2018 Vol. 9, No. 2
2018, 9(2): 129-135.
doi: 10.15886/j.cnki.rdswxb.2018.02.001
Abstract
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Abstract:
The crude nutrients, amino acids, and minerals profiles of Sesuvium portulacastrum and Caulerpa lentillifera were determined and their nutritional values were evaluated. The results revealed that S.portulacastrum and C. lentillifera contained high moisture（more than 90%）. The contents of ash, crude polysaccharides and crude fibers in both species of plants were higher, up to 80% of the dry weight. The contents of crude fat in S.portulacastrum and C. lentillifera were 14.23% and 9.22%, respectively. The crude lipids were quite low, amounting to about 2.16% and 0.81% of the dry mass of S.portulacastrum and C. lentillifera,respectively. Although both S.portulacastrum and C. lentillifera contained low protein, the amino acid analysis showed they had a well-arranged complete set of amino acids, and that ttheir amino acid scores were 61.31 and66.69, respectively, higher than that of Laminaria japonica（47）and Porphyra haitanensis（54）. The first limited amino acids were cystine + methionine. Flavor amino acids in S.portulacastrum and C. lentillifera accounted for40.69% and 49.17% of the total amino acids, respectively, and the contents of glutamic acid, proline acid, glycine acid, and aspartic acid as well as minerals such as Na, K, Mg, Ca, Fe, Mn, Zn, and Se were quite high in both species of plants. This experiment showed that both S.portulacastrum and C. lentillifera had rich contents of essential amino acids and minerals, and hence have a high edible value for development.
The crude nutrients, amino acids, and minerals profiles of Sesuvium portulacastrum and Caulerpa lentillifera were determined and their nutritional values were evaluated. The results revealed that S.portulacastrum and C. lentillifera contained high moisture（more than 90%）. The contents of ash, crude polysaccharides and crude fibers in both species of plants were higher, up to 80% of the dry weight. The contents of crude fat in S.portulacastrum and C. lentillifera were 14.23% and 9.22%, respectively. The crude lipids were quite low, amounting to about 2.16% and 0.81% of the dry mass of S.portulacastrum and C. lentillifera,respectively. Although both S.portulacastrum and C. lentillifera contained low protein, the amino acid analysis showed they had a well-arranged complete set of amino acids, and that ttheir amino acid scores were 61.31 and66.69, respectively, higher than that of Laminaria japonica（47）and Porphyra haitanensis（54）. The first limited amino acids were cystine + methionine. Flavor amino acids in S.portulacastrum and C. lentillifera accounted for40.69% and 49.17% of the total amino acids, respectively, and the contents of glutamic acid, proline acid, glycine acid, and aspartic acid as well as minerals such as Na, K, Mg, Ca, Fe, Mn, Zn, and Se were quite high in both species of plants. This experiment showed that both S.portulacastrum and C. lentillifera had rich contents of essential amino acids and minerals, and hence have a high edible value for development.
2018, 9(2): 136-141.
doi: 10.15886/j.cnki.rdswxb.2018.02.002
Abstract:
A dominant bacterial strain isolated from the lesion tissues of the inspected dead Crocodylus siamensis in Lingshui,Hainan Province was identified via morphological observation,and physiological and biochemical test.The results showed that this isolated strain was gram-negative and was almost identical in characteristics to Aeromonas hydrophila. The phylogenetic analysis based on 16 S rRNA gene sequences further indicated that the isolate was clustered in the genus Aeromonas,with its sequence having the maximum similarity（99. 9%） with that of Aeromonas hydrophila subsp. hydrophila. The artificial infection test showed that the isolate was highly morbigenous to NIH mice with the half median lethal dose of 2. 5 × 105 cfu·m L-1. The sensitivity tests of this isolate with 27 antibiotics demonstrated that the isolate was sensitive to 13 antibiotics,such as amikacin,ciprofloxacin,cefoperazone,etc,and resistant to 9 antibiotics such as erythromycin,ampicillin,streptomycin etc.
A dominant bacterial strain isolated from the lesion tissues of the inspected dead Crocodylus siamensis in Lingshui,Hainan Province was identified via morphological observation,and physiological and biochemical test.The results showed that this isolated strain was gram-negative and was almost identical in characteristics to Aeromonas hydrophila. The phylogenetic analysis based on 16 S rRNA gene sequences further indicated that the isolate was clustered in the genus Aeromonas,with its sequence having the maximum similarity（99. 9%） with that of Aeromonas hydrophila subsp. hydrophila. The artificial infection test showed that the isolate was highly morbigenous to NIH mice with the half median lethal dose of 2. 5 × 105 cfu·m L-1. The sensitivity tests of this isolate with 27 antibiotics demonstrated that the isolate was sensitive to 13 antibiotics,such as amikacin,ciprofloxacin,cefoperazone,etc,and resistant to 9 antibiotics such as erythromycin,ampicillin,streptomycin etc.
2018, 9(2): 142-146.
doi: 10.15886/j.cnki.rdswxb.2018.02.003
Abstract:
Agarases are the enzymes which catalyze the hydrolysis of agar. They have wide applications in food industry, cosmetics, and medical fields since they produce oligosaccharides with remarkable enzyme activities. A Vibrio sp. strain, named HN897, was isolated from seawater samples in the South China coastal area using TCBS agar plate. This strain was identified as an agarase-producing bacterium by observation of clear zones around the colonies using agar as the sole carbon source. Phylogenetic analysis based on 16 S r RNA gene shows that the agar-degrading bacterium HN897 belongs to the member of the genus Vibrio and is close to Vibrio astriarenae.The agarase activity of the strain was determined by using reducing dinitrosalicylic acid method（DNS method）, and the agarase activities of the crude enzymes in the supernatant of HN897 culture of the TSB and LB mediums were0.366 U·m L-1 and 0.413 U·m L-1, respectively, indicating that this strain has potential applications in the production of agaro-oligosaccharide.
