROC 22 was most seriously infected with RSD, and its RSD positive detection rate was 44.44%, while sugarcane cultivar Haitang 22 was less infected with RSD and its RSD positive detection rate was 15.38%. It can be seen that sugarcane ratoon stunting disease is common in sugarcane cultivars in China.
2019, 10(4): 319-323.
doi: 10.15886/j.cnki.rdswxb.2019.04.003
Abstract:
Universal primers were designed for ITS, matK and psbA-trnH sequences of endangered orchids for DNA barcoding and their PCR reaction system optimized. Sixteen species of endangered orchids were amplified by using PCR and sequenced, and their PCR amplification and sequencing efficiencies were compared. The results showed that the primers for the ITS, matK and psbA-trnH sequences had higher amplification success rate and sequencing success rate for species of the endangered orchid plants. The optimum annealing temperatures for the PCR reaction were 54 ℃ for ITS and 50 ℃ for matK and psbA-trnH. The targeted bands obtained under the above reaction systems and conditions were clear and bright, and the ITS, matK and psbA-trnH sequences can be used as a combination of DNA barcodes to identify the species of endangered orchid plants.
Universal primers were designed for ITS, matK and psbA-trnH sequences of endangered orchids for DNA barcoding and their PCR reaction system optimized. Sixteen species of endangered orchids were amplified by using PCR and sequenced, and their PCR amplification and sequencing efficiencies were compared. The results showed that the primers for the ITS, matK and psbA-trnH sequences had higher amplification success rate and sequencing success rate for species of the endangered orchid plants. The optimum annealing temperatures for the PCR reaction were 54 ℃ for ITS and 50 ℃ for matK and psbA-trnH. The targeted bands obtained under the above reaction systems and conditions were clear and bright, and the ITS, matK and psbA-trnH sequences can be used as a combination of DNA barcodes to identify the species of endangered orchid plants.
2019, 10(4): 324-330.
doi: 10.15886/j.cnki.rdswxb.2019.04.004
Abstract:
In order to study the mechanism of the change of tissue morphology in the effect of enhanced UV-B radiation on photosynthesis of mango leaves, robust mango trees of "Tainong No.1" were treated with UV-B UV lamp at the doses of 24 kJ·m-2·d-1（low dose） and the 96 kJ·m-2·d-1（high dose） to simulate enhanced UV-B radiation in the field. The changes of tree yield and main fruit quality, leaf photosynthetic physiological indexes and leaf microstructure were observed. The results showed that the high-dose treatment resulted in a significant decrease in tree yield and a significant decrease in fruit quality. Low-dose treatment had no significant effect on tree yield and fruit quality. The high-dose treatment reduced the net photosynthetic rate, transpiration rate and stomatal conductance of the leaves, and the difference between the low-dose treatment and the control was not significant. The high-dose treatment resulted in fragmentation of leaf palisade tissue cells into small cells which were mixed with sponge tissue cells. The sponge tissue cells became larger and the cell gap became wider. The low-dose treatment resulted in production of shorter and thicker palisade cells but with structural integrity. The high-dose treatment resulted in significant thickening of the cuticle on the surface of the leaves compared to the control, while cuticle thickening in the low-dose treatment was not significant. It can be seen that high-dose treatment inhibits leaf photosynthesis by destroying the photosynthetic structure of mesophyll, and hinders the absorption of carbon dioxide and transpiration by thickening the surface of the leaf surface, thereby causing the trees to reduce yield and the quality of the fruit; The low-dose treatment had a certain influence on the leaf microstructure, the basic structure of which was not destroyed, and had no significant effect on photosynthesis. Therefore, the low dose treatment had no significant effect on tree yield and fruit quality.
In order to study the mechanism of the change of tissue morphology in the effect of enhanced UV-B radiation on photosynthesis of mango leaves, robust mango trees of "Tainong No.1" were treated with UV-B UV lamp at the doses of 24 kJ·m-2·d-1（low dose） and the 96 kJ·m-2·d-1（high dose） to simulate enhanced UV-B radiation in the field. The changes of tree yield and main fruit quality, leaf photosynthetic physiological indexes and leaf microstructure were observed. The results showed that the high-dose treatment resulted in a significant decrease in tree yield and a significant decrease in fruit quality. Low-dose treatment had no significant effect on tree yield and fruit quality. The high-dose treatment reduced the net photosynthetic rate, transpiration rate and stomatal conductance of the leaves, and the difference between the low-dose treatment and the control was not significant. The high-dose treatment resulted in fragmentation of leaf palisade tissue cells into small cells which were mixed with sponge tissue cells. The sponge tissue cells became larger and the cell gap became wider. The low-dose treatment resulted in production of shorter and thicker palisade cells but with structural integrity. The high-dose treatment resulted in significant thickening of the cuticle on the surface of the leaves compared to the control, while cuticle thickening in the low-dose treatment was not significant. It can be seen that high-dose treatment inhibits leaf photosynthesis by destroying the photosynthetic structure of mesophyll, and hinders the absorption of carbon dioxide and transpiration by thickening the surface of the leaf surface, thereby causing the trees to reduce yield and the quality of the fruit; The low-dose treatment had a certain influence on the leaf microstructure, the basic structure of which was not destroyed, and had no significant effect on photosynthesis. Therefore, the low dose treatment had no significant effect on tree yield and fruit quality.
