Abstract:The full length coding sequence without the TAA stop codon of LRR-RLKs gene (RLK6) of Arabidopsis thaliana was cloned by RT-PCR and fused with green fluorescent protein （GFP） gene to construct a plant expression vector.The stable Arabidopsis transformants were observed using confocal laser scanning microscope.The result indicated that RLK6-GFP fusion protein was localized in the plasma membranes.Consistent location was obtained by the experiment of RLK6-GFP transient expression in living Arabidopsis protoplasts.To visualize the temporal and spatial expression patterns RLK6 in plant tissue,a 2 063 bp promoter fragment of RLK6 was fused with the GUS gene to generate transgenic plants.GUS activity was detected in seedlings,roots and flowers,especially in anther,but hardly detected in stems,rosette leaves and dry seeds.Consistent result was obtained by RT-PCR analysis.Overall,these data implied that RLK6 might involve in the signaling pathway of flower organs development or related processes.

Abstract:The semi-thin sections or ultra-thin sections were made by resin embedding technique using the upper region of the dying stem of AtRabD2b-cosuppressed plant.The sections were observed using light microscope or transmission electron microscopy (TEM) to study the cellular process of the stem death.The results indicated that:(1)The death was firstly initiated from several periphery epidermal cells,and then spread from cell to cell both laterally and longitudinally throughout the whole stem section.(2)Several abnormal phenomenons such as the condensation and peripheral location of chromatin,the decrease of the numbers of internal thylakoid membranes of chloroplast and the autophagy of organelles by vacuole were observed.These features revealed that PCD occurs in the dying cells of the mutant apical stem.It also suggested that AtRabD genes are essential for the cell survival in the apical stem.

Abstract:Using fluorescence microscopy combined with pharmacological methods,we studied the effects of exogenous CO and NO on the DNA degradation and survival rate of aleurone cells in germinating rice (Oryza sativa L.) seeds and its aleurone layers under drought stress.The results showed:(1)The treatment of drought stress promoted the aleurone cells death,and the death of aleurone cells near the embryo occurred earlier than those in the far embryo.(2)Exogenous CO and NO donors alleviated the degradation of DNA in rice aleurone cells under drought stress,and delaying the process of cell death.Meanwhile,effects of CO and NO were reversed by CO specific inhibitor and NO scavenger,and shortening the process of cell death.(3)Exogenous CO and NO donor promoted the germination of rice seeds under drought stress.However,CO specific inhibitor and NO scavengers inhibited the germination of rice seed under drought stress.(4)The experimental results also revealed that CO mediated by NO regulated the aleurone cells death and germination of rice seeds under drought stress.

Abstract:Morphology,cytology and STS,SSR markers were adopted to identify the dwarf line WB7-3 selected from the progenies of common wheat cv.7182×two-rowed barley.The results showed that WB7-3 grew evenly presenting favorable agronomic traits and its plant height was very low;the chromosome number of WB7-3 in root tip cells was 42 with 21 bivalents observed in most PMC at MⅠ,and no fluorescence signals appeared in genomic in situ hybridization (GISH) analysis using barley whole genome DNA;but special strip of barley emerged in WB7-3 at STS marker ABC454-one specific STS primer from barley.Meanwhile,the result of amplification using 210 SSR markers from wheat each chromosome was that all strips of wheat emerged in WB7-3 except four markers (Xgdm35,Xgdm5,Xgwm261 and Xgwm455) which from the short arm of 2D chromosome.It showed that WB7-3 was probably a 2DL/2HS small fragment translocation line.

Abstract:In this test,‘Chuannong 1 loquat’ (C1) was taken as the experimental material which was derived from a low seediness line of degenerated seeds of‘Dawuxing’ loquat.The self-pollination of ‘Dawuxing’ loquat was the control treatment.The growth of pollen tubes in the styles was observed with fluorescence microscopy.The results showed that:(1)Pollens germination and pollen tube growth were normal in cross-pollination of C1 and it took about 48 hours for pollen tubes to reach the base of style.(2)The pollens could germinate on stigma and the pollen tubes could growth in the styles after self-pollination of C1,but it took quite a long time.Most pollen tubes could reach the upper or middle of style but stopped growing 36 hours after self-pollination of C1,and meanwhile there were some incompatibility-phenomenon that the form of tube apex was abnormal and fluoresced more obviously,and only few pollen tubes could reach the base of style.C1 behaved gametophytic self-incompatibility (GSI).The self-incompatibility of C1 was one of the important reasons for its seed abortion.