Agarases are the enzymes which catalyze the hydrolysis of agar. They have wide applications in food industry, cosmetics, and medical fields since they produce oligosaccharides with remarkable enzyme activities. A Vibrio sp. strain, named HN897, was isolated from seawater samples in the South China coastal area using TCBS agar plate. This strain was identified as an agarase-producing bacterium by observation of clear zones around the colonies using agar as the sole carbon source. Phylogenetic analysis based on 16 S r RNA gene shows that the agar-degrading bacterium HN897 belongs to the member of the genus Vibrio and is close to Vibrio astriarenae.The agarase activity of the strain was determined by using reducing dinitrosalicylic acid method（DNS method）, and the agarase activities of the crude enzymes in the supernatant of HN897 culture of the TSB and LB mediums were0.366 U·m L-1 and 0.413 U·m L-1, respectively, indicating that this strain has potential applications in the production of agaro-oligosaccharide.
2018, 9(2): 147-155.
doi: 10.15886/j.cnki.rdswxb.2018.02.004
Abstract:
The long-term abuse of antibiotics has led to the rapid growth of drug-resistant bacteria in the environment. The distribution and mechanism of antibiotics resistance genes（ ARGs） have attracted public attention.ARGs,as an emerging contaminant,not only have a serious impact on the environment,but also pose a potential threat to the health of organisms and human beings. The surface sediment of the mangrove area in Dongzhai Harbor,Haikou,Hainan,China was collected in the mangroves,near the mangroves and the mud flats in August,2017 to determine the abundance of ARGs by using real-time quantitative PCR in a view to investigate the pollution of chloramphenicol resistance genes（ CRGs） in this area. The distribution of CRGs in the sediment samples in the mangroves,near the mangroves and in the mud flats was analyzed and compared,and the correlation between the CRGs and the environmental factors were analyzed. The results showed that this area was seriously polluted by CRGs,with an absolute abundance of CRGs being 108 copies · g-1. CRGs with different resistance mechanisms had different compositional ratios in the environmental samples,of which the cml gene was always the highest in the compositional ratios of all the samples,indicating that the resistant mechanism of CRGs is based on active efflux of antibiotics. The sediment samples in the mangroves showed higher absolute abundance of CRGs than those near the mangroves or in the mud flats. Correlation analysis between the CRGs and the environmental factors showed that NO2--N was highly significantly correlated with the CRGs.
The long-term abuse of antibiotics has led to the rapid growth of drug-resistant bacteria in the environment. The distribution and mechanism of antibiotics resistance genes（ ARGs） have attracted public attention.ARGs,as an emerging contaminant,not only have a serious impact on the environment,but also pose a potential threat to the health of organisms and human beings. The surface sediment of the mangrove area in Dongzhai Harbor,Haikou,Hainan,China was collected in the mangroves,near the mangroves and the mud flats in August,2017 to determine the abundance of ARGs by using real-time quantitative PCR in a view to investigate the pollution of chloramphenicol resistance genes（ CRGs） in this area. The distribution of CRGs in the sediment samples in the mangroves,near the mangroves and in the mud flats was analyzed and compared,and the correlation between the CRGs and the environmental factors were analyzed. The results showed that this area was seriously polluted by CRGs,with an absolute abundance of CRGs being 108 copies · g-1. CRGs with different resistance mechanisms had different compositional ratios in the environmental samples,of which the cml gene was always the highest in the compositional ratios of all the samples,indicating that the resistant mechanism of CRGs is based on active efflux of antibiotics. The sediment samples in the mangroves showed higher absolute abundance of CRGs than those near the mangroves or in the mud flats. Correlation analysis between the CRGs and the environmental factors showed that NO2--N was highly significantly correlated with the CRGs.
2018, 9(2): 156-162.
doi: 10.15886/j.cnki.rdswxb.2018.02.005
Abstract:
Benzo[a]pyrene（Ba P） is a widely distributed persistent organic pollutant in the environment. Isolating microbia from the gut of earthworm Eisenia fetida is a new bioremediation technique for degradation of Ba P. A strain（BJ-1）was isolated from the gut of earthworm through spread plate after 8 mg·L-1 Ba P stress culture. This strain was identified by the methods of morphologic observation, physiological and biochemical experiments as well as 16 S r RNA gene sequence analysis. The Ba P degradation ability of BJ-1 was tested by using high performance liquid chromatography（HPLC）. The results showed that the strain BJ-1 was a Gram-negative bacterium, which belonged to Pseudomonas stutzeri. After being cultured in Ba P（8 mg·L-1）as the sole carbon source for 28 days at30 ℃, the BJ-1 degraded Ba P at a rate of 86.01% and a density of 0.424（OD600 nm）. The results indicated that the Ba P-degrading strain could be isolated from the gut of earthworm, enriching the microbial resources for degrading Ba P. It provides a newviewfor the bioremediation of Ba P in the environment.
Benzo[a]pyrene（Ba P） is a widely distributed persistent organic pollutant in the environment. Isolating microbia from the gut of earthworm Eisenia fetida is a new bioremediation technique for degradation of Ba P. A strain（BJ-1）was isolated from the gut of earthworm through spread plate after 8 mg·L-1 Ba P stress culture. This strain was identified by the methods of morphologic observation, physiological and biochemical experiments as well as 16 S r RNA gene sequence analysis. The Ba P degradation ability of BJ-1 was tested by using high performance liquid chromatography（HPLC）. The results showed that the strain BJ-1 was a Gram-negative bacterium, which belonged to Pseudomonas stutzeri. After being cultured in Ba P（8 mg·L-1）as the sole carbon source for 28 days at30 ℃, the BJ-1 degraded Ba P at a rate of 86.01% and a density of 0.424（OD600 nm）. The results indicated that the Ba P-degrading strain could be isolated from the gut of earthworm, enriching the microbial resources for degrading Ba P. It provides a newviewfor the bioremediation of Ba P in the environment.
