Abstract:In this study,a saltinduced MYB transcription factor gene,TaSIM,was isolated from cDNAs library of wheat leaves under salt stress.The full length TaSIM cDNA is 1 213 bp,including an ORF of 831 bp.This cDNA sequence encoded a polypepide of 276 amino acid residues with a predicted molecular mass of 29.903 kD and a basic isoelectric point of 10.12,and two highly conserved SANT domain in the encoded putative protein.The phylogenetic analysis showed that TaSIM has the highest similarity with XP_003576185 from Brachypodium distachyon.Semiquantitative RTPCR analysis revealed that TaSIM gene was obviously induced by salt stress.Subcellular localization assay indicated the TaSIMhGFP fusion protein was located in the nucleus.The results suggested that TaSIM transcription factor might be involved in salt stress response of wheat.

Abstract:Plant mitogenactivated protein kinases (MAPKs) have been implicated in plant defense as a new component of the defense signaling pathways.In this study,a Sclerotinia sclerotiorum cDNA clone in Brassica campestris ssp.chinensis cv.Duanbaigeng was isolated and characterized.The gene was designated as BcMPK4 (DDBJ accession number AB557751),which contains 1 334 bp nucleotide and encodes 373 amino acids.BcMPK4 had different homology score of amino acid compared with MPK4 genes of other plants.Phylogenetic analysis revealed the evolutionary conservation of these proteins among diverse species.Southern blotting hybridization with genomic DNA showed that BcMPK4 belonged to a multigene family.Realtime quantitative PCR analysis revealed that BcMPK4 transcript was increased after inoculated with S.sclerotiorum.Expression characterization of BcMPK4 in Brassica campestris ssp.chinensis indicated that it might be involved in host resistance against S.sclerotiorum.

Abstract:The gene fragment homologous with peach CAT1 gene up to 88%,was obtained from the SSH libraries of Dongzao (Ziziphus jujuba cv Dongzao) halfred and red fruit.Based on the fragment,specific primers were designed for 5′ and 3′RACE amplification resulted in a sequence of 1 586,which contains a 1 479 bp complete open reading frame and encodes 492 amino acids,with a conserved functional domain of CAT gene family.It was named ZjCAT,with GenBank accession number JN831452.Amino acid sequence analysis indicated that,ZjCAT was high identity with the catalases of Prunus persica,Gossypium hirsutum and many other plants,and it belonged to the class Ⅲ.The results of realtime PCR showed that the gene differentially expressed in different tissues and at different fruit maturity stages,of which the expression in halfred stage was the highest,indicating its possible important roles in regulating the senescence of Dongzao fruit.

Abstract:To provide an insight into stress defense mechanism of birchleaf pear,a choline monooxygenase gene (PbCMO) was cloned via reverse transcriptase PCR,the rapidamplification of cDNA ends (RACE) and long PCR methods.At the same time,PbCMO sequence characteristics were analyzed by the bioinformatics software.Furthermore,semiquantitative PCR with crossintron primers was adopted to study the expression patterns of PbCMO gene under abiotic stresses.The results showed that:(1)PbCMO cDNA sequence contained a 1 227 bp length coding region which encoded 408 amino acid residues.PbCMO genomic DNA sequence length was 2 928 bp which consisted of 10 exons and 9 introns.Predicted isoelectric point and relative molecular mass of PbCMO were 6.19 and 46.27 kD,respectively.PbCMO encoded polypeptide included Riesketype ironsulfur ［2Fe2S］ clusterbinding region and the conserved residues of the mononuclear Febinding motif.Homology analysis showed that the deduced PbCMO protein was highly similar with medlar CMO protein (71%).Phylogenetic analysis also indicated that PbCMO was more related to medlar CMO.(2)PbCMO gene expression was inducible and its transcription abundances climbed up quickly after 100 mmol/L NaCl,10% (W/V) PEG6000,180 mmol/L mannitol or 20 μmol/L ABA treatment.It is showed that PbCMO expression was response to salt,drought,osmotic and ABA stress.Conclusively,PbCMO was involved in the defense mechanism against abiotic stress in birchleaf pear.