2019, 10(4): 331-337,438.
doi: 10.15886/j.cnki.rdswxb.2019.04.005
Abstract:
The net photosynthetic rate of flag leaf at heading, full heading and milky ripening stages, stem and leaf characteristics and yield of Shanlan upland rice were measured under the four cultivation methods: flooding irrigation, moistening irrigation, dry land sprinkler irrigation and traditional rainfed farming. The results showed that the Shanlan upland rice under dry land sprinkler irrigation had the highest stomatal conductance and transpiration rate, which delayed the senescence of functional leaves and contributed to significantly higher biomass accumulation than those under flood irrigation, moistening irrigation and traditional rainfed farming. Compared with the traditional rainfed farming, dry land sprinkler irrigation significantly increased the net photosynthetic rate of flag leaf of Shanlan upland rice, and also increased the number of effective panicles, the number of grains per panicle, seed setting rate and 1 000-grain weight, resulting in a significant increase in yield（203.10%）. In addition, dry land sprinkler irrigation saved water, which is the best cultivation method of shanlan upland rice.
The net photosynthetic rate of flag leaf at heading, full heading and milky ripening stages, stem and leaf characteristics and yield of Shanlan upland rice were measured under the four cultivation methods: flooding irrigation, moistening irrigation, dry land sprinkler irrigation and traditional rainfed farming. The results showed that the Shanlan upland rice under dry land sprinkler irrigation had the highest stomatal conductance and transpiration rate, which delayed the senescence of functional leaves and contributed to significantly higher biomass accumulation than those under flood irrigation, moistening irrigation and traditional rainfed farming. Compared with the traditional rainfed farming, dry land sprinkler irrigation significantly increased the net photosynthetic rate of flag leaf of Shanlan upland rice, and also increased the number of effective panicles, the number of grains per panicle, seed setting rate and 1 000-grain weight, resulting in a significant increase in yield（203.10%）. In addition, dry land sprinkler irrigation saved water, which is the best cultivation method of shanlan upland rice.
2019, 10(4): 338-342.
doi: 10.15886/j.cnki.rdswxb.2019.04.006
Abstract:
Seven varieties of sweet potato（Ipomoea batatas Lam.） were planted in a field experiment to observe their difference in selenium-enrichment ability between the varieties and between the parts of the plants of the same variety in Se-enriched sandy land in Chengmai, Hainan. The results found that the seven sweet potato varieties in the field experiment were significantly different in selenium enrichment ability. The variety′Xushu 18′ had a total selenium content of 0.005 43 mg·kg-1, the highest in selenium-enriching ability, followed by the variety′Gaoxi 14′(0.004 6 mg·kg-1), and the variety Ning Zishu 1 was the lowest with the total selenium content of 0.004 18 mg·kg-1. In addition, different parts of sweet potato plants were significantly different in selenium-enriching ability. The whole leaf had the highest selenium-enriching ability, followed by the stem, while the roots were the lowest. The variety′ Xushu 18′ contained 0.002 9 mg·kg-1 of selenium in their leaves, the highest among all the varieties.
Seven varieties of sweet potato（Ipomoea batatas Lam.） were planted in a field experiment to observe their difference in selenium-enrichment ability between the varieties and between the parts of the plants of the same variety in Se-enriched sandy land in Chengmai, Hainan. The results found that the seven sweet potato varieties in the field experiment were significantly different in selenium enrichment ability. The variety′Xushu 18′ had a total selenium content of 0.005 43 mg·kg-1, the highest in selenium-enriching ability, followed by the variety′Gaoxi 14′(0.004 6 mg·kg-1), and the variety Ning Zishu 1 was the lowest with the total selenium content of 0.004 18 mg·kg-1. In addition, different parts of sweet potato plants were significantly different in selenium-enriching ability. The whole leaf had the highest selenium-enriching ability, followed by the stem, while the roots were the lowest. The variety′ Xushu 18′ contained 0.002 9 mg·kg-1 of selenium in their leaves, the highest among all the varieties.