2018, 9(2): 163-169.
doi: 10.15886/j.cnki.rdswxb.2018.02.006
Abstract:
MYC transcription factors or Myelocytomatosis proteins（MYCs） play a very important role in the signal transduction of jasmonic acid. Five genes of the MYC gene family of Hevea brasiliensis had been cloned, and their functions had been reported. However, the specific locations of the MYC gene family members on the chromosome have not been reported. In this experiment, the locations of 5 genes of MYC family of H. brasiliensis were physically located on the chromosomes by using fluorescence in situ hybridization（FISH） technique. Rubber clone Reyan 7-33-97 of H. brasiliensis was used as an experimental material. The results show that both HblMYC2 and HblMYC5 genes were located on the long arm of chromosome 9, with an average distance of 47.96 and 47.22 from the centromere, respectively; HblMYC1 and HblMYC3 genes were located on the long arm of 6 th and 8 th chromosomes, respectively, with a respective average distance of 32.56 and 62.77 from the centromere; HblMYC4 was located on the short arm of 5 th chromosome, with an average distance of 55.67 from the centromere. This study explored the specific locations of the 5 genes and their relationships on chromosomes, which can provide cytological basis for genomics and molecular marker assisted breeding of H. brasiliensis.
MYC transcription factors or Myelocytomatosis proteins（MYCs） play a very important role in the signal transduction of jasmonic acid. Five genes of the MYC gene family of Hevea brasiliensis had been cloned, and their functions had been reported. However, the specific locations of the MYC gene family members on the chromosome have not been reported. In this experiment, the locations of 5 genes of MYC family of H. brasiliensis were physically located on the chromosomes by using fluorescence in situ hybridization（FISH） technique. Rubber clone Reyan 7-33-97 of H. brasiliensis was used as an experimental material. The results show that both HblMYC2 and HblMYC5 genes were located on the long arm of chromosome 9, with an average distance of 47.96 and 47.22 from the centromere, respectively; HblMYC1 and HblMYC3 genes were located on the long arm of 6 th and 8 th chromosomes, respectively, with a respective average distance of 32.56 and 62.77 from the centromere; HblMYC4 was located on the short arm of 5 th chromosome, with an average distance of 55.67 from the centromere. This study explored the specific locations of the 5 genes and their relationships on chromosomes, which can provide cytological basis for genomics and molecular marker assisted breeding of H. brasiliensis.
2018, 9(2): 170-175.
doi: 10.15886/j.cnki.rdswxb.2018.02.007
Abstract:
In this paper, we cloned a Rboh gene from cassava-MeRbohE, the whole length of the gene is 5 397 bp,open reading frame is 2 775 bp, encoding 925 amino acids, the molecular weight of the protein is 104.8 KDa, and the theoretical isoelectric point of the protein is 8.90, the protein structure has typical plant Rboh gene family characteristics. The results of q RT-PCR showed that the expression of MeRbohE gene was the highest in the roots,followed by the stems, and the lowest in the leaves; the expression of MeRbohE gene was up-regulated after being induced by low temperature（4 ℃）, high salt（300 mmol·L-1 Na Cl） and 100 mmol·L-1 ABA. The results indicated that the gene could respond to biological stress and lay a foundation for elucidating the mechanism of cassava Rboh gene in stress resistance.
In this paper, we cloned a Rboh gene from cassava-MeRbohE, the whole length of the gene is 5 397 bp,open reading frame is 2 775 bp, encoding 925 amino acids, the molecular weight of the protein is 104.8 KDa, and the theoretical isoelectric point of the protein is 8.90, the protein structure has typical plant Rboh gene family characteristics. The results of q RT-PCR showed that the expression of MeRbohE gene was the highest in the roots,followed by the stems, and the lowest in the leaves; the expression of MeRbohE gene was up-regulated after being induced by low temperature（4 ℃）, high salt（300 mmol·L-1 Na Cl） and 100 mmol·L-1 ABA. The results indicated that the gene could respond to biological stress and lay a foundation for elucidating the mechanism of cassava Rboh gene in stress resistance.
2018, 9(2): 176-182.
doi: 10.15886/j.cnki.rdswxb.2018.02.008
Abstract:
Taraxacum koksaghyz Rodin, belonging to the genus Taraxacum F. H. Wigg. and the family Composite,is a perennial herb. It is considered to be a potential alternative source of natural rubber and an ideal model plant for the study of rubber biosynthesis. In order to establish a genetic transformation system for suspension cells of T.koksaghyz Rodin, the sensitivity of suspension cells of T. koksaghyz Rodin to Ticarcillin（a fungicide for Agrobacterium tumefaciens） and Hygromycin B were determined. The suspension cells were infected with Agrobacterium tumefaciens GV3101 which carried the vector p CAMBIA1302, and then the gene expression of GFP and Hyg in the suspension cells was detected to observe the success of the genetic transformation. The result showed that Ticarcillin at a concentration range of 0-300 mg·L-1 had no effect on the suspension cells, and that the suitable concentration of Hygromycin for selective calli was 10 mg·L-1. GFP fluorescent detection and PCR detection of the Hyg and GFP gene showed that transgenic positive calli were efficiently produced when A.tumefaciens at OD600=0.6, carrying the vector p CAMBIA1302, was mixed with the suspension cells at a ratio of 1∶1.2 for 30 mins, transferred into a co-culture medium for culture for 10 days, and then to a selective culture medium for culture. This study lays the foundation for further optimization of the genetic transformation system for the suspension cells of T. koksaghyz Rodin.
