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2011  Vol. 29  No. 4

Abstract:
Based on morphological and anatomical observation of the fruit of 21 representative Bupleurum taxa,the following results were found:(1) Most Chinese Bupleurum species had bilaterally compressed fruit and divided into three main fruit shapes,namely cylindrical,oblong,and ovate.(2) Crystals deposited in mesocarp cells of "basal Apioideae",Saniculoideae,and Hydrocotyloidea were not found in Bupleurum.(3) According to oil canal numbers in the furrow,Chinese Bupleurum were divided into two groups.The first group had single vittae in each furrow and the second group had three or more vittaes per furrow.From previous anatomical and molecular studies on Apiaceae,we concluded that:(1) The evolutionary trend of vittae in Bupleurum was from one to two or more in each furrow,and Chinese species represented the derived taxa within this genus;(2) Bupleurum was very likely an intermediate group between"basal Apioideae"and"remaining Apioideae"or a collateral branch of Apioideae;(3) The morphological and anatomical features of Bupleurum fruit can be used as evidence of inter-and intraspecific taxonomy.Lastly,a key to species was also given based on fruit characters.
Abstract:
Ribulose 1,5-bisphosphate carboxylase /oxygenase(Rubisco,EC 4.1.1.39) is the key photosynthesis enzyme in plants,whose large subunit is encoded by the chloroplast rbcL gene.To better understand the molecular adaption mechanisms of Pteridaceae ferns acclimating to xeric habitats,both adaptive evolutionary and coevolutionary analyses were performed on the rbcL gene sequences of 53 Pteridaceae xeric fern species.The adaptive evolutionary analyses under variable ω ratio sites as well as SLAC,REL and FEL methods indicated that 15 amino acid residues(66S,84E,139L,235G,245I,252A,273Y,295K,296N,299M,307G,330E,349S,365F and 404A) were positively selected.In particular,three sites(245I,252A and 273Y) played an important role in maintaining enzymatic function.The subsequent coevolutionary analysis revealed two groups of coevolutionary residues(139L,273Y and 295K) and(273Y,295K and 349S),which showed that their coevolutionary patterns were significantly related to protein hydrophobicity and molecular weight.This research consolidated that evolutionary models using ω as an indicator of selective pressure provide valuable analysis of the adaption of protein encoding sequences.In addition,this study also demonstrated that Pteridaceae ferns may respond to xeric habitats by adaptively modifying the rbcL gene.
Abstract:
The chromosome number and karyotype of seven species of Indigofera L.were studied by applying the root tip squash technique.Results show that six species were diploid(2n= 2x=16),while Indigofera zollingeriana Miq.was tetraploid(2n= 2x= 32).The karyotypes of I.zollingeriana Miq.and I.silvestrii Pamp.belonged to 2A,while the others were 1A.The karyological difference between species was small.Most chromosomes in the tested seven species were metacentric.The karyomorphology of I.delavayi Franch.,I.scabrida Dunn,I.silvestrii Pamp.,I.szechuensis Craib and I.zollingeriana Miq.are reported here for the first time.
Abstract:
The genus Rehmannia Liboschitz,which is endemic to China,was revised accor-ding to extensive examinations of herbarium specimens and living plants and field investigations.Five species of the genus Rehmannia were recognized and R.elata N.E.Brown ex Prain was relegated to synonymy under R.piasezkii Maxim. Morphological description,geographical distribution and a key are provided.
Abstract:
Dipteridaceae is a natural taxon,containing a single genus,Dipteris Reinwardt and eight species,of which three are occuring in China,D.chinensis Christ,D.conjugata(Kaulf.) Reinw.and D.wallichii(R.Br.) T.Moore.Two species are found in Yunnan,China,D.chinensis Christ and D.wallichii(R.Br.) T.Moore.A newly recorded species,D.wallichii(R.Br.)T.Moore from Yunnan,China,was reported and a key to the species and new color plates are provided.
