Abstract:In order to quantify and separate the effects of key climatic factors on the radial growth at different altitudes in Altay Mountains of Xinjiang, China, the correlation analysis and multivariate linear regression analysis between the standard chronologies of Siberian larch (Larix sibirica), at high-, mid-and low-altitude stands, and climate factors were studied. The absolute and relative importance of different climate factors in the linear model were further calculated. The results showed that the radial growth of trees were significantly correlated with the current-June temperature (positive) and last-July precipitation (negative) at high altitude, which explain 33.1% of the total variance in tree radial growth and the relative contribution rate was 66.2% and 33.8%, respectively. The radial growth of trees were significantly correlated with the current-June temperature (positive) and last-June precipitation (negative) at mid-altitude, which explain 26.8% of the total variance in tree radial growth and the relative contribution rate was 40.1% and 59.9%, respectively. The radial growth of trees were significantly correlated with the last-June temperature (negative) and last-July precipitation (positive) at low altitude, which explain 29.4% of the total variance in tree radial growth and the relative contribution rate was 31.9% and 68.1%, respectively. So, it was suggested that the main climatic factors affecting the radial growth in Altay Mountains varies with altitude. The temperature and precipitation were the main limiting factors at high and low altitude, respectively.

Abstract:To achieve a better understanding about the elevation heterogeneity in tree growth-climate association in southeastern China, four tree-ring width chronologies of Pinus massoniana from eastern foot of Wuyi Mountains in Fujian were established, and the relationship between radial growth and climate factors along elevation were investigated by bootstrapped correlation analysis and linear mixed effect model (LME). The results showed that radial growth of trees at higher elevation had higher sensitivity to climate and higher consistency between sites, mainly reflected as the positive correlations with the winter-spring temperature/sunshine conditions and precipitation in July. Moreover, the linear mixed effect model using three monthly climate factors, such as monthly mean daily maximum temperature in last December, monthly total sunshine hours in current January, and monthly total precipitation in current July, can explain 50% of total variance of radial growth at higher elevation, and the both fronts play a leading role in the model with cumulative relative contribution rate of 80%. So, it was suggested that the pre-growing season temperature/sunshine condition are the main factor regulating tree radial growth at high elevation, and that these trees might have higher sensitivity to future climate changes and forest management policies should take this into account. Moreover, the results showed that the trees at high elevation in subtropical forest had the potential to be used for tree ring-climate reconstruction.

Abstract:In order to understand the purifying effect of native aquatic plants on eutrophic water, five representative native aquatic plants in Guangdong Province were selected with Eichhornia crassipes as a control for studying the removal rate of total nitrogen (TN), total phosphorus (TP), and the growth and absorption ability of six plants in two kinds of eutrophic water were also studied. The results showed that the TN removal rate of 5 native plants in low and high polluted water increased 3.8%-13.3% and 13.2%-17.1% compared with the blank control, while TP removal rate increased 15.2%-22.1% and 11.3%-57.6%, respectively. Eleocharis plantagineiformis was suitable for purifying low nitrogen water, while Polygonum lapathifolium for high nitrogen water. Saururus chinensis was suitable for low phosphorus water, while Trapa komarovii for low nitrogen or high phosphorus water. Ludwigia adscendens was suitable for the two kinds of eutrophic water and had excellent purification effect for high phosphorus water. All 5 native plants could grow vigorously in low and high eutrophic water and the net growth rate of biomass of Ludwigia adscendens reached up to 375.5% and 539.8%, respectively, showing the best, followed by Trapa komarovii. But the control plant Eichhornia crassipes decayed and died under high polluted water, which aggravated water pollution. Ludwigia adscendens and Trapa komarovii had perfect absorption effect on pollutants, and the TP absorption capacity was better than that of other plants (P<0.05). So, it was suggested that all of five native plants could be used as alternative plants for the restoration of eutrophic water in Guangdong, among them Ludwigia adscendens and Trapa komarovii had excellent development potentiality.

