Growth,physiological characteristics and ion distribution of NaCl stressed Alhagi sparsifolia seedlings

Alhagi sparsifolia is a leguminous perennial desert species that is plays an important role in dune stabilization and revegetation of degraded desert ecosystems. We investigated the effects of three different levels of salinity (50, 150, 250 mmol/L NaCl) on the growth, shoot photosynthetic parameters and salt distribution amongst different plant organs in one-year-old A. sparsifolia seedlings in a pot experiment over a 50 d period. The minimum (predawn) and maximum (midday) water potentials of A. sparsifolia seedlings decreased with the increase of external NaCl concentrations as a consequence of the osmotic or water deficit effect of saline solutions outside the roots. Salinity also reduced gas exchange parameters in A. sparsifolia, with seedlings subjected to salinity having lower photosynthesis rates and reduced stomatal conductances compared to the control. The reductions in photosynthetic rates in high salinity treatments of the A. sparsifolia seedlings were mainly caused by stomatal limitation. Consequently plants growing at greater external NaCl concentrations had significantly lower biomass accumulation compared to the control grown at 50 mmol/L. However, plants exposed to higher salinity were able to maintain growth throughout the experiment but allocated a greater proportion of biomass belowground. Plants exposed to higher external salinity levels had increased concentrations of Na+ and Cl- ions in shoots and roots, suggesting that A. sparsifolia seedlings were utilizing Na+ and Cl- as osmolytes to increase the cellular osmolality and decrease their water potential. We observed the greatest NaCl concentrations in the plants treated with 150 mmol/L NaCl indicating that there may be a threshold level of NaCl that can be tolerated by the plants. In conclusion our results indicate that A. sparsifolia seedlings are moderately salt tolerant. Photosynthetic gas exchange parameters were reduced by greater external salinity but the seedlings maintained substantial photosynthetic rates even under high salinity s     

Studies on the overexpression of the soybean GmNHX1 in Lotus corniculatus： The reduced Na^＋ level is the basis of the increased salt tolerance

Soil salinity is one of the major factors reducing plant growth and productivity. The detrimental effects of salt on plants are a consequence of both a water deficit resulting in osmotic stress and the excess so- dium ions on critical biochemical processe…     

Identification and characterization of a salt tolerance-responsive gene( AtGRP9) of Arabidopsis

Soil salinity is one of the important limiting factors for plant growth and development. A cDNA clone encoding a glycine-rich protein (designated AtGRP9) was identified from Arabidopsis by functional expression of the plant cDNA library in the fission yeast S. pombe. Yeast cells overexpressing AtGRP9 displayed significantly enhanced salt tolerance. Northern analysis showed that expression of AtGRP9 in Arabidopsis was induced by NaCl and plant hormone abscisic acid (ABA). These results suggest that AtGRP9 may be involved in the salt stress response in Arabidopsis.     

Antioxidant responses and salt stress tolerance of Aloe vera irrigated by seawater with different salinity

The variations of antioxidant enzyme activities including superoxide dismutase （SOD： EC 1.15.1.1）, peroxidase （POD： EC 1.11.1.7） and catalase （CAT： EC 1.11.1.6）, lipid peroxidation and major electrolytes in Aloe vera irrigated for three years with seawater having different salinity were studied. The results indicate that POD activity increased significantly at 10% seawater level, whereas decreased at higher seawater levels. The SOD activity decreased with increasing seawater concentration except for treatment with 100% seawater （denoted as T100%） under long-term salt stress. Salinity decreased CAT activity,and increased lipid peroxidation and cell membrane injury. In addition, Ca^2＋ content was high in Aloe irrigated by seawater of low salinity level, but low in Aloe irrigated by seawater of high salinity level. An opposite trend was observed for the effect of seawater on Na^＋ content of plants. K^＋ and Mg^2＋ contents remain relatively stable under various seawater levels, which benefit plant growth.     

