Cyanobacteria are important photosynthetic autotrophic microorganisms and are considered as one of the most promising microbial chassises for photosynthetic cell factories. Glycogen is the most important natural carbon sink of cyanobacteria, playing important roles in regulating its intracellular carbon distributions. In order to optimize the performances of cyanobacterial photosynthetic cell factories and drive more photosynthetic carbon flow toward the synthesis of desired metabolites, many strategies and approaches have been developed to manipulate the glycogen metabolism in cyanobacteria. However, the disturbances on glycogen metabolism usually cause complex effects on the physiology and metabolism of cyanobacterial cells. Moreover, the effects on synthesis efficiencies of different photosynthetic cell factories usually differ. In this manuscript, we summarized the recent progress on engineering cyanobacterial glycogen metabolism, analyzed and compared the physiological and metabolism effects caused by engineering glycogen metabolism in different cyanobacteria species, and prospected the future trends of this strategy on optimizing cyanobacterial photosynthetic cell factories.
Carbon/metabolism* ; Carbon Dioxide/metabolism* ; Cyanobacteria/metabolism* ; Glycogen/metabolism* ; Metabolic Engineering ; Photosynthesis/physiology*

Light is the main source for plants to obtain energy.Asarum forbesii is a typical shade medicinal plant, which generally grows in the shady and wet place under the bushes or beside the ditches.It can grow and develop without too much light intensity.This experiment explores the effects of shading on the growth, physiological characteristics and energy metabolism of A.forbesii, which can provide reference and guidance for its artificial planting.In this experiment, A.forbesii was planted under 80%, 60%, 40%, 20% and no shade.During the vigorous growth period, the photosynthetic physiological characteristics such as fluorescence parameters, photosynthetic parameters, photosynthetic pigment content and ultrastructure, as well as the content of mitochondrial electron transport chain(ETC) synthase and nutrients were measured.The results showed that the photosynthetic pigment content, chlorophyll fluorescence parameters and net photosynthesis rate(P_n) decreased with the decrease of shading.Under 20%-40% shading treatment, the plants had damaged ultrastructure, expanded and disintegrated chloroplast, disordered stroma lamella and grana lamella, and increased osmiophi-lic granules and starch granules.The activities of nicotinamide adenine dinucleotide dehydrogenase(NADH), succinate dehydrogenase(SDH), cytochrome C oxidoreductase(CCO) and adenosine triphosphate(ATP) synthasewere positively related to light intensity.With the reduction of shading, the content of total sugar and protein in nutrients increased first and then decreased, and the content was the highest under 60% shade.In conclusion, under 60%-80% shading treatment, the chloroplast and mitochondria had more complete structure, faster energy metabolism, higher light energy-conversion efficiency, better absorption and utilization of light energy and more nutrient synthesis, which was more suitable for the growth and development of A.forbesii.
Asarum ; Chlorophyll/metabolism* ; Chloroplasts ; Energy Metabolism ; Photosynthesis/physiology* ; Plant Leaves/metabolism*

Co-culture systems consisted of photosynthetic microorganisms and others heterotrophic microbes have attracted great attention in recent years. These systems show many advantages when compared with single culture grown under autotrophic conditions, such as less vulnerable to pollution and more stability, thus have been applied to wastewater treatment, soil remediation, biodegradable harmful substances, and production of high value-added products. In order to explore basic theory and further applications, we summarize here recent progresses in artificial co-culture systems of using photosynthetic microorganisms, to provide a current scientific understanding for the rational design of the co-culture system based on photosynthetic microorganisms using synthetic biology.
Coculture Techniques ; Heterotrophic Processes ; Microbiological Techniques ; trends ; Microbiota ; physiology ; Photosynthesis ; physiology ; Synthetic Biology ; trends

Exogenous calcium can enhance the resistance of certain plants to abiotic stress. Research have demonstrated that exogenous calcium could enhances the resistance of honeysuckle under salt stress by promoting the transmission of photosynthetic electrons.The aim of this study was to investigate the effects of exogenous calcium on the contents of Na~+,K~+,Ca~(2+),Mg~(2+)and the expression of photosynthetic related genes Cab and rbc L. In this study,we used ICP-OES to analysis ion contents and used qRT-PCR to analysis the expression patterns of Cab and rbc L. The results showed that CaCl_2 significantly enhanced the K~+-Na~+,Ca~(2+)-Na~+,Mg~(2+)-Na+ratio of honeysuckle treated with 50 and 100 mmol·L~(-1) NaCl. Meanwhile,Cab and rbc L were significantly up-regulated under short-term salt stress,and CaCl_2 promoted this trend. From the two gene expression patterns,rbc L rapidly up-regulated on the first day of stress and then decreased,and was more sensitive to environmental changes. In summary,exogenous calcium could alleviate salt stress and increase plant development by increasing intracellular K~+-Na~+,Ca~(2+)-Na~+,Mg~(2+)-Na+ratio,and the transient overexpression of Cab and rbc L.
Calcium ; physiology ; Cations ; analysis ; Lonicera ; physiology ; Photosynthesis ; Salt Stress