Taraxacum koksaghyz Rodin, belonging to the genus Taraxacum F. H. Wigg. and the family Composite,is a perennial herb. It is considered to be a potential alternative source of natural rubber and an ideal model plant for the study of rubber biosynthesis. In order to establish a genetic transformation system for suspension cells of T.koksaghyz Rodin, the sensitivity of suspension cells of T. koksaghyz Rodin to Ticarcillin（a fungicide for Agrobacterium tumefaciens） and Hygromycin B were determined. The suspension cells were infected with Agrobacterium tumefaciens GV3101 which carried the vector p CAMBIA1302, and then the gene expression of GFP and Hyg in the suspension cells was detected to observe the success of the genetic transformation. The result showed that Ticarcillin at a concentration range of 0-300 mg·L-1 had no effect on the suspension cells, and that the suitable concentration of Hygromycin for selective calli was 10 mg·L-1. GFP fluorescent detection and PCR detection of the Hyg and GFP gene showed that transgenic positive calli were efficiently produced when A.tumefaciens at OD600=0.6, carrying the vector p CAMBIA1302, was mixed with the suspension cells at a ratio of 1∶1.2 for 30 mins, transferred into a co-culture medium for culture for 10 days, and then to a selective culture medium for culture. This study lays the foundation for further optimization of the genetic transformation system for the suspension cells of T. koksaghyz Rodin.
2018, 9(2): 183-188.
doi: 10.15886/j.cnki.rdswxb.2018.02.009
Abstract:
The leaves of a medicinal plant Calotropis gigantea were extracted with ethanol, and the chemical constituents of the ethanol extracts of the leaves were identified by gas chromatography-mass spectrometry（GC-MS）spectrometer to evaluate their antioxidant activity. The contents of total polyphenols and total flavonoids in the ethanol extract of the leaves, and the DPPH and hydroxyl free radical scavenging effects and the total reducing capacity of the extract were determined. The results indicated that the ethanol extract of the leaves of C. gigantea had a high anti-oxidant activity and that the alcohols content of the extract was the highest（60.2%）, followed by the esters（24.09%）. Lupeol（26.7%） was the main single component of the extract. The total polyphenols content was（26.22 ± 0.01） mg·g-1 DW（GAE）, and the total flavonoids content was（0.70 ± 0.02） mg·g-1 DW（RE）. The IC50 values of the extract in scavenging the activities of DPPH and hydroxyl free radicals were 0.33 g·L-1 and 0.21 g·L-1,respectively, which were not significant different from those of the control Lupeol and TBHQ, respectively.Moreover, the total reducing capacity of the extract was increased with the increase of the sample concentration.The ferric reducing antioxidant power was 0.69 mmol·L-1 FeSO4·7 H2O·g-1 DW. This indicates that the ethanol extract of the leaves of C. gigantea showed excellent antioxidant activity, which provides guidance for the further development and utilization of the extracts.
The leaves of a medicinal plant Calotropis gigantea were extracted with ethanol, and the chemical constituents of the ethanol extracts of the leaves were identified by gas chromatography-mass spectrometry（GC-MS）spectrometer to evaluate their antioxidant activity. The contents of total polyphenols and total flavonoids in the ethanol extract of the leaves, and the DPPH and hydroxyl free radical scavenging effects and the total reducing capacity of the extract were determined. The results indicated that the ethanol extract of the leaves of C. gigantea had a high anti-oxidant activity and that the alcohols content of the extract was the highest（60.2%）, followed by the esters（24.09%）. Lupeol（26.7%） was the main single component of the extract. The total polyphenols content was（26.22 ± 0.01） mg·g-1 DW（GAE）, and the total flavonoids content was（0.70 ± 0.02） mg·g-1 DW（RE）. The IC50 values of the extract in scavenging the activities of DPPH and hydroxyl free radicals were 0.33 g·L-1 and 0.21 g·L-1,respectively, which were not significant different from those of the control Lupeol and TBHQ, respectively.Moreover, the total reducing capacity of the extract was increased with the increase of the sample concentration.The ferric reducing antioxidant power was 0.69 mmol·L-1 FeSO4·7 H2O·g-1 DW. This indicates that the ethanol extract of the leaves of C. gigantea showed excellent antioxidant activity, which provides guidance for the further development and utilization of the extracts.
2018, 9(2): 189-197.
doi: 10.15886/j.cnki.rdswxb.2018.02.010
Abstract:
Analysis of population dynamics has rarely been used in orchids in China. According to the investigation of biological characteristics of and the population monitoring of Dendrobium sinense, an endemic orchid in Hainan, the survival number in each age-class, the emergence frequency and the number of filial generations of D. sinense were computed, and the reproductive behavior and mechanisms of D. sinense were described. The population static life table and fecundity table as well as the survival curve and age pyramid were prepared based on the survival number in each age class and the number of filial generations, and a Leslie matrix model were established to predict the numeric dynamics of the populations. Reproductive behavior and breeding strategy were analyzed based on the observation ofphenological characteristics and clonal growth of D. sinense. The relationship of the numeric dynamics of the populations of D. sinense with its reproductive behavior and its age pyramid were analyzed. Results showed that the age pyramid was kettle-shaped and that the survival performance of populations was similar to that of Deevey type I. The net reproduction rate, the intrinsic increase rate and the finite increase rate of D. sinense were very low, which indicates that the populations were in decline, which was similar to the prediction by Leslie matrix model.Reproductive behavior of D. sinense included both sexual reproduction and clonal growth. Clonal growth could increase the number of individuals prolong the life of individuals, maintain the populations and accumulate nutrients for sexual reproduction. The average flowering and seed setting rates were 19.38% and 25.61%,respectively, and seed germination of D. sinense were limited, causing serious shortage in supply of seedlings of D. sinense. Therefore, it is imperative to conduct ex situ conservation and field domestication of tissue cultured seedlings of D. sinense.
