Abstract:In order to test the tissue expression pattern of endosomal AtNHX6 gene, we amplified the promoter sequence of AtNHX6 gene from Arabidopsis thaliana, a 1 922 bp upstream of reading frame (ORF) by PCR. The fusion expression vector pCAMBIA1381proNHX6GUS was successfully constructed by the AtNHX6 gene promoter and GUS gene and introduced into the A. thaliana (ecotype Columbia 0) by the floral dip procedure. The homozygous T₃ transgenic A. thaliana lines was identified by PCR amplification of a 2 187 bp fragment. The expression pattern was monitored using GUS histochemical staining. The results showed that GUS staining was preferentially observed in cotyledons, hypocotyls and flowers of transgenic seedlings carrying the AtNHX6 promoter. In these organs, the highest GUS activity was detected in the vasculature, although GUS was widely expressed. In true leaves, GUS activity was only partially detected for the AtNHX6 promoter. In the root, GUS was expressed in the root hair and lateral root growth site. In immature siliques, GUS staining was restricted to the silique tip and base for the AtNHX6 promoter, but was detected only in fruit stalks in mature siliques. In flowers, GUS staining was observed in the filament of the stamens and pollen grains within the anthers and the ovarian stigma for the AtNHX6 promoter. Results from histochemical GUS assay suggested that fusion expression vector of AtNHX6 gene promoter and GUS was successfully constructed and it drives the expression of GUS gene successfully. The results also showed that AtNHX6 gene predominantly expressed in vascular tissues of cotyledons, hypocotyls, roots, flowers and siliques and the growth site of root hair and lateral root, as well as filaments, pollen, ovarian stigma of A. thaliana.

Abstract:To study the response of Gibberellins Insensitive gene (AtGAI) from amaranth to gibberellin, we cloned GAI gene from Amaranthus tricolor L. ‘Dahong’ by RTPCR combined with RACE technology, which is named as AtGAI (GenBank accession number: MK049175).The results showed that: (1) the AtGAI gene contains an open reading frame of 1 818 bp that encoding 605 amino acids. (2) Bioinformatics analysis indicated that AtGAI belongs to GAI family containing two conserved domains of DELLA and GRAS. (3) Phylogenetic tree analysis showed that the AtGAI protein was relatively close to the GAI protein of Amaranthus hypochondriacus. (4) Microscopic observation and betalain content analysis showed that the betalain was mainly distributed in the epidermis and parenchyma cells around the vascular bundle sheath of cotyledons and hypocotyls, and the GA₃ concentration was negatively correlated with the betalain content. (5) qRTPCR analysis showed that GA₃ inhibited the expression of AtGAI, AmMYB1, AmaDODA and AmCYP76AD1 genes in cotyledons and hypocotyls. The results suggest that GA₃ may regulate the betalain metabolism by affecting the expression of AtGAI gene.

Abstract:In order to reveal the function of WRKY gene in pepper, we cloned the fulllength 1 647 bp cDNA of WRKY gene from pepper PI201234 and named as CaWRKY8. Bioinformatics analysis indicated that the gene contains a 1 647 bp complete open reading frame (ORF) box encoding 548 amino acid residues. Amino acid sequence analysis revealed that the CaWRKY8 encoded protein contains two WRKY domains belonging to Group I. The amino acid sequence alignment showed that there was a high degree of conservation between CaWRKY8 and the amino acid sequences of pepper WRKY25, potato WRKY, tomato predicted WRKY26, tobacco predicted WRKY33 and kiwi WRKY. Realtime fluorescence quantitative analysis showed that CaWRKY8 was induced by salt, high temperature, drought and Phytophthora capsici, and CaWRKY8 peaked at 3 h under salt and drought treatments by 2.38 and 121.10 times of control, respectively. Under high temperature and P. capsici treatment, the peak reached at 12 h, which was 6.12 and 6.81 times of the control, respectively. The above results indicate that CaWRKY8 played an important role in the response of pepper to stress.

