Advance Search

2012  Vol. 30  No. 3

Abstract:
Euptelea pleiospermum,a Tertiary relic and East-Asian endemic species,is a rare and threatened species in China,which requires protection.Based on stem mapping data,the spatial characteristics of E.pleiospermum in the Shennongjia Mountains were examined by nearest neighbor distance statistics.Following the pattern differences and changes within and between each life-history stage (represented by size class,seedling ≤2.5 cm, 2.5 cm < sapling≤7.5 cm,adult tree >7.5 cm in DBH),the pattern-forming processes such as seedling establishment,recruitment and intra-specific competition were inferred and assessed.Euptelea pleiospermum was overall aggregated at the neighborhood scale.Sizes of small individuals (seedlings or saplings) showed no correlation with distances to nearest larger individuals (saplings or adult trees).Within a given radius of focal large-size individuals (saplings or adult trees),the probability of occurrence of size-identical and smaller individuals (seedlings or saplings) were approximately equal.Mean nearest neighbor distance from large-size individuals to nearest individuals in consecutive lower class (sapling vs.nearest seedling,or adult tree vs.nearest sapling) did not differ significantly from that measure within large size classes (within sapling or adult tree classes).Both summed sizes of nearest neighbor pairs and sizes of focal individuals were significantly correlated with nearest neighbor distances.Mean nearest neighbor distance within sapling class did not differ from the expected one within random-mortality-introduced seedling class, and likewise mean nearest neighbor distance within adult class did not differ from the expected one within random-mortality-introduced juvenile class (seedlings+saplings).These results suggest that (1) the aggregated distribution of E.pleiospermum may be due to the effects of seed dispersal and/or habitat heterogeneity on seedling establishment,(2) within their neighborhood established large individuals of E.pleiospermum did not appear to limit the locations and growth of smaller con-specific individuals,but neighbor-interactions may have an effect on long-term recruitment,(3) intra-specific competition existed in the E.pleiospermum population but it was not strong enough to produce distance-dependent mortality.
Abstract:
The spatial heterogeneity dynamics of canopy structure were successively investigated (from 2008 to 2010) in Chebaling montane evergreen broadleaved forest following an ice storm in 2008.We used hemispherical photography to acquire canopy pictures and geostatistics to analyze the spatial heterogeneity and spatial autocorrelation of canopy structure.The mean,standard deviation,variation coefficient,minimum and maximum of canopy openness,and spatial heterogeneity of canopy structure decreased from 2008 to 2010,and the values were more similar to each other in 2009 and 2010.Geostatistical analysis indicated that semivariance function of the 2008 canopy structure fitted with the pure nugget model and demonstrated stochastic factors in interpreting canopy structure,while 2009 and 2010 fitted with the spherical model and demonstrated structural factors,especially in 2010.No spatial autocorrelation was found in the canopy structure of 2008,while spatial autocorrelation became stronger with time.Our results indicated that canopy structure could recover to its pre-disaster level gradually without human intervention and reflect spatial distribution in natural state conditions.
Abstract:
Based on long-term tracking retest data and three structure parameters (mingling intensity,neighborhood comparison and uniform angle index),we investigated the effects of four different selective cutting intensities (low intensity of 13.0% in volume,medium intensity of 29.1%,high intensity of 45.8%,and over-high intensity of 67.1%) on forest spatial structure change in a natural forest.After low and medium selective cutting forest,plot average mingling and neighborhood comparison increased while high and over-high selective cutting decreased.Selective cutting did not change the forest spatial distribution pattern.However,the variety of forest plot showed aggregated distribution,and medium selective cutting in random distribution state forest number increased considerably.After low and medium selective cutting,forest spatial structure was optimized in general.
Abstract:
Based on field investigation and literature survey,the species composition,geographical elements,and endangered state of aquatic vascular plants in the Yangtze Delta were analyzed.We found 185 wild species belonging to 90 genera and 39 families in this area,most of which were distributed in habitats such as ditches, rice-fields, and ponds.Additionally,emergent plants were the main type in terms of life form.This flora was chiefly temperate in nature according to areal-type analysis both at the level of genera and of species.In light of IUCN Red List Categories and Criteria (Edition 3.1),those species were classified into 9 types, including Regionally Extinct (RE) 1,Critically Endangered (CR) 3,Endangered (EN) 8,and Vulnerable (VU) 10.Finally,we also examined the main reasons causing these aquatic plants to become threatened.