Analysis of population dynamics has rarely been used in orchids in China. According to the investigation of biological characteristics of and the population monitoring of Dendrobium sinense, an endemic orchid in Hainan, the survival number in each age-class, the emergence frequency and the number of filial generations of D. sinense were computed, and the reproductive behavior and mechanisms of D. sinense were described. The population static life table and fecundity table as well as the survival curve and age pyramid were prepared based on the survival number in each age class and the number of filial generations, and a Leslie matrix model were established to predict the numeric dynamics of the populations. Reproductive behavior and breeding strategy were analyzed based on the observation ofphenological characteristics and clonal growth of D. sinense. The relationship of the numeric dynamics of the populations of D. sinense with its reproductive behavior and its age pyramid were analyzed. Results showed that the age pyramid was kettle-shaped and that the survival performance of populations was similar to that of Deevey type I. The net reproduction rate, the intrinsic increase rate and the finite increase rate of D. sinense were very low, which indicates that the populations were in decline, which was similar to the prediction by Leslie matrix model.Reproductive behavior of D. sinense included both sexual reproduction and clonal growth. Clonal growth could increase the number of individuals prolong the life of individuals, maintain the populations and accumulate nutrients for sexual reproduction. The average flowering and seed setting rates were 19.38% and 25.61%,respectively, and seed germination of D. sinense were limited, causing serious shortage in supply of seedlings of D. sinense. Therefore, it is imperative to conduct ex situ conservation and field domestication of tissue cultured seedlings of D. sinense.
2018, 9(2): 198-202.
doi: 10.15886/j.cnki.rdswxb.2018.02.011
Abstract:
In order to study the efficient synthesis of bacterial cellulose（BC） and the factors affecting the stable high yielding BC synthesis, 8 cellulose-producing bacterial species were cultured in Asai chemically-defined medium to observe the effects of ethanol on BC synthesis to select highyielding bacterial species. These highyielding species were used as models to analyze their sensitivity and tolerance to ethanol. The results showed that the effects of ethanol on the 8 cellulose-producing species were quite different in BC synthesis. Of the 8 cellulose-producing species, 5 from the genus Komagataeibacter, and Acetobacter bogorensis were improved in BC synthesis, especially K. nataicola and K. xylinus which had most significant improvement（P ＜ 0.05）, while an unknown species from the genus Komagataeibacter was not significantly improved and K. europaeus was inhibited in BC synthesis. A K. nataicola strain Y19 was screened to show high sensitivity and tolerance to ethanol. This strain increased BC yield sharply by 6.6 times in the Asai medium supplemented with 0.5%（similarly hereinafter）ethanol and by 8.3 times to 7.12 g·L-1 at the presence of 1% ethanol, and then declined gradually the growth rate of BC synthesis with the increase of ethanol in the Asai medium. The BC yield of the strain was 44% lower than that of the control when the Asai medium was added with ethanol by up to 5%. This suggested that K. nataicola Y19 had an improving effect in response to ethanol at a wide range of concentrations from 0.5% to 4%, which would explain the vital significance to the large-scale BC production practice by using natural pre-fermented coconut water. On the other hand, one high yield and one inhibition strain were selected, which would lay good foundation for further mechanism study on ethanol effect.
In order to study the efficient synthesis of bacterial cellulose（BC） and the factors affecting the stable high yielding BC synthesis, 8 cellulose-producing bacterial species were cultured in Asai chemically-defined medium to observe the effects of ethanol on BC synthesis to select highyielding bacterial species. These highyielding species were used as models to analyze their sensitivity and tolerance to ethanol. The results showed that the effects of ethanol on the 8 cellulose-producing species were quite different in BC synthesis. Of the 8 cellulose-producing species, 5 from the genus Komagataeibacter, and Acetobacter bogorensis were improved in BC synthesis, especially K. nataicola and K. xylinus which had most significant improvement（P ＜ 0.05）, while an unknown species from the genus Komagataeibacter was not significantly improved and K. europaeus was inhibited in BC synthesis. A K. nataicola strain Y19 was screened to show high sensitivity and tolerance to ethanol. This strain increased BC yield sharply by 6.6 times in the Asai medium supplemented with 0.5%（similarly hereinafter）ethanol and by 8.3 times to 7.12 g·L-1 at the presence of 1% ethanol, and then declined gradually the growth rate of BC synthesis with the increase of ethanol in the Asai medium. The BC yield of the strain was 44% lower than that of the control when the Asai medium was added with ethanol by up to 5%. This suggested that K. nataicola Y19 had an improving effect in response to ethanol at a wide range of concentrations from 0.5% to 4%, which would explain the vital significance to the large-scale BC production practice by using natural pre-fermented coconut water. On the other hand, one high yield and one inhibition strain were selected, which would lay good foundation for further mechanism study on ethanol effect.
2018, 9(2): 203-206.
doi: 10.15886/j.cnki.rdswxb.2018.02.012
Abstract:
In recent years gray leaf spot disease occurred seriously on sweet pepper in Hainan,and mainly infected leaves which were covered with gray perforated lesions,giving serious impact on the quality and yield of sweet pepper. Pathogens were isolated from the leaf tissue of the sweet pepper infected with the gray leaf spot,and identified as Stemphylium lycopersici based on their morphology and r DNA ITS sequence. A field trial was conducted to control the gray leaf spot disease by using 4 fungicides,i. e. difenoconazole fluxapyroxad,trifloxystrobin fluopyram,tetramycin and difenoconazole. The results showed that 2 fungicides,12% difenoconazole fluxapyroxad SC（ Jiangong） and 42. 8% Trifloxystrobin fluopyram SC（ Lunaseng）,had a good effect on the control of the gray leaf spot on sweet pepper in the field,with their respective controlling effect of 77. 51% and 75. 01% at day 14. The controlling effect of 10% difenoconazole WG（Shigao） was slightly lower,only 27. 51%.
In recent years gray leaf spot disease occurred seriously on sweet pepper in Hainan,and mainly infected leaves which were covered with gray perforated lesions,giving serious impact on the quality and yield of sweet pepper. Pathogens were isolated from the leaf tissue of the sweet pepper infected with the gray leaf spot,and identified as Stemphylium lycopersici based on their morphology and r DNA ITS sequence. A field trial was conducted to control the gray leaf spot disease by using 4 fungicides,i. e. difenoconazole fluxapyroxad,trifloxystrobin fluopyram,tetramycin and difenoconazole. The results showed that 2 fungicides,12% difenoconazole fluxapyroxad SC（ Jiangong） and 42. 8% Trifloxystrobin fluopyram SC（ Lunaseng）,had a good effect on the control of the gray leaf spot on sweet pepper in the field,with their respective controlling effect of 77. 51% and 75. 01% at day 14. The controlling effect of 10% difenoconazole WG（Shigao） was slightly lower,only 27. 51%.
