Physiological regulation of salicylic acid on Helianthus tubeuosus upon copper stress and root FTIR analysis / 生物工程学报

Phytoremediation plays an important role in the treatment of heavy metal pollution in soil. In order to elucidate the mechanism of salicylic acid (SA) on copper absorption, seedlings from Xuzhou (with strong Cu-tolerance) and Weifang Helianthus tuberosus cultivars (with weak Cu-tolerance) were selected for pot culture experiments. 1 mmol/L SA was sprayed upon 300 mg/kg soil copper stress, and the photosynthesis, leaf antioxidant system, several essential mineral nutrients and the changes of root upon copper stress were analyzed to explore the mechanism of copper resistance. The results showed that Pn, Tr, Gs and Ci upon copper stress decreased significantly compared to the control group. Meanwhile, chlorophyll a, chlorophyll b and carotenoid decreased with significant increase in initial fluorescence (F0), maximum photochemical quantum yield of PSⅡ (Fv/Fm), electron transfer rate (ETR) and photochemical quenching coefficient (qP) content all decreased. The ascorbic acid (AsA) content was decreased, the glutathione (GSH) value was increased, the superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) activity in the leaves were decreased, and the peroxidase (POD) activity was significantly increased. SA increased the Cu content in the ground and root system, and weakened the nutrient uptake capacity of K, Ca, Mg, and Zn in the root stem and leaves. Spray of exogenous SA can maintain the opening of leaf stomata, improve the adverse effect of copper on photosynthetic pigment and PSⅡ reaction center. Mediating the SOD and APX activity started the AsA-GSH cycle process, effectively regulated the antioxidant enzyme system in chrysanthemum taro, significantly reduced the copper content of all parts of the plant, and improved the ion exchange capacity in the body. External SA increased the content of the negative electric group on the root by changing the proportion of components in the root, promoted the absorption of mineral nutrient elements and the accumulation of osmoregulatory substances, strengthened the fixation effect of the root on metal copper, and avoided its massive accumulation in the H. tuberosus body, so as to alleviate the inhibitory effect of copper on plant growth. The study revealed the physiological regulation of SA upon copper stress, and provided a theoretical basis for planting H. tuberosus to repair soil copper pollution.

Response of growth and photosynthetic characteristics of Polygonatum cyrtonema to shading conditions / 中国中药杂志

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.

Effects of light intensities on growth,physiological characteristic and chemical composition of Viola yedoensis / 中国中药杂志

The study is aimed to investigate the effects of light intensities on growth,photosynthetic physiology,antioxidant systems and chemical composition of Viola yedoensis and provide cultivation references for V.yedoensis.Five groups of V.yedoensis were planted under five light intensities conditions,namely 100%,80%,50%,35%,5%of full sunlight,and then morphological index,growth,chlorophyll fluorescence parameters,photosynthetic parameters and antioxidant enzyme system indexes were measured during harvest.The results showed that there was no significant difference in the biomass of V.yedoensis among 35% -100%full sunlight,but the biomass of those were significantly higher than that in the 5%full sunlight treatment(P<0.05).The net photosynthetic rate,transpiration rate,stomatal conductance,intercellular CO_2 concentration and water use efficiency increased firstly and then decreased with the decrease of light intensity;F_m,F_v/F_mand Yield in 5% full sunlight treatment were significantly lower than those in the other four groups(P<0.05).The structure of chloroplast was normal under light intensity ranged from 50%to 100% full sunlight.The lamellar concentration of chloroplast matrix decreased and the starch granules decreased in 35% full sunlight treatment,and the margin of lamellar layer of chloroplast and substrate were blurred,and the starch granules were small and the number of starch granules decreased significantly under 5% full sunlight.MDA content in 5%full sunlight treatment was significantly higher than those in the other four groups(P<0.05).The total coumarin content and total flavonoid content decreased with the decrease of light intensity.In summary,the light in-tensity range suitable for the growth of V.yedoensis is wide(ranging from 35% to 100% full sunlight).The content of flavonoids and coumarins is positively correlated with light intensity.

Photosynthetic physiological characteristics of Angelica dahurica var.formosana from Sichuan province in different growth years / 中国中药杂志

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.

Seagrasses in tropical Australia, productive and abundant for decades decimated overnight.

Seagrass ecosystems provide unique coastal habitats critical to the life cycle of many species. Seagrasses are a major store of organic carbon. While seagrasses are globally threatened and in decline, in Cairns Harbour, Queensland, on the tropical east coast of Australia, they have flourished. We assessed seagrass distribution in Cairns Harbour between 1953 and 2012 from historical aerial photographs, Google map satellite images, existing reports and our own surveys of their distribution. Seasonal seagrass physiology was assessed through gross primary production, respiration and photosynthetic characteristics of three seagrass species, Cymodocea serrulata, Thalassia hemprichii and Zostera muelleri. At the higher water temperatures of summer, respiration rates increased in all three species, as did their maximum rates of photosynthesis. All three seagrasses achieved maximum rates of photosynthesis at low tide and when they were exposed. For nearly six decades there was little change in seagrass distribution in Cairns Harbour. This was most likely because the seagrasses were able to achieve sufficient light for growth during intertidal and low tide periods. With historical data of seagrass distribution and measures of species production and respiration, could seagrass survival in a changing climate be predicted? Based on physiology, our results predicted the continued maintenance of the Cairns Harbour seagrasses, although one species was more susceptible to thermal disturbance. However, in 2011 an unforeseen episodic disturbance – Tropical Cyclone Yasi – and associated floods lead to the complete and catastrophic loss of all the seagrasses in Cairns Harbour.

Photosynthetic characteristics of Scutellariae baicalensis / 中草药

the terminal leaves,light saturation point was 1 302 ?mol/(m2?s),light compensation point was 101.5 ?mol/(m2?s);The diurnal change trend of Pn showed a double peak curve,presenting a typical phenomenon of "photosynthesis midday depression".There was a close correlation between Pn and stomatal conductance (Gs)(r=0.88,P

Leaf photosynthetic characteristics and its response for light intensity of three species of Dendrobium Sw.in Huoshan County / 中草药

Objective To investigate the suitable light intensity of plant growth of Dendrobium Sw.through study on photosynthetic characteristics.Methods The photosynthesis curves of light intensity, chlorophyll fluorescence parameter of different light intensity and inductivity of non-photochemical quenching of chlorophyll fluorescence in 3.0?104 lx on three species of Dendrobium Sw.in Huoshan (D.huo- shanens, D.candium, and D.moniliforme) were determined.Results Three species of Dendrobium Sw.were shadow plants for their response on light intensity, light saturation point, light compensate point, net photosynthesis rate, and apparent quantum efficiency are lower during photosynthesis.The photoinhibitory effect was formed on Dendrobium Sw.leaf when they grew in more than 4.0?104 lx.Conclusion Although three species of Dendrobium Sw.in Huoshan grow in (0.2-2.0)?104 lx normally, they are suitable to grow in (2.5-3.0)?104 lx instead of growing more than 4.0?104 lx.