The responses of the growth and metabolism activity of Phanerochaete chrysosporium （P. chrysosporium） to cadmium （Cd）, lead （Pb） and their combined pollution stress, were investigated in plate and liquid culture...The responses of the growth and metabolism activity of Phanerochaete chrysosporium （P. chrysosporium） to cadmium （Cd）, lead （Pb） and their combined pollution stress, were investigated in plate and liquid culture conditions. The diameter of colony, biomass ofP. chrysosporium, ligninolytic enzyme activities and bioaccumulation quantity of heavy metals were detected. The results indicated that Cd was more toxic than Pb to P. chrysosporium and the toxicity of Cd and Pb to P. chrysosporium was further strengthened under Cd＋Pb combined pollution in different culture conditions. Heavy metals Cd and Pb had indirect influence on the production of ligninolytic enzymes by directly affecting the fungal growth and metabolic activity, and by another way in liquid culture. In addition, the results provided an evidence of the accumulation of Cd and Pb on the mycelia ofP. chrysosporium.展开更多
Low-temperature soluble carbohydrate accumulations are commonly associated with anthocyanin coloration, attenuated growth and cold adaptation of cool-season grasses. The vrn-1 gene has potent effects on vernalization ...Low-temperature soluble carbohydrate accumulations are commonly associated with anthocyanin coloration, attenuated growth and cold adaptation of cool-season grasses. The vrn-1 gene has potent effects on vernalization requirement, growth, and soluble carbohydrate accumulations of the winter-annual Triticeae species. Two hundred and four unmapped AFLP markers and genome-specific DNA markers genetically linked to the vrn-1 gene were used to detect QTL controlling soluble carbohydrate accumulations, anthocyanin coloration and growth characteristics in a segregating population derived from open pollinated Leymus cinereus x L. triticoides hybrids. These perennial Triticeae grasses are distinguished by adaptation and growth habit. As expected, positive trait correlations and pleiotropic gene effects were detected for soluble carbohydrate accumulations and anthocyanin coloration. Likewise, positive trait correlations and pleiotropic gene effects were detected for tillering, leaf development, leaf growth, regrowth and rhizome spread. However, soluble carbohydrate accumulations were not associated with attenuated growth. In fact, several DNA marker alleles, including one near vrn-Ns1, had positive effects on soluble leaf carbohydrate concentrations and low temperature growth. The corresponding DNA marker near vrn-Ns1 had more specific effects on tillering. We speculate that vrn-1 exerts quantitative effects on low-temperature soluble leaf carbohydrate accumulations and growth habit of the perennial Leymus. However, a number of other DNA markers displayed highly significant effects on soluble carbohydrate accumulations and various growth characteristics. Findings indicate that anthocyanin coloration may be a useful phenotypic marker for soluble carbohydrate accumulation. Although variation for soluble carbohydrates was not associated with attenuated growth in this population, this trait was under genetic control.展开更多
In order to clarify the relationships between soil pH and flue-cured tobacco growth and dry matter accumulation, effects of soil pH on root morphology and vigor, aboveground agronomic traits and dry matter accumulatio...In order to clarify the relationships between soil pH and flue-cured tobacco growth and dry matter accumulation, effects of soil pH on root morphology and vigor, aboveground agronomic traits and dry matter accumulation of flue-cured tobacco were investigated by pot experiment. The results showed that on the whole, the intensity of soil pH on flue-cured tobacco growth and dry matter accumulation ranked as pH=6＇s 〉 pH=7＇s 〉 pH=5＇s 〉 pH=4＇s 〉 pH=8＇s. Acidic soil （pH=4） was not conducive to the early growth of tobacco plants, reduced root vigor and affected dry matter accumulation; and alkaline soil （pH=8） was not conducive to the growth of tobacco roots and shoot, reduced root vigor and affected dry matter accumulation. In conclusion, the suitable pH of soil for growth of flue-cured tobacco in Xiangxi is 5-7, but weakly acidic soil is the best.展开更多
A laboratory experiment was conducted to assess the bioaccumulation of Pb^2＋ and its effects on growth, morphology and pigment contents of Spirulina （Arthrosl）ira）platensis. The specimen cultured in Zarrouk liquid...A laboratory experiment was conducted to assess the bioaccumulation of Pb^2＋ and its effects on growth, morphology and pigment contents of Spirulina （Arthrosl）ira）platensis. The specimen cultured in Zarrouk liquid medium was treated with various initial metal concentrations （0, 5, 10, 30, 50 and 10μgmL^-1）. The growth ofS. platensis was adversely affected by Pb〉 at high concentrations （30, 50 and 100μgmL^-1）. However, at low concentrations （5μgmL^-1）, Pb^2＋ could stimulate its growth slightly. The pigment contents （chlorophyllα and β carotene） were decreased in a dose-dependent manner. The highest reductions （67% and 53% respectively in chlorophyll α andβ carotene） were observed in 100 μg mL^-1 treatment group. The LC50 （96 h） of Pb^2- was measured as 75.34 μg mL^-1. Apart from a few cases of filament breakages at elevated concentrations （50 and 100 μgmL^-1）, morphological abnormalities are not specific. Metal bioaccumulation increased with Pb^2- concentrations, but decreased with exposure time. The maximum accumulated amount was 188 mgg^-1 dry weight. The bioconcentration factor （BCF） reached to a peak at day 2, followed by a gradual reduction tbr all the exposure concentrations. S. platensis is able to tolerate considerably high Pb^2＋ concentrations. Consequently it can be used as a potential species to remove heavy metal from contaminated waters.展开更多