2018, 9(2): 207-213.
doi: 10.15886/j.cnki.rdswxb.2018.02.013
Abstract:
A cultivar of hot pepper（Capsicum chinense Jacquin）, native to Hainan, was pot cultured and treated with different levels of water stress to study the relationship between stress induction and pungent taste of hot pepper for exploration of the mechanism of pungency regulation in the hot pepper. The contents of capsaicin and capsaicinoid, and the physiological and biochemical indexes and growth of the hot pepper under water stress were determined and the relationship between the pungency and related physiological and biochemical indexes of the hot pepper under water stress were analyzed. The results showed that the hot pepper under water stress increased their contents of capsaicin and capsaicinoid by 45.57% and 47.69%,respectively,as compared with the control. The hot pepper under water stress increased its pungent flavor, but tended to reduce its leaf area, chlorophyll content, water potential and relative water content. The proline content in the hot pepper under water stress continued to increase, consistent with the trend of capsaicinoids content; and the changes in plant height and stem diameter and pungent flavor wer not significant, while the increment in fruit size（i.e. fruit length and fruit width） was reduced significantly and negatively correlated with the content of capsaicinoids, which was confirmed by related studies. The hot pepper under water stress decreased and then increased specific leaf area, relative conductivity, content of malondialdehyde（MDA） as well as the activities of superoxide dismutase（SOD）, catalase（CAT） and peroxidase（POD） in the antioxidant protective enzyme system, which was consistent with the changes of thecapsaicinoids accumulation rate.Chlorophyll, relative conductivity and malondialdehyde content are the responses of the hot pepper plants to drought tolerance. When the water stress was low, the anti-oxidant enzyme activity in the hot pepper was lower,and the capsaicin accumulation rate was lower as well. With the increase of water stress, the antioxidant enzyme activity in the hot pepper began to increase and the accumulation of capsaicinoids accelerated.However, when the water stress increased to a certain extent, the activity of antioxidant enzymes continued to rise in the hot pepper, while the rate of accumulation of capsaicinoids began to decrease. Therefore, a certain degree of water stress can increase the content of capsaicinoids, but severe water stress will reduce the accumulation of capsaicinoids.
A cultivar of hot pepper（Capsicum chinense Jacquin）, native to Hainan, was pot cultured and treated with different levels of water stress to study the relationship between stress induction and pungent taste of hot pepper for exploration of the mechanism of pungency regulation in the hot pepper. The contents of capsaicin and capsaicinoid, and the physiological and biochemical indexes and growth of the hot pepper under water stress were determined and the relationship between the pungency and related physiological and biochemical indexes of the hot pepper under water stress were analyzed. The results showed that the hot pepper under water stress increased their contents of capsaicin and capsaicinoid by 45.57% and 47.69%,respectively,as compared with the control. The hot pepper under water stress increased its pungent flavor, but tended to reduce its leaf area, chlorophyll content, water potential and relative water content. The proline content in the hot pepper under water stress continued to increase, consistent with the trend of capsaicinoids content; and the changes in plant height and stem diameter and pungent flavor wer not significant, while the increment in fruit size（i.e. fruit length and fruit width） was reduced significantly and negatively correlated with the content of capsaicinoids, which was confirmed by related studies. The hot pepper under water stress decreased and then increased specific leaf area, relative conductivity, content of malondialdehyde（MDA） as well as the activities of superoxide dismutase（SOD）, catalase（CAT） and peroxidase（POD） in the antioxidant protective enzyme system, which was consistent with the changes of thecapsaicinoids accumulation rate.Chlorophyll, relative conductivity and malondialdehyde content are the responses of the hot pepper plants to drought tolerance. When the water stress was low, the anti-oxidant enzyme activity in the hot pepper was lower,and the capsaicin accumulation rate was lower as well. With the increase of water stress, the antioxidant enzyme activity in the hot pepper began to increase and the accumulation of capsaicinoids accelerated.However, when the water stress increased to a certain extent, the activity of antioxidant enzymes continued to rise in the hot pepper, while the rate of accumulation of capsaicinoids began to decrease. Therefore, a certain degree of water stress can increase the content of capsaicinoids, but severe water stress will reduce the accumulation of capsaicinoids.
2018, 9(2): 214-218.
doi: 10.15886/j.cnki.rdswxb.2018.02.014
Abstract:
The dredger filled land in the tropics is mainly composed of coral sand accumulated without native ecosystem. Man-made vegetation and ecological systems need to be constructed to create a livable ecological environment for the production and living of the people living in the dredger filled land. Coral sand contains very low water and it is difficult for plants to survive and grow on it. It is necessary to study the water content of coral sand and the change of water content in the coral sand when planted with Scaevola sericea, which is significant to make the planting and water management schemes in the backfilled land with coral sand. The results showed that the water content of coral sand above 50 cm deep ranged from 6.1% to 10.9%. After 7 days of planting, the water content of the soil in the backfilled land was 9.4% for coral sand, 14.5% for mixed soil, and 31.6% for organic soil,while the water content of coral sand was falling from 17.6% to 13.0% in the second day and then maintaining at about 10%. The results proved that as the site condition of cultivation, the coral sand mixed with organic manure and yellow loam can improve the water content and water retention capacity of the backfilled soil, which is beneficial to improvement of the survival rate of plants cultivated and water utilization rate.