Abstract:In this study,realtime PCR or Northern blotting was employed to analyze the expression patterns of the CBP60g gene in wildtype Arabidopsis thaliana after Pseudomonas syringae and abiotic stress treatment.In addition,the expression of pathogeninduced genes in wildtype,cbp60g1 mutant and CBP60g overexpression plants after P.syringae inoculation were compared.The results showed:(1)Transcript of CBP60g was induced by P.syringae,high salt,cold and wounding treatment in wildtype plants.(2)The expression of pathogeninduced genes PR5 and AIG1 in the CBP60g overexpression plants was enhanced after P.syringae inoculation and was reduced in the mutant.(3)AtMYB2,an abioticstress induced gene reported previously,was also induced by Pst DC3000,and reached to a higher level in overexpression plants than in wildtype.Taken together,these results indicate that CBP60g involved in A.thaliana multiple stresses response.

Abstract:To investigate the role of AtNHX5 in plant salt resistance,the plant expression vector pROKⅡAtNHX5 was constructed and introduced into Arabidopsis thaliana.RTPCR assay showed that:(1)AtNHX5 was overexpressed in the transgenic lines.(2)Several transgenic homozygous lines and wildtype plants were evaluated for salt stress tolerance,the results suggest that AtNHX5 transgenic plants were more tolerant to high NaCl concentrations during germination and seedling stages when compared with wildtype plants.Under saline conditions,both fresh and dry weights of the transgenics as well as Na⁺ and K⁺ contents were much higher than that of wildtype.To take transgenic plant a14 as an example,the shoot fresh weight,dry weight and K⁺ content were 1.27,1.54 and 1.16 fold,respectively compared with wild types under 200 mmol/L NaCl treatment,which were significantly higher than that in wild types.These results demonstrate that overexpression of AtNHX5 in Arabidopsis promoted the absorbing capacity of K⁺ and enhanced the salt tolerance of plants.

Abstract:Simple Sequence Repeats (SSR) were surveyed in citrus BACEnd sequence (BES) for the development of new SSR markers to extend and saturate existing genetic map.22 403 SSRs with 1～6 bp motif were identified in 46 339 citrus BESs retrieved from NCBI.The estimated frequency of SSRs was approximately 1/1.25 kb,nearly twice the frequency found in Citrus Expressed Sequence Tags.323 primers were selected in the present mapping study,of which 40 were mononucleotide repeats,184 dinucleotide repeats,99 trinucleotide or above repeats.Polymorphism tests showed that 316 primerpairs (98%) could be amplified successfully and 173 pairs (55%) were polymorphic.Among the polymorphic primers,15 pairs were of mononucleotide repeats,100 pairs of dinucleotide repeats,58 pairs of trinucleotide or above repeats.A new linkage map was produced by combining the segregating data of new markers and markers in the previous map.When compared with the published map,the new map integrated 334 SSR markers,9 linkage groups and covered 844.2 cM of citrus genome with an average genetic distance standing at 2.53 cM.The results demonstrated that citrus BES was good for SSR marker development and the developed markers were useful in extending and saturating the citrus genetic maps.So this will provide a reference for development of other species SSR markers and lay a good foundation for citrus gene mapping,mapbased cloning and markerassisted breeding.

Abstract:In order to analyze the genetic diversity among germplasm of cultural walnuts,16 SSR primer pairs were used to amplify SSR fragments with 44 samples of Juglans regia from different ecological types,8 samples of Juglans sigillata,and 7 cultivars of Amerian walnut.The 16 pairs of SSR primers generated a total of 87 alleles.The number of alleles per locus ranged from 4 to 9,and averaged 5.4.The observed heterozygosity (Ho) of 16 SSR loci ranged from 0 to 0.931 0,and averaged 0.389 4.The value of allelic polymorphism information content (PIC) ranged from 0.376 2 to 0.786 3,and averaged 0.663 2.The heterozygosity of 59 cultural walnut samples ranged from 0.133 to 0.813,and averaged 0.387.It showed that the heterozygosity of cultural walnuts was low.In the dendrogram,the walnut samples from Qinling Mountain and those from Huabei should belong to the same ecological type.Wild walnut samples from Xinjiang Gongliu County should belong to the one absolute ecological type,that was different from Xinjiang ecological type and Huabei ecological type.The American walnuts and J.sigillata,should be different ecological types in J.regia.

