Abstract:To explore the potential roles of oxalic acid (OA) in the pathogenesis of Sclerotina sclerotiorum,we sprayed 30 mmol/L OA evenly onto 3-week-old Arabidopsis and found AtWRKY63 was markedly induced by OA.To further elucidate the function of AtWRKY63,we obtained pure line of AtWRKY63-overexpression Arabidopsis by constructing AtWRKY63-overexpression vector and transforming Arabidopsis.The Arabidopsis plants overexpressing AtWRKY63 showed enhanced resistance to S.sclerotiorum.Histochemical staining revealed that overexpression of AtWRKY63 induced oxidative burst in host plants,which suppressed the hyphal growth of S.sclerotiorum,and consequently inhibited fungal infection.qRT-PCR analysis indicated that AtWRKY63 may involve in salicylic acid-dependent and jasmonic acid-dependent defense signaling pathway,thus,confers the resistance to S.sclerotiorum.

Abstract:Alfalfa varieties ‘Zhongmu No.2’ was acted as the wild-type material.Agrobacterium-mediated method was used to introduce dehydrin gene(AmDHN) into alfalfa.PCR and southern blot methods were used to detect the presence of AmDHN in transgenic alfalfa plants.The expressions of AmDHN and cold-related genes were detected in transgenic plants of T₀ generations through RT-PCR and qRT-PCR.The content of proline and MDA of two plants were detected.Cold resistance of the transgenic alfalfa plants was detected by molecular level and physiological characteristics,which will provide a basis for new transgenic alfalfa material with resistance to cold stress.The main results are summarized as follows:(1)Expression of AmDHN was determined at different levels in transgenic alfalfa plants.(2)After being treated with 4 ℃,expressions of cold-related genes(CBF2,CBF3,ProDH and CAS17) were dramatically higher than WT.Expressions of CBF2,CBF3 and CAS17 increased significantly after being treated 5 h,reached an extremely significant level(P＜0.05),as compared with WT plants.The level of ProDH transcripts reached the maximum at 7 d after treatment by 4 ℃,their maximum were 2.5,4,1.6 and 3 times than WT,respectively.(3)The contents of both proline and MDA were increasing with extending treatment time.The content of proline of transgenic plants was significantly higher than that of WT.The content of MDA was significantly lower than that of WT,both goes up to an extremely significant level at 14 d after the treatment.These results suggested that transgenic plants may be more resistance to cold stress compared with WT.These imply that AmDHN proteins may protect the enzyme activity and membrane systems from freezing injury.Simultaneously,AmDHN may regulate indirectly cold tolerance of the plants through regulating the expressions of cold-related genes.

Abstract:In this study,the gene GPX(glutathione peroxidase) was cloned by RACE from the seeds of ‘Hongyushizi’,a cultivar of pomegranate.The expression of PgGPX in different organs of ‘Hongyushizi’ and its leaves under salt stress were analyzed by Real-time PCR.The results showed that the length of PgGPX was 872 bp and its ORF was 504 bp which encoding 168 amino acids.Bioinformatics analysis showed PgGPX possessed a typical conserved domain of GSH-Peroxidase and had high consistency with Theobroma cacao,Litchi chinensis,Ricinus communis and Zea mays as 90.30%,87.40%,86.80% and 86.20%,respectively.The real-time PCR results showed the expression of PgGPX in leaf,petal and aril were all detected and its expression had tissue specificity.The expression levels of PgGPX increased obviously under salt stress indicated that it may play an important role in stress reaction.

Abstract:Rice blast and bacterial blight,caused by Magnaporthe oryzae and Xanthomonas oryzae pv.oryzae,respectively,are two principal diseases worldwide.Meanwhile,these diseases are also the major limitations in rice production in China.Lijiangxintuanheigu(LTH) is a highly susceptible cultivar to rice blast,while Tetep(TTP) has broad-spectrum resistance against the pathogens.However,the molecular mechanism underlying the difference on disease resistance in LTH and TTP is largely unknown.To identify the nucleotide difference in multiple resistance genes between these two cultivars efficiently,6 known R genes were amplified from LTH and TTP,respectively.The PCR products were mixed with a 10-cycle difference in Ct value and sequenced together by the next-generation sequencing(NGS) technology.The results were validated by traditional sequencing strategy.Our results revealed that the NGS can rapidly identified nucleotide polymorphisms from multiple PCR-amplified products of different cultivars in single sequencing run,which is more economical and more efficient to find sequence difference of target genes among different cultivars.Additionally,we found that the sequence of R genes in TTP is more similar to that of original functional alleles,while the sequence of R genes in LTH has more mutations that altering amino acid.