Abstract:In this study, three SOD genes were cloned from Brassica campestris L. ssp. chinensis(L.) var. utilis Tsen et Lee by homologous cloning and bioinformatics were analyzed. The expression patterns of three SOD genes in different tissues and under low temperature stress were analyzed by qRTPCR. The results showed that: （1） the ORF of Cu/ZnSOD, FeSOD and MnSOD genes were obtained and named BclCZSD, BclFSD and BclMSD. Their sequence length were 459, 639 and 696 bp, encoding 152, 212 and 231 amino acids, respectively. (2) Bioinformatics analysis showed that all three proteins were stable hydrophilic proteins without transmembrane structure and signal peptide. The secondary structure of BclCZSD protein was mainly random coil and had two Cu/ZnSOD domains, BclFSD and BclMSD proteins were mainly alpha helix and had one Mn/FeSOD domain. Evolutionary analysis showed that BclCZSD and BclMSD proteins were first clustered in one branch with SOD protein in Brassica napus, and BclFSD protein was clustered in one branch with Brassica oleracea, Raphanus sativus, Brassica napus and Brassica rapa. (3) The results of qRTPCR showed that BclCZSD, BclFSD and BclMSD genes were expressed with different expression profile in the roots, stems, leaves and petioles. The expression level of the 3 genes increased first and then decreased with the extension of time under low temperature. These results provide a foundation for the low temperature response mechanism study of SOD genes in Brassica campestris L. ssp. chinensis(L.) var. utilis Tsen et Lee.

Abstract:In this study, based on bioinformatics analysis, a WRKY transcription factor gene was cloned from Stylosanthes guianensis (Aubl.) by RTPCR and named as StWRKY45. The largest open reading frame (ORF) of this gene is 924 bp, encoding 307 amino acids ,with a molecular mass of 35.62 kD and an isoelectric point of 9.81. Phylogenetic tree analysis indicated that StWRKY45 belongs to the WRKY gene of WRKY transcription factor class Ⅱ, and has the closest relationship with Arabidopsis AtWRKY45 and AtWRKY57. The results of Realtime PCR showed that under the nonphosphorus stress (control), StWRKY45 gene was expressed in roots, stems and leaves of S. guianensis seedlings, but the expression level was relatively low; under low phosphorus stress, the expression of StWRKY45 gene in roots, stems and leaves increased gradually with the prolongation of stress time, and the expression level was the highest in leaves. The relative expression of leaves and stems reached the highest at 96 h after low phosphorus stress. They were 20.47 times and 9.38 times of the control, respectively, but the relative expression in roots reached the highest at 72 h after low phosphorus stress, which was 9.29 times of the control. Studies have shown that StWRKY45 gene is induced by lowphosphorus stress, suggesting that StWRKY45 gene may be involved in the response of S. guianensis to low phosphorus stress.

Abstract:Goldenlike (GLK) transcription factors play an important role in the growth and formation process of plant leaves and fruit chloroplast. In this study, Solanum lycopersicum (AC) transformed with SlGLK1 and SlGLK2 genes (ACCS SlGLK1, ACCS SlGLK2 and ACOE SlGLK2) was used as the research material, to detect the content of chlorophyll and the expression analysis of related transcription factor genes such as SlGLK1, SlGLK2, TKN2 (Transcription Factor of Knotted Like Gene), TKN4 (Transcription Factor of Knotted Like Gene) and APRR2 (Arabidopsis Pseudo Response Regulator 2Like) in different developmental stages of green fruits, BRIX and total sugar in mature transgenic fruits. The results showed that: (1) the leaf color in cosuppressed SlGLK1 gene plants became obviously lighter, and the fruit color of overexpressed SlGLK2 turned dark green, which corresponded to the detection of chlorophyll content in fruit. The chlorophyll content in the top of cosuppressed SlGLK1 fruit was the lowest in all materials, but the bottom of fruits were 5-6 times higher in overexpressed SlGLK2 than that of AC. (2) 0.3% of BRIX and 5.34 mg/g of total sugar has been increased in overexpressed SlGLK2 gene fruits, respectively. (3) The qPCR of SlGLK1 and SlGLK2 genes showed that the expression in the transgenic materials was significantly increased more than 5 times, even in the cosuppressed transgenic lines. TKN2 might be located upstream of the SlGLK2 gene and regulate SlGLK2 transcription factor. Therefore, SlGLKs transcription factor played an important role in improving the quality of tomato fruit by regulating the synthesis of chlorophyll in leaves and fruits, especially in enhancing the green of tomato leaves and fruit and increasing the BRIX and total sugar in mature fruits.