Abstract:A unknown function protein gene SikSD-82 was cloned from Saussurea involucrata Kar.et Kir.cDNA library under cold-stress.Physicochemical properties and molecular features of SikSD-82 were predicted by bioinformatic analysis showed that SikSD-82 gene encoding a stable protein with 262 amino acids,which contains a conserved Wali7(wheat aluminum induced protein) ,a member of Gn_AT_Ⅱ superfamily,had significant identity of 60.89% with stem-specific proteins from Ricinus communis.Phylogenetic analysis indicated that SikSD-82 protein was most closely related to Solanum lycopersicum stem specific protein.The subcellular localization of SikSD-82 was found mostly in the nucleus .Under aluminum stress,SikSD-82 transgenic plant accumulate less A1 and MDA concentration in roots than that of wild-type plants,and their roots are longer than that of wild-type plants’,which shows that SikSD-82 transgenic plants have more aluminum tolerance than that of wild-type plants.

Abstract:In this study,a new flavonoid-3′,5′-hydroxylase (F3′5′H) gene,named PgF3′5′H (The accession number in GenBank:JQ403611) was isolated from the flower of Platycodon grandiflorus by using RT-PCR and RACE approaches.The full length cDNA sequence of PgF3′5′H is 1 787 bp,with an ORF of 1 599 bp encoded 532 amino acids.Multiple sequence alignment showed that the PgF3′5′H was highly similar with F3′5′H of other plants,and contained several known motifs including “PPGP” motif,I-helix,P450 haem-binding and a special sequence with 9 amino acids liked the Campanula medium F3′5′H.Semi-quantitative RT-PCR analysis showed that the expression level of the PgF3′5′H,with the development of P.grandiflorus flowers and the appearance of anthocyanins in flower tissue,was obviously increased,and got to the maximum in blue buds of the fourth flower developing stages,but absent in leaves.It was speculated that the PgF3′5′H might play an important role in blue anthocyanidin biosynthetic pathway of P.grandiflorus flowers.

Abstract:Late embryogenesis abundant (LEA) proteins could be induced in plants under stress conditions.In this study,an LEA encoding gene fragment was isolated from the suppression subtractive hybridization library of Caragana korshinskii Kom.,and the full length cDNA was cloned by rapid amplification of cDNA ends technique.Sequencing results showed that the full length cDNA was 870 bp,with an open reading frame of 510 bp.It encodes a protein composed of 169 amino acids with a calculated molecular mass of 17.03 kD,and a theoretical pI of 9.3.The deduced protein is strongly hydrophilic.Sequence and phylogenetic analysis indicated that the protein belongs to the LEA4 subfamily,therefore it was designated as CkLEA4.Real-time quantitative PCR analysis showed that the transcript of CkLEA4 was induced strongly under different treatments,including ABA,salt and drought.These results indicated that CkLEA4 might be involved in stress responses of C.korshinskii Kom.

Abstract:Young seedlings were treated by 300 mmol/L NaCl and harvested after being treated for 0,1,2,4,8,16,24 and 48 hours for RNA extraction.Northern Blot was performed to check the expression of AtPUB18.The result showed that the expression was induced by high salinity stress and reached the peak after treatment for 4 h followed by decreasing to the lowest level after 16 h treatment.PCR was performed to clone the promoter of AtPUB18 which is composed of 1 974 bp.Analysis of the sequence of this promoter displayed that many cis-elements associated with abiotic stress localized in promoter,such as HSE,LTR,MBS and ABRE.The promoter were cloned into pCambia1300-221-GUS to drive the expression of GUS.Histochemical staining revealed that the expression level of GUS without salt treatment was very low,but the expression of GUS became much stronger after 4 h of 300 mmol/L NaCl treatment.Our results manifested that the expression of AtPUB18 can be induced by salt stress and the promoter of AtPUB18 is a high salinity-induced promoter.

Abstract:The ubiquitin-conjugating enzyme E2 gene,designated as BcUBCE2,was isolated from Brassica chinensis L.by cDNA-AFLP and RACE technologies.The full length sequence of BcUBCE2 gene was 830 bp,contained an open reading frame(ORF) of 456 bp that encoded 152 amino acid residues.Structural analysis revealed that the sequence contains an E2 ubiquitin-conjugating enzyme active site and a highly conserved cysteine.Phylogenetic analysis showed that BcUBCE2 protein has the closest relative with E2 protein from Arabidopsis thaliana.qRT-PCR results showed that the existence of BcUBCE2 was detectable in root,stem and leaf.The expression level of BcUBCE2 gene reached the highest under copper stress for 10 d.This showed that the BcUBCE2 gene may play an important role in the response to copper stress.