Interaction between seed size and NaCl on germination and early seedling growth of some Turkish cultivars of chickpea （Cicer arietinum L.）

Chickpea is an important food legume crop of Turkey and is largely grown for human consumption on low moisture or salt-affected soils. The objective of the study was to find the effects of NaCl stress at electrical conductivities of 4.5, 8.6, 12.7 and 16.3 dS/m and seed sizes （7, 8 and 9 mm） on germination and early seedling growth of three popular chickpea cultivars （AKN-97, Gokce and Uzunlu-99）. Mean frequency of germination, germination time, germination index, root length, shoot length and seedling fresh weight showed seed size-dependent responses ofcultivars to salt stress. In general, small seeds germinated and grew more rapidly compared to medium and large seeds of the same cultivars against all levels of salt stress, with the best results in cultivar Uzunlu-99. No effect of NaCl treatments was observed on frequency of germination; however, a drastic decrease in early seedling growth was recorded at increased NaC1 concentrations. Regression analysis results showed a significantly positive relationship （P〈0.01） between seed size and mean germination time, whereas a significantly negative relationship was recorded between seed size and germination index, root length, shoot length. Moreover, linear regression values apparently confirmed that increased seed size in each cultivar affected decreased germination index, root and shoot lengths with enhanced mean germination time. Thus, it was concluded that the use of small seeds could considerably reduce the production costs of chickpea in salt-affected soils.     

Structure of aqueous sodium sulfate solutions derived from X-ray diffraction

A rapid liquid X-ray diffractometer was used to study the time-averaged and space-averaged structure of aqueous sodium sulfate solutions at 298 and 323 K. Difference radial distribution functions of the solutions were obtained from accurate diffraction data. The interaction distances of Na^＋-OH2 and S-H2O in solutions were found to be 0.235 and 0.385 nm, respectively, after deconvolution of superposition peaks by Gaussian multi-peak fitting program. The characteristic distance of the NaSO; contact ion pairs in higher concentration solutions was determined to be 0.345 nm, suggesting that the Na^＋ ions coordinated with SO4^2- ions in the mono-dentate form. Effects of concentration and temperature on the hydration structure of the solutions were discussed in the present paper. With a decrease in concentration, the contributions of the H2O to the diffraction pattern increase, the average coordination number of the Na^＋ ions hardly changes, while the hydration number of SO4^2- ions increases slightly. The formation of NaSO; contact ion pairs becomes easier at higher temperature. The structure of hydrogen bond in dilute solutions is broken to a considerable extent with rising temperature, and the peak at 0.290 nm splits into two peaks at 0.275 and 0.305 nm, respectively.     

Ecological functions of ciliated protozoa in marine ecosystem： effects of ammonium on the population growth of Euplotes vannus

The effects of ammonium on the population growth of the marine ciliate, Euplotes vannus, were examined using ecotoxicological method, h is showed that ammonium exerts inhibitory effects on the growth of the ciliate populations in a concentration-dependent way. Statistical analvsis reveals that the population growth dynamics exposed to ammoniunt-N concentration over 100mg/L are significantly different from that in the control at P 〈 0.05 level. Linear regression determined that the 24h, 36h, 48h, 60h, 72h and 84h IC50 values of ammonium-N are 19.68, 201.51, 167.49, 47.86, 50.43 and 43.11 concentration over 100mg/L, respectively （ P 〈 0.05; pH 8.2; salinity 28 ppt; temperature, 25℃ ）. The results indicate that the tolerance to ammonium in E. vannus is considerably higher than that of the larvae or juveniles of some metozoa, such as cuhured prawns and oysters. Therefore, it is believed that the high tolerance to ammonium is necessary for eiliated protozoa to play positive roles in maintaining and improving water quality in marine ecosystems, especially in the intensive aquacuhure waters with high-level ammonium. In addition, the correlation between /C50 values and exposure time was discussed.     

Discovery of organic connection of Chiropteris Kurr and Nystroemia Halle from Early Permian of western Henan, China

Nystroemia reniformis (Kawasaki) comb. nov. is proposed based on specimens showing organic connections between Chiropteris reniformis Kawasaki and Nystroemia pectiniformis Halle from the Lower Permian of Dengfeng in Henan. Vegetative leaf has a long petiole, reniformed, cordate at the base, entire or slightly undulate at the margin;veins are fine, bifurcating repeatedly and finally becoming reticulate and forming polygonal or rhomboidal meshes.Fertile shoot arises from bract axils. The form of the bract is identical to that of a vegetative leaf. Ovuliferous organ arises from the axU of leafy organ, or in other ease, both ovulfferous and leafy organs irregularly arise from the axis of the fertile shoot respectively. Numerous bicornute platyspermic seeds are arranged in two rows, obconical, with micropyle pointing upwards. It may represent a new extinct gymnosperms.     