Abstract:The genetic diversity of 16 Fritillaria thunbergii Miq.populations of three varieties (Xiaye,Kuanye and Duozi) distributed in Zhangshui,Yinjiang and Longguan,Yinzhou District and Ningbo of Zhejiang Province was investigated by RAPD and ISSR techniques.The results showed that:(1)The polymorphism percentages of 11 Xiaye varietes,3 Kuanye varieties and 2 Duozi varieties were 24.22%,3.81% and 0.69%,respectively.It indicated that the Xiaye variety had the highest genetic divergence and the richest genetic diversity,followed by the Kuanye variety,and the Duozi variety was the last.(2)The genetic relationship within the variety was closer than that between them.Kuanye and Duozi varieties showed a closer genetic relationship,and it was suggested that both of them may be selected from the original Xiaye variety.(3)The genetic diversity within 16 F.thunbergii Miq.populations revealed that Ht was 0.250 1±0.033 5,Hs was 0.053 2±0.009 7,G_{st was 0.787 1 and Nm was 0.135 3.The result showed that the main genetic divergence of F.thunbergii Miq.existed within the populations and the gene flow between populations was very low.}

Abstract:The karyotypes of 8 populations of Coptis teeta,which distributed in different ecological areas (4 in east slope and the other 4 in west slope of Mt.Gaoligong),were studied using the methods of root tip squash and carbol fuchsin dyeing.The results show as follows:(1)In these populations,the chromosome numbers are same 2n=2x=18;(2)Except that the karyotype of one population in east slope belongs to 3A type,the karyotypes of rest 7 populations belong to 2A type;(3)Despite the fact that the karyotypical features appear to be similar for the populations in the same ecological area (i.e.east slope or west slope),large karyotypical differences exist among those populations in different ecological areas.First,the occurrence and numbers of acrocentric chromosomes (st chro.) and telocentric chromosomes (t chro.) are variable among the populations in the east and west slope.Second,the degrees of karyotype asymmetry of the populations in east slope are higher than those of the populations in west slope.

Abstract:The morphology of spores of 2 genera,22 species of Huperziaceae from China was examined using scanning electron microscope (SEM).The present investigation provides scientific basis for Huperziaceae classification and system evolution.The results show that the spores,with a trilete,are radially symmetrical and tetrahedron.The spores are often obtuse triangle,rounded triangular or suborbicular in polar view,and fanshaped or nearly elliptic in equatorial view.The three margins of the trilateral spore depress inwards in Huperzia or protrude outwards in Phlegmariurus.The length of polar axis is about 16~26 μm.Spore length of equatorial axis is about 22~36 μm.The spores possess exospores,but no perispore formation.The exospores form profile of fossulate ornamentations,which are factually elliptic or irregular pits,with different size,depth and electronic density.From spore morphology and ornamentation types,it is concluded that the discrepancies between the two genera,Huperzia and Phlegmariurus are evident.However,the discrepancies of ornamentations inner each genus are less distinct.

Abstract:The transverse sections of leaf blades of the major species of sect.Elymus,sect.Turczaninovia and sect.Macrolepis in Elymus were examined.The results showed that:(1)The leaf blade consists of epidermis,mesophyll and vascular bundle,which is isobilateral leaf.It belongs to the typical festucoid type.Namely,shape,magnitude and arrangement of epidermises are asymmetric.The mesophyll is not distinguished into palisade tissue and spongy tissue.They have double layer bundle sheath.The ambient mesophyll cells arranged irregularly and sclerenchyma is joined to epidermis.There are also obvious differences existing on the transverse section characteristics of leaf blades including shape,magnitude and depth of furrows in upper epidermises,number of large vessels,etc.(2)According to the evolutionary trends of transverse section characteristics of three sects,their evolutionary positions and relationships were inferred.The results show that the sect.Elymus is the most primitive one among the three sects,the sect.Turczaninovia is slightly more advanced than the former,and the sect.Macrolepis is the most advanced of them.The sect.Elymus might produce immediately the sect.Turczaninovia,whereas the sect.Macrolepis might derive immediately form the sect.Turczaninovia.The biosystematic relationships of these three sects are corroborated by the evolutionary trend of external morphology.