The dredger filled land in the tropics is mainly composed of coral sand accumulated without native ecosystem. Man-made vegetation and ecological systems need to be constructed to create a livable ecological environment for the production and living of the people living in the dredger filled land. Coral sand contains very low water and it is difficult for plants to survive and grow on it. It is necessary to study the water content of coral sand and the change of water content in the coral sand when planted with Scaevola sericea, which is significant to make the planting and water management schemes in the backfilled land with coral sand. The results showed that the water content of coral sand above 50 cm deep ranged from 6.1% to 10.9%. After 7 days of planting, the water content of the soil in the backfilled land was 9.4% for coral sand, 14.5% for mixed soil, and 31.6% for organic soil,while the water content of coral sand was falling from 17.6% to 13.0% in the second day and then maintaining at about 10%. The results proved that as the site condition of cultivation, the coral sand mixed with organic manure and yellow loam can improve the water content and water retention capacity of the backfilled soil, which is beneficial to improvement of the survival rate of plants cultivated and water utilization rate.
2018, 9(2): 219-224.
doi: 10.15886/j.cnki.rdswxb.2018.02.015
Abstract:
Eucalyptus bark is a common organic waste and should be treated when used as substrate. Seed germination experiment is one of the typical toxicological experiments for higher plants and can be used to test the toxicity of eucalyptus bark. In this context eucalyptus barks were treated with water, alkali or composting（naturally well composting） and were used as germination substrates to culture Pakchoi with the soil substrate as the control to observe the effect of the eucalyptus bark treatments on the germination of Pakchoi seeds. The results showed that the eucalyptus barks treated with water or alkali suppressed the seed germination of Pakchoi, whereas the naturally well-composted eucalyptus barks did not inhibit the seed germination of Pakchoi. The Pakchoi seeds cultured on the naturally well-composted barks were not significantly different in germination rate and germination potential from the control, and the Pakchoi had a seed germination index of ＞80%, and increased its plant height, root length, and fresh weight by 26.9%,26.57% and 89.36%, respectively. The correlation analysis showed that the seed germination of Pakchoi was mainly affected by total nitrogen, available nitrogen, available potassium and C/N.This indicates that the naturally well-composted eucalyptus barks can be used for development and utilization.
Eucalyptus bark is a common organic waste and should be treated when used as substrate. Seed germination experiment is one of the typical toxicological experiments for higher plants and can be used to test the toxicity of eucalyptus bark. In this context eucalyptus barks were treated with water, alkali or composting（naturally well composting） and were used as germination substrates to culture Pakchoi with the soil substrate as the control to observe the effect of the eucalyptus bark treatments on the germination of Pakchoi seeds. The results showed that the eucalyptus barks treated with water or alkali suppressed the seed germination of Pakchoi, whereas the naturally well-composted eucalyptus barks did not inhibit the seed germination of Pakchoi. The Pakchoi seeds cultured on the naturally well-composted barks were not significantly different in germination rate and germination potential from the control, and the Pakchoi had a seed germination index of ＞80%, and increased its plant height, root length, and fresh weight by 26.9%,26.57% and 89.36%, respectively. The correlation analysis showed that the seed germination of Pakchoi was mainly affected by total nitrogen, available nitrogen, available potassium and C/N.This indicates that the naturally well-composted eucalyptus barks can be used for development and utilization.
2018, 9(2): 225-233.
doi: 10.15886/j.cnki.rdswxb.2018.02.016
Abstract:
Environmental data and the data of the invasive plants from field sampling were analyzed by using Max Ent and Arc GIS to predict the distributions of suitable adaptivity areas for six major invasive plants,Chromolaena odorata,Praxelis clematidea,Mimosa pudica,Conyza sumatrensis,Wedelia trilobata,Lantana camara,in Hainan Province,China. Results showed that the adaptivity of the 6 major invasive plants tended to decrease gradually from coastal areas to inland areas,which might be due to difference in climatic distribution,to high elevation,or to the change of landuse types. Jackknife analysis showed that land use types were highly associated with the area of the suitable habitats of the invasive plants and were hence the most important environmental factors affecting the distribution of the six terrestrial invasive plants. Moreover,the area of suitable habitats of different invasive plants is also influenced by elevation,slope aspect,annual range of temperature,and seasonal variation of rainfall. Further analysis using Jackknife method also showed that the adaptivity of the 6 invasive plants was very high in the habitats of the surroundings of the village,the urban construction land and other construction lands like those in salt mine,industrial area,factories,mills,stoneworks,and higher in the habitats of woodland and grassland,but rather weak in the forested land（natural or artificial forests with canopy closure of ＞ 30%） and grassland with high vegetation coverage（Natural grassland,improved grassland and cut-and-carry grassland with a vegetation coverage of ＞ 50%）.
Environmental data and the data of the invasive plants from field sampling were analyzed by using Max Ent and Arc GIS to predict the distributions of suitable adaptivity areas for six major invasive plants,Chromolaena odorata,Praxelis clematidea,Mimosa pudica,Conyza sumatrensis,Wedelia trilobata,Lantana camara,in Hainan Province,China. Results showed that the adaptivity of the 6 major invasive plants tended to decrease gradually from coastal areas to inland areas,which might be due to difference in climatic distribution,to high elevation,or to the change of landuse types. Jackknife analysis showed that land use types were highly associated with the area of the suitable habitats of the invasive plants and were hence the most important environmental factors affecting the distribution of the six terrestrial invasive plants. Moreover,the area of suitable habitats of different invasive plants is also influenced by elevation,slope aspect,annual range of temperature,and seasonal variation of rainfall. Further analysis using Jackknife method also showed that the adaptivity of the 6 invasive plants was very high in the habitats of the surroundings of the village,the urban construction land and other construction lands like those in salt mine,industrial area,factories,mills,stoneworks,and higher in the habitats of woodland and grassland,but rather weak in the forested land（natural or artificial forests with canopy closure of ＞ 30%） and grassland with high vegetation coverage（Natural grassland,improved grassland and cut-and-carry grassland with a vegetation coverage of ＞ 50%）.