Synthesis and characterization of a three-ring bent-core compound

To investigate the vacuum-deposited films of the banana-shaped mesogens, we prepared a three-ring bent-core （that is, banana-shaped） compound m-bis（4-p-octoxysryrenyl）benzene （m-OSB） and used it as a prototype for studying the related film physics. Herein the synthesis and the structural characterization of m-OSB are reported.^13C and ^1H NMR spectra and ^1R spectrum confirm that m-OSB has a symmetric and all-trans conformation. The results of differential scanning calorimetry, polarizing optical microscopy and X-ray diffractometry indicate that no liquid crystalline phase but two crystalline phases are present in this material： phase Ⅰ （T〈66℃） and phase Ⅱ （66~C〈T〈157℃）; an isotropic state is observed at above 157℃. Combining the X-ray diffraction and the electronic diffraction, we assign the room-temperature crystalline phase I to orthorhombie system and P212121 space group with cell parameters of a = 7.43A°. b=6.34A°, c=72.07A°, and α=β=γ=90°. Molecular modeling reveals that the molecules in the unit cell adopt a layered structure with an antiferro-eleetrie alignment. The structure of phase Ⅱ is very similar to that of phase Ⅰ. Nonlinear optical measurement shows that m-OSB is active for the second harmonic generation （SHG）. Such characterization of the bulk material is necessary for the understanding of the growth and microstructures in the films.     

Prokaryotic expression, localization and function of the infectious laryngotracheitis virus glycoprotein G

The infectious laryngotracheitis virus （ILTV） glycoprotein G （gG） gene of E3 and Zhonghai strains was cloned, sequenced and compared with the gG gene of other Type Ⅰ animal herpesviruses. To find the localization and the function of the gG in the infected cells, the 35 kD fusion protein （His-GG） was expressed by inserting the coding region of gG except for the signal peptide into pET30a （＋）. After purification of the His-GG fusion protein, the rats＇ antibody to the His-GG was prepared and purified by using the protein G Sepbarose. Results of laser scanning confocal microscopy （LSCM） detection showed that the ILTV gG was in the perinuclear region and membrane of chicken embryo liver （CEL） and kidney （CEK） cells, and that the gG accumulated more in the coalescent part than in the other parts of the adjacent CEL or CEK cells. The plaque size and the one-step growth curve tests suggested that the ILTV gG was required for viral growth by cell-to-cell direct infection in tissue-cultured CEL cells.     

Genetic relationships among Chinese and American isolates of Phytophthora sojae assessed by RAPD markers

The genetic diversity of three geographic populations of Phytophthora sojae from China and the United States was determined using random amplified polymorphic DNA （RAPD）. The purpose was to explore genetic relationships among Chinese and American isolates of the organism. 21 random primers were selected among 200 random primers screened. A total of 223 reproducible RAPD fragments were scored among 111 individuals, of which 199 （89.23%） were polymorphic. Analysis of genetic variation showed that there existed higher genetic variation in the United States population in comparison to the Chinese populations. Nei＇s genetic identity and principal component analysis indicated that the populations of Fujian and United States are closer to each other than to Heilongjiang populations. Shannon-Wiener diversity index revealed that the United States populations have a higher genetic di- versity than that of Chinese populations. These data are in support of the hypothesis that P. sojae in the United States might not have been introduced from China.     

The short C-terminal hydrophilic domain of NhaH Na^＋/H^＋ antiporter from Halobacillus dabanensis with roles in resistance to salt and in pH sensing

The Na^＋/H^＋ antiporter plays key roles in maintaining low cytoplasmic NaNa^＋ level and pH homeostasis, while little is known about the Carboxyl-terminal hydrophilic tails of prokaryotic antiporters. In our previous study, the first Na^＋/H^＋ antiporter gene nhaH from moderate halophiles was cloned from Halobacillus dabanensis D-8 by functional complementation. A topological model suggested that only nine amino acid residues （^395PLIKKLGMI403） existed in the hydrophilic C-terminal domain of NhaH. The C-terminal truncated mutant of NhaH was constructed by PCR strategy and designated as nhaH△C. Salt tolerance experiment demonstrated that the deletion of hydrophilic C-terminal nine amino acid residues significantly inhibited the complementation ability of E. coil KNabc, in which three main Na^＋/H^＋ antiporters nhaA, nhaB and chaA were deleted. Everted membrane vesicles prepared from E. coil KNabc/nhaHAC decreased both Na^＋/H^＋ and Li^＋/H^＋ exchange activities of NhaH, and also resulted in an acidic shift of its pH profile for Na^＋, indicating a critical role of the short C-terminal domain of NhaH antiporter in alkali cation binding/translocation and pH sensing.     

