Relationship Between Polyamine Metabolism in Roots and Salt Tolerance of Barley Seedlings

Plant growth rate (GR), contents of free polyamines (fPAs) and bound polyamines (bPAs) and activities of some key enzymes involved in polyamine (PA) metabolism in the roots of two barley (Hordeum valgare L.) cultivars differing in salt sensitivity were investigated with 0-300 mmol/L NaCl treatments. With 0-200 mmol/L NaCl treatments, activities of arginine decarboxylase (ADC) and transglutaminase (TGase) and PA oxidase (PAO) in the roots of barley seedlings all increased, while TGase and PAO activities decreased slightly at 300 mmol/L NaCl. As a result, free Put (fPut) content increased continuously with increasing concentrations of NaCl, while levels of free Spd (fSpd) and an unknown PA (fPAx) and bPAs (bPut, bSpd and bPAx), as well as (fSpd + fPAx)/fPut ratio rose at 50-200 mmol/L NaCl and reduced at 300 mmol/L NaCl. However, no significant change in the tetra-amine spermine (Spin) content was observed. Statistical analysis showed that GR was very significantly positively correlated with (fSpd + fPAx)/fPut ratios and the contents of bPAs, whereas a significant inverse correlation existed between GR and the ratios of fPA contents to bPA levels. These results showed that, under salt stress, the balance between fSpd, fPAx and fPut levels and an equipoise between fPA and bPA contents in roots were important to salt tolerance of barley seedlings.

Effects of Salinity Stress on the Levels of Covalently and Noncovalently Conjugated Polyamines in Plasma Membrane and Tonoplast Isolated from Barley Seedlings

When the 7_d old barley ( Hordeum vulgare L.) seedlings were treated with different concentrations of NaCl for 3 d, the levels of the noncovalently conjugated polyamines (PAs) in the plasma membrane and tonoplast vesicles and the covalently conjugated PAs in the membrane proteins were promoted by NaCl of low concentrations and suppressed by NaCl of high concentrations. Among the noncovalently conjugated PAs in the vesicles, spermidine (Spd) level was the most abundant, while putrescine (Put) content was predominant among the covalently conjugated PAs, accounted for 40%-70%, 35%-60%, respectively. In addition, the TLC (thin_layer chromatography) profiles of the benzoylated PAs presented an unknown polyamine with Rf =0.92 (X 0.92 ), which conjugated covalently and noncovalently in root tonoplast and its content changed as well as Spd with NaCl treatment. The total PA contents in the roots were higher than that in the leaves, and the types and contents of covalently and noncovalently conjugated PAs in the tonoplast were higher than those in the plasma membrane. The results showed that the above two PAs associated with the membrane might be essential in salt adaption of cells and the maintenance of membrane function.

Mechanism of the Effect of Polyamines on the Activity of Tonoplasts of Barley Roots Under Salt Stress

The seeds of barley Hordeum vulgare L. cv. Jian 4) were soaked with 0.1 mmol/L putrescine (Put) and 0.5 mmol/L spermidine (Spd), and then the seedlings were treated with 200 mmol/L NaCl. The growth rate (GR), dry matter accumulation, distribution of ions, the amount of polyamines (PAs) bound to tonoplast proteins as well as lipid composition and the activity of tonoplast vesicles isolated from roots were investigated. The results showed that soaking with Put or Spd could retard salt injury, promote GR and dry matter accumulation, and increase K+/Na+ in the roots. Compared with NaCl_treated plants, phospholipid content in root tonoplast rose by soaking with Put and Spd, while the level of galactose in lipids was decreased. Moreover, the ratio in noncovalently conjugated PA contents of (Spd+PAx (an unknown PA)) to (Put+Dap (diaminopropane)), and the total contents of covalently and noncovalently conjugated PAs were all increased. Statistical analysis indicated that the ratio of (Spd+PAx) to (Put+Dap) was significantly and positively correlated with the activities of membrane associated enzymes H+_ATPase and H+_PPase.