Abstract:The leaf epidermis of 12 species of the genus Dianthus was investigated using light microscopy (LM) andscanning electron microscopy (SEM).The stomata size,density and index were measured and counted.The results show that the shape of leaf epidermal cells (surface view) is rectangular and irregular polygon.The papillae were found in Dianthus acicularis,Dianthus elatus and Dianthus turkestanicus.The shape of stoma can be divided into three types:oval,ovate and oblong.Thus,there are significant value in the taxon and relationship research between species of the genus Dianthus.

Abstract:In this research,Sesuvium portulacastrum,a mangrove plant was used as material.Watercultured seedlings of samphire,which are at the same growth status,were treated in nutrient solution with different concentrations of Hg²⁺ in it.The ultrastructure change of S.portulacastrum mesophyll cell,which was respond to different concentrations of Hg²⁺,was observed by TEM(Transmission Electron Microscope) to probe the effect of Hg²⁺ to S.portulacastrum mesophyll cells.The result shows that:Hg²⁺ can lead to different poisoning symptoms to chloroplast,mitochondria,nucleus and membrane system in diachyma cells.With the increase of Hg²⁺ concentration,the number of chloroplast in diachyma cells is decreasing.The shapes of chloroplast change from ship type to long or giant type.The thylakoid system is also injured,and grana lamella is getting dim.The number of mitochondria is determined by Hg²⁺ concentration,and its shape changes from rodlike to round or ellipse.The double membrane system and cristae of mitochondria is also becoming dim.The nuclei are injured in different degrees and the nucleolus changes from one to more and finally disappear.The membrane forms protuberances into the intracytoplasmic and then change to bubbles.The cell will disintegrate with the decrease of organelles under the stress of high concentration of Hg²⁺.

Abstract:Tomato cv.L402 was used as plant material.Resistance to gray mold and activities of defensive enzymes were investigated after sprayed Ca²⁺ or its antagonist on tomato.The results showed that:(1)Resistance to gray mold were improved significantly for induced and uninduced leaves in tomato treated with SA.Induced resistance was farther enhanced by Ca²⁺ but restrained badly by chelator as EGTA or the plasmalemma Ca²⁺ channel blocker as LaCl₃.(2)Activities of PAL,PPO and POD in induced and uninduced leaves also rose after treated the plant with SA.This response was promoted by exterior Ca²⁺ and suppressed by the inhibitor of Ca²⁺ such as EGTA and La³⁺ in a general way.(3)Activities of CAT and SOD induced by SA were not regulated by Ca²⁺ or inhibitor of Ca²⁺.Consequently,modulating of calcium on the induced resistance to tomato gray mold by SA may has relations with the activities of defensive enzymes such as PAL,PPO and POD in tomato leaves.

Abstract:A hydroponic culture experiment was conducted to study on the physiological characteristics and growth of Apium graveolens L.var.dulce DC.seedlings under the different NO₃^- concentration (0，1，5，10，15，50，100 and 150 mmol·L^-1).The results showed that：(1)With NO₃^- concentration increased（1～50 mmol·L^-1），the heights,biomass,shoot/root ratio and leaf area of the seedlings increased;the absorption of N,P,and K nutrients improved;the content of chlorophyll and the MDA increased;and the activities of POD and CAT increased.(2)When the NO₃^- concentration was equal to or higher than 100 mmol·L^-1,the biomass and the content of chlorophyll decreased;the absorption of P,and K nutrients reduced;the MDA,soluble protein and sugar content，SOD activity appeared its highest peak;and the activities of POD and CAT decreased.We can concluded that the NO₃^- concentration of 15 mmol·L^-1 favored the growth of celery;and the NO₃^- concentration of 100 mmol·L^-1 caused the nitrate stress to the plant growth and resulted in injury to membrane lipid peroxidation，but the antioxidation enzyme and osmatic adjustment substance could adjust themselves to avoid nitrate stress harms,which led to some tolerant ability of Apium graveolens L.var.dulce DC to nitrate stress condition.