2019, 10(4): 343-351.
doi: 10.15886/j.cnki.rdswxb.2019.04.007
Abstract:
Fifty species of traditional Chinese medicinal plants, such as Rheum officinale, Cortex Phellodendri and Coptis chinensis, etc, were employed to test their antibacterial effect on Vibrio fluvialis and Staphylococcus aureus by using Oxford-cup tests In Vitro. The traditional Chinese medicinal plants that had optimal effect in single prescription were chosen, based on which combined prescriptions with two or three species of the traditional Chinese medicinal plants were prepared and compared in their antibacterial activity. The concentrations of the prescriptions of the traditional Chinese medicinal plants used for test were 60 and 240 mg·mL-1, respectively. The antibacterial test was made with 3 replicates each treatment. Meanwhile 8 antibiotics were tested Against Vibrio fluvialis. This experiment was conducted to screen single and combined prescriptions of traditional Chinese medicinal plants and antibiotics that are sensitive to Vibrio fluvialis. Results showed that single prescriptions of the traditional Chinese medicinal plants such as Coptis chinensis, Terminalia chebula, etc had obvious inhibitory effect against V. fluvialis（highly sensitive）. The combined prescriptions of the traditional Chinese medicinal plants with Cortex Phellodendri and Coptis chinensis as a component in the combinations had obvious inhibitory effect when their treatment concentrations were 60 mg·mL-1. When the concentration was set at 240 mg·mL-1, 9 combined prescriptions with Cortex Phellodendri and Coptis chinensis as the component in the combinations of two species of traditional Chinese medicinal plants were very highly sensitive to Vibrio fluvialis. At the concentration of 240 mg·mL-1 4 combined prescriptions with combination of three species of the traditional Chinese medicinal plants such as Coptis chinensis, Radix Isatidis and Cortex Phellodendri had obvious inhibitory effect. Vibrio fluvialis was susceptible to enrofloxacin, oxytet racycline, Florfenico, oxytetracycline and trimethoprim. Some prescriptions of traditional Chinese medicinal plants had no obvious inhibitory effect. Four combined prescriptions with combination of three species of traditional Chinese medicinal plants such as Coptis chinensis, Radix isatidis and Cortex Phellodendri had the highest inhibitory effects. Combined prescriptions with 3 species of traditional Chinese medicinal plants in a combintation, or a combination of prescriptions of traditional Chinese medicinal plants and antibiotics might have good inhibition Against Vibrio fluvialis.
Fifty species of traditional Chinese medicinal plants, such as Rheum officinale, Cortex Phellodendri and Coptis chinensis, etc, were employed to test their antibacterial effect on Vibrio fluvialis and Staphylococcus aureus by using Oxford-cup tests In Vitro. The traditional Chinese medicinal plants that had optimal effect in single prescription were chosen, based on which combined prescriptions with two or three species of the traditional Chinese medicinal plants were prepared and compared in their antibacterial activity. The concentrations of the prescriptions of the traditional Chinese medicinal plants used for test were 60 and 240 mg·mL-1, respectively. The antibacterial test was made with 3 replicates each treatment. Meanwhile 8 antibiotics were tested Against Vibrio fluvialis. This experiment was conducted to screen single and combined prescriptions of traditional Chinese medicinal plants and antibiotics that are sensitive to Vibrio fluvialis. Results showed that single prescriptions of the traditional Chinese medicinal plants such as Coptis chinensis, Terminalia chebula, etc had obvious inhibitory effect against V. fluvialis（highly sensitive）. The combined prescriptions of the traditional Chinese medicinal plants with Cortex Phellodendri and Coptis chinensis as a component in the combinations had obvious inhibitory effect when their treatment concentrations were 60 mg·mL-1. When the concentration was set at 240 mg·mL-1, 9 combined prescriptions with Cortex Phellodendri and Coptis chinensis as the component in the combinations of two species of traditional Chinese medicinal plants were very highly sensitive to Vibrio fluvialis. At the concentration of 240 mg·mL-1 4 combined prescriptions with combination of three species of the traditional Chinese medicinal plants such as Coptis chinensis, Radix Isatidis and Cortex Phellodendri had obvious inhibitory effect. Vibrio fluvialis was susceptible to enrofloxacin, oxytet racycline, Florfenico, oxytetracycline and trimethoprim. Some prescriptions of traditional Chinese medicinal plants had no obvious inhibitory effect. Four combined prescriptions with combination of three species of traditional Chinese medicinal plants such as Coptis chinensis, Radix isatidis and Cortex Phellodendri had the highest inhibitory effects. Combined prescriptions with 3 species of traditional Chinese medicinal plants in a combintation, or a combination of prescriptions of traditional Chinese medicinal plants and antibiotics might have good inhibition Against Vibrio fluvialis.