Abstract:Two tissues, the bark located at downside of shoot site of cuttings and leaf located at top of shoot, were sampled to compare the transcriptome profiles between upright and inverted cuttings of P. yunnanensis in vegetative growth stage (August). The results showed：（1） a different transcriptome profiling changing induced by cutting inversion from the two tissues. A total of 358 587 unigenes was obtained by transcriptome sequencing. Then, 6 512 DEGs were selected in leaf samples and 12 020 DEGs were selected in bark samples. （2） In total, 552 DEGs were identified by KEGG databases in leaf tissue and assigned to 122 metabolic pathways. The main significant enriched pathways were plantpathogen interaction, amino sugar and nucleotide sugar metabolism, pentose and glucuronate interconversions, galactose metabolism, biosynthesis of amino acids, and ascorbate and aldarate metabolism. The changing USPase encoded by 39 DEGs impacted on cell wall metabolism of leaf tissue. （3）In bark tissue, 1 623 DEGs identified by KEGG databases were mapped to 128 pathways, among which carbon metabolism, ribosome, biosynthesis of amino acids, and phenylpropanoid biosynthesis were main enriched pathways. （4）Furthermore, a large number of DEGs were found in ROS metabolic reactions, including enzymes in Calvin cycle related to ROS production system and POD and cysteine synthase (i.e. cysK and MET17) related to ROS removal system have large number of DEGs, indicated a change of ROS concentration balance induced by inversion and a activated defend system in bark tissue of cuttings.

Abstract:363 clones of Populus deltoides were used as test materials. Based on 20 pairs of SSR molecular marker amplification data, 10%, 15%, 20%, 25%, 30%, 35% and 40% sampling ratios were set to construct the primary core collection of P. deltoides. The validity of the core collection was supported by ttest using genetic parameters such as the average number of observed alleles (Na). Retention ratio of genetic diversity such as average observed allele number (Na) between core collection, reserve collection and original collection, and the core collection was further confirmed by the PCoA analysis. The results were described as follows: (1) A total of 278 polymorphic loci was detected by 20 pairs of SSR primers. The genetic diversity parameters I and H were 1.667 and 0.688 2, respectively, indicating that the southern type of P. deltoides germplasm resources were rich in genetic variation. （2） Comparing the average Na, I and H changes to determine the optimal sampling ratio of 15%, obtaining 54 core collections and 309 reserve collection, ttest analysis suggested that there was not a significant correlation between average Na, I and H of primary core collection and the original collection (P> 0.05), except for the average Na, the retaining ratios of Ne, Ho, I and H was 111%, 105%, 104% and 104%, respectively. （3）Principal coordinate analysis (PCoA) showed that the primary core collection was not only similar to the original germplasm distribution, but also distributed uniformly and comprehensively, which could represent the geometric distribution of the original germplasm in the figure. These results demonstrated that the 45 accessions as primary core collection could preserved most of the alleles and genotypes of the original germplasm, Some genetic diversity indexes increase while the genetic redundancy and genetic repetition was removed，which mean that the primary core collection could stand for original collection excellently.