临床毒理学

9807864 Docetaxel 诱导的周围神经中毒性/Hilkens P H E//Neurology.-1996,46（1）.-104～108 湘医图9807865 银类无机抗菌药对齿科材料的应用（第1报）:离子纯TM的各种毒性试验[日,英摘]/永川一广//日补齿会志.一1996,40（5）.-97～102 冀医情9807866

Accumulation of High Molecular Weight Glutenin Subunits in Superior and Inferior Grains of Winter Wheat

The difference in accumulation of high molecular weight glutenin subunits （HMW-GS） in superior and inferior grains results in the non-uniformity of grain quality in winter wheat （Triticum aestivum L.）. The HMW-GS accumulation and glutenin macropolymer （GMP） content were studied in superior and inferior grains during the grain filling period, using the sodium dodecyl sulfate polyacrylamide gel electrophoresis （SDS-PAGE）. Compared to inferior grains, HMW-GS was formed earlier and total accumulation amount was higher in superior grains. The total HMW-GS content was higher in superior grain than that in inferior grain except at maturity. For individual HMW-GS types, the accumulation and content of subunit 7 were the highest, followed by subunit 12, while that of subunit 8 were the lowest, followed by subunit 2 in superior grain. In contrary, the accumulation and content of subunit 7 at maturity were significantly higher than subunit 8, but they were similar between subunit 2 and subunit 12 in inferior grain. Moreover, the accumulation of subunit 7 and 12 in superior grain were significantly higher than that in inferior grain. However, compared to the inferior grain, the GMP accumulation was higher, while content was lower in superior grain at maturity.

Clinical Observation on Treatment of Migraine with Acupuncture

Objective： To study the effect of puncturing points Taiyang （Ex-HN 5）, Jiaosun （TE 20）, Qiuxu （GB 40） and Shenmai （BL 62） on migraine. Methods： The 120 cases in the treatment group were treated with routine acupuncture therapy, while the 40 cases in the control group were treated with Ergotamine and Caffeine Tablet, and then the therapeutic effect and recovery time of the two groups were compared. Results： The recovery rate of the treatment group was 90.0%, which is higher than 70.0% of the control group （P〈 0.01）. The total effective rate of the treatment group was 100%, which is better than 92.5% of the control group （P 〈 0.05）, The therapeutic effect of the treatment group was significantly better than the control group and the treatment group needed shorter treatment period （P 〈 0.05）. Conclusions： Acupuncture has higher recovery rate and total effective rate as well as shorter treatment period than oral ergotamine and caffeine tablets, which indicated that acupuncture is superior to the routinely-administered oral western tablets in treating migraine.

Using DGT to Assess Cadmium Bioavailability to Ryegrass as Influenced by Soil Properties

A generally accepted method for predicting the bioavailability and transfer of cadmium(Cd) from soil to plants has not yet been established. In this study, the diffusive gradients in thin films(DGT) and conventional extraction methods for metal fractions were used to investigate how effective these methods were at predicting Cd bioavailability to ryegrass(Lolium perenne) and to assess whether these holistic variables were independent of the soil property variables. The influences of soil properties on the predictive capabilities of the different methods were evaluated using multivariate statistics. The Cd concentrations in the shoots and roots of ryegrass correlated more closely with the effective Cd concentration measured by DGT(CE), compared with those with soil total Cd, pore water Cd, and ethylenediaminetetraacetic acid disodium salt(Na2EDTA)- and acetic acid(HOAc)-extractable Cd. When soil properties were included in a stepwise multiple linear regression, Cd transfer to L. perenne was negatively influenced by p H and positively influenced by organic matter(OM). The multivariate statistics showed that the adjusted correlation coefficients for the plots involving soil total Cd, pore water Cd, and Na2EDTA- and HOAc-extractable Cd had been significantly improved after considering the influences of soil properties, which suggested that these methods were p H and OM dependent. For CE, the relationship was p H independent or only dependent in strongly acidic soils. These results suggested that the main soil factors affecting bioavailability had the lowest impact on the DGT technique. Therefore, the DGT technique provided significant advantages over conventional methods when assessing Cd bioavailability.