Abstract:In order to understand remediation effect of wollastonite (WS) and 4A molecular sieve (MS) on Cd-contaminated soils collected from northern Guangdong Province, the absorption of heavy metal and nutrient of lettuce (Lactuca sativa) was studied by using pot experiment. The results showed that the available Cd and Pb contents of soil significantly reduced with ≥660 mg Si/kg MS and WS, on the contrary, those increased with low dose (220 mg Si/kg). Therefore, it indicated that ≥660 mg Si/kg MS and WS had significant inhibitory effect on the accumulation of Cd and Pb of lettuce. WS inhibited lettuce Cd uptake through enhancing Ca-Cd competition rather than reducing Cd availability in soil. MS reduced Ca, Mg, Mn and Zn contents and slightly increased Cu content in lettuce. WS decreased Mn and Zn contents and slightly increased Ca and Cu contents in lettuce. The lettuce yield reduced by 29% with high dose of MS (880 mg Si/kg), and increased by 10%-12% with high dose of WS (≥660 mg Si/kg). In conclusion, WS had better performance in boosting crop yield and decreasing crop Cd, showing a potential for remediation of Cd-contaminated soils. Besides, the decreases of Zn and Mn contents in crops should be addressed by the proper addition of Zn and Mn nutrients into soils.

Abstract:Predicting the potential geographic distribution of a species and its response to climate change is of great significance for the conservation of biodiversity and the sustainable development of ecosystems. Phoebe sheareri is widely used in building furniture because of its heavy weight, hardness, and uniform structure. However, because it has a weak natural ability to regenerate and because unprecedented damage has occurred in its natural habitat, wild germplasm resources are getting exhausted. In order to understand the effect of climate on distribution of P. sheareri, its suitable distribution region was simulated by using Maxent and Genetic Algorithm for Rule-set Prediction (GARP), the main environmental factors were analyzed, and the changes in distribution area under four climate change scenarios were predicted. The results showed that P. sheareri was suitable for distribution in the middle and lower reaches of the Yangtze River and south provinces. Annual precipitation, mean temperature of the driest quarter, precipitation seasonality, relative humidity and sunshine duration from June to August were the main factors affecting the distribution of P. sheareri, and these factors contributed 84.3% of the variation. Under climate change scenarios, by both Maxent and GARP models, the suitable area in Guangdong, Yunnan, Guangxi, and Hainan would decrease significantly for this species, while that in central Shaanxi, southern Henan, eastern Anhui, and northern Jiangsu would increase. Therefore, under climate change scenarios, the suitable habitat would expand geographically to the north. These should provide a useful reference for the conservation and cultivation of Phoebe sheareri.

Abstract:Xylem growth of trees plays an important role in slowing global warming. In order to understand the intra-annual xylem growth dynamics of subtropical Castanea henryi and its response to climate in Dinghushan mountain in south China, the xylem of C. henryi was continuously monitored by microcore sampling technology, the xylem growth in 2015 was fitted by generalized additives models, and the relationship between the xylem growth rate and climate factors was analyzed by using mixed-effect models. The results showed that xylem growth of C. henryi in Dinghushan Mountain kept almost whole year of 2015, and showed significant seasonal differences. The xylem grew rapidly before 200 days of 2015 (early growing season), and showed a down trend in growth rate after 300 days of 2015 (late growing season). The xylem growth rate during early growing season was positively correlated with temperature and photosynthetically active radiation, but that between xylem growth rate and climate factors during late growing season was not significant. So, it was reflected that there were seasonal differences in xylem formation and its regulating mechanism of south subtropical broad-leaved tree C. henryi of China, showing the adaptability of xylem formation to the environment. These could provide data support for deeply understanding and predicting of trees growth in subtropical forest ecosystem under the background of climate change.

Abstract:In order to reveal the status of Cordyceps sensu lato resource in Weishan County, Yunnan Province, the species diversity of Cordyceps sensu lato was studied based on field survey, morphological observation and multigene (nrSSU, nrLSU, EF1-α, RPB1 and RPB2) phylogenetic analysis. The results showed that there were 341 strains of Cordyceps sensu lato collected from 5 plots, belonging to two families and five genera, including seven suspected new species. The hosts of Cordyceps sensu lato were Lepidoptera, Coleoptera, Hymenoptera and Dermaptera, respectively. The dominant genus was Cordyceps collected 7 species 215 strains, and C. militaris was dominant species collected 93 strains. The species diversity and richness of Cordyceps sensu lato were the highest in plot of Red River Source and the lowest in plot of Xiao Jizu Shan. Based on the accumulative curve, it was indicated that most of Cordyceps sensu lato had been collected in Weishan area. So, these would provide the basis for protection and sustainable utilization of Cordyceps sensu lato in Yunnan Province.