Abstract:
Epiphytes have been well characterized in terms of the morphological and eco-physiological traits that permit them to thrive in the complex forest canopy.Our aim was to characterize and analyze the morphological and eco-physiological traits of different canopy-dwelling epiphytes in a lower subtropical evergreen broad-leaved forest in Southern China.Results showed that the differences in morphological and eco-physiological characteristics between the upper and lower canopy-dwelling epiphytes were largely explained by changes in environmental factors such as photosynthetic active radiation (PAR),temperature,and humidity within the complex forest canopy.Two epiphytes,Dischidia chinensis and Psychotria serpens located in the upper canopy had low Tr (0.17±0.02 mmol H2O and 0.34±0.05 mmol H2O,respectively) and low Pmax (2.2±0.1 μmol CO2·m-2·s-1 and 3.2±0.4 μmol CO2·m-2·s-1,respectively) associated with thick leaf (558±63 μm and 217.1±33.1 μm,respectively) and small stomata size (185.7±3.7 μm2 and 225.4±5.2 μm2,respectively) to adapt to their upper dwelling environments (high temperature,low air humidity and high PAR).At the same time,the special structures led to high WUE (11.35±0.87 μmol CO2/mmol H2O and 7.88±1.31 μmol CO2/mmol H2O,respectively).However,the lower canopy-dwelling epiphytes Fissistigma glaucescens and Piper hancei had thin leaf (90.8±9.9 μm and 114.9±18.2 μm,respectively) and large stomata size (260.6±6.3 μm2 and 362.5±8.7 μm2,respectively).The ratios of palisade to spongy tissues thickness (P/S),the thickness of leaf epidermis thickness and other structures also changed with various canopy-dwelling heights.In comparison with Dischidia chinensis and Psychotria serpens located at upper canopy-dwelling conditions, Fissistigma glaucescens and Piper hancei showed high Pmax (9.5±1.3 μmol CO2·m-2·s-1 and 7.1±0.8 μmol CO2·m-2·s-1,respectively),high Tr (0.67±0.10 mmol H2O and 0.74±0.13 mmol H2O,respectively),and low WUE (4.4±1.0 μmol CO2/mmol H2O and 3.4±0.9 μmol CO2/mmol H2O,respectively),which was 1.2-3.3 times (Pmax), 1.2-2.3 times (Tr),and 30%-48% higher (WUE).
Abstract:
Male sterility and seeding ability of the cytoplasmic male sterility line of leafy mustard (0912A) (Brassica juncea) were evaluated by fertility and floral characters. With 0912A and its maintainer line (0912B) as maternal parents and five typical inbred lines as male pa-rents,ten F1 hybrids were produced to study the effects of male sterile cytoplasm and heterosis.The results showed that the sterility of 0912A was steadily complete,the fertility and sterile plant rate were 100%,and the seed-set was normal.The heterosis of yield-related traits was obvious, but not for the quality traits.Male cytoplasm had a distinct negative effect on weight per plant,but the heterosis of hau cytoplasmic F1 was still significant.The male cytoplasmic effect on hybrid traits varied with different nuclear genetic background,and the negative effect of cytoplasm could be reduced or eliminated by choosing suitable male parents.
Abstract:
Fifteen novel α-gliadin genes from Aegilops tauschii×Secale cereale amphiploids were amplified and cloned using conserved primers specific to wheat α-gliadin genes.A total of 15 sequences were obtained with lengths ranging from 843 to 897 bp,containing ORFs encoding peptides with 280 to 298 amino acids and GenBank accession numbers JQ029719,JQ046392 to JQ046405,respectively.A BLAST search showed that these sequences belonged to typical structural characters of α-gliadin genes reported previously.Comparative analysis of homologous proteins showed that they were members of the α-gliadin super-family,of which two sequences were synonymous mutations.Searching for four different T cell stimulatory epitopes for celiac disease patients,it was found that eight of fifteen sequences did not contain the Glia-α-2 and Glia-α-9 epitope typical feature.The phylogenetic trees based on the amino acids sequence of Secale and Aegilops indicated that the cloned gliadin genes clustered in the clade of Aegilops α-gliadin gene.
Abstract:
Our flora survey of Guangdong Nanling National Nature Reserve revealed 46 rare and endangered plant species in 29 families and 39 genera,including 6 ferns,11 gymnosperm species,and 29 angiosperm species.Five species were under Class Ⅰ National Protection,while 29 species were under Class Ⅱ,based on the National Protection List 1999.Nineteen species were proposed to be included in the national protection list and 20 at the provincial level,of which six species were newly recorded in Guangdong and nine were endemic to Northern Guangdong and Nanling.Human activities were the main threatening factor in the reserve,and several suggestions are given in regards to the protection of these rare and endangered plants.
Abstract:
The Yachang forest region is rich in wild orchid diversity, with 156 orchid species belonging to 52 genera distributed in the hills throughout the Yachang Orchid Nature Reserve.The orchids’ distribution in the Yachang region is,however,uneven and naturally or unnaturally fragmented.In particular, there are sixteen distribution hotspots with large concentrations of orchid species and populations within the region.The continuing existence of these rich wild orchid resources are threatened by disturbance from human activities, livestock grazing,and other fast-changing environmental conditions within the Yachang region.We recommend that the conservation strategies of the wild orchids in Yachang should include primarily of in-situ conservation measures, supplemented by ex-situ conservation. Yachang Orchid Nature Reserve should complete and improve its protection facilities as soon as possible,including the completion of a wild orchid germplasm bank,construction of fences around orchid-rich areas that are subject to heavy herbivory from livestock,and intensification of foot-patrols in these areas.