Abstract:In order to rapidly identify the tolerance to low temperature of Desmodium intortum, the physiological response to low temperature stress (4℃) was studied by comparing with Macroptilium atropurureum, a high quality forage widely planted in southern provinces in China. The results showed that under low temperature stress, the effective quantum yield (Yield) and electron transfer rate (ETR) from the 2nd to 8th day decreased significantly in M. atropurureum than those in D. intortum (P<0.05). The superoxide dismutase (SOD) activity increased and catalase (CAT) activity decreased significantly (P<0.05) for both D. intortum and M. atropurureum under low temperature stress. Specifically, the decrease of CAT activity in D. intortum was lower than that in M. atropurureum. The peroxidase (POD) activity of D. intortum did not change (P>0.05) under low temperature, while POD activity in M. atropurureum decreased by 47.11%. The contents of free proline (Pro) and soluble sugar were significantly higher in D. intortum than those in M. atropurureum (P<0.05) under low temperature. According to regression analysis, resistance index and nutrient composition analysis, D. intortum was superior to M. atropurureum in cold resistance and nutritional value. Furthermore, Yield, ETR, CAT, Pro and soluble sugar of D. intortum could be used asimportant physiological indexes for identification of cold tolerance.

Abstract:In order to evaluate genetic diversity of Camellia oleifera resources in Hainan Island, the genetic diversity and relationship among 31 populations were analyzed by using SRAP molecular marker. The results showed that the genetic diversity of C. oleifera resources in Hainan Island was low, the percentage of polymorphic bands (PPB), Nei's genetic diversity index (H) and Shannon's information index (I) were 98.30%, 0.222 8 and 0.353 8 at the species level, and 40.96%, 0.138 5 and 0.208 3 at the population level, respectively, which was inconsistent with their rich phenotypic diversity in Hainan. The coefficient of genetic differentiation among populations (G_st) was 0.380 5, and the gene flow (N_m) was 0.813 9 between different populations, indicating that genetic differentiation was high with limited gene flow among populations. The genetic variation mainly existed within populations (61.95%) and few among them (38.05%). The genetic distance ranged from 0.022 6 to 0.276 4, with the mean of 0.107 7 between 31 populations, which revealed the relatively close genetic relationship among the populations. UPGMA cluster analysis showed that 31 populations could be divided into 6 groups at the genetic distance of 0.11, showing obvious administrative area, but had little to do with geographical distance. So, it was suggested that the relatively close genetic relationship of C. oleifera resources in Hainan Island might cause self-incompatibility, which could be the main internal cause for blooming but low yield of C. oleifera forests in Hainan Island.

Abstract:To reveal the genetic diversity of naturalized Narcissus tazetta var. chinensis populations in eastern coast of China, 49 individuals from five representative populations distributed in Shanghai, Zhejiang and Fujian Proviences were evaluated by using two chloroplast DNA matK and trnH-psbA fragments. The results showed that total of six haplotypes were identified from the combined two sequences with an alignment length of 1 443 bp. The genetic diversity of naturalized population was in order of DLSY > PTD > NJD=ZZ > CMD. AMOVA analysis showed that the variation within populations was the main source of the genetic variation (91.98%) and low genetic differentiation between populations (F_st=0.080 22). Insignificant phylogeographic structure was detected at species level (N_st=0.020 < G_st=0.031; P<0.05). Mantel test showed a significant linear correlation between genetic distance and geographical distance (r=0.929, P=0.02<0.05). The neutrality test combined bimodal curve in mismatch distribution analysis both rejected the hypothesis of the demographic expansion of these populations. Analysis of median network and phylogenetic NJ tree based on the distribution of haplotype both divided all the populations into two major branches. These indicated a low level of genetic diversity with a weak genetic differentiation among Narcissus tazetta var. chinensis populations in eastern coast of China. Genetic variation mainly occurs in populations, while species had experienced no demographic expansion. These might likely owing to the gene flows which were caused by the combination of islands segregation, biological characteristics, habitat heterogeneity as well as human disturbance.