Abstract:
Based on an investigation of bryophytes on ten islands and one peninsula of the southeastern sub-region of the Thousand-Island Lake,the composition of bryophytes and the effects of habitat fragmentation on their diversity were studied.The results showed 129 species belonging to 71 genera and 37 families,among which 3 species were new to Zhejiang province.Geophytia,petrophytia and epixylophytia were dominant bryophyte communities.The bryoflora of the Thousand-Island Lake was characterized by East Asia elements represented by 39.45% of the entire species,followed by North Temperate elements and Tropical Asia elements which accounted for 20.18% and 18.35%,respectively.The distribution of 58 bryophyte species was affected by island area,while 29 species was unaffected.The relationship between island size and bryophyte richness showed a positive correlation.
Abstract:
To clarify the present protected status and the development law for vegetation in northern Guangdong,China,the frequency and age structures of dominant species in 18 forest communities were studied by using the method of vegetation quadrat and numerical analysis.The results showed that among 1265 frequency values,78.38% was in Grade A(present frequency of species among 1%-20%),15.38% in Grade B(21%-40%),2.91% in Grade C(41%-60%),1.87% in Grade D(61%-80%) and 1.46% in Grade E(81%-100%) according to the Raunkiaer’s Frequency System of five grades.The frequency law was A>B>C>D>E.Among the 16 age structures of dominant species populations,in which the frequency was more than 60%(grade D and E),the declining populations were Liquidambar formosana,Cunninghamia lanceolata,Castanopsis carlesii,Pinus massoniana,Alniphyllum fortunei,Cinnamomum porrectum,Castanopsis lamontii and Choerospondias axillaries;the increasing populations were Castanopsis hystrix,C.fissa,and C.fabric;and the stable populations included Castanopsis eyrei,Schima superba,Machilus thunbergii,Diospyros morrisiana,and Michelia maudiae.As the forest in northern Guangdong has developed by succession and protection for a relative long time,the present status of the forest showed the declination of conifers trees and deciduous broad-leaf trees,and provided a foundation for the future development of vegetation typical of ever-green broad leaf forests and its dominant species.The results also provided scientific basis for the construction and sustainable development of nature reserves in northern Guangdong,China.
Abstract:
Distribution,resource,population structure and community character of rare and endangered species Parakmeria lotungensis were investigated.The results showed that P.lotungensis had a sporadic distribution among tropical and subtropical forests between 18°44’-29°24’N,107°50’-119°09’E,with a total population of less than 15000 individuals among which less than 2500 were mature individuals.Habitat fragmentation and biological and ecologi-cal characteristics of P.lotungensis were important factors for population regeneration.Human destruction was most direct factor contributing to the rapid reduction of the population.Protection strategies of P.lotungensis are discussed.
Abstract:
Qinglan Mangrove Reserve is located in Wenchang city in northeast Hainan Island,China.To understand species diversity,we investigated all vegetation in this area.A total of 172 vascular plant species were recorded,belonging to 148 genera and 62 families.Among them,24 species were true mangrove species,accounting for 92.31% of mangrove species in the province(26 species),85.71% of mangrove species in whole country(28 species),and 27.91% of mangrove species in the world(86 species).In the survey plots(4040 m2),3670 trees belonging to 29 mangrove species which were more than 1.5 m high were recorded.Among them,Sonneratia caseolaris and Bruguiera sexangula had the highest importance values of 12.90 and 12.33,respectively.In individual quantity,however,Ceriops tagal and Rhizophora stylosa were most dominant.The Qinglan Mangrove Reserve can be divided into one vegetation type group,one vegetation type(Broad-leaved forest),two formation groups(Mangrove and Semi-Mangrove) and twelve formations(Form.Bruguiera sexangula + Xylocarpus granatum,Form.Sonneratia alba+ Lumnitzera racemosa,Form.Rhizophora apiculata + Bruguiera sexangula,Form.Sonneratia caseolaris,Form.Aegiceras corniculatum,Form.Sonneratia alba,Form.Avicennia marina + Sonneratia alba + Ceriops tagal,Form.Rhizophora stylosa + Ceriops tagal,Form.Ceriops tagal,Form.Rhizophora stylosa,Form.Lumnitzera racemosa,Form.Lumnitzera racemosa + Bruguiera sexangula).After 19 years,Form.Bruguiera gymnorrhizaand Form.Nypa fruticans have vanished,the Scyphiphora hydrophyllacea community has fragmented into many small plaques,a new Xylocarpus granatum community has formed,and other communities,like Sonneratia caseolaris have remained stable.