The bioaccumulation and toxicity of heavy metals were reviewed with special reference to microalgae, the key compo- nent of the food web in aquatic ecosystems. Heavy metals enter algal cells either by means of active ...The bioaccumulation and toxicity of heavy metals were reviewed with special reference to microalgae, the key compo- nent of the food web in aquatic ecosystems. Heavy metals enter algal cells either by means of active transport or by endocytosis through chelating proteins and affect various physiological and biochemical processes of the algae. The toxicity primarily results from their binding to the sulphydryl groups in proteins or disrupting protein structure or displacing essential elements. Metals can break the oxidative balance of the algae, inducing antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GPX) and ascorbate peroxidase (APX). The amount of oxidized proteins and lipids in the algal cells thus indicates the severity of the stress. Algal tolerance to heavy metal is highly dependent upon the defense response against the probable oxidative damages. Pro- duction of binding factors and proteins, exclusion of metals from cells by ion-selective transporters and excretion or compartmen- talization have been suggested with regard to reducing heavy metal toxicity. However, a comprehensive description on the mecha- nisms underlining metal toxicity of microalgae and gaining tolerance is yet to be elaborated.展开更多
In this paper we consider a generalize dynamic entropy measure and prove that this mea- sure characterizes the distribution function uniquely. Also we propose cumulative resi- dual R^nyi entropy of order statistics an...In this paper we consider a generalize dynamic entropy measure and prove that this mea- sure characterizes the distribution function uniquely. Also we propose cumulative resi- dual R^nyi entropy of order statistics and prove that it also determines the distribution function uniquely. Applications of entropy concepts to DNA sequence analysis, the ulti- mate support for the biological systems, have been widely explored by researchers. The entropy measures discussed here can be applied for analysis of ordered DNA sequences.展开更多
基金Projects(21477027,51278176)supported by the National Natural Science Foundation of ChinaProject(2014A020216048)supported by the Science and Technology Planning Project of Guangdong Province,ChinaProject(2015M582363)supported by the China Postdoctoral Science Foundation
文摘The responses of the growth and metabolism activity of Phanerochaete chrysosporium （P. chrysosporium） to cadmium （Cd）, lead （Pb） and their combined pollution stress, were investigated in plate and liquid culture conditions. The diameter of colony, biomass ofP. chrysosporium, ligninolytic enzyme activities and bioaccumulation quantity of heavy metals were detected. The results indicated that Cd was more toxic than Pb to P. chrysosporium and the toxicity of Cd and Pb to P. chrysosporium was further strengthened under Cd＋Pb combined pollution in different culture conditions. Heavy metals Cd and Pb had indirect influence on the production of ligninolytic enzymes by directly affecting the fungal growth and metabolic activity, and by another way in liquid culture. In addition, the results provided an evidence of the accumulation of Cd and Pb on the mycelia ofP. chrysosporium.
文摘Low-temperature soluble carbohydrate accumulations are commonly associated with anthocyanin coloration, attenuated growth and cold adaptation of cool-season grasses. The vrn-1 gene has potent effects on vernalization requirement, growth, and soluble carbohydrate accumulations of the winter-annual Triticeae species. Two hundred and four unmapped AFLP markers and genome-specific DNA markers genetically linked to the vrn-1 gene were used to detect QTL controlling soluble carbohydrate accumulations, anthocyanin coloration and growth characteristics in a segregating population derived from open pollinated Leymus cinereus x L. triticoides hybrids. These perennial Triticeae grasses are distinguished by adaptation and growth habit. As expected, positive trait correlations and pleiotropic gene effects were detected for soluble carbohydrate accumulations and anthocyanin coloration. Likewise, positive trait correlations and pleiotropic gene effects were detected for tillering, leaf development, leaf growth, regrowth and rhizome spread. However, soluble carbohydrate accumulations were not associated with attenuated growth. In fact, several DNA marker alleles, including one near vrn-Ns1, had positive effects on soluble leaf carbohydrate concentrations and low temperature growth. The corresponding DNA marker near vrn-Ns1 had more specific effects on tillering. We speculate that vrn-1 exerts quantitative effects on low-temperature soluble leaf carbohydrate accumulations and growth habit of the perennial Leymus. However, a number of other DNA markers displayed highly significant effects on soluble carbohydrate accumulations and various growth characteristics. Findings indicate that anthocyanin coloration may be a useful phenotypic marker for soluble carbohydrate accumulation. Although variation for soluble carbohydrates was not associated with attenuated growth in this population, this trait was under genetic control.