Abstract:Phoebe bournei (Hemsl.) Yang requires higher soil moisture, in order to improve the survival rate of afforestation.The aim of this research was to investigate the drought tolerant of the P. bournei. The experiment was conducted to determine the changes of proteome, and physiological and biochemical indexes of P. bournei under different drought stress durations (7 d, 14 d drought treatments and 7 d after rewatering restoration) to reveal the molecular mechanism. Results showed that: (1) fiftyone differentially expressed proteins were founded in the P. bournei leaves by using twodimensional electrophoresis (2DE) under different drought stresses. Fortyfive differentially expressed proteins were successfully identified by MALDITOF/TOF. These identified differential proteins are closely related to some processes of physiological metabolism, including photosynthesis, carbohydrate and energy metabolism, stress response and defense, posttranslational modifications, protein conversion and molecular chaperone functions. (2) At the same time, we found that the main trend of the content of MDA involved in membrane lipid peroxidation, the activities of SOD, CAT, POD associated with defense, and the activities of PFK, AGPase, PK and the content of PDH related to sugar metabolism were declined and significantly changed (P<0.01) in the leaves of P. bournei under 14 d continued drought stress. Reduced photosynthesis，plant defense systems，as well as energy and sugar metabolism under drought stress may be the physiological and biochemical reasons that the species was not a drought tolerant plant. The present study provided a theoretical basis for the molecular breeding of droughttolerant P. bournei in the future.

Abstract:A pot experiment was conducted to study the effect of three different temperature treatments (5 ℃, 25 ℃ and 35 ℃) on the color changes and nutritional quality of purple pakchoi ‘Ziyi’(Brassica campestris ssp. chinensis Makino)，providing a suitable temperature to improve the highquality purple pakchoi in cultivation techniques. The results showed that: (1) the leaves of purple pakchoi were dark purple with the prolongation of treatment time at low temperature of 5 ℃. On the contrary, when the leaves were exposed to high temperature of 35 ℃, the color of the leaves gradually became light until the leaves became green, it was consistent with the change of anthocyanin content in leaves. (2) Compared with treatment at 25 ℃, the contents of reducing sugar, soluble sugar and total sugar in the leaves of purple pakchoi decreased gradually after being exposed to high temperature (35 ℃), but increased firstly and then decreased with the prolongation of low temperature treatment at 5 ℃, and the range of decrease under high temperature was greater than that under low temperature. Similarly, the contents of soluble protein, reducing ascorbic acid and amino acid also decreased under high temperature stress, but they increased significantly under low temperature. On the contrary, the activity of ascorbic acidperoxidase (APX), the contents of cellulose and nitrate increased gradually under high temperature stress and decreased significantly under low temperature. The results indicated that purple pakchoi leaves were affected by the different temperatures, the low temperature accelerated anthocyanin accumulation, while it was inhibited to accumulate the anthocyanin content at the high temperature. Low temperature could promote the accumulation of the contents of soluble protein, ascorbic acid and amino acid, reduce the content of cellulose, change the phenotypic characteristic of leaf color and improve nutritional quality in purple pakchoi. On the contrary, high temperature could reduce the appearance and nutritional quality of purple pakchoi.