Adaptation to salinity in mangroves: Implication on the evolution of salt-tolerance

A plant＇s adaptation to its environment is one of the most important issues in evolutionary biology. Mangroves are trees that inhabit the intertidal zones with high salinity, while salt tolerance competence of different species varies. Even congeneric species usually occupy distinct positions of intertidal zones due to differential ability of salt tolerance. Some species have different ecotypes that adapt well to littoral and terrestrial environments, respectively. These characteristics of mangroves make them ideal ecological models to study adaptation of mangroves to salinity. Here, we briefly depict adaptive traits of salt tolerance in mangroves with respect to anatomy, physiology and biochemistry, and review the major advances recently made on both the genetic and genomic levels. Results from studies on individual genes or whole genomes of mangroves have confirmed conclusions drawn from studies on anatomy, physiology and biochemistry, and have further indicated that specific patterns of gene ex- pression might contribute to adaptive evolution of mangroves under high salinity. By integrating all information from mangroves and performing comparisons among species of mangroves and non-mangroves, we could give a general picture of adaptation of mangroves to salinity, thus providing a new avenue for further studies on a molecular basis of adaptive evolution of mangroves.     

Clone of Chinese Jinan red-cross yellow cattle and evaluation of reproductive characteristics of cloned calf

Somatic cell clone technology is a viable approach to preserving endangered livestock and wildlife genetic resources. In the present research, somatic cell nuclear transfer （SCNT） was performed using granulose cells from the critical endangered Chinese red-cross yellow cattle as donor cells. A total of 211 oocytes were manipulated and 166 （79%） of them were successfully enucleated. 112 （67.4%） SCNT embryos were reconstructed, 94 （83%） of them cleaved, and 48 （43 %） of them developed to blastocyst stage. SCNT blastocysts were transferred to 6 Holstein recipients, and 2 （33%） of them were found to be pregnant. One of them maintained to term and delivered a calf, whereas another aborted. Effect of different fusion buffer （mannitol vs. Zimmerman fusion buffer） and different activation methods （calcium ionophore＋6-DMAP vs. cycloheximide＋CB） on fusion rate and development of SCNT embryos were investigated. The results indicated that： （i） on condition of two DC pulses of 2.5 kV/cm for 10 μs each, fusion rates were higher in mannitol solution than in Zimmerman fusion buffer （71% vs. 61%, respectively, p 〈 0.05）, but the blastocysts rates did not differ between two treatments （36 % vs. 39 %, p〉0.05 ）; （ii） There was no significant difference in development rates to the blastocyst stage for SCNT embryos activated by calcium ionophore＋6-DMAP or by cycloheximide＋CB （42% vs. 46%, respectively, p〉0.05）. Microsatellite DNA analysis examining 28 loci confirmed that the cloned calf was genetically identical to the donor Jinan red-cross yellow cattle and different from the recipient females. Growth and reproductive performance of cloned cow were evaluated, and there were no difference i cross-red n it between cloned and normal control Jinan yellow cattle. Furthermore, the cloned yellow cow has delivered a healthy yellow calf.     

Phylogenetic relationships of native and introduced Bemisia tabaci (Homoptera:Aleyrodidae) from China and India based on mtCOI DNA sequencing and host plant comparisons

