Abstract:In order to understand the taxonomic significance of caryopsis characters in Avena L. (Poaceae), the micromorphology of 27 species caryopsis were observed under stereoscopic microscopy and scanning electron microscopy, and its taxonomic significances were analyzed combining with molecular phylogenetic reconstruction. The results showed that there were three shapes of caryopses in Avena, including fusiform, oblanceolate and elliptic, and three spermoderm sculpturing patterns, including striate, ribbed and reticulate. Caryopsis shapes, spermoderm sculpturing patterns and stylopodium persistence patterns showed limited taxonomic significance at the infrageneric level, and caryopsis size and macrohair density were of important diagnostic characters at the interspecific level, while caryopsis ventral face, compression, and embryo proportion had limited diagnostic significance at the interspecific level in Avena. Avena macrostachya Balansa ex Coss. & Durieu should be treated as a member of Avena due to its caryopsis characters of fusiform and striate sculpturing pattern falling within the variation scope of caryopsis micromorphological characters of Avena. The differences of caryopsis size, shapes,spermoderm sculpturing patterns between A. nuda L. and A. sativa L. supported that A. nuda should be treated as a separate species. The wide variation ranges of caryopsis size, macrohair density and embryo proportion indicated that they were the adaptive consequences of wide variation range of climate condition across the geographical distribution region of Avena. The caryopses of concave ventral face have a relatively small bulk, which may have aided rapid development and maturation, a rhythm that is of particular value in short growth period in temperate and cold distribution region for Avena.

Abstract:In order to understand the development of ovule and female gametophyte in Paphiopedilum barbigerum Tang et Wang, an endangered species in Orchidaceae, the growth dynamic of its capsule was studied by conventional paraffin section method. The results showed that the number of seeds in capsule increased rapidly during 60-75 days after pollination, and its capsule would be full of seeds at 120 days after pollination. The ovule primordium, a row of cells surrounded by a layer of epidermal cell, began to differentiate at 40 days after pollination. The archesporial cell under the epidermal cells at the end of placenta finger structure differentiated into megaspore mother cell at 60 days after pollination. The megaspore mother cell eventually formed the mature embryo sac after meiosis and mitosis. It took about 135 days from pollination to maturation of embryo sac, and seeds attached to placenta had differentiated obviously. The development of embryo sac was Allium type. The mature ovule was anatropous with thin nucellus and single integument. The mature embryo sac had 8 nuclei. These would provide theoretical basis for studying in reproductive biology and establishment of reproductive system.

Abstract:In order to make sure endangered medicinal plant resource in Jinfo Mountain, based on field investigation, specimen collection and identification for five years, the evaluation system of endangered medicinal plants in Jinfo Mountain was established including six indicators, e.g. deposit coefficient, endanger coefficient, genetic coefficient, valuable coefficient, conservation coefficient and breed coefficient. The results showed that 149 wild medicinal plants (including varieties and forms) in Jinfo Mountain suffered serious threat, belonging to 73 families and 113 genera. Seventy-four species needed to be key protected, such as Paris polyphylla, Euchresta japonica, Semiliquidambar cathayensis, Cibotium barometz, Gastrodia elata, Polygonatum sibiricum, Bletilla striata and so on. Sixty-five species needed to be took protective measures, e.g. Iris tectorum, Dioscorea zingiberensis, Cephalotaxus fortunei, Uncaria rhynchophylla, Cimicifuga foetida, Taxus wallichiana var. chinensis, Trichosanthes rosthornii, Penthorum chinense and so on. Ten species needed to be took general protective measures. According to priority protection value and resource utilization state, the proposal protection grades of 149 endangered medicinal plants in Jinfo Mountain were listed, in which 53 species to grade I, 48 species to grade II and 48 species to grade III.

Abstract:In order to understand the variation pattern and adaptive mechanism of endemic medicinal plant Berberis guizhouensis Ying (Berberidaceae) from Guizhou Province, its characteristics of vegetative organs and flowers in field populations were studied in Weining Xian, Guizhou Province, southwestern China. The description of the floral characters was supplemented. The results showed that there was abundant variation among different traits within a population and the same trait in different populations. Coefficient of variation (CV) ranged from 0.03 to 0.57, and the CV values of vegetative traits were higher than those of floral traits. One-Way ANOVA analysis revealed that there was significant difference in some flower characters among populations (P<0.05). Cluster analysis showed that Xiaobaiyan population formed a separate clade, which could be caused by environment pressure selection. PCA analysis showed that there was coordinated ecological adaptation between floral and vegetation traits in maintaining the stability of morphological structure.

Abstract:Delphinium muliense W. T. Wang (Ranunculaceae) was published in both Latin and Chinese. Its type correction has been wrongly cited as T. T. Yü (= T. T. Yu) 6988 in the Latin protologue, although correctly cited as T. T. Yü 6989 in the accompanying Chinese translation of the Latin protologue. The collection T. T. Yü 6988 belongs to Allium prattii C. H. Wright ex Hemsl. in the Amaryllidaceae.