Abstract:A flowering-related MADS-box gene named NtAP1 (GenBank accession JN704304) was cloned from the flower bud of Narcissus tazetta var.chinensis using RT-PCR and RACE methods.The cDNA is 1 155 bp in length with an open reading frame 762 bp which is capable of encoding 253 amino acids.Phylogenetic analysis indicated that the gene belonged to the APl/AGL9 family AP1 lineage.RT-PCR revealed that the existence of NtAP1 was detectable in flowers,which the levels were the highest in pistil.This showed that the NtAP1 gene which cloned in this study did not play an important role in the formation process of double flowers of ‘Yulinglong’.

Abstract:To clarify the obscured taxonomic status of Fauriella Besch.,we carried out phylogenetic analyses inferred from cp trnL-F,rps4 and nr ITS,with increased samples of Fauriella and related genera,and Hookeria Sm.selected as outgroup.The phylogenetic trees were conducted by Bayesian analyses,ML analyses,and MP analyses.The results were as follows:(1)The final alignment used for phylogenetic analyses contained 1 744 positions,including 747 nuclear region positions and 997 plastid positions;(2)There was no significant topological conflict among the consensus trees,which showed that Fauriella clustered with the members of Pylaisiadelphaceae and indicated that Fauriella should be put into Pylaisiadelphaceae;(3)The relationship between Fauriella tenerrima Broth.and Fauriella tenuis (Mitt.) Cardot is obscured;(4)3 species of Myurella Bruch & Schimp.are clustered with the members of Plagiothecium Bruch & Schimp.,which is congruent with the point that Myurella should be transferred to Plagiotheciaceae.

Abstract:Interspecific relationships in Rehmannia,a quasi-endemic genus in China,are still unresolved.In this study,we used multiple individuals to reconstruct the phylogenetic tree on the basis of chloroplast and nuclear genes.Our results are shown as follows:(1)Monophyly of Rehmannia is strongly supported and R.chingii,a sister or consecutive sister species to R.henryi,is the basic taxon in the genus.R.piasezkii-R.elata and R.glutinosa-R.solanifolia form two highly supported pairs of sister species.(2)Phylogenetic tree constructed by using multiple individual is more informative to uncover the complicate relationships among species.(3)Analysis of ancestral distribution area reconstructed by RASP indicates that there are three times of dispersals and two times of vicariances in the speciation history of Rehmannia,which are closely related to climate changes during Late Miocene and early Pliocene.We also proposed some advices to explore the speciation procedure in the genus.

Abstract:Huperzia serrata,an important traditional Chinese herb,has become a threatened species resulting from over-exploitation and habitat fragmentation in China.We assessed the levels and pattern of the genetic variation within and among four populations of this species in Wuling Mountains area using amplified fragment length polymorphism (AFLP) markers.(1)Seven primer combinations used in the study amplified 615 discernible bands with 549 being polymorphic,indicating a considerable high level of specific genetic diversity (at species level:percentage of polymorphic loci PPB=89.27%,effective number of alleles N_e=1.257,Nei’s gene diversity H=0.178,and Shannon’s information index I_sp=0.298;at population level:PPB=71.42%,N_e=1.235,H=0.154,and Shannon’s information index I_pop=0.251).The differences among populations in levels of genetic diversity were obvious,with the highest level (PPB=81.95%) in PBY population and the lowest level (PPB=64.55%) in TFS population.(2)A low level of genetic differentiation among populations was detected based on Nei’s genetic diversity analysis (G_ST=0.159),Shannon’s diversity index (0.16).Further AMOVA analysis also revealed a low level of genetic differentiation among populations (Φ_ST=0.242,P＜0.001).(3)An extraordinarily high level of gene flow (N_m=2.647) may result from out-breeding and extensive wind-dispersal spores.(4)Nei’s genetic identity (I_N) values between population pairs ranged from 0.927 9～0.969 4.A Mantel test showed no significant correlation between genetic distance and geographical distance (r=0.269,P=0.887),suggesting that the gene flow be not restricted geographically.In general,population genetic diversity and genetic structure are mainly determined by population history.The level of the genetic diversity in the less disturbed and stable populations which are dominated by clonal reproduction is lower than those of new young populations which are built by sexual reproduction.A number of factors that might affect the genetic profiles of H.serrata include clonal growth,selective effect of niche and outcrossing,as well as the effective wind-dispersal of spores.