Abstract:
The classification and ordination of wetland vegetation in the Tian’ezhou Oxbows of the Yangtze River were studied using two-way indicator species analysis(TWINSPAN) and detrended correspondence analysis(DCA).A total of 234 samples collected from the wetland vegetation in the Tian’ezhou Oxbows were classified into 28 associations by TWINSPAN and the community characteristics of every association were described.The DCA ordination reflected the relationship between plant community type and the environmental gradient.The results showed that soil type and humidity were the main factors influencing the structure and distribution of wetland community.The TWINSPAN classification showed an explicit distribution scope in the DCA ordination plot,which better reflected the relationships between communities and environmental factors when combined with TWINSPAN quantitative classification.
Abstract:
We choose three different inundation sites(long-term inundation,short-term inundation and no inundation) to investigate the morphological responses to temporal inundation of a perennial grass Carex argyi,a dominant species in Swan Islet Wetland,China.The results showed that plant height,leaf length,and width of leaf blade were sensitive to inundation.This sensitivity was different among the three sites.Plant height and leaf length were increased from short-term inundation but were inhibited under long-term or no inundation.Plant height reached a maximum before and after inundation and remained steady.Long-term inundation facilitated leaf extension and leaf blade width and increased the above-ground biomass of the species.Although total soil nitrogen concentration was significantly different among different sites of inundation,it had no significant effect on these sensitive characteristics of this species.Our results indicated that C.argyi could adjust their leaf shapes and resource allocation patterns to inundation at the temporal scale,which might benefit population maintenance and stability.
Abstract:
We studied the effects of exogenous spermidine(Spd) on free polyamines content and polyamine biosynthesis gene expression in cucumber(Cucumis sativus L.cv.Jinchun No.2) seedlings under salt stress with solution culture.Plant height,stem diameter,and fresh and dry weight were significantly reduced by treatment with 75 mmol/L NaCl,while the inhibition of seedling growth was alleviated by spraying 1 mmol/L Spd.Free polyamine content was significantly increased in leaves when exposed to salt stress,and exogenous Spd application to leaves further promoted free Spd and spermine(Spm),but reduced free putrescine(Put).Expression analysis of polyamine synthase genes showed that salt stress up-regulated adc,odc,samdc and spds gene expression,and exogenous Spd application further up-regulated samdc gene expression and down-regulated adc,odc,spds gene expression.The results revealed that exogenous Spd regulated polyamine metabolism in cucumber seedlings under salt stress,inhibited free Put accumulation by reducing adc,odc gene expression,increased free Spd and Spm accumulation by up-regulated samdc gene expression,and alleviated the inhibition of plant growth under salt stress.
Abstract:
UDP-glucose pyrophosphorylases(UGPases,EC 2.7.7.9) are key enzymes in plant carbohydrate metabolism and cell wall biosynthesis,catalyzing the reversible production of glucose-1-phosphate and UTP from UDP-glucose and pyrophosphate.The rice(Oryza sativa L.) genome contains two homologous UGPase genes,Ugp1 and Ugp2.The Ugp1 gene is globally expressed throughout the plant and is critical for plant growth and pollen development.In the present study,possible effects of sugars on Ugp1 expression were tested with excised rice leaves.The Ugp1 was up-regulated by feeding sucrose,glucose and fructose to excised rice leaves.The sucrose effect on Ugp1 was mimicked by exposure of dark-adapted leaves to light.The sugar signaling pathway for Ugp1 expression was dependent on hexokinase,as N-acetyl-glucosamine(NAG,a specific HXK inhibitor) was effective in inhibiting sugar-mediated up-regulation of Ugp1.However,NAG could only partially inhibit Ugp1 expression induced by glucose together with fructose,suggesting an unknown signaling pathway was also critical for regulation of Ugp1 expression.Using two-dimensional gel electrophoresis in combination with western blot analysis,we also demonstrated that sucrose-mediated up-regulation of Ugp1 had no effect on multiple rice UGPase isoforms.