Abstract:Expression pattern of GmARF10 gene was analyzed by real-time quantitative PCR(qPCR) method.The working model between Gm-miR160 and its targets was investigated by mining soybean and Arabidopsis genome data,and the resistant version vector GmARF10∷mGmARF10(mGmARF10) was constructed.The mGmARF10 vector was transformed into wild type soybean by Agrobactium-mediated method and transgenic plants were phenotyped physiologically and molecularly.The results showed that transcripts of GmARF10 exhibit the highest levels in floral organs and the lowest levels in stems among the tested soybean organs.Moreover,its transcriptional level was found lower in first trifoliolate leaves than either in cotyledons or in unifoliolate leaves.There is no dramatically difference between the transgenic leaves and the control leaves in respect of leaf shape and size.However,the leaves of transgenic plants show decreased levels in chlorophyll content and maximum quantum efficiency(F_v/F_m) and increased transcription of GmCYSP1,a senescence-associated marker.Taken together,these results suggest that the soybean auxin response factor GmARF10 may be involved in leaf senescence and likely act as a positive regulator in leaf senescence.

Abstract:An alien disomic addition line,‘Shannong 120211’,which derived from the progeny of Thinopyrum intermedium and common wheat cv.‘Yannong15’,were identified in morphology,cytology,genome in situ hybridization(GISH),powdery mildew resistance and salt tolerance.Resistance identification of adult in field and seeding in lab showed that ‘Shannong 120211’ was nearly immune to powdery mildew.Compared with the ‘Shanrong 3’,which was highly resistant to salt,the result of salt tolerance is level 2.The results demonstrated that the main morphological traits of ‘Shannong 120211’,with the chromosome number of 2n=44 in root tip cells and chromosome configuration of 2n=22Ⅱat PMC MI.The results of GISH showed that there were two chromosomes of ‘Shannong 120211’ with obvious hybridization signals,which further proved that ‘Shannong 120211’ was an alien disomic addition line with a pair of Th.intermedium chromosomes in wheat background.Using 71 pairs chromosome specific molecular markers of group E to analyze the ‘Shannong120211’,we found marker BE494262 could reveal the specific band of Th.intermedium and be used to identify ‘Shannong 120211’.Using Thinopyrum elongatum and the addition line of Cs-Thinopyrum elongata(1E^e-7E^e) to further located the BE494262 at 2E^e,which identified that the added chromosomes of ‘Shannong 120211’ came from the 2E^e of T.intermedium.

Abstract:A 160 recombinant inbred lines(RILs) were derived from a cross between ‘PI183967’and a cultivated Northern Chinese inbred line‘931’.The constructed genetic map and phenotypic data in different seasons were used to identify the quantitative trait loci(QTL) associated with fruit length(Fl) and stalk length(Fsl).Results showed that:(1)8 QTLs related to Fl and Fsl were located on Chr.3,4,5,6 and 7 with LOD between 2.78 and 10.24,which explained 7.4%-32.7% of the phenotypic variation.Of those QTLs,there were 4 QTLs which explained over 10% phenotypic variation and 4 QTLs which could be detected in different seasons.(2)4 QTLs(Fl3.1,Fl4.1,Fl5.1,Fl6.1) associated with fruit length and 4 QTLs(Fsl3.1,Fsl 5.1,Fsl6.1,Fsl7.1) associated with stalk length.(3)Fl6.1 and Fsl6.1 could be detected in 2012,2013 spring and autumn which located on 109.2 cM of chromosome 6 between SSR17591 and C80.The range of phenotypic variation of Fl6.1 was 13.8%-32.7% and Fsl6.1 was 12.1%-24.1%.(4)Fl3.1 and Fsl3.2 were located between SSR16152 and SSR07706.The QTL of Fl3.1 was detected in 2012 autumn and 2013 spring and autumn,explaining 25.1% of the phenotypic variation in all,while Fsl3.2 was just detected in 2012 autumn,which explained 8.8% of the phenotypic variation.Therefore,the region of SSR17591-C80 on Chr.6 and SSR16152-SSR07706 on Chr.3 were major regions which controlled fruit length and stalk length.The two regions should been put key location for the future research on fruit length and stalk length.

Abstract:The chromosome numbers and karyotypes of five species from genera Paraprenanthes Chang ex Shih,Pterocypsela Shih and Notoseris Shih(Compositae-Cichorium) were investigated with the conventional pressing plate method.The results show that their chromosome numbers all are 2n=18 and karyotype of Paraprenanthes diversifolia is reported for the first time.The karyotype formulas are expressed as 2n=8m+10sm(2SAT) for P.diversifolia,2n=4m+10sm+4st for Pterocypsela indica,2n=10m+8sm(2SC) for Notoseris macilenta,2n=10m(2SAT)+8sm for N.triflora,2n=12m(2SAT)+6sm for N.porphyrolepis.Paraprenanthes and Notoseris belong to Stebbins “2A” type and Pterocypsela belongs to Stebbins “3A” type.