Abstract:ISSR markers were used to analyze the genetic diversity and genetic structure of 6 natural populations of Camellia pubipetala.Eleven primers were used to amplify DNA samples from 150 individuals,and a total of 92 loci were detected.The genetic diversity of C.pubipetala is relatively high both at the species level and population level.At the species level,the percentage of polymorphic bands (PPB) is 80.43%,Nei’s gene diversity (h) is 0.245 1,Shannon information index (I) is 0.377 6.At the population level,PPB range from 58.70%~66.30%,h range from 0.199 7~0.229 3,I range from 0.300 9~0.343 8.A low level of genetic differentiation among populations was detected based on Nei’s genetic diversity analysis (G_st=0.126 6) and analysis of molecular variance (Φ_st=11.37%).Gene flow (N_m) among the populations is high (3.448 0).A mantel test showed there was a significantly correlation between genetic and geographic distance among the populations studied (r=0.755 1,P<0.05).Relatively high genetic diversity within the population and the low population differentiation of C.pubipetala might be related to its out-crossing mating system and bird pollination.

Abstract:Many studies have shown that methanol(CH₃OH) application can promote growth of various plants.Among the mechanisms of CH₃OH stimulating plant growth,the carbon source hypothesis obtained the most supporting evidence.We attempted to verify the carbon source hypothesis by study the association between the effects on stimulating growth and CH₃OH metabolism in Petunia hybrida.The results showed that:(1)The addition of 2 and 6 mmol/L CH₃OH to MS agar medium all promoted the growth of P.hybrida,but the effect of the former (low concentration) was better than that of the latter (high concentration),and the latter induced stronger oxidative stress.(2)The analysis on ¹³CH₃OH metabolism in P.hybrida under different concentrations by ¹³C-NMR demonstrated that the amount of [U-¹³C]Fruc and [U-¹³C]Gluc produced from 6 mmol/L ¹³CH₃OH treatment was significantly greater than those from 2 mmol/L ¹³CH₃OH,which results indicated that the carbon source from methanol was assimilated to form carbohydrates through the Calvin cycle.However,this part of carbon source might have little contribution to stimulating growth of P.hybrida.These evidences suggested that there is not association between the effects on stimulating growth and methanol metabolism in P.hybrida,and this experiment do not support the carbon source hypothesis.

Abstract:The effects of 0.2 mmol·L^-1 exogenous salicylic acid (SA) on seed germination,seedling morphology and biomass,membrane peroxidation,antioxidant enzymes in leaves of soybean (Glycine max L.) seedlings under 100 mmol·L^-1 NaCl stress were investigated by incubating with sand culture.The results showed that seed germination and seedling growth were significantly inhibited under NaCl stress;Relative electrolyte leakage and thiobarbituric acid reactive substance (TBARS) content were markedly increased;Activities of superoxide dismutase (SOD),catelase (CAT) and ascorbate peroxidase (APX) reduced constantly in leaves of soybean seedling under NaCl stress.While exogenous SA promoted seed germination and rootstock growth,increased biomass accumulation,reduced relative electrolyte leakage and TBARS content,improved activities of SOD,CAT and APX.The results suggested that NaCl stress inhibited significantly soybean seed germination and seedling growth,while certain concentration of exogenous SA could enhance seed vigor and antioxidant enzymes activities,reduce the degree of membrane lipid peroxidation,alleviate damages by NaCl stress,and promote salt resistance of soybean seedlings under NaCl stress.

Abstract:In this study,the Tamba Black soybean (RB) was used as the experimental material to analysis the physiological mechanism of exogenous IAA increasing Al resistance by investigation the effect of exogenous IAA on the contents of endogenous IAA,H₂O₂,MDA,Al,citrate exudation and the activities of the plasma membrane (PM) H⁺-ATPase under Al stress.The results showed that after exposure to 25,50 and 200 μmol·L^-1 AlCl₃ for 24 h,the contents of endogenous IAA,citrate exudation and the activities of the PM H⁺-ATPase in RB roots were firstly promoted,then decreased.However,the contents of H₂O₂ and MDA were increased significantly with Al concentrations increasing.Additionally,the contents of Al,MDA and H₂O₂ in RB roots were significantly decreased while 50 μmol·L^-1 IAA was added to 25,50 and 200 μmol·L^-1 Al treatment solutions.Furthermore,the citrate exudation increased approximately 2.39,1.73 and 6.85-fold and the activities of the PM H⁺-ATPase enhanced approximately 1.09,1.74 and 1.45-fold than that of only Al treatment in RB roots,respectively.Taken together,our results indicated that exogenous application of IAA significantly enhanced Al resistance of RB by enhancement of citrate exudation and the PM H⁺-ATPase activity under Al stress.

