[Sodium Selenite Regulates Growth and Uptake of Se,As and Heavy Metals of Trillium tschonoskii].

Objective: To study the influence of different concentrations of selenium on the growth and absorbing of Se,Cd,Pb,Hg and As in Trillium tschonoskii. Methods: Trillium tschonoskii was treated with different concentrations of exogenous selenium, arsenic and heavy metals,and then the mass growth, leaf area,root number and other indicators reflecting its growth rule were calculated. Atomic fluorescence method was used to measure the absorption contents of Se,Cd,Pb,Hg and As. Results: The relative mass growth,leaf area and root number of Trillium tschonoskii increased at first and then decreased with the increasing of exogenous selenium concentrations. When the concentration of selenium was 25 mg / kg,the relative mass growth,leaf area and root number of Trillium tschonoskii reached a maximum. When selenium concentrations was over than 30 mg / kg,it inhibited the growth and development of Trillium tschonoskii. Trillium tschonoskii absorbing Cd,Pb,Hg and As had a regular of first decreasing then increasing and last decreasing. It reached the lowest when selenium concentrations at the range of 10 ~ 15 mg / kg. . Conclusion: Selenium had both stimulating effect and inhibiting effect on the growth and development of Trillium tschonoskii. Different selenium concentrations have different effects in absorbing Cd,Pb,Hg and As of Trillium tschonoskii

The calcium sensor CBL7 modulates plant responses to low nitrate in Arabidopsis.

Calcium (Ca(2+)) serves as a critical messenger in a number of adaptation and developmental processes. In plants, CBL family represents a unique group of calcium sensors that decodes calcium signals. Several CBL members have been functionally characterized in the model plant Arabidopsis thaliana, but the role of CBL7 remains unknown. Here, we report that CBL7 is involved in the regulation of low-nitrate response in Arabidopsis. Expression of CBL7 was predominant in the root of young seedlings and substantially induced by nitrate starvation. Cbl7 mutant was more inhibited in root growth upon nitrate starvation compared to the wild-type. Interestingly, the growth arrest of cbl7 under low-nitrate conditions relied on acidic pH. Further analyses revealed that expression of two high-affinity nitrate transporter genes, NRT2.4 and NRT2.5, was down-regulated in cbl7 under nitrogen-starvation condition. Accordingly, the cbl7 mutant plants retained lower nitrate content than wild-type plants under low-nitrate condition. Taken together, our results uncover a novel role of CBL7 in the response to nitrate deficiency in Arabidopsis.

[Response surface analysis for optimization of comprehensive extraction of flavonoid and polysaccharide in fermented Ampelopsis grossedentata].

OBJECTIVE: To explore the comprehensive extraction conditions of flavonoid and polysaccharide in fermented Ampelopsis grossedentata. METHODS: On the basis of single factor experiments, response surface analysis (RSA) was used to optimize the extraction of flavonoid and polysaccharide in fermented Ampelopsis grossedentata. RESULTS: The optimal conditions were as follows: temperature 96 degrees C, time 1.6 h, solid-liquid ratio 1:21. Under these conditions, the total flavonoids extraction yield was 22.94%, the polysaccharide extraction yield was 2.13%. CONCLUSION: This study provides a reference for the comprehensive extraction of flavonoid and polysaccharide in fermented Ampelopsis grossedentata, and lays a foundation for the comprehensive development and utilization of Ampelopsis grossedentata.

[Optimize extraction process of polysaccharide in Trillium tschonoskii].

OBJECTIVE: To optimize the extraction process of polysaccharide in Trillium tschonoskii. METHODS: The influence of temperature, time, solid-liquid ratio and extraction times on extraction yield of the polysaccharide in fleshy roots of Trillium tschonokii were discussed with orthogonal test method. RESULTS: The impact sequence of the factors on the extraction rate of polysaccharide in Trillium tschonoskii was as follows: extraction times > time > solid-liquid ratio > temperature; The optimal extraction condition was extraction temperature of 80 degrees C, extraction time of 4.5h, solid-liquid ratio of 1:40 and extracted three times. CONCLUSION: Under these optimal conditions, the extracting rates of polysaccharide in Trillium tschonoskii is 6.75%. The content of polysaccharide is high which can be exploited and utilized as another new ingredient.