Abstract:Pennisetum sinese has become a prospective material for phytoremediation of heavy metal pollution, because of its advantages of rapid growth and large biomass. Drought is the main factor that affects its growth and phytoremediation ability. A pot experiment was conducted to study the effects of drought treatment (25% FC), Cd treatment (3 mg·kg^-1) and its interaction treatment on growth, photosynthesis, content of reactive oxygen species, antioxidant enzyme activity, Cd accumulation and distribution characteristics of P. sinese. Results showed that： （1） the biomass accumulation and photosynthetic activity of P. sinese were significantly inhibited by drought treatment, Cd treatment and interaction treatment, but the tolerance coefficient of P. sinese was relatively high under these treatments when compared to the controls. The MDA content and the POD and CAT activities in leaves increased to a certain degree under these treatments, while the activity of APX increased significantly only under interaction treatment. Both Cd treatment and interaction treatment induced significant reduction of SOD activity. （2） In terms of biomass accumulation and membrane damage caused by reactive oxygen species (represented by MDA), interaction treatment did not cause more serious negative effects than any single treatment. （3） Under the Cd treatment and interaction treatment, the content of Cd in all the organs of P. sinese increased significantly, and was mainly distributed and accumulated in roots. Though the interaction treatment significantly reduced the Cd concentration in P. sinese, it did not reduce the Cd concentration in shoots significantly. Above results suggested that P. sinese have strong tolerance to drought and Cd pollution, and interaction treatment would not cause more serious adverse defects, but would significantly reduce the Cd concentration in roots of P. sinese. Therefore, planting P. sinese in the area affected by both drought and Cd pollution might obtain a prospective phytoremediation effect.

Abstract:The potted seedlings of Malus baccata were used as materials in the treatments of simulated suboptimal rootzone temperature（5 ℃） in culture room. The treatments included the suboptimal rootzone temperature (L), L + exogenous GABA (LG) and L + VGB (LV), the white roots were cut at 0, 12, 24, 48, 96, and 144 h after treatment, respectively. We measured the contents of endogenous GABA, osmotic adjustment substances and reactive oxygen species, the activities of antioxidant enzymes to investigate the regulating effect of GABA on the antioxidant system in roots under suboptimal rootzone temperature. The results showed that: (1) the endogenous GABA content in the roots of Malus baccata increased under the L treatment, osmotic adjustment substances accumulated in different degrees. And as a consequence, the contents of superoxide anion (O₂^-·) and hydrogen peroxide (H₂O₂) increased significantly. The peroxidation in roots was deepened. (2) Exogenous GABA increased the contents of endogenous GABA in roots, soluble sugar, soluble protein and proline (Pro) in the roots, significantly enhanced the activities of superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) in roots, and effectively reduced the contents of H₂O₂ and O₂^-·, which meant exogenous GABA could significantly alleviate the degree of membrane lipid peroxidation. (3) The effect of VGB, which is the specific inhibitor of GABA (LV), treatment was opposite to that of LG treatment. Those results indicated that the GABA metabolism had a positive effect on the defense of the roots to the oxidative stress triggered by suboptimal rootzone temperature, and exogenous GABA had the effect of enhancing the antioxidant capacity of the roots through regulating endogenous GABA metabolism.

Abstract:In order to study the needs and adaptability of Camellia azalea to sunlight, we studied the effects of the shading treatments at different degrees ［0 (CK), 30%, 50% and 80%］ on leaf growth, photosynthetic pigments contents, primary metabolite contents and relative conductivity of C. azalea seedlings (2.5 a). The results showed that: (1) the shading significantly promoted the growth of C. azalea leaves, and the leaf number, total leaf area, average leaf area, specific leaf area, and leaf water content were at the highest level under 50%-80% shading condition. (2) The total chlorophyll content, chlorophyll a content, chlorophyll b content, carotenoid content and SPAD value of C. azalea leaves increased to a certain extent under shading condition, and reached the highest level under 80% shading condition. (3) With the increase of shading intensity, the contents of soluble sugar, soluble protein in leaves decreased firstly and then increased, and they were at the lowest level under 50% shading condition; the content of starch in leaves increased firstly and then decreased, and it was at the highest level under 50% shading condition. (4) Shading significantly reduced the relative conductivity of leaves. With the increase of shading intensity, it showed the trend of decreased firstly and then increased, and at the lowest level under 50% shading condition. Therefore, C. azalea seedlings have a strong adaptability to low light condition, and the moderate shading treatment (50% shading condition) helps leaf growth and development of Camellia azalea seedlings.