Abstract:
Eutrophication wastewater from twice filtered fishponds was used as the culture medium,into which carbon,nitrogen,and phosphorus were added.The influences of different concentrations of inorganic carbon,total nitrogen,and total phosphorus of sewage on biomass,li-pid content,and hydrocarbon content of Botryococcus braunii were studied.The following results were reported: (1) Using NaHCO3 as the carbon source,the biomass and lipid content of B. braunii were the highest at the inorganic carbon concentration of 5-10 mg/L,while the highest hydrocarbon content was at the inorganic carbon concentration of 15 mg/L.(2) Using KNO3 as the nitrogen source,the biomass of B. braunii was the highest at the total nitrogen concentration of 15 mg/L; the highest lipid content was at the total nitrogen concentration of 2 mg/L; the highest hydrocarbon content was at the total nitrogen concentration of 20 mg/L.(3) Using KH2PO4 as the phosphorus source,the biomass of B. braunii was the highest at a total phosphate concentration of 2 mg/L while the highest lipid content and the highest hydrocarbon content were at a total phosphorus concentration of 1.5 mg/L.
Abstract:
Agrostophyllum planicaule is reported from China for the first time.This species is characterized by its flat stem, broader leaves over 1.5 cm wide,and column with two fresh,horn-like projections at the base.
Abstract:
Two species of Rubus subsect.Lineati (Focke) Yü et Lu,viz.R.calophyllus Clarke.and R.splendidissimus Hara,were found for the first time in China.Both were collected from Motuo County in Xizang (Tibet).A key to R.subsect.Lineati distributed in China is given.
Abstract:
A lichen species,Lobothallia radiosa (Hoffm.) Hafellner (Megasporaceae) is newly recorded from Xinjiang,China.Its morphology, anatomical and chemical characters as well as habitat are reported. A key to Chinese species of Lobothallia and 5 color photographs of L.radiosa are also provided.
Abstract:
A pollen-specific gene,PSG076,with unknown function,was isolated from Austrian wheat ‘Ferdinand’.To obtain pollen-specific promoter in wheat genetic engineering,the promoter region of PSG076 gene was isolated by an improved inverse-PCR (IPCR) method.A 1.4 kb promoter sequence was cloned and analyzed by Bioinformatics tools.Some cis-acting elements or enhancers conferred to pollen-specific expression were found,such as AGAAA,GTGA, AGGTCA and AAATGA.This suggested that PSG076 promoter might be a pollen-specific promoter with strong activity.The results also showed that the improved IPCR method was efficient to isolate the flanking unknown sequence,especially in promoter isolation.
Abstract:
Transgenic technology has now become one of the most important measures in plant directional genetic improvement,while the establishment of a high-efficiency regenerating system must be the basis and prerequisite of genetic transformation.In the present research,explants (leaf,petiole and stem segments) excised from 25-30 day-old in vitro seedlings of Fagopyrum dibotrys were used as materials for inducing callus and plant regeneration.Results showed that MS+2,4-D 4.0 mg/L+6-BA 1.0 mg/L was beneficial for leaves to form callus (89%).Internodal cuttings formed callus (87%) on MS medium supplemented with 2,4-D 2.0 mg/L+6-BA 1.0-2.0 mg/L,and the highest callus induction from the petiole was only 54% on MS+2,4-D 4.0 mg/L+6-BA 2.0 mg/L+IBA 0.2 mg/L media.The medium of MS+6-BA 2.0 mg/L+TDZ 0.2 mg/L+NAA 0.2 mg/L was prior to callus differentiation and shoot organogenesis.The optimum medium for producing roots (96.67%) was half-strength MS medium supplemented with NAA (0.5 mg/L).Hardened plantlets via acclimatization were successfully transplanted to a field (80%),with the regenerated plants normal morphologically and in growth characters.The high-efficient stable organogenesis regeneration system of Fagopyrum dibotrys will make it possible for genetic transformation and enlarging medical resources for this species.
Abstract:
We explored optimized induction and differentiation medium and culture conditions to establish a protocol of rapid clonal propagation of Ligusticum chuanxiong Hort.The petioles were the best explant and Murashige and Skoog (MS) medium containing 2.0 mg/L KT and 0.5 mg/L IAA was suitable for high-frequency shoot regeneration.The results suggested that callus were induced from petioles of aseptic seedlings in dark conditions.And then these callus were subcultured for 15 days in light conditions,about 44.4% frequency of shoot regeneration was induced.The rooting percentage of the regenerated shoots reached 90% on 1/2 MS supplemented with 0.5 mg/L NAA and 0.5 mg/L IBA.Approximately 95% rooted shoots survived in a greenhouse.