Abstract:Climate change and elevated CO₂ concentration affect productivity and carbon balance of forest ecosystems. Timberline tree, Larix chinensis is extremely sensitive to climate change. In order to understand the carbon source/sink dynamics, the BIOME-BGC model was used to simulate the productivity, carbon storage and carbon use efficiency (CUE) of Larix chinensis in the northern slope of Qinling Mountains during 1959-2016, and the future trend of carbon source/sink function was projected by climate scenario setting method. The results showed that in the past 58 years, the average NPP, GPP and NEP were 328.59, 501.56 and 31.42 g C m^-2a^-1, respectively. The average carbon storage was 35.38 kg C m^-2a^-1, and the average CUE was 0.65. Except that 1960-1961, 1969-1970 and 1997-1999 were "carbon source" years, the rest were "carbon sink" years, showing the characteristics of "carbon source-carbon sink-carbon source" during the whole year. Overall, carbon storage increased and the potential carbon sequestration capacity was relatively stable. The positive effects of GPP, NPP and carbon storage were in the order of temperature increment > CO₂ concentration enhancement, while the opposite effect of NEP had adverse order. Rainfall enhancement had counteraction on productivity and carbon storage, and temperature increment had a negative effect on CUE. Temperature and CO₂ concentration were the limiting factors for the growth of L. chinensis in northern slope of Qinling Mountains, and the limitation of temperature was stronger than that of CO₂ concentration. In the future, the increase of temperature or CO₂ concentration will benefit the function of carbon sink, and the increase of precipitation will weaken the effect of carbon sink. In the RCP4.5 and RCP8.5 scenarios, the productivity and carbon storage of L. chinensis showed an upward trend in 21 century, and RCP8.5 increased slightly more than RCP4.5. The potential carbon sequestration capacity was still strong. January to March, October to December would be "carbon source" month, and May to September would be "carbon sink" month. These revealed the effects of temperature, precipitation and CO₂ concentration on carbon source/sink of L. chinensis under the background of climate change. The increase of temperature and CO₂ concentration were the promoting factor for carbon sink of L. chinensis, while the increase of precipitation was the limiting factor.

Abstract:In order to prevent and remove effectively invasive plant Praxelis clematidea, the potential distribution area and dominant environment variables were predicted by using the maximum entropy model (Maxent) and the Geographic Information System (GIS) technology. The accuracy of prediction was evaluated at "excellent" level by AUC (area under curve) method. The results showed that the prediction of Maxent model had high reliability. The potential suitable growth area of P. clematidea in China was 785 985 km², accounting for 8.19% of all China land area. This species mainly distributed in southern and southeastern China, especially in Fujian, Guangdong, Hainan and Guangxi (high suitable areas). The distribution of P. clematidea in Fujian Province was the widest, which 61.98% of the area was suitable for growth. It was high suitable area of P. clematidea in coast of south Fujian, but the population density in the north of Fujian was low relatively. The minimum temperature in February might be the restrictive variable of the distribution of P. clematidea with the contribution rate of 61.7%. Precipitation of the driest quarter and maximum temperature in September have a certain influence on its distribution. These provided a theoretical basis for the prevention and control of P. clematidea and some effective measures must be taken to prevent its spread for the further.

Abstract:In order to reveal the spatial temporal distribution pattern of water resource in China, six factors, including precipitation, aridity, evapotranspiration, slope, vegetation, and catchment area, were introduced, an improved water resource gridded model for China was proposed based on partition-weight assignment method. The results showed that the improved water resource gridded method based on second-order basin had high applicability for China, with the overall SE of 7.89% for third-order basins and 7.25% for provincial admini- strative units. The spatial allocation precision of Yangtze River basin, Songhua River basin, and southeastern River Basins was better than that of Yellow River Basin, Huaihe River Basin, and northwestern River Basins, which was significantly influenced by the nature factors, such as precipitation and evapotranspiration. There was a rising tendency from northwest to southeast in spatial distribution of water resources, which was basically consistent with the spatial pattern of precipitation. The water resources of the southern River Basins mainly came from precipitation, and the glacial melt water was the main water sources of the northwestern River Basins and most inland River Basins. The relationship between the water resource and GDP density differed with the urban city scale and geographical locations. These could provide scientific bases and decision support for the management of regional water resource.