2019, 10(4): 352-359.
doi: 10.15886/j.cnki.rdswxb.2019.04.008
Abstract:
Hami melon（Cucumis melon L.） was treated with a combination of microbial fertilizer and amino acid water-soluble fertilizer in a fertilizer trial in Ledong, Hainan to analyze the changes of complex microbial communities structure and physicochemical properties of the soil. Soil samples at different growth stages of Hami melon were collected for analysis of soil physicochemical properties and high-throughout sequencing of soil bacterial community. Soil analysis showed that the contents of soil alkali-hydrolyzed nitrogen and available potassium were increased in the treatment groups, and that the numbers of root-knot nematodes（RN） and saprophytic nematodes（SN） were decreased. High-throughput sequencing of soil microorganisms showed that the soil bacterial flora in the treatment group were relatively stable in structure, with their relationship being far between the treatment and control groups but close between treatment groups. Compared with the control group, the treatment groups were most abundant in Proteobacteria and Acidobacteria at the phylum level, and had at the class level a lower relative abundance in Alpha-proteobacteria and Gamma-proteobacteria containing pathogenic bacteria and a higher relative abundance in Nitrosomonadales which play an important role in nitrification and Myxococcales which could produce good secondary metabolites. It was concluded that the combined application of compound microbial agent and amino acid water-soluble fertilizer significantly improved the soil physical and chemical properties and bacterial community.
Hami melon（Cucumis melon L.） was treated with a combination of microbial fertilizer and amino acid water-soluble fertilizer in a fertilizer trial in Ledong, Hainan to analyze the changes of complex microbial communities structure and physicochemical properties of the soil. Soil samples at different growth stages of Hami melon were collected for analysis of soil physicochemical properties and high-throughout sequencing of soil bacterial community. Soil analysis showed that the contents of soil alkali-hydrolyzed nitrogen and available potassium were increased in the treatment groups, and that the numbers of root-knot nematodes（RN） and saprophytic nematodes（SN） were decreased. High-throughput sequencing of soil microorganisms showed that the soil bacterial flora in the treatment group were relatively stable in structure, with their relationship being far between the treatment and control groups but close between treatment groups. Compared with the control group, the treatment groups were most abundant in Proteobacteria and Acidobacteria at the phylum level, and had at the class level a lower relative abundance in Alpha-proteobacteria and Gamma-proteobacteria containing pathogenic bacteria and a higher relative abundance in Nitrosomonadales which play an important role in nitrification and Myxococcales which could produce good secondary metabolites. It was concluded that the combined application of compound microbial agent and amino acid water-soluble fertilizer significantly improved the soil physical and chemical properties and bacterial community.
2019, 10(4): 360-366.
doi: 10.15886/j.cnki.rdswxb.2019.04.009
Abstract:
The antibacterial effect of tea saponin on Bacillus subtilis sp., Salmonella sp., Listeria sp., Escherichia coli sp., Pseudomonas fluorescens sp., Staphylococcus aureus sp. and Pseudomonas aeruginosa sp. was studied. The best bacteriostatic effect of tea saponin was on Salmonella sp which was used for test to observe the antibacterial mechanism of tea saponin against Salmonella sp in growth, morphology, extracellular protein, alkaline phosphatase and K+ leakage. The number of colonies of Salmonella sp., pH and water retention rate were used as indexes to evaluate the preservation of chicken breast meat by using tea saponin. The results showed that tea saponin mainly changed the permeability of cell membrane and cell wall and destroyed its barrier by destroying the normal morphology of the cells, which led to leakage of alkaline phosphatase and cell contents such as K+, protein to achieve its antibacterial function. Tea saponin inhibited the growth and reproduction of Salmonella sp. in chicken breast, slowed down the rate of pH rise, and delayed the decline of water retention rate, which indicates that tea saponin can be used as a natural bacteriostatic agent for chicken breast preservation.
The antibacterial effect of tea saponin on Bacillus subtilis sp., Salmonella sp., Listeria sp., Escherichia coli sp., Pseudomonas fluorescens sp., Staphylococcus aureus sp. and Pseudomonas aeruginosa sp. was studied. The best bacteriostatic effect of tea saponin was on Salmonella sp which was used for test to observe the antibacterial mechanism of tea saponin against Salmonella sp in growth, morphology, extracellular protein, alkaline phosphatase and K+ leakage. The number of colonies of Salmonella sp., pH and water retention rate were used as indexes to evaluate the preservation of chicken breast meat by using tea saponin. The results showed that tea saponin mainly changed the permeability of cell membrane and cell wall and destroyed its barrier by destroying the normal morphology of the cells, which led to leakage of alkaline phosphatase and cell contents such as K+, protein to achieve its antibacterial function. Tea saponin inhibited the growth and reproduction of Salmonella sp. in chicken breast, slowed down the rate of pH rise, and delayed the decline of water retention rate, which indicates that tea saponin can be used as a natural bacteriostatic agent for chicken breast preservation.