Phylogenetic relationships for Bemisia tabaci were reconstructed by analysis of a ～780 bp fragment of the mitochondrial cytochrome oxidase I (mtCOI) gene with an emphasis on geographic range and distribution among eight eudicot plant families that are common hosts of B. tabaci worldwide to elucidate key phylogeographic linkages between populations extant in China (n=31) and India (n=34). Bootstrap values for the Maximum Parsimony tree were highly robust for all major nodes involving the major Asian clade, subgroups, and sister groups within, at 92%—100%. Between-clade distances for the Southeast Asia and three other major clades, e.g. from sub-Sahara Africa, North Africa-Mediterranean, and the Americas, were approximately >16% divergent. Two major Asian subgroups (I, II) were resolved, which represented populations indigenous to the region, comprising two (I a, I b) and five (II a—e) sister groups, respectively, which diverged by 11%. Two distinct populations from sunflower in Hyderabad grouped separately within the two Asian subgroups. All other populations grouped uniquely within Asian subgroup II or I. The "B" biotype was identified in 23 collections from China at 97.3%—99.5% nucleotide identity with "B" biotype reference sequences; it was not identified in collections from India. The majority of haplotypes were associated with 3—4 plant families, with one exception that for sister group IId (sesame, India), it might be monophagous. Thus, B. tabaci from the southeastern and near eastern regions of the Asian continent comprise of a large number of ancestral, richly divergent, mostly polyphagous populations. This region is therefore hypothesized to constitute an important Old World center of diversification for the B. tabaci complex, together with sub-Saharan Africa.     

Phylogenetic relationships of native and introduced Bemisia tabaci (Homoptera:Aleyrodidae) from China and India based on mtCOI DNA sequencing and host plant comparisons

Phylogenetic relationships for Bemisia tabaci were reconstructed by analysis of a ～780 bp fragment of the mitochondrial cytochrome oxidase I (mtCOI) gene with an emphasis on geographic range and distribution among eight eudicot plant families that are common hosts of B. tabaci worldwide to elucidate key phylogeographic linkages between populations extant in China (n=31) and India (n=34). Bootstrap values for the Maximum Parsimony tree were highly robust for all major nodes involving the major Asian clade, subgroups, and sister groups within, at 92%—100%. Between-clade distances for the Southeast Asia and three other major clades, e.g. from sub-Sahara Africa, North Africa-Mediterranean, and the Americas, were approximately >16% divergent. Two major Asian subgroups (I, II) were resolved, which represented populations indigenous to the region, comprising two (I a, I b) and five (II a—e) sister groups, respectively, which diverged by 11%. Two distinct populations from sunflower in Hyderabad grouped separately within the two Asian subgroups. All other populations grouped uniquely within Asian subgroup II or I. The “B” biotype was identified in 23 collections from China at 97.3%—99.5% nucleotide identity with “B” biotype reference sequences; it was not identified in collections from India. The majority of haplotypes were associated with 3—4 plant families, with one exception that for sister group IId (sesame, India), it might be monophagous. Thus, B. tabaci from the southeastern and near eastern regions of the Asian continent comprise of a large number of ancestral, richly divergent, mostly polyphagous populations. This region is therefore hypothesized to constitute an important Old World center of diversification for the B. tabaci complex, together with sub-Saharan Africa.     

Salt glands inGlycine soja L. China

A scanning electron microscope observation is carried out on Glycine soja L., which grows around the estuary of the Yellow River, in Kenli County, Shandong Province. It is first discovered that there are salt glands, in the shape of balls, on the surface of the stems and leaves of G. soja L., and distributed at the intercellular layer. With a handle at the base, the salt glands are not equal in size, and show a layer-upon-layer structure. They have a diameter of 21.6 μm, a handle length of 1.2 μm, their secretory pore's diameter is 5.6 μm. There are two ways to secrete salt ions: younger glands secrete salt ions through the secretory pore, and mature glands by breaking themselves.     

Introduction of AtNHX1 into beet improved salt-tolerance of transgenic plants

AtNHX1 gene encoding the Na ^＋/H ^＋ antiport on the vacuole membrane of Arabidopsis was transferred into small bud tips of 1-3mm in length derived from immature inflorescence cultures of six genotypes of beet （ Beta vulgaris L. ） by the infection of Agrobacterium tumefaciens and transgenic plants with improved salt-tolerance were obtained. When transgenic plants at 5-leaf stage were potted in sand and irrigated with solutions containing a range of concentrations of NaCl （171-513mM）, they showed minor symptoms of damage from salinity and better tolerance than the controls. There were considerable discrepancies of salt-tolerance between transgenic plants originated from the same genotype and also between different genotypes. After vernalization, bolting transgenic plants were enveloped with two layers of gauzes for self-pollination. T1 seedlings tolerant to 342-427mM NaCl were obtained respectively. These results revealed that it was feasible to improve salt-tolerance of beets by the introduction of AtNHX1 gene into cultured bud cells.