Abstract:Based on the morphological observation and anatomical study,we revealed the developmental characteristics of bulbil,which is the vegetative propagule of Banxia(Pinellia ternata).The bulbil of P.ternata was formed in the lower part of petiole.In young leaves,it was started from the parenchyma cells that located in the adaxial part near the outer ring of three-ring vascular bundle.Dedifferentiation cells divided continuously to form the primodia of bulbil.The primodia differentiated to form the shoot apical meristem(SAM) on the top and to form the infant bulbil after it grew enough to protrude the surface of petiole.There was not root formation for developing bulbil.Bulbil growth stopped because of leaf senescence naturally.Our results indicated that bulbil of P.ternata was vegetative progagule that resembles the adventitious bud.The development of bulbil in P.ternata was different from the formation of bulbils in other kinds of plant species.

Abstract:In the development process of the fruit of Lycium barbarum L.,we measured the starch content and starch metabolism related enzyme activities in the fruit,and observed plasmid ultrastructure and starch histochemical localization in the peel cells systematically.The results showed that:(1)Starch content in the fruit of L.barbarum L.increased first and then reduced with the development of fruit,14 d after flowering its content reached the highest(13.85 mg·g^-1).(2)In the fruit,α amylase activity and β amylase activity along with the fruit mature,presents the tendency of increase gradually,and α amylase activity is always higher than β amylase activity.(3)Histochemistry and ultrastructure studies have shown that the amyloplast enriched much more starch grain before veraison stage(24 days after blossom),but starch grain almost disappeared during the second rapid growth stage,meanwhile the starch grain was not observed in chloroplast.The starch was a transient form of carbohydrate accumulation during fruit development,which was available to form sugar concentration gradient between “source” and “sink” and accelerate sugar unloading from phloem and played an important role in maintain the sink capacity in early phase fruit.With the sink capacity increasing during the second rapid growth stage,the starch was degraded into reducing sugars by the action of amylase and accumulated in fruit parenchyma cell.

Abstract:Wild Delphinium grandiflorum L.in Beijing was introduced and blossom character was observed.Pollen viability,stigma receptivity,pollen and ovule ratio (P/O) and OCI were examined,and artificial pollination test was developed.The results are as follows:(1)The inflorescence of D.grandiflorum had a raceme containing 3-15 flowers.The pedicel was 1.5-3.8 cm in length.The blossoming period of single flower and inflorescence were 10 d and 15-18 d,respectively.(2)The pollen viability increased at the early stage and decrease later in daily variation.The stigma had receptivity at 5-6 days after blooming and had no receptivity on the first 4 days.(3)Its P/O was 2 159.14,and OCI was 5.According to the artificial pollination test,D.grandiflorum could set seeds and the seed setting rate was 100% under natural conditions.The phenomenon of self pollination autonomy and partly self-compatible could be observed;furthermore.The seed setting was restricted by pollinators without apomixes.(4)The main visiting insects of D.grandiflorum were Amegilla (s.str.) quadrifasciata (Villers) and Eristalis arbustorum (L.).The research suggested that the breeding system of D.grandiflorum belonged to facultative xenogamy or obligate outcrossing,accompanied with partly self-compatiblity.The pollinator was necessary.

Abstract:Grass pea(Lathyrus sativus L.) seedlings cultured in hydroponic solution for 7 days were used as experimental materials.Different concentrations of H₂O₂ were applied to hydroponic solution for 24 h to stress L.sativus seedlings.In order to reveal the tolerance mechanisms of oxidative stress in L.sativus roots,the extent of oxidative stress and the response of antioxidant system to oxidative stress were analyzed in roots.Results showed that:(1)The weight of fresh roots reduced significantly.However there was no significant change in the number of lateral roots with H₂O₂ concentration increasing.(2)The scope and extent of H₂O₂ staining was significantly increased,but the apical region always remained relatively low levels of H₂O₂.In contrast,the scope and extent of O^-·₂ staining were significantly reduced and the apical region always maintained a high level of O^-·₂.(3)The content of ascorbic acid(ASC) and the activities of catalase(CAT),peroxidase(POD) and ascorbate peroxidase(APX) all exhibited a decrease trend after an initial increase.However,superoxide dismutase(SOD) has been showing an upward trend.The results above showed that O^-·₂ accumulation could be positively related to the growth and vigor of L.sativus root and H₂O₂ accumulation could be positively related to the extent of oxidative stress.The studies also confirmed that low concentrations of H₂O₂ treatment could improve the scavenging ability of antioxidant system for ROS in L.sativus roots.