Abstract:In order to understand the water use characteristics of gymnosperms and angiosperms in warm area, the sap flow of two gymnosperms, Taxodium ascendens and T. distichum, two angiosperms, Liquidambar formosana and Michelia chapensis, was continually monitored by using Granier's thermal dissipation probes (TDP) in Guangdong Province of southern China. The results showed that whole tree transpiration rate and daily water consumption were positively correlated with photosynthetically active radiation and vapor pressure deficit. In the dry season, the water transport capacity in Taxodium ascendens and T. distichum was significantly smaller than that in L. formosana and M. chapensis, while it was just the reverse in the wet season. So, these could provide scientific basis for landscape gardening and management in south China.

Abstract:In order to reveal the difference of water ecophysiological adaptation of plants in humid and seasonal arid habitats, the structure and functional traits of leaves and petioles of six palm species in South China Botanical Garden, Chinese Academy of Sciences were studied, including three species originally distributed in moist habitats (SOMH): Licuala ramsayi, Areca catechu and Ptychosperma salomonense, and three species in seasonally dry habitats (SODH): Washingtonia robusta, Livistona australis and L. saribus. The results showed that hydraulically weighted vessel diameter (D_h), theoretical hydraulic conductivity (K_th), leaf turgor loss point (TLP) vulnerability index (VI) and specific leaf area (SLA) of SOMH were significantly greater than those of SODH, whereas SODH had the significantly greater vein density (VD) than SOMH. Meanwhile, the VI and TLP had positive correlation with K_th, indicating that there was a trade-off between the hydraulic efficiency and safety for these palm species. In conclusion, the leaf hydraulic efficiency of SOMH was higher than that of SODH, but the leaf hydraulic safety was lower than that of SODH. It was revealed that the differences in water ecophysiological strategies of palm plants in different habitats.

Abstract:In order to screen total RNA extraction method from flowers of Dendrobium officinale, eight methods were compared, including improved CTAB-LiCl method (M1), improved CTAB-isopropanol method (M2), improved SDS-LiCl method (M3), improved SDS-isopropanol method (M4), Quick RNA Isolation Kit (Huayueyang, China; M5), Column Plant RNAout 2.0 Kit (Tiandz, China; M6), RNAprep Pure Plant Plus Kit (Tiangen, China; M7) and Plant Total RNA Extraction Kit (Biospin, China; M8). The results showed that the integrity of total RNA extracted using M4 and M5 was good, with distinct electrophoresis bands of 28S and 18S rRNA. The spectrophotometric values of A_{260 nm}/A_{280 nm} ranged from 1.8 to 2.0, and the A_{260 nm}/A_{230 nm} value was more than 2.0. The yields of total RNA extracted using M4 and M5 were (159.45±1.45) and (170.84±3.53) μg/g, respectively. Additionally, the total RNA of D. huoshanense, D. nobile, D. chrysotoxum and D. loddigesii extracted by M4 and M5 was verified to meet the quality requirements on integrity, purity and concentration. The total RNA of D. officinale extracted by M4 and M5 was used as template, and the amplified Actin gene showed a single band, consisting with the prediction. Therefore, M4 and M5 were effective methods to extract total RNA from flowers of Dendrobium plants, especially D. officinale.

Abstract:In order to identify the pathogens of walnut blight in Sichuan Basin Area, the pathogens was isolated by using tissue isolation method, and the pathogenicity was tested using Koch's postulates. The pathogen was identified based on morphological characteristics and sequence analysis of 16S rDNA, and the resistance of 18 cultivars (clones) of Juglans regia was evaluated through field infection using the isolated strain. The results showed that the morphology of isolated pathogen were similar with Xanthomonas, which sequence of 16S rDNA showed 99% similarity with X. arboricola (GenBank No. KP340804.1). Therefore, X. arboricola was identified as the pathogen caused the walnut blight in Sichuan basin area. The incidence and disease index of 18 walnut cultivars (clones) were ranged from 35.07% to 78.57%, and 17.71% to 51.96%, with the coefficient of variation of 17.62% and 28.78%, respectively. Based on the resistance evaluation, five highly resistance cultivars (clones) were selected. Therefore, these would provide basis for pathogenesis mechanism of walnut blight and resistance breeding.