Abstract:In order to reveal the feasibility of exogenous SA relieving the damage of high temperature stress on Fritillaria anhuiensis and to study chronergy,potcultured F.anhuiensis seedlings were foliage sprayed 0.5 mmol/L SA 1,3,5,7 days before being placed under high temperature (36℃)stress for 24 hours,and then those treated materials were transfered in normal condition (day 25℃/night 20℃) for growth recovery for 48 h.The result showed that:Within 3 days,the foliage sprayed SA significantly increased the content of chlorophyll a and soluble protein,effectively reduced relative conductivity and the content of MDA;at the same time,the foliage sprayed SA enhanced the activity of SOD and POD,but the activity of CAT were negatively influenced.The above action effects were obviously weakened 5 days after the foliage spraying of SA.Moreover,those action effects were almost lost 7 days after the first spraying.We can conclude that foliage sprayed 0.5 mmol/L SA could effectively relieve the damage of high temperature stress on F.anhuiensis leaves by increasing the content of osmoregulation substance and the activities of protective enzymes,and that it was efficient within 3 days.

Abstract:To improve rooting rate of Cerasus subhirtella var.pendula and study the mechanism of promoting rooting by electrostatic field,four treatments with 1.5,3.0,4.5,6.0 kV/cm of electrostatic field were set.The effects of different treatments of electrostatic field on rooting,functions of physiology and biochemistry of C.subhirtella var.pendula cuttings were studied.The results showed as follows:(1)The contents of soluble protein and soluble sugar in cuttings were significantly increased by electrostatic field with 1.5～4.5 kV/cm. The most effective treatment was 4.5 kV/cm,the largest growth reached 43% and 44.1% compared with the CK,respectively.(2)Enzyme activities of peroxidase (POD) and indoleacetic acid oxidase (IAAO) in cuttings were significantly increased and decreased by electrostatic field with 1.5～4.5 kV/cm,respectively.The most effective treatment was 4.5 kV/cm,the largest growth and reduction reached 58.9% and 17.5% compared with the ck,accordingly.(3)The number of root per plant,length of roots，fresh weight of root，root activity,cuttings survival rate were significantly increased by electrostatic field with 3.0 and 4.5 kV/cm.The most effective treatment was 4.5 kV/cm and the growth rates reached 127.4%,29.2%,88.9%,107.1%,116.3% compared with the CK,respectively.The above results show that contents of soluble protein,soluble sugar and the enzyme activities of the POD and IAAO in cutting of C.subhirtella var.pendula can be effectively regulated by suitable electrostatic field,and the cutting survival rate can be significantly improved.The optimal intensity of electrostatic field is 4.5 kV/cm.

Abstract:Effect of superabsorbent polymers (SAP) on the growth and chlorophyll content of leaves,as well as the photosynthesis was conducted with pepper variety ‘Chaoyue No.5’in flowering stage under 10 days and 20 days medium water stress and the subsequent recovery process.The results showed that:(1)Water stress inhibit the growth mass,chlorophyll content and photosynthesis.(2)Adding 2‰ of SAP significantly decreased L_s,WUE,significantly increased the plant height,stem diameter,dry fresh weight,chlorophyll content,and P_n,C_i,G_s,T_r under the water stress.(3)Under moderate water stress SAP can significant mitigate this damage in a short period of time,while the effect of SAP is limited with the time.(4)When resumed the normal water supply,the plant growth,chlorophyll content and photosynthetic parameters were significantly higher with SAP than that without SAP,while the recovery effect under short time stress was significantly better than that under long time stress.It indicates that SAP treatment could increase photosynthetic parameters,improve the growth and relieve the water stress of damage on pepper by increasing the content of chlorophyll,and with the shorter time of water stress,the better effect of the SAP.