An ATP signalling pathway in plant cells: extracellular ATP triggers programmed cell death in Populus euphratica.

We elucidated the extracellular ATP (eATP) signalling cascade active in programmed cell death (PCD) using cell cultures of Populus euphratica. Millimolar amounts of eATP induced a dose- and time-dependent reduction in viability, and the agonist-treated cells displayed hallmark features of PCD. eATP caused an elevation of cytosolic Ca(2+) levels, resulting in Ca(2+) uptake by the mitochondria and subsequent H(2) O(2) accumulation. P. euphratica exhibited an increased mitochondrial transmembrane potential, and cytochrome c was released without opening of the permeability transition pore over the period of ATP stimulation. Moreover, the eATP-induced increase of intracellular ATP, essential for the activation of caspase-like proteases and subsequent PCD, was found to be related to increased mitochondrial transmembrane potential. NO is implicated as a downstream component of the cytosolic Ca(2+) concentration but plays a negligible role in eATP-stimulated cell death. We speculate that ATP binds purinoceptors in the plasma membrane, leading to the induction of downstream intermediate signals, as the proposed sequence of events in PCD signalling was terminated by the animal P2 receptor antagonist suramin.

[Study on the characteristics of three-dimensional fluorescence excitation-emission spectra of methanol and ethanol].

For the purpose of revealing the spectra characteristics of methyl and ethanol, and establishing a method for distinguishing each other, the fluorescence features of methyl and ethanol were studied by three-dimensional fluorescence excitation-emission matrix spectra. The results obtained showed that there were two peaks in the three-dimensional fluorescence excitation-emission matrix spectra of methyl, and the intensities of the two peaks were positively related to the concentration of methyl when it was less than 15%. On the other hand, a whole fluorescence peak was only observed in the three-dimensional fluorescence excitation-emission matrix spectra of ethanol, and the intensity of the peak was positively correlated to the content of ethanol when it was less than 50%. There was a higher fluorescence efficiency for the methanol as compared to the ethanol. When the methyl was used for organic solvents to study the fluorescent nature of the organic matter, the fluorescence emitted by the methyl should be deduced. The locations of the fluorescence peaks of the methyl and ethanol were different. The peaks of the methyl were located at 225/350 nm and 250/375 nm, while the peak of the ethanol was characterized by 240/310 nm. Therefore, the fluorescence peak locations of the two alcohols could be applied to discriminate each other.

Conserved mechanism for vacuolar magnesium sequestration in yeast and plant cells.

Magnesium (Mg2+) is an essential nutrient for all life forms. In fungal and plant cells, the majority of Mg2+ is stored in the vacuole but mechanisms for Mg2+ transport into the vacuolar store are not fully understood. Here we demonstrate that members of ancient conserved domain proteins (ACDPs) from Saccharomyces cerevisiae and Arabidopsis thaliana function in vacuolar Mg2+ sequestration that enables plant and yeast cells to cope with high levels of external Mg2+. We show that the yeast genome (as well as other fungal genomes) harbour a single ACDP homologue, referred to as MAM3, that functions specifically in vacuolar Mg2+ accumulation and is essential for tolerance to high Mg. In parallel, vacuolar ACDP homologues were identified from Arabidopsis and shown to complement the yeast mutant mam3Δ. An Arabidopsis mutant lacking one of the vacuolar ACDP homologues displayed hypersensitivity to high-Mg conditions and accumulated less Mg in the vacuole compared with the wild type. Taken together, our results suggest that conserved transporters mediate vacuolar Mg2+ sequestration in fungal and plant cells to maintain cellular Mg2+ homeostasis in response to fluctuating Mg2+ levels in the environment.

Four plasma membrane-localized MGR transporters mediate xylem Mg2+ loading for root-to-shoot Mg2+ translocation in Arabidopsis.