Abstract:A pot experiment was performed to study the drought resistance of Eucalyptus grandis Hill ex Maiden saplings under different nitrogen(N) application levels.The experiment consisted of two steps,firstly three N treatments (N₀,supplied no extra urea,and N₁ and N₂,supplied urea 1.4 and 2.8 g·pot^-1,respectively) were carried out in advance for 20 days and afterwards the drought stress[continuous drought for 0 d(D₀),3,6,9,12,15 and 18 d)] was conducted respectively to each N treatment.The results showed that:(1)Under the drought condition,the leaf water content (LWC),leaf relative water content (LRWC) and leaf water retention (LWHC) of saplings in N₁ and N₂ were lower than those in N₀ level,and the differences in the middle stage of drought were most obvious,which indicated that nitrogen application before drought probably led to negative impact to leaf water physiology of E.grandis saplings.(2)As for the soluble protein (SP) and soluble sugar (SS),the differences between nitrogen treatments were not significant in the early days of drought,but when drought for 9 ~ 18 d,the increase of SP and SS in N₀ were more obvious than those in N₁ and N₂,and the change trend of those in N₁ and N₂ were relatively gentle,indicating that nitrogen addition was adverse to the accumulation of SP and SS of E.grandis saplings.However the increase rate of proline (Pro) in N₁ and N₂ was higher than that in N₀ with the extension of drought.(3)With the aggravation of drought stress,the contents of H₂O₂ and MDA in E.grandis saplings in treatment N₁ and N₂ were obviously higher than those in treatment N₀,which indicated that nitrogen addition brought about more serious water deficiency of E.grandis saplings and produced more reactive oxygen species (ROS).(4)Nitrogen addition did not significantly change SOD activity and AsA content of E.grandis saplings in the process of drought stress,but POD activity in N₁ and N₂ was obviously higher than that in N₀.(5)Nitrogen addition increased the pigment content of E.grandis saplings and kept at a higher level and correspondingly the net photosynthesis rate(P_n) was at a high level at the beginning of drought stress (0~3 d),but with drought time prolonged,P_n declined more rapidly,and change trend of transpiration rate (T_r) and Stomatal conductance (G_s) were nearly same as P_n.The results suggested that nitrogen addition could enhance the photosynthesis and assimilation ability of E.grandis when soil moisture is sufficient,and promote its growth.However it is more likely to encounter water deficit in face of drought stress and reduce its ability to drought resistance.Thus in the process of management of E.grandis plantation,nitrogen addition should not be implemented before the coming of drought or seasonal drought.Otherwise irrigation or some watering measures should be taken.

Abstract:In this study,the seedlings of the wetland emergent plant,Canna generalis Bailey,were used as the experimental materials.Pretreatment of the seedlings with 150 μmol/L MgCl₂ was conducted under the greenhouse conditions for 12 h.Subseqently,treatment of the seedlings with farmland wastewater containing 10 mg/L nitrate (NO₃--N) was performed to investigate the effects of MgCl₂ pretreatment on the nitrate absorption efficiency,the plasma membrane H⁺-ATPase and H⁺ pump activities and the interaction of plasma membrane H⁺-ATPase and 14-3-3 protein of C.generalis in farmland wastewater.The results showed that pretreatment of 150 μmol/L MgCl₂ for 12 h increased the nitrate absorption efficiency of C.generalis Bailey in farmland wastewater by 11%.Compared with those in the roots of the plants without MgCl₂ pretreatment,both the plasma membrane H⁺-ATPase and H⁺ pump activities in C.generalis roots with MgCl₂ pretreatment were significantly elevated.MgCl₂ pretreatment also enhanced plasma membrane H⁺-ATPase and 14-3-3 protein interaction in C.generalis roots.These results suggested that MgCl₂ pretreatment increased the Plasma membrane H⁺-ATPase activity by enhancing its interaction with 14-3-3 protein,thereby increasing the nitrate absorption efficiency of C.generalis in farmland wastewater.