2019, 10(4): 367-371.
doi: 10.15886/j.cnki.rdswxb.2019.04.010
Abstract:
The antimicrobial activity and aflatoxin degrading activity of Trichoderma viride against Aspergillus flavus were determined by using plate confrontation culture, fermentation broth inhibition experiment, ELISA and thin layer chromatography. The results showed that with the increase of culture time Trichoderma viride increased its antagonistic effect against A. flavus and tended to expand gradually to surround A. flavus with an antagonistic band being 5.5 mm wide. Fermentation broths at different incubation time and concentrations all showed an inhibitory effect against A. flavus, inhibited the production of toxins and degraded aflatoxin B1, and the degrading rate was upto 95% when the fermentation broth was 5%. Field experiment found that the fermentation broths reduced significantly aflatoxin contamination of peanut before harvest at a rate of 97%, and at the same time inhibited greatly the growth of A. flavus in the soil. The results showed that the fermentation broths of T. viride maybe contain antibacterial active substances which could inhibit the growth of A. flavus and degrade aflatoxin.
The antimicrobial activity and aflatoxin degrading activity of Trichoderma viride against Aspergillus flavus were determined by using plate confrontation culture, fermentation broth inhibition experiment, ELISA and thin layer chromatography. The results showed that with the increase of culture time Trichoderma viride increased its antagonistic effect against A. flavus and tended to expand gradually to surround A. flavus with an antagonistic band being 5.5 mm wide. Fermentation broths at different incubation time and concentrations all showed an inhibitory effect against A. flavus, inhibited the production of toxins and degraded aflatoxin B1, and the degrading rate was upto 95% when the fermentation broth was 5%. Field experiment found that the fermentation broths reduced significantly aflatoxin contamination of peanut before harvest at a rate of 97%, and at the same time inhibited greatly the growth of A. flavus in the soil. The results showed that the fermentation broths of T. viride maybe contain antibacterial active substances which could inhibit the growth of A. flavus and degrade aflatoxin.
2019, 10(4): 372-379.
doi: 10.15886/j.cnki.rdswxb.2019.04.011
Abstract:
Endophytic fungi and bacteria are critical throughout the life cycle of Orchidaceae plants. Phalaenopsis deliciosa（Orchidaceae） was used as test material to isolate the endophytic fungi and bacteria from its fresh roots in routine sterile culture, and the isolates were then identified by using molecular markers to reveal their characteristics and diversity. The results showed that a total of 38 strains of endophytic fungi were isolated from the roots of P. deliciosa and identified as 5 OTUs belonging to 1 phylum, 2 classes, 4 orders, 4 families and 5 genera, and that the dominant genera were Lasiodiplodia and Aspergillus, while a total of 54 strins of endophytic bacteria were isolated and 17 OTUs were identified to belong to 3 phyla, 5 classes, 6 orders, 9 families, 12 genera, and that the dominant genera were Bacillus and Enterobacter. The results will provide reference for symbiotic germination and raising of mycorrhiza-based seedlings of P. deliciosa and for further study of the relationship between endophytic microorganisms and orchids.
Endophytic fungi and bacteria are critical throughout the life cycle of Orchidaceae plants. Phalaenopsis deliciosa（Orchidaceae） was used as test material to isolate the endophytic fungi and bacteria from its fresh roots in routine sterile culture, and the isolates were then identified by using molecular markers to reveal their characteristics and diversity. The results showed that a total of 38 strains of endophytic fungi were isolated from the roots of P. deliciosa and identified as 5 OTUs belonging to 1 phylum, 2 classes, 4 orders, 4 families and 5 genera, and that the dominant genera were Lasiodiplodia and Aspergillus, while a total of 54 strins of endophytic bacteria were isolated and 17 OTUs were identified to belong to 3 phyla, 5 classes, 6 orders, 9 families, 12 genera, and that the dominant genera were Bacillus and Enterobacter. The results will provide reference for symbiotic germination and raising of mycorrhiza-based seedlings of P. deliciosa and for further study of the relationship between endophytic microorganisms and orchids.