Abstract:In order to construct high-quality normalized full-length cDNA library of Cestrum nocturnum L., the library from its flowers was established successfully by combined modified SMART technology, DSN digestion with desalting of ligation product. The results showed that transformation efficiency of the ligation product without desalting was 7000 colonies per microliter, and theoretical recombination rate was 96%, whereas, the transformation efficiency increased up to 4.1×10⁶ colonies per microliter, and theoretical recombination rate was 98% after the ligation product desalting. Actually, blue colonies also contained the insert fragments, and, the recombination rate was to 100%. The average size of inserts in the library was about 1.6 kb. Five hundred colonies including 50 blue colonies were randomly picked for sequencing from the library, 464 effective sequences were obtained including 426 unigenes (accounting for 91.8%), which were composed of 26 contigs and 400 single genes, redundant rate was only 8.1%. So, it was suggested that the quality of the normalized cDNA library was better than that of ordinary cDNA libraries, which could be used for further research of screening of functional genes and their related information.

Abstract:In order to understand the effects of ultraviolet-B (UV-B) radiation on active constituents and antioxidant activity in fresh Bolbostemma paniculatum (Maxim.) Franque, the contents of active ingredient and antioxidant activities were studied. The results showed that the contents of reducing sugar and emodin increased by 60.17% and 209.60%, respectively, radiated by 100 kJ m^-2 UV-B. Compared to control, the reducing capacity and DPPH· scavenging ability of B. paniculatum significantly enhanced (P<0.01). Therefore, UV-B radiation could increase active ingredient contents and antioxidant activities of B. paniculatum, and its quality could be improved if radiated with UV-B before processed.

Abstract:In order to understand the effects of rhizosphere N supply on the growth and nutritional quality of purple pak-choi (Brassica campestris ssp. chinensis var. communis), the physiological and nutrition characters were studied treated with different levels of NH₄NO₃. The results showed that the fresh and dry weight, root activity, free amino acid content of purple pak-choi increased initially and then slightly decreased with the N level increment. Nitrate reductase (NR) activity, contents of chlorophyll, NO₃^- and soluble protein, and DPPH· radical scavenging rate increased, activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) isozymes showed upward trend, while the contents of relative anthocyanin, soluble sugar, vitamin C (Vc) and total phenols, and FRAP value decreased. Meantime, the fresh and dry weight of purple pak-choi treated with 75-300 mg L^-1 NH₄NO₃ was low. The fresh and dry weight treated by 1200 mg L^-1 NH₄NO₃ was lower than that by 600 mg L^-1 NH₄NO₃, more NO₃^- accumulated in plant led to decline of nutrient quality, and NH₄NO₃ deposited in rhizosphere. So, the optimum level of NH₄NO₃ was 600 mg L^-1 because of high fresh and dry weight, balanced nutrition and strong antioxidant ability.

Abstract:In order to understand the relation between reactive oxygen (ROS) metabolism of tomato (Lycopersicon esculentum) rootstock seedlings and their resistance to Meloidogyne incognita, a high sensitive rootstock ‘Ls-89’ and a high resistant rootstock ‘Banzhen 2’ were planted in pots and inoculated with M. incognita, the effect of M. incognita infection on ROS metabolism and related enzyme activities in tomato rootstock seedlings was studied. The results showed that ROS level and related enzyme activities in roots and leaves had no significant difference between two varieties uninfected by M. incognita. After inoculated by M. incognita, both O₂·^- generation rate and H₂O₂ content in roots and leaves of two varieties increased, and those in ‘Banzhen 2’ were significantly higher than those in ‘Ls-89’, while MDA content in ‘Ls-89’ was significantly higher than that in ‘Banzhen 2’. At the early stage of infection, SOD activity decreased in roots and leaves of both varieties, and the decline in ‘Banzhen 2’ was bigger than that in ‘Ls-89’. The POD and CAT activities changed hardly at early stage of infection, and then significantly enhanced in middle and late infection stage. Therefore, the resistant rootstock seedlings had strong lipid antioxidant ability and high ROS level, and SOD activity in tomato rootstock seedlings was sensitive to the infection of M. incognita.

Abstract:In order to reveal the endangered mechanisms of Dracaena cambodiana, the effects of pericarp, temperature, soil moisture and light intensity on seed germination of D. cambodiana were studied, and its environment adaptability was analyzed. The results showed that seed germination of D. cambodiana was significantly inhibited by pericarp, and could be significantly promoted by removing pericarp and watering pericarp soak solution. Seed germination was very sensitive to temperature with suitable temperature of 25℃, and seeds could not germinate under below 15℃ or above 30℃. Alternating-temperature had certain facilitation to seed germination. The germination of D. cambodiana seeds need high shading density, light intensity had significant effect on seed germination. The germination of D. cambodiana seeds was insensitive to soil moisture, there were not significant differences on GP (germination rate), CRG (coefficient of germination rate), GTL (germination time lag) and GI (germination index) among soil moistures ranged from 9.09% to 20.00%. Therefore, the germination of D. cambodiana seeds strongly depended on pericarp and microenvironment factors, i.e. temperature and light intensity. The microenvironment changes caused by habitat destruction might be one of main reasons for failure of sexual reproduction and endangerment of D. cambodiana.