Abstract:The effects on the photosynthetic pigments,the diurnal changes of chlorophyll fluorescence parameters and ultrastructure used by 0.20 mg·kg^-1 as CK and 0 mg·kg^-1 as molybdenum deficiency treatment were studied on flue-cured tobacco of fast growing period,which is one of the model crop materials.The results showed that:(1)The contents of chlorophyll and carotenoid in tobacco leaves under molybdenum deficiency were significantly lower than those under Mo-fertilized treatment.(2)The net photosynthetic rate(P_n) declined under molybdenum deficiency earlier than that under Mo-fertilized treatment in a day,and the P_n of tobacco in Mo-fertilized treatment was a typical bimodal daily variation.(3)Under molybdenum deficiency,the maximal photochemical efficiency(F_v/F_m)decreased significantly at 12:00 and increased slightly at 16:00.At 10:00,the electron transport rate(ETR) and the quantum yield(Y) began to decrease,but the initial fluorescence(F₀)and the non-photochemical quenching efficiency(NPQ) increased sharply,then they did not recover to the level at 8:00.In contrast,under Mo-fertilized treatment,the F_v/F_m was stable,ETR and Y reached the lowest point at 14:00 and then increase slightly at 16:00.F₀ and NPQ increased slower during 12:00-14:00,and recovered to the level at 8:00.(4)The grana layer of the ultrastructure of tobacco leaves under molybdenum deficiency expanded to deformation and loose.The amyloid number was less and grew worse.While the grana layer of the tobacco in Mo-fertilized treatment were arranged neatly,and the amyloid grew well.In summary,under molybdenum deficiency,the contents of the photosynthetic pigments of fast growing period tobacco decrease,ultrastructure grows worse,and the chlorophyll fluorescence parameters are sensitive to the bright-light and high-temperature,photosynthetic primary action is inhibited,so the P_n and photosynthetic carbon assimilation product decreased.

Abstract:Using detached leaves of three Olea europaea varieties (‘Gordal’,‘Chenggu 32’ and ‘Frantoio’) as experimental materials,we determined their physiological and biochemical indexes,to explore the mechanism on drought resistance of different olive varieties under 30% PEG stress.The results showed that:(1)With the time of osmotic stress prolonged,the water and chlorophyll contents in detached leaves of different olive varieties decreased,while the relative electrolytic leakage and MDA content increased significantly.The result indicated that,the osmotic stress caused deterioration of water conditions,decomposition of chlorophyll,aggravation of lipid peroxidation and damage of cell membrane of the leaves;meanwhile,relative content of bound water and free water,O^-·₂ producing rate,SOD activity and regulatory substances in leaves of three olive varieties showed a rising trend.(2)Inter-species comparison,with the time of osmotic stress prolonged,MDA content of ‘Frantoio’ leaves was lower than that of ‘Gordal’ and higher than that of ‘Chenggu 32’.In the same period,changes on the contents of bound water and free water,superoxide anion production rate,SOD activity in different species leaves showed similar performance.In conclusion,the results indicated that the drought resistance of the three olive varieties was ‘Chenggu 32’>‘Frantoio’>‘Gordal’;furthermore,higher ratio of bound water content/free water content,less O^-·₂ producing rate,higher SOD activity and more regulatory substances of ‘Chenggu 32’ under the osmotic stress can guarante the leaves of ‘Chenggu 32’ had the strongest ability of osmoregulation and the strongest ability to endure dehydration and lipid-peroxidation under the osmotic stress,so the drought resistance of ‘Chenggu 32’ was better than that of ‘Gordal’ and ‘Frantoio’.

Abstract:The physiological biochemical mechanism of heat stress Potentilla fruticosa was investigated through measuring the changes of physiological and biochemical indicators in leaves of the 2-years old P.fruticosa under the conditions to 6 d high temperature stress (42 ℃ from 9:00 to 15:00 and 30 ℃ during the rest time of each day) and 1 d recovery (Control,30 ℃ from 6:00 to18:00 and 20 ℃ during the remainder time of each day).Results showed that the membrane permeability,the contents of MDA,soluble sugar content and free proline content increased gradually,while the activity of SOD decreased,the activities of POD,CAT and APX first rose and then declined with the high temperature stress.All the indicators under the heat stress were significantly higher than that of control.However,the membrane permeability had no significant difference with control.All the indicators following 1 d recovery were almost same with control.P.fruticosa could increase the adaptability to heat stress by increasing the contents of osmoregulation substances such as soluble sugar and proline.In addition,P.fruticosa would improve the resistance to heat stress by increasing the activities of antioxidases such as POD,CAT and APX to remove the excess H₂O₂ and active oxygen to maintain the dynamic balance of generation and removal of reactive oxygen of cells.