Abstract:To explore the effects of elevated CO₂ on photosynthesis characteristics and biomass allocation in Lycium barbarum. With L. barbarum seedlings as research materials， we applied open top chamber (OTC)， a facility to control changed CO₂ concentration to simulate natural environment in experiment. We conducted three gradients of CO₂ concentration， the control group is (380±20)μmol/mol（CK），which is ambient CO₂， and elevated was (570±20)μmol/mol（TR1）， （760±20）μmol/mol（TR2）. The effects of elevated CO₂ on photosynthesis and biomass allocation of L. barbarum seedlings were assessed by net photosynthetic rate（P_n）， light response curves， CO₂ response curves and dry weight during seedlings exposed to all three treatments （CK， TR1， TR2） after 90 and 120 days in 2017 and 2018. Results showed: （1） when treated for 90 days in 2017， the TR1 and TR2 in P_n of L. barbarum seedlings were increased significantly than that of control (P<0.05). After 120 days， the P_n of TR1 was decreased significantly compared with CK (P< 0.05). While P_n of TR1 was 4.77% lower than CK when we repeated the test after 90 days in 2018 (P>0.05). The treatment of TR1 and TR2 was higher in P_n than CK after 120 days，but the difference between them was not significant （P>0.05）. （2） With the rising of CO₂ concentration， it is similar that the intercellular CO₂ concentrations (C_i) of TR1 and TR2 treatment were soared respectively than ambient CO₂ in 2017 and 2018 (P<0.05). With the time prolonging until 120 days， the stomatal conductance (G_s) of TR1 and TR2 dropped conspicuously than that of CK (P<0.05). No difference in water use efficiency （WUE） in 2017， but it raised obviously than control after 120 days in 2018. （3） At 90 days， the light saturation point and CO₂ saturation point of treatment TR1 and TR2 were all rising than control， which was maintained in 120 days，but the CO₂ assimilation rate of TR2 was declined. （4） The biomass allocation of L. barbarum seedlings increased signally in its aboveground with CO₂ rising， thus less allocated in underground organs （P<0.05）. We concluded that slightly elevated CO₂ could promote the photosynthesis of L. barbarum seedlings， as a result of photosynthesis， the biomass accumulation in L. barbarum seedlings was tend to its aboveground organs， while underground was reduced remarkably. With the concentration and incubation time extending， the photosynthesis in L. barbarum seedlings showed a downregulation trend， which revealed by its P_n， G_s and photosynthetic CO₂ assimilation rate decreased.

Abstract:In order to clarify the effect of afforestation of Dodonaea viscosa on the native plant species diversity in karst area of Beipan River, we are adopting the community sample survey method to investigate the plant communities under different D. viscosa coverages (0, 20%, 40%, 60%, 80% and 100%), comparing and analyzing the species diversity of the plant communities. The results are as follows: (1) with the increase of D. viscosa coverage, the number of species in the community and phanerophytes slightly decrease, and the remaining species are mostly herbage of hemicryptophyte, cryptophyte and therophyte. (2) With the increase of D. viscosa coverage, Margalef index, Simpson index, Shannonwiener index and Pielou index all showed a downward trend, the plant species and quantity decrease, the community structure tend to be simple and the stability decrease. (3) With the increase of D. viscosa coverage, the species composition of the community is constantly replaced, and the species substitution rate of herbaceous plants is higher than that of woody plants. However, the variation trend of substitution rate among community species first decreased and then increased, while the species similarity coefficient between adjacent two coverings (0% and 20%, 20% and 40%, 40% and 60%, 60% and 80%, and 80% and 100%) first increased and then decreased. The results showed that when the D. viscosa coverage reaches 60% or higher, the local plant species richness and diversity are relatively low, the species distribution is uneven, the community structure become simple and the stability is poor, which is not good for the community to develop to a higher stage.

