Effects of EDTA and Zn Stress on Physiological Characteristics of Medicago sativa L.

[Objectives]The paper was better understand the mechanisms of Zn plant uptake in the presence of EDTA and to evaluate the contributions of Zn-EDTA complexes to Zn uptake.[Methods]Three alfalfa cultivars were cultivated for 60 d before exposure to 0,250μg Zn and 250μg Zn+10μg EDTA per kg soil for 50 d.Zn concentrations in tissues were analyzed by flame atomic absorbance spectrometry.Subsequently,Zn amount per plant,translocation factor(TF)and bio-concentration factor(BCF)were calculated.Nonenzymatic compounds in tissues were analyzed spectrophotometrically.[Results]Application of Zn+EDTA expressively increased biomass of different tissues of three alfalfa cultivars.Among the three alfalfa cultivars,Medicago sativa ssp.displayed the highest Zn concentration in tissues,the largest Zn amount in aerial parts,and the highest BCF in aerial parts under Zn+EDTA exposure.Under Zn+EDTA stress,increases in free proline in roots,stem,and leaves of M.sativa ssp.were found.Inhibited O_(2)^(·-)production in stem and leaves,increases in soluble sugar,but decreases in soluble protein were observed in M.sativa ssp.[Conclusions]M.sativa ssp.is superior to other two cultivars for Zn phyto-remediation,and its well-coordinated physiological changes under Zn+EDTA exposure confer the great Zn tolerance of this cultivar.

Zinc Tolerance and Accumulation in Four Alfalfa(Medicago sativa)Varieties

To evaluate the zinc(Zn)remediation capacity of four alfalfa species,the effects of different concentrations of Zn on plant growth,Zn uptake and translocation as well as uptake of other nutrients were investigated.The results showed that the Zn tolerance index of Aohan was significantly higher than other species.Among the four species,Aohan had the highest concentration of Zn in roots,followed by Golden Empress,Sanditi and Longxi.Aohan had the highest bioconcentration factor(BCF)in leaves.Whereas,Sanditi and Longxi had the lowest BCF in stem and roots,respectively.The translocation factor of Golden Empress was significantly lower than other species.The Zn accumulation rate of Aohan was higher than other species regardless of the concentration of Zn.Longxi had the lowest allocation of Zn in leaves and Golden Empress had the lowest allocation of Zn in roots.The concentrations of other elements(Fe and Mg)in leaves were decreased with Zn additions,but the interactions between Zn and other elements in roots varied with species.These results indicated that suitable species of alfalfa could successfully be used for the phytoremediation of Zn-contaminated soils.

Phytoremediation capacity of the hyperaccumulator Solanum nigrum L.and Solanum lycopersicum L.cultivars at the flowering stage in cadmium-polluted soil

Dear Editor,Remediation of cadmium(Cd)-contaminated soil is a popular topic in global environmental science.Phytoremediation using hyperaccumulators or certain plants to accumulate and remove Cd from polluted soils is a promising approach.Wei et al.(2005)first described Solanum nigrum L.as a Cd hyperaccumulator.Subsequently,various aspects of S.nigrum,including the protective effects on proline,physiological and biochemical responses,earthworms,arbuscular mycorrhizal fungi,and fertilizers and the intercropping with Solanum photeinocarpum,have been extensively studied(Xu et al.,2009;Khan et al.,2014;Wang et al.,2015;Tang et al.,2017;Yang et al.,2019).

过表达MtVP1对马铃薯表型及糖代谢的影响

I型H^(+)-PPase参与糖异生和蔗糖分解代谢,利用不同的糖(蔗糖、葡萄糖和果糖)饲喂拟南芥(Arabidopsis thaliana)Ⅰ型H^(+)-PPase基因不同类型的突变体,产生的表型不一致,因此,推测Ⅰ型H^(+)-PPase可能存在其它影响糖代谢的机制。为进一步明确该酶对糖代谢的影响,以过表达MtVP1的马铃薯(Solanum tuberosum)渭薯4号为研究对象,观察不同培养条件下的表型,监测糖含量变化,并利用转录组测序分析转录谱。结果表明,过表达MtVP1马铃薯表现出红色茎、紫色花和表皮毛更发达,单株块茎数减少,块茎变大,块茎皱缩速度加快;转基因马铃薯块茎中淀粉、葡萄糖和果糖含量显著下降,芽中葡萄糖和果糖含量也显著下降。果糖饲喂导致转基因马铃薯花青素含量显著降低;转基因马铃薯体内果糖-1,6-二磷酸酶和果糖-2,6-二磷酸酶基因表达上调3–7倍。研究结果为进一步从糖代谢角度探究Ⅰ型H^(+)-PPase的生理功能提供参考。

The effects of different electrode materials on seed germination of Solanum nigrum L.and its Cd accumulation in soil

The effects of different electrode on Solanum nigrum L.seed germination were determined.The result showed that germination percentage(GP)of seeds in treatment T2(titanium elec-trode)was 26.6%higher than in control(CK,without electric field).High potassium and calcium concentrations were beneficial for seed enzymatic activity in treatment T2,which could partly explain the increase in GP.Cd accumulation(μg/pot)in S.nigrum treated with any electric field was significantly higher(p<0.05)than in CK without electric field.Specif-ically,Cd accumulation under the treatment T3(stainless steel electrode)was the highest both in roots and shoots;this accumulation in shoots and roots were 74.7%and 67.4%higher for stainless steel than in CK.This increase must have been associated with a higher Cd concentration in plants and did not exert a significant effect on the biomass.In par-ticular,Cd concentrations in roots and shoots under stainless steel treatment were both significantly higher than in CK(p<0.05),which had to be related to the higher available Cd concentration in the soil in the middle region.Furthermore,it could be attributed to al-tered soil pH and other soil properties.Moreover,none of the biomasses were significantly affected(p<0.05)by different electrode materials compared to CK.