Chlorophyll content,leaf mass to per area,net photosynthetic rate and bioactive ingredients of Asarum heterotropoides var. mandshuricum,a skiophyte grown in four levels of solar irradiance were measured and analyzed in order to investigate the response of photosynthetic capability to light irradiance and other environmental factors. It suggested that the leaf mass to per area of plant was greatest value of four kinds of light irradiance and decreasing intensity of solar irradiance resulted in the decrease of leaf mass to per area at every phenological stage. At expanding leaf stage,the rate of Chla and Chlb was 3. 11 when A. heterotropoides var. mandshuricum grew in full light irradiance which is similar to the rate of heliophytes,however,the rate of Chla and Chlb was below to 3. 0 when they grew in shading environment. The content of Chla,Chlb and Chl( a+b) was the greatest value of four kinds of light irradiance and decreasing intensity of solar irradiance resulted in its decreasing remarkably( P<0. 05). The rate of Chla and Chlb decreased but the content of Chla,Chlb and Chl( a+b) increased gradually with continued shading. The maximum value of photosynthetically active radiation appeared at 10: 00-12: 00 am in a day. The maximum value of net photosynthetic rate appeared at 8: 30-9: 00 am and the minimum value appeared at 14: 00-14: 30 pm at each phenological stage if plants grew in full sunlight. However,when plants grew in shading,the maximum value of net photosynthetic rate appeared at about 10: 30 am and the minimum value appeared at 12: 20-12: 50 pm at each phenological stage. At expanding leaf stage and flowering stage,the average of net photosynthetic rate of leaves in full sunlight was remarkably higher than those in shading and it decreased greatly with decreasing of irradiance gradually( P < 0. 05). However,at fruiting stage,the average of net photosynthetic rate of leaves in full sunlight was lower than those in 50% and 28% full sunlight but higher than those in 12% full sunlight. All photosynthetic diurnal variation parameters of plants measured in four kinds of different irradiance at three stages were used in correlation analysis. The results suggested that no significant correlation was observed between net photosynthetic rate and photosynthetically active radiation,and significant negative correlation was observed between net photosynthetic rate and environmental temperature as well as vapor pressure deficit expect for 12% full sunlight. Positive correlation was observed between net photosynthestic rate and relative humidity expect for 12% full sunlight. Significant positive correlation was observed between net photosynthetic rate and stomatal conductance in the four light treatments. Only,in 12% full sunlight,the net photosynthetic rate was significantly related to photosynthetically active radiation rather than related to environmental temperature,vapor pressure deficit and relative humidity. In each light treatment,a significant positive correlation was observed between environmental temperature and vapor pressure deficit,relative humidity as well as stomatal conductance. Volatile oil content was 1. 46%,2. 16%,1. 56%,1. 30% respectively. ethanol extracts was 23. 44%,22. 45%,22. 18%,21. 12% respectively. Asarinin content was 0. 281%,0. 291%,0. 279% and 0. 252% respectively. The characteristic components of Asarum volatile oil of plant in different light treatments did not change significantly among different groups.
Asarum ; physiology ; radiation effects ; Chlorophyll ; analysis ; Photosynthesis ; Plant Leaves ; radiation effects ; Sunlight

Exogenous calcium can enhance the resistance of certain plants to abiotic stress. However,the role of calcium insaltstressed honeysuckle is unclear. The study is aimed to investigate the effects of exogenous calcium on the biomass,chlorophyll content,gas exchange parameters and chlorophyll fluorescence of honeysuckle under salt stress. The results showed that the calcium-treated honeysuckle had better photochemical properties than the salt-stressed honeysuckle,such as PIABS,PItotal,which represents the overall activity of photosystemⅡ(PSⅡ),and related parameters for characterizing electron transport efficiency φP0,ψE0,φE0,σR,and φR are significantly improved. At the same time,the gas exchange parameters Gs,Ci,Trare also maintained at a high level. In summary,exogenous calcium protects the activity of PSⅡ,promotes the transmission of photosynthetic electrons,and maintains a high Ci,therefore enhances the resistance of honeysuckle under salt stress.
Calcium ; pharmacology ; Chlorophyll ; analysis ; Lonicera ; drug effects ; physiology ; Photosynthesis ; Plant Leaves ; Salt Stress