Abstract:Heterogeneous environment affects the distribution and diffusion of species at different ecological levels, which may thus significantly affect the invasion situation of alien species. Here, we analyzed the structure characteristic of aquatic invasive Alternanthera philoxeroides community and divided its association types based on 23 sampling plots (10 m × 10 m) spanned from 21°N-31°N in China, by using the method of twoway indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA). Meanwhile, we also analyzed the relationships among species distribution, population characteristics of A. philoxeroides and various environmental factors using redundancy analysis (RDA) to provide references for biological invasion control and native biodiversity protection. The results showed that: (1) 23 plots recorded 48 plant species, which belonged to 21 families and 42 genera, A. philoxeroides had the largest dominance, the dominant accompanying species were Paspalum paspaloides, Leersia hexandra, Polygonum hydropiper. (2) 23 plot communities were divided into 6 associations, among those, A. philoxeroides + P. paspaloides + Oenanthe javanica was the main association type. (3) 48 plant species were divided into 4 functional groups, including pioneer species group, dominant accompanying species group, secondary companion species group, and avoiding species group. The DCA differentiation of functional groups was larger than that of association types. (4) Species distribution was mainly determined by ammonia and conductivity of waters. However, species richness and population characteristics of A. philoxeroides were multiply influenced by conductivity, longitude, elevation and dissolved oxygen. Additionally, the aquatic A. philoxeroides invasion situation was largely depended on its asexual branch numbers and coverage. Our research clearly indicates that the structure of aquatic invasive A. philoxeroides community is relatively simple. We should intensify the invasion monitoring and maintain higher habitat heterogeneity, for alleviating the invasion progress in aquatic ecosystems.

Abstract:Based on seed plants in Flora of Enshi, combining with field investigation statistics in natural reserves, we studied the species diversity, composition of genera, families and floristic components in Southwest of Hubei. Results showed that: (1) there were 3 053 seed plant species in Southwest of Hubei, belonging to 1 008 genera and 164 families, which accounted for 74.79% species of Hubei, 11.20% of China. Among them there were 9 families, 28 genera, and 45 species in Gymnosperm, and 155 families, 980 genera, and 3 008 species in Angiosperm. In addition, there were 1 576 herbplants in total, which showed multiple life forms, abundant herb species, more perennial, deciduous species, various rare and endangered plants and high biodiversity in studied area. (2) Rosaceae (210 species), Compositae (198 species), Liliaceae (131 species), Gramineae (126 species) and Leguminosae (111 species) contained more species than other families in Southwest of Hubei. Among characteristic families, Betulaceae had the highest importance value （22.00）. Genera and species tend to concentrate in limited number of families, large families and genera possessed obvious superiority. The monotypic or oligotypic families and genera were much abundant. (3) The natural flora of seed plants in Southwest of Hubei were divided into 11 arealtypes and 14 variations in families. The tropical elements took 65.25% (77 families), 38 families (32.20%) were temperate ones, and 2 families were endemic to China (1.69%), tropic distribution compositions hold a dominant position. Genera were divided into 15 arealtypes and 23 variations. 41.06% (388 genera) of total genera were tropic composition, 51.32% (485 genera) were temperate composition, and 6.03% (57 genera) were endemic to China. Species were divided into 15 arealtypes. The temperate elements took 59.70% (1 572 species), 934 species (35.47%) were tropical ones. 110 species were endemic to China (4.18%). Arealtypes in genera and species were dominated by temperate element. Based on this study, the flora of Southwest of Hubei were of characteristics with transition of tropical and temperate zone. The flora was ancient, and geographical components were complex.