2019, 10(4): 380-386.
doi: 10.15886/j.cnki.rdswxb.2019.04.012
Abstract:
The data of soil survey in rubber plantations in Hainan State Farms was analyzed to evaluate the land productivity in the rubber plantations by using four clustering algorithms（K-Means, Two-Step, Kohonen and TwoStep-AS）. According to the Silhouette coefficients, TwoStep-AS clustering models were established for cluster analysis of the indexes of the land productivity in the Hainan State Farm rubber plantations. After repeated iterations, the land in rubber plantations of Hainan State Farms was divided into three types, and the indexes affecting the land type of the rubber plantations were selected, including annual average rainfall, effective soil thickness, total nitrogen, north latitude, and soil-forming parent material.
The data of soil survey in rubber plantations in Hainan State Farms was analyzed to evaluate the land productivity in the rubber plantations by using four clustering algorithms（K-Means, Two-Step, Kohonen and TwoStep-AS）. According to the Silhouette coefficients, TwoStep-AS clustering models were established for cluster analysis of the indexes of the land productivity in the Hainan State Farm rubber plantations. After repeated iterations, the land in rubber plantations of Hainan State Farms was divided into three types, and the indexes affecting the land type of the rubber plantations were selected, including annual average rainfall, effective soil thickness, total nitrogen, north latitude, and soil-forming parent material.
2019, 10(4): 387-395.
doi: 10.15886/j.cnki.rdswxb.2019.04.013
Abstract:
Topsoil（0-10 cm） samples from 58 quadrates in the rainy season were collected from a 60 ha forest dynamics plot in Jianfengling, Hainan Province, and their enzyme activities such as sucrase activity, urease activity, catalase activity, and acid phosphatase activity were determined. The major factors affecting the enzyme activities were analyzed by using redundancy analysis, taking into account data on soil physical and chemical properties, vegetation, etc. Results showed that the activities of soil sucrase, urease, catalase and acid phosphatase in the rainy season were（15.36～60.94）mg·g-1·d-1,（0.30～0.68） mg·g-1·d-1,（4.77～9.90） mL·g-1·h-1),（0.61～1.13） mg·g-1·h-1, respectively. The 58 quadrates in the forest dynamics plot were divided into four terrains: flat slope, gentle slope, moderate slope and ridge. The distribution of the enzyme activities of the quadrates in the redundancy analysis showed that slope had a great effect on the soil enzyme activities, and that the flat terrain were significantly lower in the activities of urease, catalase and acid phosphatase activities than the ridge terrain during the rainy season（P<0.05）. The redundancy analysis of the relationship between soil enzyme activity and environmental factors showed that soil organic carbon and total nitrogen were the main factors affecting the soil enzyme activity.
Topsoil（0-10 cm） samples from 58 quadrates in the rainy season were collected from a 60 ha forest dynamics plot in Jianfengling, Hainan Province, and their enzyme activities such as sucrase activity, urease activity, catalase activity, and acid phosphatase activity were determined. The major factors affecting the enzyme activities were analyzed by using redundancy analysis, taking into account data on soil physical and chemical properties, vegetation, etc. Results showed that the activities of soil sucrase, urease, catalase and acid phosphatase in the rainy season were（15.36～60.94）mg·g-1·d-1,（0.30～0.68） mg·g-1·d-1,（4.77～9.90） mL·g-1·h-1),（0.61～1.13） mg·g-1·h-1, respectively. The 58 quadrates in the forest dynamics plot were divided into four terrains: flat slope, gentle slope, moderate slope and ridge. The distribution of the enzyme activities of the quadrates in the redundancy analysis showed that slope had a great effect on the soil enzyme activities, and that the flat terrain were significantly lower in the activities of urease, catalase and acid phosphatase activities than the ridge terrain during the rainy season（P<0.05）. The redundancy analysis of the relationship between soil enzyme activity and environmental factors showed that soil organic carbon and total nitrogen were the main factors affecting the soil enzyme activity.
2019, 10(4): 396-405.
doi: 10.15886/j.cnki.rdswxb.2019.04.014
Abstract:
In the tropical coastal forest of Mountain Tongguling in the northeastern Hainan, quadrats with the same slope aspect and elevation in a permanent sampling site of the natural forest were selected to analyze the composition and horizontal distribution characteristics of arboreal lichens and their relationship with the forest tree species in the quadrats with first 20 tree species of higher important value in the forest community through positioning sampling. The results showed that the lichens resources were abundant on the trunks of the forest trees in this area. In the quadrats 26 species of arboreal lichens and 31 species of lichen-associated fungi were collected. At the same altitude, the composition of lichen community was scattered and distributed randomly. The preferential distribution height of arboreal lichens was 0.6-1.4 m on the trunk when the lichens were sampled from the trunk 0-2.0 m above the ground. Among all the hosts Daphnia hainanensis hosted most of the lichens. The preference of lichens was independent of the status of tree species in the community, and the random distribution of lichens may be related to the random distribution of hosts.