Abstract:
Kenaf is a Hibiscus member in the Malvaceae family,and exhibits fast growth,high-yield,and strong stress adaptability.The aim of the present research was to study the effect salt concentration stress on the growth and antioxidant enzyme activity of Kenaf seedlings,and further explore the physiological mechanisms of salt tolerance.Kenaf seedlings were subjected to 0 mmol/L and 140 mmol/L NaCl for 3 d,6 d and 9 d in half strength Hoagland nutrient solution and as well as 0 mmol/L,70 mmol/L,140 mmol/L,200 mmol/L NaCl concentrations for 6 d.Following treatment,weight,root length,stem length,leaf H2O2,and malondialdehyde(MDA) content,as well as the activity of superoxide dismutase(SOD),peroxidase(POD),catalase(CAT) and glutathione reductase(GR),of the fresh plant samples weremeasured.The results showed that(1) Fresh weight of the treated groups were reduced by 19.63%,19.35% and 39.03%,respectively with length of treatment.Plant height decreased by 25.59%,19.17% and 18.48%,respectively.In addition,SOD activity first increased and then decreased,while POD activity showed the opposite trend.The content of MDA and H2O2,and CAT and GR activity had positive correlations with stress time compared to the controls.(2) With the increase in stress concentration,fresh weight of the treatment groups was reduced by 16.79%,19.35% and 44.73%,respectively.In addition,plant height decreased by 11.21%,19.17% and 23.62%,respectively.The SOD activity was higher than the control group;however,no significant differences were observed among the three.The contents of MDA and H2O2,and the activity of CAT and GR increased with time,but POD activity first decreased and then increased.The effects of salt stress of the kenaf seedlings increased with time and salt concentration when treating with different NaCl concentrations.The SOD and POD activities increased slightly,or even decreased,while the CAT and GR activities were relatively higher.Both CAT and GR may play an important role when responding to salt stress of kenaf seedlings.
Abstract:
A single-harvested cultivar, ‘Jiangshujiao’,and a double-harvested cultivar,‘Fenghongzao’,of Zizania latifolia were used as experimental materials to determine the content of non-protein-thiols(NPT),glutathione(GSH),and phytochelatins(PCs).To clarify the tolerance mechanism of Zizania latifolia to Cd2+ and Pb2+ stress,accumulation of Cd2+ and Pb2+ in subcellular fractions were also investigated.The results showed that content of NPT,GSH,and PCs and the accumulation of Cd2+ and Pb2+ in subcellular fractions increased significantly when treated with Cd2+ and Pb2+ stress.Content was higher when treated with combined stress than single stress.Content of NPT,GSH and PCs were significantly lower in leaves than in roots.The cell wall and the soluble fraction of cells had higher Cd2+ and Pb2+ accumulation levels than the protoplast and the organelles,respectively.
Abstract:
Anatomical and histochemical methods were used to investigate the structure of vegetative organsand the location of terpenoids and flavonoids in Chloranthus multistachys Pei.The root cortex cells showed a disordered arrangement and had larger intercellular spaces;the stem cortex cells also showed a disordered arrangement and the stem phloem was surrounded by strands of fiber;leaves had a bifacial structure,palisade tissue and sponge tissue were clearly differentiated,there were no hairs on the upper and lower epidermis of the leaf,and the stomatal apparatuses were of anomocytic type and occurred only on the lower epidermis.The histochemistry results of terpenoids and flavonoids localization were similar in the vegetative organs in Chloranthus multistachys Pei,both of which were mainly distributed in the cortex of the root,the cortex of the stem and phloem cells.