Abstract:In order to reveal the ecophysiological strategies of leaf construction in Magnoliaceae evergreen and deciduous species, the characters related with leaf lifespan and leaf construction cost of six Magnoliaceae species, including three deciduous species, Yulania cylindrical, Y. denudate and Y. jigongshanensis, and three evergreen species, Magnolia grandiflora, Michelia figo and M. shiluensis were compared. The results showed that construction cost per leaf area (CC_area) of deciduous species was significantly lower than that of evergreen species, but their construction cost per leaf dry mass (CC_mass) was similar. Nitrogen and phosphorous concentration (N_mass, P_mass) in leaves of deciduous species were significantly higher than that of evergreen species. Evergreen species had significantly low specific leaf area (SLA) but long leaf lifespan (LLS). There were a negative correlation between CC_area and LLS, whereas other three traits (SLA, N_mass and P_mass) had a positive correlation with LLS. In conclusion, deciduous species adopted the low-cost strategy, with short leaf lifespan and high SLA to obtain more light source and nutrition storage compared to evergreen species. It was revealed the ecophysiological strategy of deciduous species of Magnoliaceae to adapt short growth season and low hydrothermal condition in north subtropics.

Abstract:In order to understand the salt related genomics in leaves of Mesembryanthemum crystallinum, the expression of transcriptome genes was studied under 400 mmol L^-1 NaCl stress by using Illumina Hiseq TM2500 high-throughput sequencing technology. The results showed that there were 13.01 Gb Clean Data from the leaves treated with 400 mmol L^-1 NaCl and untreated, the Q30 base was more than 90.08%. Among them, there were 123 differential expression genes (DEGs), including 73 up-regulated genes and 50 down-regulated genes, in which 96 genes were annotated. The eight salt-resistance DEGs of were screened out based on GO, COG and KEGG annotation. The plant hormone metabolism-related genes, including abscisic acid 8'-hydroxylase gene, indole-3-acetamide synthase gene, jasmonate ZIM structure domain protein gene were down-regulated, auxin responsive protein and cytokinin synthase genes were up-regulated. The sugar metabolism-related raffinose synthase genes was up-regulated, and plasma membrane H⁺-ATPase and dehydrated protein genes were up and down-regulated, respectively. These would provide a foundation for studing on salt tolerance genomics and molecular biology of M. crystallinum.

Abstract:In order to understand the function of POR gene in Cymbidium sinense ‘Dharma’, one POR gene family member CsPORB was cloned from young leaves. The CsPORB gene contained an open reading frame of 1 200 bp, which encoded a protein of 399 amino acids with molecular weight of 43.13 kDa and theoretical isoelectric point of 9.30. Sequence alignment showed that CsPORB was highly homologous to the sequence of POR family protein of other species, indicating conservative evolution of this gene family. The CsPORB expression showed obviously difference in different developmental stages and tissues, and high expression in growing young leaves. Furthermore, both of the PORB and its downstream chlorophyll biosynthesis enzyme activity increased in transgenic 35S:CsPORB Arabidopsis, as well as chlorophyll content, especially 35S:CsPORB transgenic plants remained green under dark for one week. Therefore, CsPORB could play an important roles in chlorophyll synthesis pathway of Cymbidium sinense ‘Dharma’.

Abstract:In order to understand the chemical constituents of dregs of Brucea javanica, ten compounds were isolated and purified by column chromatography. On the basis of spectral data, their structures were identified as p-hydroxybenzoic acid (1), p-hydroxy-benzaldehyde (2), 3,4-dihydroxybenzoic acid (3), 3,4-dihydroxy- benzaldehyde (4), coniferaldehyde (5), sinapaldehyde (6), 1H-indole-3-carbaldehyde (7), 1H-indole-3-carboxylic acid (8), β-sitosterol (9), and brusatol (10). Compounds 4-6 and 8 were obtained from B. javanica for the first time.

Abstract:In order to understand the changes in volatile organic compounds (VOCs) of figs and its regulation to pollinators, the compositions of VOCs at three floral phases were determined in Ficus hispia, and the behavioral responses of pollinators to different developmental syconia were observed by using Y-tube olfactometer. The results showed that there were 64 compounds were detected in syconia at three phases. Among them, four compounds, such as undecane, β-elemene, β-selinene, and α-muurolene, might be the active substances attractive to pollinators. So the specific chemical signal of F. hispida to attract its pollinator was achieved by "generalization" strategy. The NMDS results showed that the VOCs of syconia at prefemale phase were similar to those at female phase, but those at interfloral phase were significantly different from those at the other two phases. There was a clear tendency for pollinators to select the syconia at prefemale and female phases, but avoid the ones at interfloral phase, indicating that there was a "push-pull" interaction mode between the figs and their pollinators. The VOCs released by syconia at pre-female phase could strengthen pollinator attraction. In addition, the VOCs vary among individuals at the same developmental phase showed VOCs emission was affected by the environment, especially at interfloral phase. These would help for understand the composition characteristics of VOCs in Ficus and the chemical signal function in maintaining fig-fig wasp mutualisms.