Abstract:Distribution (county) of every species of Fagaceae in China was searched by plant professional websites, published papers and books. Geographic information System was used in the paper. Map of spatial distribution of genera was made by the county and Fagaceae of China. Number, area and perimeter of every patch were gotten quantitatively from the map. Shape index of patch, largest patch index, Shannons and Simpsons evenness indexes were calculated. Spatial distribution and its characters of every genus in Fagaceae were analyzed. It provided a basis for quantitative research of spatial distribution in flora. Results showed that: (1) spatial distribution of genera of Fagaceae in China is continuous area or area disjunction. There are scattered area, main and secondary area, and main area in area disjunction. Differences of spatial distribution in genera are showed by thematic map and quantitative data. (2) Distribution area and the largest patch area of genera of Fagaceae in China are in subtropical zone which locates in southern China. They distribute continuously to tropical zone, but patch occupies splitsite and small area in temperate zone. Flora in subtropical zone of China should be Paleotropic Kingdom. (3) Trigonobalanus, Castanopsis and Lithocarpus should be Trop. As. and Trop. Amer. Disjuncted according to their distributions in world and China.

Abstract:The artificially cultivated P. qinlingensis was used as an experimental material. The variation law of floral organs was discussed and the causes of variation were analyzed, through the observation and statistics of the organ morphology and number. The results showed that: (1) a total of 17 species of corolla variation, 7 types of fertile stamens and 5 types of sepal variants were found in the 1996 P. qinlingensis flowers observed. The total mutation rates were 34.57%, 38.38% and 32.67%, respectively. (2) P. qinlingensis peduncle may be branched, and the number of sepals was 2~3 on the peduncle. (3) Correlation analysis showed that the number of lower lips was positively correlated with the number of fertile stamens, and the number of upper lips was negatively correlated with the number of fertile stamens. The correlation coefficients were 0.927 4 and -0.481 1, respectively. This may be related to the growth of P. qinlingensis fertile stamens in the inner base of the lower lip of the corolla, combined with floral diagram analysis. The abundant variation types of P. qinlingensis in this study may lay a foundation for the study of system evolution, floral organ development, reproductive ecology and molecular genetics in the future, and provide ideas for cultivating varieties with different ornamental values.

Abstract:A thoroughly study is carried out on an Achnanthidium species from Li River in Wuling Mountains area using light and scanning electric microscopy. The results confirm that this Achnanthidium species is indeed Achnanthidium rostropyrenaicum. A. rostropyrenaicum possesses two key features: the linearlanceolate valve outline with rostrate ends and the slightly convergent or nearly parallel striae distributed at the ends of the raphe valve. The hymens, which were not involved in the original description, also are studied. The hymenes are sievelike. This study expands the knowledge of the morphological structure and geology distribution of A. rostropyrenaicum.

Abstract:Consumption of plantderived food is considered as the main source for intake of toxic element cadmium (Cd) and arsenic (As) in human. Deepening the molecular understanding of the pathways responsible for Cd and As can enable the development of crop varieties with low toxic metal element contents in their edible parts. Based on substantial research progress of Cd and As accumulation in model plants in recent years, transporters mediating the uptake of Cd and As, the speciation and biotransformation mechanisms of As, factors controlling the efficiency of roottoshoot translocation and the partitioning of Cd and As through the node have been reviewed and the prospects in this field have also been proposed.

Abstract:Gentianaceae are famous alpine plants and distributed widely in temperate regions of the world. They are used in medicine as well as in gardening. Gentianaceae contain six tribes, in which Gentianeae (includes subtribe Gentianeae and Swertiinae) takes up more than a half of the species in Gentianaceae. Amounts of studies about taxonomy and evolution have performed in Gentianeae, especially after technology of molecular biology has been widely applied in this group. Here, we review recent studies that reported the taxonomy and evolution in Gentianeae. The new genera and taxa in Gentianeae were summarized as well. Finally, we highlight some open questions for future researches of taxonomy and evolution of Gentianeae (1) morphological character is important for taxonomy and evolution studies; (2) publication of new species should be cautious; (3) singlecopy nuclear gene should be used in phylogenetics; (4) hybridization and polyploidization should be paid more attention in the evolution of Gentianeae.