Abstract:Selecting Ziziphus jujuba Mill.cv.Lingwuchangzao as materials,we determined the changes of the soluble sugar contents and the activities of sucrose metabolism-related enzymes during the development of leaf and carpopodium to study the relationship between the sugar accumulation and its metabolizing enzymes in leaf and carpopodium during the development of fruit.The result showed that:(1)The leaf and carpopodium all mainly accumulated sucrose;the contents of glucose and fructose in leaf and carpopodium kept stable and increased slightly with fruit development,but the contents of sucrose decreased at early stage and increased quickly later.The content of sucrose was higher than that of glucose and fructose all the time.(2)The acid invertase(AI) activity in leaf and carpopodium was significantly higher than that of the neutral invertase(NI) during the whole growth development period of fruit.AI activity increased at early stage and kept stable at later stage,but the change trend of the activities of sucrose synthase(SS) and sucrose phosphate synthase(SPS) was different.(3)The sucrose synthase activity in the sucrose decomposition direction(SSd) plays important regulation role in accumulating sucrose in leaf and carpopodium.To sum up,the SSd plays important regulative role in accumulating sucrose in leaf and carpopodium.

Abstract:Through soaking seeds with different concentrations of GA₃ combination of variable temperature stratifications,we analyzed the content of four hormones(GA₃,IAA,ABA,ZR) in seeds of different periods by high performance liquid chromatography and measuring the embryo length and seed germination rate of M.sieboldii,to learn the relationship among the development of embryo,the levels of endogenous hormones and the regulation of seed dormancy and germination,to provide a theoretical basis for further study of seed dormancy mechanism,to provide a theoretical basis for further research on seed dormancy mechanism.we came to certain conclusions as below:(1)Embryo of mature seeds of M.sieboldii developed incompletely and seed dormancy was mainly due to high concentration of ABA and low concentrations of GA₃;(2)GA₃ treatments could stimulate the morphological maturation of seeds by 30 days,and treatment with GA₃ of 1 500 mg·L^-1 saw the best effect;(3)The whole temperature stratification process could be divided into three stages:Stage Ⅰ(0-70 d),this stage was to complete the further differentiate of the seed embryo;Stage Ⅱ(70-120 d) was the fast grow period of embryo;Stage Ⅲ(120-150 d),seed dormancy was broken absolutely and seeds had the ability to sprout.Whether seeds can break dormancy depends on stage Ⅰ and stage Ⅱ;(4)The changes of GA₃/ABA,IAA/ABA and ZR/ABA consist of embryo growth and development during the ripening of the seeds.The relative level of hormones played an important role in seed dormancy regulation.

Abstract:In order to investigate the difference of quality and aroma composition of ‘Kyoho Grape’ between normal fruit under open cultivation and secondary fruit under protected cultivation,we used the solid phase micro-extraction(SPME) and gas chromatography-mass spectrometry(GC-MS) for determination.The result showed:(1)The single fruit weight,longitudinal diameter and transverse diameter of secondary fruits under protected cultivation were reduced by 8.23%,11.74% and 10.63% respectively,compared with ‘Kyoho Grape’ normal fruit with open cultivation.The total soluble sugar content increased by 8.95%,titratable acid content increased but the difference was not significant,fruit Vc content(1.47 mg·kg^-1) was significantly lower(2.00 mg·kg^-1) than that of control.The peel proanthocyanidins content were 3.37 times more than that of control and fruit color was significantly deeper than that of control.(2)Aldehydes were the richest compounds in secondary fruits of ‘Kyoho Grape’ with relative content of 53.55%,while esters were the richest in normal fruits with relative content of 61.36%.The relative content of ethyl acetate under open cultivation and the secondary fruit under protected cultivation were both higher,it showed that the two had obvious strawberry flavor.But aromatic compound of the highest relative content was 2-hexenal(41.14%) in secondary fruit.It was significantly higher than that of control(16.31%).The result showed that total soluble sugar content of secondary ‘Kyoho Grape’ was higher than that under open cultivation,but the fruit was smaller.Because 2-hexenal of grape berries had the very important influence on the aromatic components constitutes,it could change fruit flavor.Therefore,there were certain differences on fruit flavor between protected cultivation and open field cultivation of ‘Kyoho Grape’.