Abstract:In order to understand the resistance mechanism of casuarinas (Casuarina equisetifolia) against Ralstonia solanacearum, the changes in contents of tannin and phenols in casuarinas infected by R. solanacearum were analyzed. The results showed that the change trends of tannin and phenols contents in provenances with different resistibility were different. The contents of tannin and phenols in high- and media-resistant provenances increased at first and then decreased with the peak of 126 mg g^-1, and the peak of media-resistant provenances came later. The susceptible provenances showed rising trend. After infected with R. solanacearum, the condensed tannin content increased gradually in three provenances, and that in the high-resistant provenances were 70.33% higher than that in susceptible provenances. The content of flavone in resistant provenances showed S type rising trend, while that in susceptible provenances increased slowly. Therefore, it was demonstrated that there were different defense mechanisms between resistant and susceptible provenances. The greater the content of secondary compounds increase, the stronger bacteriostasis and antioxidant activities, Casuarina equisetifolia would show higher resistance to bacterial wilt.

Abstract:In order to explore the karyotype and genome size of Daemonorops jenkinsiana, the root and stem tips from its seedlings were used as experimental materials. The karyotype of D. jenkinsiana, including chromosome number and morphology were analyzed by combining the conventional method of somatic cell chromosome preparation with microphotography. Meanwhile, the DNA content, genome size and ploidy of leaves were determined by flow cytometry using Lycopersicon esculentum as an internal reference. The results showed that the stem tip of D. jenkinsiana was an ideal material for chromosome preparation, and the chromosome number was 2n=24, along with the formula of karyotype was K(2n)=1M+17m+5sm+1st, and the karyotype was "2C". The karyotype asymmetry index of D. jenkinsiana was 61.20%. The DNA content of D. jenkinsiana was about 1.57 pg with the genome size of 1 535.53 Mb, and the DNA ploidy was diploid (2n). This was reported the karyotype and genome size of D. jenkinsiana for the first time, which provided a reference for studying the karyotype and genome of other species in Daemonorops and related genus.

Abstract:Stephania brevipes Craib (Menispermaceae), previously known only from Thailand is reported from Vietnam for the first time. It is morphologically allied to S. longa Lour., but differs in having broadly triangular-ovate to triangular-oblate leaves, a small male inflorescence axillary or on leafless stems with shorter peduncle, yellowish sepals, red-violet petals, and endocarps with fewer transverse ridges. A detailed morphological description, a line drawing and color plate as well as distribution and ecology information of this species are given. The vouchers are kept in the herbaria of Vietnam National Museum of Nature (VNMN) and South China Botanical Garden, Chinese Academy of Sciences (IBSC).

Abstract:Gastrodia albida T. C. Hsu & C. M. Kuo were discovered from 2 Nature Reserves in Guangdong Province, and the vouchers were kept in the herbaria of South China Botanical Garden, Chinese Academy of Sciences (IBSC). It's distinguished by its perianth tube with moderately verrucose throughout, larger free portions of the petals, truncate based lip and absence of a rostellum. Detail descriptions, colour plates and notes on the species are provided.

Abstract:The name Artemisia anomala var. acuminatissima (Asteraceae-Anthemideae) was not validly published in 1992 because no type was indicated. The name was validated in 2011, so the validation in 2016 is superfluous. Correct citation of the name should be "Artemisia anomala var. acuminatissima Y. R. Ling, Bangladesh J. Plant Taxon. 18: 203. 2011", not "Artemisia anomala var. acuminatissima Y. R. Ling, Phytotaxa 273: 213. 2016".

Abstract:Ophiorrhiza ripicola Craib and O. rosacea Ridl. are reported as newly recorded species to China. They have been misidentified as O. umbricola W. W. Smith and O. subrubescens Drake in Chinese herbarium, respectively.

Abstract:Ludwigia decurrens Walt., native to America, is recently found to be naturalized in Nanchang, Jiangxi Province, China. There is wings on stem and square columnar capsule, it is easy to be distinguished from other species in the same genus of mainland China. The characteristics and habitat of the species are described, and the potential risk of invasion is briefly discussed.

Abstract:Aspidistra semiaperta Aver. et Tillich, a newly recorded species of Asparagaceae from China is reported. This species is known only from northwestern Vietnam and the limestone areas in Napo county, southwestern Guangxi, China. Charactristic description and color photos are provided. The voucher specimens are deposited in Herbarium of Guangxi Institute of Botany, Guangxi Zhuangzu Autonomous Region and the Chinese Academy of Sciences (IBK).

Abstract:Based on examination of type specimens, it was found that Lyonia danxiaensis R. H. Miao & W. Q. Li is very different from other Lyonia in having cymose inflorescence, 4-merous flowers, 16 paired stamens forming two whorls and non geniculate filaments. However, these characters match well with Diospyros. Thus, a new combination Diospyros danxiaensis (R. H. Miao & W. Q. Liu) Y. H. Tong & N. H. Xia was made here. After careful comparision of type specimens, we found that the newly published D. penghuae W. B. Liao, Q. Fan & W. Y. Zhao was identical with D. danxiaensis, and was reduced as a synonym of the latter.