Abstract:In order to find out the adaptability and coping strategies to arid environment of Apocynum venetum and A.cannabinum,water physiological characteristics and daily dynamics of photosynthetic characteristics were studied under drought stress.The results showed that:(1)With the advance of drought stress,the leaf water content and relative water content for both Apocynum decreased gradually,and A.venetum decreased greatly compared with A.cannabinum.In the same soil water grade,the leaf water content and relative water content of A.cannabinum were significantly higher than that of A.venetum,but water saturation deficit was lower than that of A.venetum.Under the different soil water contents,the relative water content of leaves in vitro of A.venetum sharply declined after two hours,and declined significantly higher than that of A.cannabinum (P<0.01);After 8 hours,the relative water content of leaves in vitro of A.cannabinum were maintained at higher level.(2)Under treatments of saturated water supply (CK),light drought stress (LS) and moderate drought stress (MS),the diurnal curves of the net photosynthetic rate (P_n),transpiration rate (T_r) and stomatal conductance (G_s) of A.venetum and A.cannabinum were “doublepeak”,while “singlepeak” under severe drought stress (SS).Compared with CK,the subpeak of P_n delayed to about 16:00 under LS and MS condition.The order of P_n and WUE of A.cannabinum were LS>CK>MS>SS,while were CK>LS>MS>SS in A.venetum,and the difference reached to the significant level (P<0.05) except for WUE index between CK and T₁ of two Apocynum.The P_n and WUE of A.cannabinum were significantly higher than that of A.venetum in same soil water grades;The daily average value of P_n and WUE in A.cannabinum were 2.28 μmol·m^-2·s^-1 and 1.41 μmol·mmol^-1,respectively.However,the A.venetum.dropped to 0.29 μmol·m^-2·s^-1 and 0.16 μmol·mmol^-1 under SS conditions.All these reflected that A.cannabinum was with higher water conservation and photosynthetic production capacity than A.venetum,and suitable to plant in Ningxia.

Abstract:In order to study the effect of different sulfur and nitrogen fertilizer combined application on N transfer and leaf senescence of winter wheat,N content、water and chlorophyll content of 3 winter wheat varieties (‘Yumai 66’ and ‘Weimai 8’ are staygreen wheat,‘Xiaoyan 6’ is nonstay green wheat) were measured.The results showed that under N₁₂₀ treatment,N content of stem and leaf,chlorophyll content of leaf with S₆₀ treatment was lower than that of other two S treatment at anthesis;Leaf water content was lower than that of other two S treatment at the late grain filling stage.Under N₂₂₀ treatment,leaf N content at anthesis,total N accumulation at harvest,N Harvest Index,water content and chlorophyll content of leaves were all higher than that of other two S treatment.The effect of sulphur on wheat depended on the amount of nitrogen application,and S demonstrated a dual character in all 3 winter wheat varieties.On the one hand,under the condition of lowerlevel nitrogen,sulphur had negative effect on the N uptake and senescence of leaf；On the other hand,under the condition of higherlevel nitrogen,sulphur had positive effect on the N uptake,senescence of leaf,grain yield and total biomass.The appropriate amount of N application for high yield was about 220 kg/hm²,and the appropriate amount of S application for high yield was about 60 kg/hm².Highlevel N and S fertilizer delay senescence more in nonstaygreen wheat than that in staygreen wheat.

Abstract:The study was intended to discuss suitable spraying amount of Mg,Zn,Mo for high yield and good quality of leafuse ginkgo.Effects of spraying different levels of Mg,Zn,Mo fertilizers on leaf yield and medicinal quality of twoyearold ginkgo seedlings were tested by indoor stimulation experiment and pot experiment.The main results were submitted as fellows:（1）Combining application of Mg,Zn,Mo fertilizers increased leaf thickness,leaf area,single plant leaf area,leaf biomass.The best treatment was Mo3（2% Mg+0.3% Zn+0.1% Mo） increasing 64.9% leaf biomass compared with that of control.(2)Positive effect of combining Mg with Zn,Mo fertilizers on chlorophyll,soluble sugar and soluble protein contents decreased with the increasing of Mg concentration.The same was also the effects of combining Zn with Mg,Mo fertilizers and combining Mo with Mg,Zn fertilizers on chlorophyll,soluble sugar contents.In contrast,the effects on soluble protein content correlated positively with Zn or Mo concentration.(3)Combining application of Mg,Zn,Mo fertilizers increased total flavonoid and terpene lactones contents,total flavonoid and terpene lactones yields per plant.The best treatment was Mo3 increasing 296% total flavonoid yield per plant and 170% total terpene lactones yield per plant compared with that of control.(4)High concentration fertilizers as Mg4,Zn4 and Mo4 decreased positive effect combining application of Mg,Zn and Mo fertilizers on some indexes in different degree..The results indicate that appropriate combined fertilization management can increase chlorophyll,soluble sugar,soluble protein contents and improve ginkgo growth and medicinal quality which increase component factors of leaf yield and medicinal quality.In the experiment,Mo3 was the perfect combination in order to increase ginkgo leaf yield and medicinal composition content and yield.