基金Supported by College Students’Innovative Experiment Plan of Hunan Agricultural University(XCX16132)Project of Tobacco Monopoly Bureau of Hunan Province(xx15-18Aa01)~~
文摘In order to clarify the relationships between soil pH and flue-cured tobacco growth and dry matter accumulation, effects of soil pH on root morphology and vigor, aboveground agronomic traits and dry matter accumulation of flue-cured tobacco were investigated by pot experiment. The results showed that on the whole, the intensity of soil pH on flue-cured tobacco growth and dry matter accumulation ranked as pH=6＇s 〉 pH=7＇s 〉 pH=5＇s 〉 pH=4＇s 〉 pH=8＇s. Acidic soil （pH=4） was not conducive to the early growth of tobacco plants, reduced root vigor and affected dry matter accumulation; and alkaline soil （pH=8） was not conducive to the growth of tobacco roots and shoot, reduced root vigor and affected dry matter accumulation. In conclusion, the suitable pH of soil for growth of flue-cured tobacco in Xiangxi is 5-7, but weakly acidic soil is the best.
基金the Chinese Scholarship Council is greatly acknowledged
文摘A laboratory experiment was conducted to assess the bioaccumulation of Pb^2＋ and its effects on growth, morphology and pigment contents of Spirulina （Arthrosl）ira）platensis. The specimen cultured in Zarrouk liquid medium was treated with various initial metal concentrations （0, 5, 10, 30, 50 and 10μgmL^-1）. The growth ofS. platensis was adversely affected by Pb〉 at high concentrations （30, 50 and 100μgmL^-1）. However, at low concentrations （5μgmL^-1）, Pb^2＋ could stimulate its growth slightly. The pigment contents （chlorophyllα and β carotene） were decreased in a dose-dependent manner. The highest reductions （67% and 53% respectively in chlorophyll α andβ carotene） were observed in 100 μg mL^-1 treatment group. The LC50 （96 h） of Pb^2- was measured as 75.34 μg mL^-1. Apart from a few cases of filament breakages at elevated concentrations （50 and 100 μgmL^-1）, morphological abnormalities are not specific. Metal bioaccumulation increased with Pb^2- concentrations, but decreased with exposure time. The maximum accumulated amount was 188 mgg^-1 dry weight. The bioconcentration factor （BCF） reached to a peak at day 2, followed by a gradual reduction tbr all the exposure concentrations. S. platensis is able to tolerate considerably high Pb^2＋ concentrations. Consequently it can be used as a potential species to remove heavy metal from contaminated waters.
文摘The bioaccumulation and toxicity of heavy metals were reviewed with special reference to microalgae, the key compo- nent of the food web in aquatic ecosystems. Heavy metals enter algal cells either by means of active transport or by endocytosis through chelating proteins and affect various physiological and biochemical processes of the algae. The toxicity primarily results from their binding to the sulphydryl groups in proteins or disrupting protein structure or displacing essential elements. Metals can break the oxidative balance of the algae, inducing antioxidant enzymes, such as superoxide dismutase (SOD), glutathione peroxidase (GPX) and ascorbate peroxidase (APX). The amount of oxidized proteins and lipids in the algal cells thus indicates the severity of the stress. Algal tolerance to heavy metal is highly dependent upon the defense response against the probable oxidative damages. Pro- duction of binding factors and proteins, exclusion of metals from cells by ion-selective transporters and excretion or compartmen- talization have been suggested with regard to reducing heavy metal toxicity. However, a comprehensive description on the mecha- nisms underlining metal toxicity of microalgae and gaining tolerance is yet to be elaborated.
文摘In this paper we consider a generalize dynamic entropy measure and prove that this mea- sure characterizes the distribution function uniquely. Also we propose cumulative resi- dual R^nyi entropy of order statistics and prove that it also determines the distribution function uniquely. Applications of entropy concepts to DNA sequence analysis, the ulti- mate support for the biological systems, have been widely explored by researchers. The entropy measures discussed here can be applied for analysis of ordered DNA sequences.