In this study,the leaves of autumn-sown Angelica dahurica var. formosana from Sichuan province in different growth years was used to explore the fitting model of photosynthetic response curve and the different photosynthetic physiological characteristics between annual and biennial A. dahurica var. formosana from Sichuan province. The results showed that the fitting model of the optimum light response curve of the leaves of A. dahurica var. formosana from Sichuan province with different growth years was all rectangular hyperbolic correction model. The light saturation points were 1 600,1 700 μmol·m-2·s-1,the light compensation points were17. 98,52. 23 μmol·m-2·s-1 in the leaves of annual and biennial plant,respectively. The diurnal variation curves of net photosynthetic rate,transpiration rate and stomatal conductance in the leaves all acted as a single peak value wave. The daily mean values of net photosynthetic rate and transpiration rate in the leaves of biennial plant were significantly higher than that of annual plant. There was no significant difference in daily mean stomatal conductance. The net photosynthetic rate was significantly positively correlated with stomatal conductance in both of the different growth years. The net photosynthetic rate of annual and biennial A. dahurica var. formosana from Sichuan province had extremely significant and significantly negative correlation with the intercellular CO2 respectively. The transpiration rate of annual plant was positively correlated with the effective photosynthetic radiation intensity and air temperature,but had significantly negative correlation with the intercellular CO2 concentration. The transpiration rate of biennial plant had extremely positive correlation with the effective photosynthetic radiation intensity,and negatively correlated with the intercellular CO2 concentration. In conclusion,the photosynthetic efficiency of the leaves in biennial plant of A. dahurica var. formosana from Sichuan province was higher than that in annual plant,but the ability to utilize weak light was lower than that of annual plant. It should be planted in the sunny field.
Angelica ; physiology ; Carbon Dioxide ; China ; Photosynthesis ; Plant Leaves ; physiology ; Plant Transpiration ; Seasons ; Temperature

As an important signal molecule, extracellular ATP(eATP) can regulate many physiological and biochemical responses to plant stress. In this study, the regulation of extracellular ATP(eATP) on chlorophyll content and chlorophyll fluorescence parameters of Angelica sinensis seedlings were studied under drought and low temperature stress. The results showed that all the chlorophyll content, the actual photochemical efficiency [Y(Ⅱ)], the electron transfer rate(ETR), the photochemical quenching coefficient(qP and qL) of A. sinensis leaves were significantly decreased under drought and low temperature stress, respectively. At the same time, non-photochemical quenching(NPQ and qN) were also all significantly increased, respectively. The application of eATP alleviated the decrease of chlorophyll content, Y(Ⅱ), ETR, qP and qL of A. sinensis leaves under drought and low temperature stress, and eliminated the increase of qN and NPQ. The results indicated that eATP could effectively increase the open ratio of PSⅡ reaction centers, and improve the electron transfer rate and light energy conversion efficiency of PSⅡ of A. sinensis leaves under drought and low temperature stress. It is beneficial to enhance the chlorophyll synthesis and the adaptability of PSⅡ about A. sinensis seedlings to drought and low temperature stress.
Adenosine Triphosphate ; pharmacology ; Angelica sinensis ; chemistry ; physiology ; Chlorophyll ; analysis ; Cold Temperature ; Droughts ; Fluorescence ; Photosynthesis ; Plant Leaves ; chemistry ; Seedlings ; chemistry ; physiology ; Stress, Physiological ; Water

The purpose of this experiment was to study the effects of different shading conditions on the growth,physiological characteristics and biomass allocation of Polygonatum cyrtonema,which offered a theoretical basis for its cultivation.Different light environments(100%,80%,60% and 35% light transmittance) were simulated with shading treatments.Growth and photosynthetic indexes of P.cyrtonema were measured and the variances were analyzed.The results show that shading decreased superoxide anion radical(O-·2)production rate and hydrogen peroxide(H_2O_2) accumulation,kept the activity of SOD,POD and CAT enzyme at a high level.Furthermore,The content of chlorophyll a and chlorophyll b,net photosynthetic rate(Pn),stomatal conductance(Gs),transpiration rate(Tr),maximal photochemical efficiency of photosystem Ⅱ(Fv/Fm),photochemical quenching index(q P) and effective quantum yield of photosystem II(ΦPSⅡ) of P.cyrtonema were increased while the intercellular CO2 concentration(Ci),Foand NPQ were decreased by shading.Shading is beneficial to P.cyrtonema growth,can increase the total biomass P.cyrtonema.The allocation proportion of biomass on the aerial portion of P.cyrtonema increased but underground parts decreased with increasing shading conditions.In this study,P.cyrtonema can grow well in shading conditions,shading is beneficial to the formation of the yield and quality of the rhizomes of P.cyrtonema,especially in 65% light transmittance.
Biomass ; Chlorophyll ; Chlorophyll A ; Photosynthesis ; Plant Leaves ; Plant Stomata ; Plant Transpiration ; Polygonatum ; growth & development ; physiology ; Sunlight

Through indoor and field comparative experiments, the properties of membrane type leaf evaporation inhibitors and its effects on photosynthesis of and compatibility and synergistic of pesticide were studied. The evaporation inhibitors and were chosen to investigate the suppression of water evaporation and the compatibility with pesticides. The effect of evaporation inhibitors on photosynthesis of leaves was determined by the chlorophyll fluorescence imaging system. The results showed that water evaporation of leaves of different leaf age were evidently suppressed after treated with evaporation inhibitor. The inhibitor was well compatible with pesticide and effectively improved the pesticide efficacy，and had no significant effect on chlorophyll fluorescence parameters. It is concluded that the evaporation inhibitor has good compatibility with the pesticide, and has remarkable effect of restraining moisture evaporation, which make it can be used for reducing the dosage and improving the efficacy of the pesticide in the field of
Chlorophyll ; analysis ; Lycium ; drug effects ; physiology ; Pesticides ; chemistry ; Photosynthesis ; Plant Leaves ; drug effects ; physiology ; Plant Transpiration