Abstract:In order to offer a scientific base and reference to rational utilization and largescale planting for introduced switchgrass (Panicum virgatum L.) in the semiarid conditions on the Loess Plateau,we investigated the photosynthetic dynamic variation,aboveground biomass production and soil moisture content profile distribution under three different row spacings,which were 20 cm（L₂₀）,40 cm（L₄₀） and 60 cm（L₆₀） on terrace land in loess hillygully region.The results indicated that:(1)The curves of diurnal variation in net photosynthetic rate (P_n) had double peaks,showing obvious midday depression.The first peak appeared at 10:00,and the second peak for L₄₀ appeared at 14:00,while for L₂₀ and L₆₀ treatments it appeared at 16:00.The daily mean values order of P_n was as follows:L₆₀>L₄₀>L₂₀.The midday photosynthesis depression under each row spacing was due to nonstomatal factor limitation.(2)The diurnal variation in WUE was similar to P_n,and the peak values appeared at 10:00 and 14:00 respectively under the three row spacing treatments,and the daily average order was L₆₀>L₄₀>L₂₀.(3)Soil volumetric moisture vertical distribution was similar under each row spacing,showing increased firstly,and decreased,and then increased with soil depth.Except in 0～50 cm soil layer,soil water storage in the other layer was not significant different among the three row spacings.Total soil water storage in 0～380 cm decreased with row spacing,showing that:L₂₀>L₄₀>L₆₀.(4)The aboveground biomass order for the three row spacing was L₂₀>L₆₀>L₄₀.Although the leaf P_n was lower,the biomass production and soil water storage were significantly higher under L₂₀,all these results suggested that the optimum row spacing was 20 cm for switchgrass on terrace land in loess hillygully region.

Abstract:A field plot sampling method was employed to investigate communities of natural forests in Zhouzhi Laoxiancheng Natural Reserve of Shaanxi.Parameters of niche breadth (B),niche similarity (L) and niche overlap (C) were calculated to analyze community characteristics.The results showed that:(1)243 species were recorded and they belong to 159 genera and 64 families.The plots were classified into 3 vegetation types and 9 formations.(2)Niche breadths of Pinus armandii and Quercus aliena var.acutiserrata were larger than other species in main tree populations,with Levins (B_i) and Hurlbert’s (B_a) values being 0.654 and 0.699,and 0.534 and 0.460 respectively;Smaller niche breadths were found in Quercus serrata var.brevipetiolata and Ulmus bergmanniana species,with B_i and B_a values being 0.064 and 0.023,and 0.049 and 0.016 respectively.(3)The species pairs which have higher niche similarity and niche overlap were Betula platyphylla and Populus purdomii,Populus davidiana and Betula utilis,with L_ij and L_ji values being 0.108 and 0.114,and 0.089 and 0.128,C_ij values being 0.939 and 0.744,respectively.The lower niche similarity and niche overlap among dominant species means less fierce interspecies competition and low spatial heterogeneity at current stage in the community succession.

Abstract:Taking the flora of Wula Mountain as study object,we analyzed geography distribution,life styles,water ecotypes of seed plants here from taxonomic grade of families,genera and species.The results compared with the flora of Inner Mongolia.The conclusions are as follows:(1)There are 426 species of seed plants in Wula Mountain,which belong to 227 genera and 67 families.Among them there are 3 families,5 genera,7species in Gymnosperm;58 families,187 genera,345 species in Dicotyledon and 6 families,35 genera,74 species in Monocotyledon.(2)Temperate components are dorminant.Herbage is dominant in life style.In water ecotype,the mesophyte is most primary,the xerophile is primary either.That means the water condition is worse and here is semidrought area.Compared with the flora of Lang Mountain,Jiufeng Mountain and Daqing Mountain,the kindred relationship between them were analyzed:the flora of Wula Mountain has near kindred relationship with Daqing Mountain in families and genera,with Jiufeng Mountain in species,but not with the flora of Lang Mountain.