In the tropical coastal forest of Mountain Tongguling in the northeastern Hainan, quadrats with the same slope aspect and elevation in a permanent sampling site of the natural forest were selected to analyze the composition and horizontal distribution characteristics of arboreal lichens and their relationship with the forest tree species in the quadrats with first 20 tree species of higher important value in the forest community through positioning sampling. The results showed that the lichens resources were abundant on the trunks of the forest trees in this area. In the quadrats 26 species of arboreal lichens and 31 species of lichen-associated fungi were collected. At the same altitude, the composition of lichen community was scattered and distributed randomly. The preferential distribution height of arboreal lichens was 0.6-1.4 m on the trunk when the lichens were sampled from the trunk 0-2.0 m above the ground. Among all the hosts Daphnia hainanensis hosted most of the lichens. The preference of lichens was independent of the status of tree species in the community, and the random distribution of lichens may be related to the random distribution of hosts.
2019, 10(4): 406-416.
doi: 10.15886/j.cnki.rdswxb.2019.04.015
Abstract:
A survey was made of the plant species composition in the area of Baishiling Ridge in Qionghai, Hainan by using a combined method of route and sample plots. The ornamental value of the plant species was evaluated with reference to the growth form, plant type and posture, as well as flower color and appearance of the plants. The survey showed that this area was boasted of 736 species of wild plants under 149 families and 468 genera, of which about 370 species were wild landscape plants with ornamental value and belonged to 118 families and 249 genera, including 21 plant species endemic to Hainan and 24 species of rare and endangered plants. Analysis of the composition of wild vegetation types in this area showed that the dominant species and common species, such as Schefflera heptaphylla, Schima superba, Acronychia pedunculata, Endospermum chinense and Engelhardia roxburghiana, were important in the communities. The wild plants in the survey were classified into 5 groups: ornamental flower, ornamental fruit, ornamental plant appearance, vertical greening, and ground cover plant based on the ornamental features and use in landscape greening. Potential wild landrace plants with ornamental and landscaping value were selected based on their ornamental traits, stress resistance and adaptability and use purpose, and some suggestions were made on conservation and development of the wild local plants.
A survey was made of the plant species composition in the area of Baishiling Ridge in Qionghai, Hainan by using a combined method of route and sample plots. The ornamental value of the plant species was evaluated with reference to the growth form, plant type and posture, as well as flower color and appearance of the plants. The survey showed that this area was boasted of 736 species of wild plants under 149 families and 468 genera, of which about 370 species were wild landscape plants with ornamental value and belonged to 118 families and 249 genera, including 21 plant species endemic to Hainan and 24 species of rare and endangered plants. Analysis of the composition of wild vegetation types in this area showed that the dominant species and common species, such as Schefflera heptaphylla, Schima superba, Acronychia pedunculata, Endospermum chinense and Engelhardia roxburghiana, were important in the communities. The wild plants in the survey were classified into 5 groups: ornamental flower, ornamental fruit, ornamental plant appearance, vertical greening, and ground cover plant based on the ornamental features and use in landscape greening. Potential wild landrace plants with ornamental and landscaping value were selected based on their ornamental traits, stress resistance and adaptability and use purpose, and some suggestions were made on conservation and development of the wild local plants.
2019, 10(4): 417-423.
doi: 10.15886/j.cnki.rdswxb.2019.04.016
Abstract:
In order to explore the factors affecting the vitality of open space in urban streets, the vitality representation and spatial composition were quantified reasonably, separately, and the vitality index and spatial composition index for the open space in the urban streets were analyzed by using binary correlation analysis in the SPSS19.0 mathematical statistical analysis software. The binary correlation analysis showed that the two indexes were highly correlated. Then correlation analysis was made between the vitality index and each of four evaluation indices（safety index, functional index, goodness index and ornamental index） in the spatial composition. The correlation analysis showed that the vitality index was highly significantly correlated with the functional index, based on which correlation analysis was then made between the vitality index and each of the impact factors in the functional index. This further correlation analysis produced sensitivity factors that affect the vitality of open space in the urban streets.
In order to explore the factors affecting the vitality of open space in urban streets, the vitality representation and spatial composition were quantified reasonably, separately, and the vitality index and spatial composition index for the open space in the urban streets were analyzed by using binary correlation analysis in the SPSS19.0 mathematical statistical analysis software. The binary correlation analysis showed that the two indexes were highly correlated. Then correlation analysis was made between the vitality index and each of four evaluation indices（safety index, functional index, goodness index and ornamental index） in the spatial composition. The correlation analysis showed that the vitality index was highly significantly correlated with the functional index, based on which correlation analysis was then made between the vitality index and each of the impact factors in the functional index. This further correlation analysis produced sensitivity factors that affect the vitality of open space in the urban streets.