Abstract:GC-MS,AAS and HPLC were selected to analyze the content of general component(crude fat,crude protein,ash,moisture,total sugar,toal dietary fiber),amino acids,trace elements,fatty acids and amygdalin in the Amygdalus pedunculata Pall.seeds,which came from four regions:Shenmu,Shaanxi;Baotou,Inner Mongolia;Alashan Inner Mongolia and Chengde,Hebei.The results showed that the content of the seeds from different areas had some difference,but there were some similarities as follows:The seeds were rich in crude fat(416-478 g/kg) and crude protein(206-286 g/kg);The amino acids in the seeds were abundant and complete in varity;All the seeds contained 9 mineral elements(K,Mg,Ca,P,Na,Fe,Zn,etc.) that were necessary for the human health;Elements like Pb,Cd,Hg,As were not found;The content of unsaturated fatty acid,most of which were oleic acid and linoleic acid,in the seed oil was over 96.8%;The content of amygdalin was 3%.The results showed that the A.pedunculata Pall.seeds can be used to produce edible oil,protein and amygdalin.That is to say,it had great economic value and it was fit to plant in the desert north of our country.

Abstract:The saturated photosynthetic rate(P_max),photosynthetic nitrogen use efficiency(PNUE),as well as their relationships with the nitrogen allocation in cell wall(N_CW/N_L),nitrogen allocation in photosynthetic enzyme(N_R/N_L) and leaf mass per unit area(LMA) of 4 trees and 4 shrubs in different successional stages of the evergreen broad-leaved forest in Tiantong National Forest Park were studied by the method of space instead of time.The result showed that:(1)There were significant differences for every index except N_L,the mean values of N_R/N_L,PNUE,P_max in earlier successional stages were higher than those in later successional stages;the species in the later successional stages had higher LMA,N_CW/N_L and M_CW/M_L.No significant differences were found among the values of N_L in the 4 trees.However,there were significant differences among the shrubs.The mean values of LMA,N_CW/N_L and M_CW/M_L in trees were higher than those in shrubs,while the N_R/N_L had an opposite tendency;the P_max and N_L of Myrica rubra were the highest,Camellia fraternal had the lowest values.Castanopsis sclerophylla had the hightest values of PNUE,Castanopsis fargesii,in the contract,the lowest.(2)With the progress of the succession,the N_R/N_L,PNUE,P_max of the earlier successional stages decrease gradually.N_CW/N_L,LMA and M_CW/M_L increase,respectively,but the species of later successional stages had a opposite trend.(3)N_R/N_L was significantly negatively correlated with the PNUE and P_max(P<0.01),respectively,while LMA,M_CW/M_L,N_CW/N_L were positively correlated with PNUE,P_max and N_R/N_L respectively(P<0.01).The research suggested that the negative correlation between N_CW/N_L and N_R/N_L and their influences on the PNUE can be explain the trade-off between the photosynthesis and persistence as well as the physiological mechanism of the succession to some extent.

Abstract:The experiment was conducted with Alhagi sparsifolia of the natural vegetation area in fllower reaches of Tarim River to investigate the change of the chlorophyll fluorescence parameters such as actual photochemical efficiency of PSⅡ(Φ_PSⅡ),electron transport rate(ETR) and photochemical quenching index(q_P) and leaf water potential under 2 times/year,1 times/year irrigation regimes(0.42 m³/m² of every time) and no irrigation(CK),and to discuss the impact of the different irrigation regimes on the chlorophyll fluorescence characteristics.The conclusions were as following:(1)With decreasing irrigation regimes,the leaf water potential of A.sparsifolia significantly decreased,and was the least under CK.(2)The q_P,Φ_PSⅡ,ETR,the maximal photochemical efficiencies of PSII(F_v/F_m),chlorophyll SPAD value and the light saturation point of A.sparsifolia were initially increased with the decreasing irrigation regimes and then it decreased.Whereas,the non-photochemical quenching(NPQ) and the yield for dissipation by down-regulation(Y_NPQ) of A.sparsifolia were also reduced first with decreasing irrigation regimes and then it improved.(3)A.sparsifolia under CK and 2 times/year irrigation regimes suffered inhibitory effect which declined its light utilization capability and photochemical reaction,However the heat dissipation ability was improved.As a result,excessive amount of irrigation(2 times/year,0.84 m³/m²) or no water supply(CK) could restrict the photochemical efficiency and photosynthetic activity of A.sparsifolia.The right time and the moderate water supply(supply water once in the spring,0.42 m³/m²) was more conducive to A.sparsifolia to adapt to drought stress and maintain normal growth photosynthesis.