Abstract:In order to understand the response to combined stresses of cadmium (Cd) and naphthalene (Nap), the germination and growth of mangrove plant Avicennia marina seedlings were studied cultured on sand in greenhouse. The results showed that the inhibition effect of seedling germination under Cd-Nap combined stress was more obvious than that under Cd stress. The survival rate increased at early stress stage, and then decreased at later stress stage. After cultured for 45 days, the inhibition effect of Cd on leaf size, stem height and biomass relieved treated with 10 mg L^-1 Nap, while inhibition effect on root growth enhanced. Compared to treatment with 25 mg L^-1 Cd, the area, length, width of leaf, stem height and biomass treated with 10 mg L^-1 Nap-25 mg L^-1 Cd increased by 9.6%, 7.9%, 7.4%, 5.1% and 20.2%, respectively, while root length decreased by 11.1% compared to treatment with 150 mg L^-1 Cd. When cultured for 90 days, the inhibitive effect of Cd-Nap stress on leaf size, stem height and root growth was stronger than that of Cd stress, but there was no significant difference in biomass. Therefore, with extension of combined stress time, the antagonistic effect of Cd-Nap on A. marina seedling growth turned into synergistic effect.

Abstract:In order to understand the growth characteristics of Artemisia annua in Wuling Mountain area, the growth and development law were studied. The results showed that the development of A. annua could be divided into six stages, including seedling stage, early branch stage, branching stage, bud stage, blooming stage and seed maturity stage. The leaf area increased most rapidly at branching stage, and the leaf area index had linear ascending with the growth of branches and leaves. Leaf area ratio overall decreased at seed maturity stage. The net assimilation rate changed slightly, which there were two small peaks at seedling and blooming stages, respectively. The relative growth rate changed greatly, crop growth rate was small at seedling and seed maturity stages, and high at branching stage. The rule of dry matter accumulation in the whole growth period appears “S” curve. During late June to late August, A. annua growth was at branching stage, dry matter accumulation rate and yield of leaves increased rapidly, so that this period was the key time of increasing yield of A. annua leaves, it should pay attention to balanced application of NPK fertilizers.

Abstract:In order to resolve a series of ecological problem caused by abuse of chemical pesticides in urban greening, the composition of essential oils from Zanthoxylum piperitum leaves were analyzed, and their insecticidal and antibacterial effects were studied. The results showed that the optimum process of petroleum ether extraction for essential oils was 4 h, 50℃, with solid-to-liquid ratio of 1:5, and the highest yield was 0.5123%. Twenty five compounds dominated by hydrocarbons, alcohols and esters were identified, accounting for 99.96% of total peak area. Among them, the components with anthelmintic, insecticidal and antibacterial activity accounted for 88.50%, such as methyl cinnamate (87.83%), limonene (0.18%), menthol (0.11%), citronellal (0.10%), α-pinene (0.08%), α-caryophyllene (0.08%), terpineol (0.04%), caryophyllene (0.03%), hydroxygermacra-1(10),5-diene (0.03%) and β-phellandrene (0.02%), et al. The DPPH· scavenging rate treated by 20 mg mL^-1 essential oils was 85.38% closed to the BHT positive control, but its reductibility was weaker than that of Vc, which might be associated with extraction process. Therefore, the essential oils of Z. piperitum leaves contained many kinds of bioactive substances, such as insecticide, insecticidal and antibacterial, it had development potential for nature plant pesticides.

Abstract:In order to find the bioactive components from the stems of Chukrasia tabularis, ten compounds were isolated from its EtOH extract by using chromatographic techniques. On the basis of spectral data, their structures were identified as 3-hydroxy-1-(4-hydroxy-3,5-dimethoxyphenyl)propan-1-one (1), 6-hydroxy-1,3,5,7-tetrameth-oxy-9H-xanthen-9-one (2), 2,6,2',6'-tetramethoxy-4,4'-bis(2,3-epoxy-1-hydroxypropyl) biphenyl (3), cleomiscosin D (4), chuktabularin A (5), chuktabularin B (6), chubularisin H (7), chubularisin I (8), tabularisin A (9), and tabularisin B (10). Compounds 1-4 were isolated from the genus Chukrasia for the first time. Furthermore, compounds 1, 2, 6, 7 and 9 exhibited inhibitory activity against α-glucosidase in vitro.

Abstract:The concepts, classification, morphology, distribution and physiological ecology characters in recalcitrant seeds were reviewed, the reasons of desiccation sensitivity and the adaptability to ecological environment of recalcitrant seeds were analyzed, its possible evolution status and effective storage technology were discussed. The development tendency and application prospects for studying on recalcitrant seeds were proposed. It was suggested that the further researches should be focus on these issues, such as habitat investigation, establishment and update of plant database in recalcitrant seeds, and analysis of the nature of recalcitrant seed based on morphological, physiological ecology and molecular biology.