2019, 10(4): 424-431.
doi: 10.15886/j.cnki.rdswxb.2019.04.017
Abstract:
In order to study the layout of street trees in tropical cities, the height and crown width of street trees as well as road width and the building height on both sides of the roads were measured in Haikou city with Haikou city as an example. The data collected was used to analyze the sun exposure to the street trees by using the SketchUp software. The results showed that there was no difference in daylight exposure duration of the street trees between the east and west sides of the north-south roads. The height of buildings and the height of street trees had a great influence on the sunshine duration of the street trees, while the width of roads generally had no effect on the sunshine duration of the street trees. The street trees along the east-west roads had longer sunlight exposure duration in the north than in the south. The height of building, the height of the street trees and the width of the roads had obvious influence on the sunshine duration of the street trees. In this context a strategy for layout of street trees was put forward. Under the same circumstances in the north-south roads where buildings are not high on both sides of the roads big shade trees, such as Ficus benjamina, Ficus altissima, Bischofia javanica, etc, are recommended for planting along both sides of the roads, or on the contrary if the buildings are high small trees such as Bauhinia purpurea, Sterculia lanceolate, etc are selected. If the road runs from east to west, big shade trees, such as Ficus altissima, Ficus benjamina, etc, are selected for planting on the north side, and small trees, such as Sterculia lanceolate, Bauhinia purpurea, etc, are planted on the south side of the road. In the narrow roads where buildings are high on both sides it is better to plant street trees in one side or plant shade shrubs, such as Bougainvillea glabra, Carmona microphylla, Fagraea ceilanica, etc.
In order to study the layout of street trees in tropical cities, the height and crown width of street trees as well as road width and the building height on both sides of the roads were measured in Haikou city with Haikou city as an example. The data collected was used to analyze the sun exposure to the street trees by using the SketchUp software. The results showed that there was no difference in daylight exposure duration of the street trees between the east and west sides of the north-south roads. The height of buildings and the height of street trees had a great influence on the sunshine duration of the street trees, while the width of roads generally had no effect on the sunshine duration of the street trees. The street trees along the east-west roads had longer sunlight exposure duration in the north than in the south. The height of building, the height of the street trees and the width of the roads had obvious influence on the sunshine duration of the street trees. In this context a strategy for layout of street trees was put forward. Under the same circumstances in the north-south roads where buildings are not high on both sides of the roads big shade trees, such as Ficus benjamina, Ficus altissima, Bischofia javanica, etc, are recommended for planting along both sides of the roads, or on the contrary if the buildings are high small trees such as Bauhinia purpurea, Sterculia lanceolate, etc are selected. If the road runs from east to west, big shade trees, such as Ficus altissima, Ficus benjamina, etc, are selected for planting on the north side, and small trees, such as Sterculia lanceolate, Bauhinia purpurea, etc, are planted on the south side of the road. In the narrow roads where buildings are high on both sides it is better to plant street trees in one side or plant shade shrubs, such as Bougainvillea glabra, Carmona microphylla, Fagraea ceilanica, etc.
2019, 10(4): 432-438.
doi: 10.15886/j.cnki.rdswxb.2019.04.018
Abstract:
The spatial syntactic theory provides a quantitative index system for the renewal of the spatial structure of the old city. Based on the spatial syntactic theory, the spatial patterns of the historical arcade streets in Haikou were quantitatively described by using the axis analysis method and the visual field analysis method, and 5 variables, i.e., integration, choice, comprehensibility, synergy and visual integration, of the historical arcade streets were analyzed to reveal the deep and intrinsic morphological characteristics of the space of the historical arcade streets. Reasonable suggestions are put forward based on the analysis for the strategy of upgrading the historical arcade streets in Haikou in order to restore the vitality of the streets for promotion of their commercial economic benefits.
The spatial syntactic theory provides a quantitative index system for the renewal of the spatial structure of the old city. Based on the spatial syntactic theory, the spatial patterns of the historical arcade streets in Haikou were quantitatively described by using the axis analysis method and the visual field analysis method, and 5 variables, i.e., integration, choice, comprehensibility, synergy and visual integration, of the historical arcade streets were analyzed to reveal the deep and intrinsic morphological characteristics of the space of the historical arcade streets. Reasonable suggestions are put forward based on the analysis for the strategy of upgrading the historical arcade streets in Haikou in order to restore the vitality of the streets for promotion of their commercial economic benefits.
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