Abstract:Terrestrial ecosystems can act as both “carbon source” and “carbon sink” in the global carbon cycle and play an important role in regulating the global carbon balance.The carbon exchange between grassland ecosystem and atmosphere is an important component of terrestrial ecosystem carbon cycle.The Loess plateau is known for its thick loess and wide distribution,which brings a great impact on the agricultural production of China,as well as the global climate change.However,the carbon sequestration potential and the capacity and distribution of carbon source/sink in the grassland ecosystem on the Loess plateau is still not clear.Based on the continuous measurement of soil respiration and net ecosystem CO₂ exchange rate between fenced and natural grazed grassland in Loess Plateau by using closed chamber method from March 2012 to February 2013,we studied the temporal variations of soil respiration and net ecosystems CO₂ exchange with the effects of soil temperature and soil moisture.The results are as follows:(1)The annual total carbon exchange in each sample plot appears as carbon sink.The annual total carbon exchange in fenced grassland is (-58.0±14.5) g·m^-2,of which growing season and non-growing season make up (-70.3±11.4) g·m^-2 and (12.4±3.1) g·m^-2,respectively.The annual total carbon exchange in natural grazed grassland is (-48.7±14.0) g·m^-2,of which growing season and non-growing season make up (-56.9±10.6) g·m^-2 and (8.1±3.3) g·m^-2,respectively.(2)The net ecosystem CO₂ exchange rate in growing season is mainly controlled by soil moisture,while in non-growing season is mainly controlled by soil temperature.The soil respiration rate is mainly affected by soil temperature and soil moisture,but the situation is different in different seasons,the effect of soil moisture is greater in growing season,while the effect of soil temperature is greater in non-growing season.(3)The difference of soil organic carbon content between two sample areas is the main cause that the soil respiration rate of fenced land is greater than natural grazed land.(4)Negative CO₂ flux was observed in the sample areas,which might be attributed to the precipitation of soil inorganic carbon,which can be accelerated in the alkaline soil (pH>8.2).

Abstract:Based on data information investigated twice in Xiaolongshan forest region of west of Qinling Mountains in 2008 and 2013,we chose trees Quercus aliena var.acuteserrata,Staphylea holocarpa and Acer davidii as research objects,and then changes of spatial pattern and correlation for the above trees in five years were analyzed with O-ring O(t) method of point pattern.Spatial pattern of Q.aliena var.acuteserrata must be discussed depending on different forest layers,but that of S.holocarpa and A.davidii and correlation of all population would not rest on forest layers for further study.The results show that:(1)Spatial pattern distribution of forest stand Q.aliena var.acuteserrata was,as a whole,random over five years.Q.aliena var.acuteserrata distributed randomly in the upper forest layer,more evenly in the middle and clumped obviously in the lower.The small number of S.holocarpa and A.davidii led to them with random distribution on most scales and then later,along with time variation,to them with lightly aggregated distribution on small part of scales.(2)For changes of spatial population correlation,there was negative correlation between S.holocarpa and Q.aliena var.acuteserrata on most scales for competition at the stage of sapling,and independent distribution on small part of scales to the certain stage of growth.The relation between Q.aliena var.acuteserrata and A.davidii,and S.holocarpa and A.davidii kept independent on the whole,but gradually the correlation existed on a small scale.The research indicates that,in different survey time,change of spatial distribution pattern for dominant trees in Q.aliena var.acuteserrata forest depended strongly on the scale,goodness of fit of the distribution pattern was high,and the forest stand on the whole was random distribution,namely spatial distribution pattern remained largely unchanged in five years;for principal species,the change of distribution pattern of Q.aliena var.acuteserrata conformed to growth regulation of communities and that of S.holocarpa and A.davidii was more affected by number of trees;change of forest spatial correlation was connected with population structure and its stage of succession;but for successional process of community,successional change of forest community in five years won’t enough represent successional rule of all forest stand,and the study must be still carried out over a long period.

Abstract:Based on the method of contiguous grid quadrate,the Emmenopterys henryi seedlings field data were sampled,I studied the spatial distribution of them by using the tests of discrete distribution pattern,dispersal index,Morisita’s pattern index,aggregation intensity and Greig-Smiths’ mean variance method.The result showed that the distribution pattern of E.henryi seedlings was clustering.The aggregate intensity was affected greatly by group scale,and dropped with the scale increasing.The trend of the aggregate intensity also declined with the increase of altitude.It was displayed that E.henryi seedlings clumped in 8-16 m² and 50-64 m² from Greig-Smiths’ mean variance analysis.A large number of E.henryi seedlings were less than 40 cm tall,and most of them died before the height of 120 cm due to the strong environmental screening.The tree coverage,shrub coverage,intensity of illumination,atmosphere temperature and atmosphere humidity were the main factor affecting on the growth,survival and distribution of E.henryi seedlings by principal component analysis.In order to promote E.henryi seedlings development,native habitat should be protected and the natural regeneration should be strengthened through by thinning,cleaning up the moss,litter and others.