Abstract:Present study explored seed dormancy type,seed germination response to temperature and water potential,and dormancy break methods of Vicia angustifolia,which extensively distributed in the Qing-Tibetan Plateau.The results showed that:(1)Fresh V.angustifolia seeds exhibited combinational dormancy,but one year stored seeds exhibited physical dormancy (PY) only.(2)Compared to one year stored seeds,fresh seeds had a narrower germination temperature range,and high temperature significantly inhibited its seed germination.Stored seeds germinated to 90% at 25 ℃,but fresh seeds germinated to 4% only.(3)Fresh seeds are more sensitive to water stress compared to stored seeds regardless of temperature.At 10 ℃,15 ℃,20 ℃,stored seeds germinated to 95%,91% and 89% at -0.4 MPa,respectively,and fresh seeds germinated to 85%,55% and 8% only.(4)Fluridon (FL) and gibberellic acid (GA₃) had no obvious effect on the germination of stored seeds,but significantly promoted the germination speed of fresh seeds at 20 ℃.Compared with the stored seeds,germination of fresh seeds are more sensitive to ABA inhibition.In addition to the highest concentration of paclobutrazol（PA,100 μmol/L),PA had no significant effect on germination of fresh and stored seeds.This suggests that ABA may be the main reason responsible for physiological dormancy of V.angustifolia seeds.Sulfuric acid scarification and cut treatment both could release seed physical dormancy effectively,and sulfuric acid scarification for 20 min is the optimal way to release physical dormancy of one year stored V.angustifolia seeds.

Abstract:During the sprouting stage in ratoon crop of sugarcane,with the methods of ELISA and bottom part sampling,we studied the relationship of changes in endogenous hormone between good (‘CYZ06-407’ and ‘CYZ06-415’) and poor (‘CYZ06-408’ and ‘CYZ06-416’) ratoonability sugarcane lines generated from one family ‘CYT97-20’×ROC25,where,good ratooning sugarcane cultivar ROC22 was used as control.The result indicated that:(1)The changes in content of IAA,content of ZR and the ratio of ZR/IAA in bottom part of stalk for good/poor ratooning lines were strong during sprouting stage.No significant difference were found between good and poor ratooning lines.(2)At bottom parts of cane stalk,the changes in content of GA₃,content of ABA,ratios of IAA/ABA and ratios of GA₃/ABA between good and poor ratooning lines differed significantly.The most significant difference were found in content of ABA,ratios of IAA/ABA and ratios of GA₃/ABA,which were important parameters;(3)Higher content of ABA in good ratooning lines than that in poor ones,lower ratios of IAA/ABA and ratio of GA₃/ABA than that in poor ones,with the declines in ratoonability,the ratios of IAA/ABA and GA₃/ABA increased.The result suggested good ratoonability was characterized high content of ABA and low ratios of IAA/ABA and GA₃/ABA,among which,content of ABA is the most important parameter for evaluating ratoonability.Meanwhile,other two important parameters IAA/ABA and GA₃/ABA ratios were recommended as well.

Abstract:Sulphur dioxide (SO₂) is one of the main atmospheric pollutants.It can seriously affected plants photosynthesis which is the key physiological processes of plants.Using fumigation treatment in sealed environmental control chambers,we studied the effect of different levels (concentration in natural condition,0.5 mg·L^-1,1.5 mg·L^-1 and 3.0 mg·L^-1 ) of SO₂ on content of chlorophyll,the photoresponse curve,photosynthetic parameters,diurnal variation of photosynthesis and sulfur concentration of potted saplings of Eucalyptus grandis and Cinnamomum pedunculatum.The results showed that:(1)SO₂ stress significantly decreased the content of chlorophyll a and chlorophyll b in E.grandis,while remarkably increased in C.pedunculatum.SO₂ stress made chlorophyll a/ b ratio of E.grandis was significantly lowered,for C.pedunculatum no significant effect on the ratio.(2)SO₂ stress significantly inhibited the net photosynthetic rate (P_n) of the two species.Stomatal conductance (G_s),intercellular CO₂ concentration (C_i) and transpiration rate (T_r) of E.grandis rose remarkably under SO₂ stress,and G_s and T_r of C.pedunculatum was significantly inhibited by SO₂,C_i firstly increased and then decreased.(3)Apparent quantum efficiency (AQY),dark respiration rate (R_d),light compensation point (LCP) and light saturation point (LSP) of E.grandis as well as R_d and LCP of C.pedunculatum first increased and then decreased with increasing concentration of SO₂,however,AQY and LSP of C.pedunculatum decreased.(4)In a day,SO₂ stress significantly increased P_n,G_s and T_r of E.grandis,and have no significant effect on P_n of C.pedunculatum,but lower concentrations of SO₂ stress significantly promoted G_s and T_r of C.pedunculatum.It was significantly restrained under high concentrations of SO₂ stress.C_i of both species were significantly inhibited under SO₂ stress.Sulfur content of both species showed an increasing trend under SO₂ stress.Overall,E.grandis may have a certain ability to adapt to lower concentration of SO₂ stress,but its resistance to high concentration of SO₂ stress is not as good as C.pedunculatum,which may be related to their different leaf morphology and physiological characteristics.