Abstract:In order to exploit the NBS-LRR resistance genes of Ipomoea triloba, a close wild relative of I. batatas, the genome sequence was screened, identified and analyzed by using pertinent software. The results showed that among the 98 025 genes identified from I. triloba, there are 282 genes encoding NBS-LRR proteins, including 80 N type, 83 NL type, 28 CN type, 57 CNL type, 10 TN type, 23 TNL and 1 RN type. NBS-LRR family genes were located in all of 16 chromosomes, each containing 1 to 65 genes. There were 55 gene clusters in genome of I. triloba, containing 63.5% of the NBS-LRR family genes. There were 7 and 11 conservative domains in CNL and TNL subfamilies, respectively. Therefore, these would provide a scientific reference for utilization of resistance resource in I. triloba.

Abstract:In order to explore the function of ERD15 gene by reverse genetics, a homozygous T-DNA insertion mutant of ERD15 gene of Arabidopsis thaliana was identified by PCR and semi-quantitative PCR. The phenotype of erd15 mutant was observed. The results showed that the number of rosette leaves in erd15 mutant increased significantly and flowering time was 3-4 days earlier, indicating that the erd15 mutant from vegetative to reproductive growth was earlier than the wild type. The main stem of wild-type A. thaliana was cylindrical with an average diameter of 1.29 mm, while that of erd15 mutant became flattened with an average diameter of 2.27 mm. Compared with the wild type, the carpel development of erd15 mutant fruit was affected, multiple rows of seed were arranged on the septum, and the length of silique was shortened by 37.67% with swelled apex, but the average seed number of silique increased in erd15 mutant. Therefore, it was suggested that ERD15 gene was involved in regulating the reproductive growth of A. thaliana.

Abstract:In order to select superior families for breeding large-size diameter of Chinese fir (Cunninghamia lanceolata), the diameter at breast height (DBH) of 28 half-sib progenies in second-generation seed orchard of Guangdong were continuously determined at 4, 9, 11, 16 and 21 years old, compared with 2 control families from primary seed orchard and 1.5 generation seed orchard of Guangdong. The result showed that DBH of Chinese fir had significant difference (P<0.01) among families at the same age, and the phenotypic and genetic coefficient ranged from 4.43% to 6.29% and from 2.95% to 3.62%, respectively. The family heritability of DBH increased from 0.3359 at 4 years old to a peak of 0.5486 at 16 years old, and then became stable at 21 years old. The genetic correlation of DBH at 9 years old was close to that at 4, 11, 16 and 21 years old, respectively. So, according to multi-year breeding values and the ratio of diameter-grade volume of family at age of 21, three families (F5, F9 and F21) were selected as the superior families for large-size timer cultivation.

Abstract:Styrax buchananii W. W. Sm., a newly recorded species of Styracaceae from China is reported. Characteristic description and voucher specimen photo are provided. The new record species could be distinguished from other related species in the genus by the young twigs densely yellow-brown stellate-pubescent, the corolla imbricate, the filaments noticeably shorter than anthers and curved at the upper part.

Abstract:Two newly naturalized species of Asteraceae, Acmella brachyglossa Cass. and Emilia praetermissa Milne-Redh. in Mainland China were reported. The former is native to Central and South America and the Caribbean, and naturalized in Taiwan. Recently a population of this species was found in Huangpu District of Guangzhou City. The previously reported new record of this species in Xiangshan County, Zhejiang Province was actually a misidentification of A. radicans var. debilis (Kunth) R. K. Jansen. Emilia praetermissa originates in West Africa, which also becomes naturalized in Taiwan. Many populations of this invasive species were discovered in Conghua District of Guangzhou City and Heshan City this year. The vouchers are housed in Herbarium of South China Botanical Garden, Chinese Academy of Sciences (IBSC).

Abstract:The origin, distribution, adaption, community structure and succession characteristics of Rhododendron were reviewed, and the further research and rational utilization prospected. The origin center of Rhododendron was southwest China and the regions from the Himalayas to northern Myanmar, and Guizhou Baili Rhododendron Forest is the widest wild Rhododendron resource bank all over the world. The adaption of Rhododendrons was closely related with homophily, elevation similarity, evolution degree, and key functional traits. The comparison method based on evolution-morphological functional characteristics provides reference for breeding Rhodo- dendrons with good adaption. Rhododendron shrub community has its own particularity, showing complex multi-level vertical structure, mosaic horizontal structure and obvious age structure. In term of succession characteristics, the view was still to be proved that Rhododendron shrub community had succession to the top level according to the large niche width of dominant species in the community and the small niche similarity ratio between populations.