Abstract:With the floral organs of ‘Eyeliner’ as explants,we established a rapid floral organ propagation technology via adventitious buds induction and callus redifferentiation.The results showed that:the contamination rate was 0 and the inducing abilities of different parts of floral organ were different,their sequence,from easy to hard,was pedicel,filament,ovary and style.Callus and adventitious sprouts was efficiently induced from in vitro filament as well as pedicel on MS medium appended with 1.0 mg·L^-1 6-BA and 0.5 mg·L^-1 NAA.The appropriate medium for adventitious buds multiplication was MS+2.0 mg·L^-1 6-BA+0.2 mg·L^-1 NAA,and MS supplemented with 1.5 mg·L^-1 6-BA+0.2 mg·L^-1 NAA was the optimum medium for callus differentiation.The appropriate medium for in vitro root and bulb formations was MS+45 g·L^-1 sucrose.The optimum way of acclimatization as follows:placing the sealed plantlets in natural environment for 3 days,and then exposing them for 2 days.The highest survival rate reached when the bulb size was 3.15 cm.The suitable transplantation matrix was peat∶vermiculite∶perlite=2∶1∶1.

Abstract:Tortella alpicola Dix.(Pottiaceae) is reported as a new record to China.It is distributed in North America,Europe and Asia.This species is characterized as plants reaching to 1 cm hight,leaf base peculiar snow-white and caducous leaf tip with several “barrel-shaped” segments.Morphological characterizations and geographical distribution of T.alpicola are given and confusion with other taxa,such as Tortella fragilis(Hook.& Wils.) Limpr.,Tortella tortuosa(Hedw.) Limpr.and Tortella humilis(Hedw.) Jenn.,is discussed.A key to the genus Tortella in China and illustrations of T.alpicola are presented.

Abstract:We examined the specimens and researched the relevant literatures.According to our study,the exchanged species’ description under Salix opsimantha Schneid.and Salix oreinoma Schneid.both were misidentified in Flora of China,S.opsimantha Schneid.var.wawashanica(Mao & P.X.He) G.Zhu should be treated as synonymy of S.oreinoma Schneid.var.wawashanica Mao & P.X.He.Salix faxoniana Schneid.should be treated as synonymy of S.opsimantha and Salix ludingensis T.Y.Ding & C.F.Fang should be treated as synonymy of S.oreinoma.Taxonomic revision of S.opsimantha and S.oreinoma was made.

Abstract:Fruit metabolomics is the second in genomics,proteomics after another emerging genomics technologies.Fruit metabolomics mainly study metabolite changes of the whole fruit or partial,helping to discover new functional genes and understanding of metabolic networks.Currently fruit metabolomics study has just started,relatively few studies,this paper describes the main fruit metabolomics research direction,technical processes and related applications.

Abstract:Reactive oxygen species (ROS) are a group of free radicals,reactive molecules and ions that are derived from O₂.It is estimated that about 1% of plants-consumed O₂ is converted to ROS in various subcellular compartments such as chloroplast,mitochondria,and peroxisome.ROS are well recognized for playing a dual role as both deleterious and beneficial factors,depending on their concentration in plants.At low concentration ROS acts as second messenger in signaling cascades that mediate several responses in plant cells,whereas at high concentration it triggers oxidative damages to biomolecules and even cell death.Equilibrium between ROS production and scavenging is crucial for plants,and monitored by an efficient antioxidative system consisting of both nonenzymic and enzymic antioxidants.This review thoroughly introduced the current proceedings of studies on plant ROS mainly in terms of their types,production sites,roles in signaling and major damages to plant cells,aiming to provide an insight for improving plant resistance to environmental stress through genetic engineering.

Abstract:As a second messenger,Ca²⁺ is involved in signal transduction pathways related to various responses to abiotic and biotic stress in plant.The specific calcium signal in plant cell is actived by different stress via stimulating calcium channel on the plant plasma membrane,then transformed to Ca²⁺ sensing proteins,such as calmodulin(CaM),Ca²⁺-dependent protein kinases(CDPK) and calcineurin B-like protein,etc.,which induced a series of physiological and biochemical processes of plant cell to the stress.Drought stress is one of the most serious abiotic stresses in the earth.Ca²⁺ signal plays a pivotal role on response to drought stress,by regulating stomatal movement,water channel protein(aquaporin,AQP) and antioxidase activity to reduce water loss and drought damage,increasing water use efficiency.Furthermore,Ca²⁺ has some ecological functions.In this paper,we also summarize the new progress Ca²⁺ signal and its regulation for response to drought stress,and propose simple prospect in the future.