Abstract:The effects of different shading treatments (25%,50%,75% and 100% of full sunlight) on the growth,photosynthetic characteristics and chlorophyll fluorescence parameters of Rosa hybrida were examined in order to know the growth and physiological responses of R.hybrida to light regimes.(1)It has been found that with the decreasing light intensity,the leaf thickness,and flower diameter and flower formation rate decreased,while the Chl content increased.The net photosynthetic rate (P_n),transpiration rate (T_r),stomatal conductance (G_s) and intercellular CO₂ concentration (C_i) all decreased with the decreasing of light intensity,while the stomatal limitation value (L_s) increased.(2)The light compensation point (LCP),light saturation point (LSP) and dark respiration rate (R_d) also decreased as a mechanism of physiological adaptability to light decreasing.The adaptability of R.hybrida to light was wide because the LSP was 600～1 200 μmol·m^-2·s^-1 and the LCP was 29.89～62.95 μmol·m^-2·s^-1.The CO₂ compensation point (CCP) was 78.16～89.41 μmol·mol^-1,the CO₂ saturation point (CSP) was about 1 100 μmol·mol^-1 and the potential maximum photosynthetic capacity (P_m) was 13.06～25.63 μmol·m^-2·s^-1,which indicated that light intensity and CO₂ concentration have greater impact on photosynthesis rate.(3)The chlorophyll fluorescence parameters indicated that with the increasing of light stress,the reaction center of PSⅡ was destroyed,photosynthetic electron transform capability was weakened and photosynthesis was restrained.It is indicated that R.hybrida is a sun plant with shade tolerance.Moderate shading (75% of full sunlight) can improve its photosynthetic capacity and the flower quality,and reduce the photoinhibition in R.hybrida.

Abstract:Species diversity and its change is one of the main indicators of community succession dynamic process.Our objective was to examine the complex relationships between the species diversity and community succession in the successive serials from Pinus tabuliformis forest to P.tabuliformis-Quercus aliena var.acuteserrata mixed forest then to the subsequent Q.aliena var.acuteserrata forest on the south-facing slopes in Qinling Mountains.Changes of species composition and diversity in each vegetation stratum were studied using the method of substituting spatial difference for time change.The results showed that:(1)312 species of vascular plants belonging to 183 genera and 73 families were recorded in 45 quadrats investigated,among which there were 136 herbs,98 shrubs encompassing woody climbers,and 78 trees.The composition of the three communities was that there were 190 species belonging to 117 genera and 52 families,129 species belonging to 95 genera and 60 families,and 178 species belonging to 109 genera and 50 families in P.tabuliformis forest,P.tabuliformis-Q.aliena var.acuteserrata mixed forest and Q.aliena var.acuteserrata forest,respectively.(2)Species evenness and species diversity in herb layer decreased significantly during community succession (P＜0.05),species richness showed a V-shaped trend;shrub layer species richness,evenness and species diversity did not change conspicuously (P＞0.05);There was a significant hump-shaped pattern in species diversity in tree layer along the succession process,and the species diversity reached a peak in the community of P.tabuliformis-Q.aliena var.acuteserrata mixed forest.The studies above indicated that:changes of species diversity presented a hump-shaped model as a whole in the process of community succession of pine oak forests on the south-facing slopes in Qinling Mountains,which agrees with the intermediate species diversity hypothesis;The species diversity may simply be one of the basis or prerequisites to the community stability.