Magnesium (Mg2+), an essential structural component of chlorophyll, is absorbed from the soil by roots and transported to shoots to support photosynthesis in plants. However, the molecular mechanisms underlying root-to-shoot Mg2+ translocation remain largely unknown. We describe here the identification of four plasma membrane (PM)-localized transporters, named Mg2+ release transporters (MGRs), that are critical for root-to-shoot Mg transport in Arabidopsis. Functional complementation assays in a Mg2+-uptake-deficient bacterial strain confirmed that these MGRs conduct Mg2+ transport. PM-localized MGRs (MGR4, MGR5, MGR6, and MGR7) were expressed primarily in root stellar cells and participated in the xylem loading step of the long-distance Mg2+ transport process. In particular, MGR4 and MGR6 played a major role in shoot Mg homeostasis, as their loss-of-function mutants were hypersensitive to low Mg2+ but tolerant to high Mg2+ conditions. Reciprocal grafting analysis further demonstrated that MGR4 functions in the root to determine shoot Mg2+ accumulation and physiological phenotypes caused by both low- and high-Mg2+ stress. Taken together, our study has identified the long-sought transporters responsible for root-to-shoot Mg2+ translocation in plants.

H2O2 and cytosolic Ca2+ signals triggered by the PM H-coupled transport system mediate K+/Na+ homeostasis in NaCl-stressed Populus euphratica cells.

Using confocal microscopy, X-ray microanalysis and the scanning ion-selective electrode technique, we investigated the signalling of H(2)O(2), cytosolic Ca(2+) ([Ca(2+)](cyt)) and the PM H(+)-coupled transport system in K(+)/Na(+) homeostasis control in NaCl-stressed calluses of Populus euphratica. An obvious Na(+)/H(+) antiport was seen in salinized cells; however, NaCl stress caused a net K(+) efflux, because of the salt-induced membrane depolarization. H(2)O(2) levels, regulated upwards by salinity, contributed to ionic homeostasis, because H(2)O(2) restrictions by DPI or DMTU caused enhanced K(+) efflux and decreased Na(+)/H(+) antiport activity. NaCl induced a net Ca(2+) influx and a subsequent rise of [Ca(2+)](cyt), which is involved in H(2)O(2)-mediated K(+)/Na(+) homeostasis in salinized P. euphratica cells. When callus cells were pretreated with inhibitors of the Na(+)/H(+) antiport system, the NaCl-induced elevation of H(2)O(2) and [Ca(2+)](cyt) was correspondingly restricted, leading to a greater K(+) efflux and a more pronounced reduction in Na(+)/H(+) antiport activity. Results suggest that the PM H(+)-coupled transport system mediates H(+) translocation and triggers the stress signalling of H(2)O(2) and Ca(2+), which results in a K(+)/Na(+) homeostasis via mediations of K(+) channels and the Na(+)/H(+) antiport system in the PM of NaCl-stressed cells. Accordingly, a salt stress signalling pathway of P. euphratica cells is proposed.

[Composition analysis and dominance test of three kinds of raw variety of Gynostemma pentaphyllum].

OBJECTIVE: To provide foundation for developing Gynostemma pentaphyllum with physic and edible use. METHOD: To plant the seven leaves with sweet taste of Enshi, Five leaves with honey taste of Enshi, Makino (picric taste) taste, in the same ecological environment in accordance with the require of mathematical statistics and give the same management, At the same time, sowing and reaping dry grass to do composition analysis; RESULT: The ginseng total saponin, the total amino acid. VitE, VitB1, VitB2 of the two new variety are 33% and 34.3%, 11.8% and 4.7%, 76% and 45.8%, 46% and 76.1%, 41.2% and 25% higher than the raw variety of Gynostemma pentaphyllam Makino respectively. All of them achieve the remarkable standard. The total sugar of the two is 16.3% and 4.4% lower than the raw variety of G. pentaphyllum respectively. CONCLUSION: The two new variety is not only with the distinct flavor and good taste, but also has wider used domain More amount of utilization, Better medical treatment and health care than the raw variety of G. pentaphyllum. It is more worthful to develop in industry domain.

Ion flux profiles and plant ion homeostasis control under salt stress.

The ability of a plant to maintain an ionic homeostasis is crucial in plant salt tolerance. Direct evidence based on data from the non-invasive measurement of ion fluxes would not only offer new insight about the function of the transporter but also provide a whole plant approach for dissecting salt adaptation mechanisms. Here, we review some reports using the ion-selective microelectrodes to characterize the net ion fluxes of tissues or cells.