Abstract:
The formation of stele schizogenous structures,the accumulation parts of effective constituents,and the relationship between structure and accumulation of effective constituents in the root of Gentiana macrophylla Pall.were researched systematically by means of plant anatomy,histochemistry,analytical chemistry and modern instrumental analysis technique.The results showed that:(1) The occurrence of stele schizogenesis in the root was caused by the abnormal activities of the vascular cadmium and xylem parenchyma cells,which caused the original vascular cylinder to divide into several relatively independent cylinders.Each of these vascular cylinders was then surrounded by suberized cells and,as a result,the axial root split into several rootlets.(2) The effective constituents were mainly present in the xylem and blast parenchyma cells of the vascular tissue.(3) The content of gentiopicrin in the split part of the root was 60% of that in the unsplit part.
Abstract:
We used macroscopic and microscopic observation methods and TLC technique to determine the pharmacognostical characteristics of the crude medicine "Zhuyajingtian"(Sedum bulbiferum Makino) for identification purpose.The results showed that identification cha-racteristics of this drug were distinctive.For example,purplish-red cells were observed in the outer cortex and the parenchyma of stele in the stem cross section,pith cells were smaller with thin walls,the lower epidermis of the leaf was covered with stomata(two or sometimes three adjacent),and several distinctive fluorescent spots were observed in the thin-layer chromatography.In the current study,the identification features of macroscopic,microscopic,and TLC of the medicine were described,and genetic relationships were inferred among the original plant and the three medicinal Sedum plants,Sedum sarmentosum Bunge,Sedum lineare Thunb and Sedum emarginatum Migo.The results provided reliable reference for identification of the crude medicine and its utilization.
Abstract:
The effects of different genotypes,plant growth regulators(PGRs) combination,leaf size and dark treatment on adventitious shoot formation and plant regeneration from leaf explants of Phalaenopsis with thidiazuron(TDZ) added were studied.The difference in the induction rate of adventitious shoots among different genotypes with same induction conditions was significant,for example,the ’Red Angle’ was the highest,up to 81.5%,Doritaenopsis Shannong ’Lassie’ and one other were 0,Doritaenopsis Queen Beer ’Red Sky’ and two others were up to 9.2%-34.9%.The adventitious shoots induction rate under TDZ treatment was significantly greater than that in the 6-BA with the same genotype.The adventitious shoots induction rate with 6-BA or TDZ added alone was superior to the combination of 6-BA or TDZ with NAA.When the leaves were younger,the adventitious shoots induction rate was higher.Short dark treatment was propitious to highly significant on adventitious shoot formation.Using 1-2 cm leaves as material,with 15 days of dark treatment and the 3 mg/L TDZ treatment in 1/2 MS culture medium,the explants induction rate and average number of adventitious shoots of ’Red Angel’ reached 100% and 18.2,respectively.This study showed that bud elongation was obviously inhibited by TDZ treatment in subculture medium.
Abstract:
To induce callus and establish rapid propagation systems for Veronica ciliate Fisch.,terminal buds from its aseptic seedlings were cultured in MS mediums with different concentration combinations of NAA and 6-BA.Results showed that the optimum medium for callus inducement was MS+6-BA 0.5 mg/L+NAA 1.0 mg/L,with the callus induction rate of 95%.The best medium for multiplication was MS+6-BA 0.5 mg/L+NAA 0.1 mg/L,with the multiplication coefficient reaching 5.4.The optimum root medium for multiple shoot clumps was 1/2 MS+IBA 0.05 mg/L,with the rooting rate reaching 95% and the root being healthiest.Under suitable hardening and transplanting conditions,the highest survival rate for the regenerated plantlets reached 40%.