Abstract:Through a field investigation and data analysis to the only distribution area of Ammodendron bifolium population in Takeermohuer Desert of the Ili River valley in Xinjiang,we aimed to learn the actuality of A.bifolium population,and forecast the future dynamics of A.bifolium population.In this research,the size structure,life tables,survival curve,mortality curve and life expectancy of A.bifolium population were studied and population dynamics were predicted by a time-sequence model.The results show that:(1)The small-sized individual in A.bifolium population were more,namely the number of Ⅰ~Ⅲ diameter individuals accounted for 70.4%,the number of Ⅳ~Ⅶ diameter individuals accounted for 27.62%,the number of Ⅷ~Ⅹ diameter individuals accounted for only 1.98%.Therefore,population structure belongs to the growth type.However,the number ofⅠdiameter individuals was less than that of Ⅱ diameter individuals,so that the natural regeneration of A.bifolium population was poor.(2)The static life table analysis show that A.bifolium population mortality was on a rising tendency,and the number of the individuals with diameter more than 3.5 cm (Ⅷ diameter) decreased rapidly with the increase of diameter grade,namely the individual closing to Ⅷ diameter was more close to the physiological longevity.(3)The survival curve of A.bifolium population mainly belonged to Deevey Ⅲ type in research area.The survival number of Ⅰ diameter individuals was less than that of Ⅱ diameter individuals,and the survival number after Ⅱ diameter individuals decreased rapidly.It indicated that the population was lack of seedling transshipment and natural regeneration was blocked.(4)Through time-sequence prediction,the population in the future would be more aging individuals.The studies suggest that A.bifolium population growth in the Ili River valley of Xinjiang was mainly limited to its biological characteristics and intraspecific competition.Thus,it was difficult for A.bifolium population to maintain the stability.As a result,the crucial factors for the natural regeneration and restoration of A.bifolium population in research aera are the protection of living individuals and their habitat and the revegetation by human.

Abstract:The protoplasts were isolated by enzymolysis method from calli of 4 cultivars of Medicago varia (‘Gannong 1’) and Medicago sativa (‘Gannong 4’,‘Algonquin’ and ‘Qingshui’) which have an excellent growth adaptability in Loess Plateau of northwest of China,and the yield and viability of these protoplasts were measured under the different enzymolysis conditions,and their influence factors,such as enzymolysis time,enzyme combination,mannitol concentration,pretreatment measures and subculture time were discussed.Results show that:(1)The optimum pretreatment measure was 0.55 mol/L sucrose or CPW solutions plasmolysis for 1 h and the optimum subculture time was 12 d for 4 cultivars.(2)The best enzyme solution combination for ‘Gannong 1’,‘Gannong 4’ and ‘Qingshui’is 2% cellulose onozuka R-10+0.5% pectinase Y-23+0.3% driselase and for ‘Algonquin’ is 2% cellulose onozuka R-10+0.5% pectinase Y-23+0.3% hemicellulose+0.3% macerozyme+0.3% driselase.Enzymolysis 12 h is best time for ‘Gannong 1’ and ‘Algonquin’,14 h is for‘Gannong 4’and 10 h is for‘Qingshui’.(3)The suitable mannitol concentration was 0.75 mol/L for ‘Gannong 1’,0.65 mol/L for ‘Gannong 4’,0.6 mol/L for ‘Algonquin’ and 0.55~0.6 mol/L for ‘Qingshui’.(4)The regenerated calli can be formed from protoplasts of 4 alfalfa cultivars both by liquid medium and solid-liquid medium,and solid-liquid double layer culture is more helpful for division and regeneration of 4 cultivars than thin layer liquid culture.

Abstract:6 species are reported as new records in Jilin Province,which belong to 5 families and 6 genera.They are Carex capricornis,Elymus dahuricus var.cylindricus,Agropyron mongolicum,Scutellaria viscidula,Spiraea aquilegiifolia,Ixeridium gracile.

Abstract:Melatonin was firstly found in plants in 1990s.In recent years,the related research on it attracted the attention of many scholars.There were many studies focusing on the content detection method of melatonin in plant,and the physiological function of melatonin in plant was also reported recently.Various methods of melatonin determination were employed for plant samples.The analysis methods included RIA,HPLC,GC,HPLC-MS and GC-MS.Among several methods,HPLC-FD and HPLC-ECD were commonly used to quantify melatonin in plants.The content of melatonin varied in different plant species and organs.Higher content of melatonin was found in seeds and flowers.Nowadays,melatonin was shown to act as a plant growth regulator that directs the differentiation of plant cells,tissues,and organs.It also appears to protect plants against environmental stress from heavy metals,UV radiation,and temperature change.However,the mechanism of its function in plants and the exact synthetic site need to be further investigated.The present paper reviewed some aspects of melatonin in plant:detection,biological synthesis and physiological functions.The potential subjects of melatonin in plant were also proposed.

Abstract:Adversity stress seriously affect growth and development of plant,even reduce crop yields.In most transgenic engineering,constitutive promoters are being used to drive the expression of exogenous genes.Recent years,constitutive promoters have been identified to improve the resistance of transgenic plants to abiotic stress,but over-expression of exogenous genes driven by constitutive promoters could cause growth stunted and yield reduction of transgenic plants.Inducible promoters only drive exogenous genes to express in special conditions,such as abiotic stress and environment inducible.This paper reviews the types and functions of inducible promoters.The prospect of stress-induced promoters was also discussed.