2018, 9(2): 234-243.
doi: 10.15886/j.cnki.rdswxb.2018.02.017
Abstract:
Invasive plants are plants that are introduced into non-native environments through human activities,which grow aggressively and spread in the natural areas,and affect plants,environments,or species in the region.An investigation was made of invasive plants growing in Danzhou Campus of Hainan University in the west part of Hainan Island during July to August 2017 to have an understanding of the invasive plants in the Campus for future control of the invasives. The Danzhou Campus falls in the tropical humid monsoonal climate and has a great variety of landscapes suitable for aggressive growth and spread of invasive plants. The investigation showed that there were51 families,152 genus and 211 species invasive plants in the Danzhou Campus,of which invasive plants of Compositae,Amaranthaceae,Gramineae and Solanaceae accounted for 12. 3%,7. 6%,7. 1% and 7. 1% respectively.Among these invasive plants,18 plant species were noxiously invasive and 30 were seriously invasive,and 91. 8%of both the noxious and the serious invasive plant species were introduced from America.
Invasive plants are plants that are introduced into non-native environments through human activities,which grow aggressively and spread in the natural areas,and affect plants,environments,or species in the region.An investigation was made of invasive plants growing in Danzhou Campus of Hainan University in the west part of Hainan Island during July to August 2017 to have an understanding of the invasive plants in the Campus for future control of the invasives. The Danzhou Campus falls in the tropical humid monsoonal climate and has a great variety of landscapes suitable for aggressive growth and spread of invasive plants. The investigation showed that there were51 families,152 genus and 211 species invasive plants in the Danzhou Campus,of which invasive plants of Compositae,Amaranthaceae,Gramineae and Solanaceae accounted for 12. 3%,7. 6%,7. 1% and 7. 1% respectively.Among these invasive plants,18 plant species were noxiously invasive and 30 were seriously invasive,and 91. 8%of both the noxious and the serious invasive plant species were introduced from America.
2018, 9(2): 244-251.
doi: 10.15886/j.cnki.rdswxb.2018.02.018
Abstract:
Based on our field research of Bailu Park which was built with the conventional concept in Sanya. The paper analyzes the traditional parks’ shortage of the use of rainwater utilization,contains use waterproof material,poor drainage pattern,water pollution,and the lack of rainwater reuse measures and rain water science education.Combined with the design of the city parks built under the concept of"sponge city"in Sanya,provides some design strategy of rainwater utilization,contains strengthen the permeability of the site,transmit rainwater directionally,filter and purify rainwater runoff,collect and storage rainwater,and add visualization of rainwater utilization design.
Based on our field research of Bailu Park which was built with the conventional concept in Sanya. The paper analyzes the traditional parks’ shortage of the use of rainwater utilization,contains use waterproof material,poor drainage pattern,water pollution,and the lack of rainwater reuse measures and rain water science education.Combined with the design of the city parks built under the concept of"sponge city"in Sanya,provides some design strategy of rainwater utilization,contains strengthen the permeability of the site,transmit rainwater directionally,filter and purify rainwater runoff,collect and storage rainwater,and add visualization of rainwater utilization design.
2018, 9(2): 252-259.
doi: 10.15886/j.cnki.rdswxb.2018.02.019
Abstract:
A landscape evaluation system was established by using Analytic Hierarchy Process（AHP） to comprehensively evaluate and analyze the landscape from the aspects of ecology, comfort, function and beauty based on the field and questionnaire surveys. The landscape of Haikou Riyue Square was taken as an example to establish its landscape evaluation system, and 18 indicator evaluation factors were identified, such as identification system, plant landscape level, pavement design, etc. The results showthat the weight of the four criterion levels, i.e.ecology, comfort, function and service, increased in the order of function（0.455） ＞ comfort（0.303） ＞ esthetics（0.157） ＞ ecology（0.085）. The overall landscape score of Riyue Square was 3.88, and the evaluation score was"good", which indicates that the public feel good about the overall landscape of Riyue Square.
A landscape evaluation system was established by using Analytic Hierarchy Process（AHP） to comprehensively evaluate and analyze the landscape from the aspects of ecology, comfort, function and beauty based on the field and questionnaire surveys. The landscape of Haikou Riyue Square was taken as an example to establish its landscape evaluation system, and 18 indicator evaluation factors were identified, such as identification system, plant landscape level, pavement design, etc. The results showthat the weight of the four criterion levels, i.e.ecology, comfort, function and service, increased in the order of function（0.455） ＞ comfort（0.303） ＞ esthetics（0.157） ＞ ecology（0.085）. The overall landscape score of Riyue Square was 3.88, and the evaluation score was"good", which indicates that the public feel good about the overall landscape of Riyue Square.
2018, 9(2): 260-266.
doi: 10.15886/j.cnki.rdswxb.2018.02.020
Abstract:
Adiantum flabellulatum L. is a small or medium-sized fern belonging to the genus Adiantum. It is dark green in leaf color and green in all seasons, and is mostly used for landscape design and medical and healthcare services. A. flabellulatum L. is often used as a foliage plant for indoor ornamental decoration and landscape design.It has a high ornamental value. Due to human disturbance and damage to its ecological environment and its man-made harvest for landscaping and medicinal preparation, the number of A. flabellulatum L. has been greatly reduced. Recent researches in A. flabellulatum L.were reviewed in terms of growth and development, rapid propagation and application of A. flabellulatum L. in landscaping and medicine in order to explore more effective ways for its conservation and propagation as well as its use in ornamental decoration and medicine.
Adiantum flabellulatum L. is a small or medium-sized fern belonging to the genus Adiantum. It is dark green in leaf color and green in all seasons, and is mostly used for landscape design and medical and healthcare services. A. flabellulatum L. is often used as a foliage plant for indoor ornamental decoration and landscape design.It has a high ornamental value. Due to human disturbance and damage to its ecological environment and its man-made harvest for landscaping and medicinal preparation, the number of A. flabellulatum L. has been greatly reduced. Recent researches in A. flabellulatum L.were reviewed in terms of growth and development, rapid propagation and application of A. flabellulatum L. in landscaping and medicine in order to explore more effective ways for its conservation and propagation as well as its use in ornamental decoration and medicine.
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