Abstract:The effects of culture medium composition and culture conditions on pollen germination and pollen tube growth of Chimonanthus praecox (L.) Link.were investigated with liquid culture.The results showed that:(1)PEG4000 was an essential culture constituent for in vitro culture to C.praecox.The pollen did not germinate in the culture medium without PEG4000;(2)Low concentration of sucrose in the medium had no effects on pollen germination and pollen tube growth.Whereas,relative high concentration of sucrose significantly inhibited pollen germination and pollen tube growth;(3)0～250 g/L PEG4000,0～50 mg/L H₃BO₃,and 0～30 mg/L Ca(NO₃)₂·4H₂O could stimulate pollen germination and pollen tube growth,but higher concentration of these constituents (250 g/L PEG4000,50 mg/L H₃BO₃,and 30 mg/L Ca(NO₃)₂·4H₂O) displayed inhibition;(4)Magnesium and potassium had no significant effects on pollen germination and pollen tube growth.In summary,the optimum culture medium composition for liquid culture to C.praecox consist of 250 g/L PEG4000,50 mg/L H₃BO₃,and 30 mg/L Ca(NO₃)₂·4H₂O.The optimum culture conditions for pollen germination and pollen tube growth of C.praecox involved pH 5.5,15℃,and 600 lx of illumination.

Abstract:Through the research of the specimens and the taxonomic literatures,it was pointed out that the illustration of the fruiting branch and the identification key of Ilex melanophylla H.T.Chang were incorrect.It was clarified that I.melanophylla H.T.Chang of Aquifoliaceae was wrongly described as I.robusta C.J.Tseng in Flora Reipublicae Popularis Sinicae and Flora of China.A taxonomic revision of I.melanophylla H.T.Chang was made.The morphological characters such as male flowering branch,infructescences,fruit,pyrenes and geographical distribution,etc.of I.melanophylla H.T.Chang were perfected,cymes of order 1 with 12fruit in the literatures was corrected as cymes of order 1 with 13fruit,and the identification key of 8 relative species including I.melanophylla H.T.Chang was rewritten.

Abstract:Altai Mountains are one of the largest mountain ranges in the Eurasian Continent.The southwest slope of middle Altai Mts.is located in Xinjiang of China,where a lot of temperate element mosses are distributed.During our recent investigation in Altai Mts,we found two new records of Dicranaceae to China——Dicranum brevifolium (Lindb.) Lindb.and Dicranella crispa (Hedw.) Schimp.Both of them were collected in Kanas Nature Reserve and Hemu Kanas Village of Burqin County of the Altai Mts.Geographically,they are only limited in a very small region in China.

Abstract:Flavonoid Omethyltransferase (FOMT) belongs to the methyltransferase family of transferase superfamily,which catalyses transferring the methyl group from SadenosylLmethionine (SAM) to hydroxyl group of flavonoid.Methylation is one of the most important modifications to the ring structure and/or acyclic side of flavonoid.Omethylation of flavonoid alters the chemical reactivity of their phenolic hydroxyl groups and enhances their lipophilicity,which increases their intracellular compartmentation as well as their antimicrobial activities.This paper reviewed the recent progress of plant Omethyltransferase in physiological/biochemical metabolisms,classification,and structure of domains of enzymes,biological function,gene cloning and expressional regulation in order to provide additional insights for further study.

Abstract:Chloroplasts are the photosynthetic organ of green plants.The complete sequences of the chloroplast genomes of flowering plants have provided fresh impetus to phylogenetic reconstruction and evolution of flowering plants.Recently the number of the completely sequenced chloroplast genomes increased sharply and the advances in chloroplast genome evolution have revolutionized our understanding of the structural mutations and reorganizations of the chloroplast genomes.This paper summarized the recent discoveries of the structural diversity of the chloroplast genomes of flowering plants.Due to the emphases of chloroplast genome sequencing on the systematically key node species,genomic data of many major taxonomic groups are still unavailable.Such gaps need to be bridged for a better understanding the evolution of both the chloroplast genomes and the flowering plants.