Abstract:In order to understand the reasons for the differences in fruit texture of Canarium album, the content of cell wall components and related enzyme activities in the fresh ‘Qinglan 1’ and the processed ‘Changying’ were studied during fruit development. The results showed that with the ripening of fruits, PME activity in ‘Qinglan 1’ was higher than that in ‘Changying’, which promoted the degradation of pectin, and the ISP content was high as well as CSP content was low. The content of cellulose in both cultivars was high, and hemicellulose content of ‘Qinglan 1’ was lower than that of ‘Changying’. The lignin content of ‘Qinglan 1’ was lower than that of ‘Changying’, and the higher PAL and POD activities could promote the increment of lignin content. Therefore, the differences of ISP, CSP, hemicellulose and lignin contents might be the reason of fruit texture differences between ‘Qinglan 1’ and ‘Changying’.

Abstract:In order to understand the function of BRI1 gene in Eucalyptus grandis, EgrBRI1 gene was cloned, and the bioinformatics and subcellular localization of EgrBRI1 were analysis. Meanwhile, the expression of EgrBRI1 gene were analyzed after treated with hormones and stresses by qRT-RCR. The results showed that the length of EgrBRI1 gene was 3 893 bp, encoding 1 197 amino acids. EgrBRI1 protein was relatively stable with complex spatial structure, which contains three motifs. EgrBRI1 protein was mainly located in cell membrane. When treated with methyl jasmonate and brassinolide, the expression of EgrBRI1 gene in leaves showed an up-regulated trend with the time, while there was no significant change by treated with salicylic acid. Under salt and cold stresses, the expression of EgrBRI1 gene was down-regulated at first and then increased with the time. These indicated that EgrBRI1 gene could respond quickly to applied hormone and play an important role in stress resistance of E. grandis, which might be achieved by responding to BR signal.

Abstract:In order to understand the biosynthetic pathway of phytosterol in Dendrobium officinale, the transcriptome sequence of stems and leaves at two growth stages was analyzed by using Illumina HiSeq 4000 high-throughput sequencing method, and the expressions of key enzyme genes for phytosterois synthesis were compared. The results showed that a total of 43 085 Unigenes were obtained by transcriptome sequencing, of which 24 459 Unigenes were annotated in Nr, Swiss-prot, KOG and KEGG databases, and 7 333 were commonly annotated. KEGG metabolic pathway analysis showed that phytosterol biosynthesis of D. officinale could be divided into three stages with 50 Unigenes (30 enzymes) involved. The expressions of DXR and HMED were significantly higher in stems and leaves than that of MK and MVD. The expression of SMT1 at mature stage was higher than that at growth stage, while the expression of SMT2 was the opposite. The expressions of SMT1 and SMT2 were higher in leaves than that in stems at the same stage. These would be lay a foundation for the development and utilization of phytosterol and regulating phytosterol biosynthesis in D. officinale.

Abstract:The flavonoid content in immature leaves was significantly higher than that in mature leaves of Myrciaria cauliflora. In order to understand the information of differentially expressed genes related flavonoid synthesis in M. cauliflora, the transcriptome of 2 kinds of leaves were sequenced by Illumina HiSeq method. The results showed that there were 59 321 Unigenes obtained from young and mature leaves, among which 32 912 unigenes were annotated by 8 databases. There were 77 Unigenes related flavonoid anabolism, and 6 genes were down-regulated significantly in mature leaves, including two CHIs, one CHS, one F3H, one 2-hydroxyiso-flavanone dehydratase gene and one ANS. The RT-PCR verified results of five differentially expressed genes were agreed with the transcriptome sequencing. So, it was suggested that there were a large number of family genes related flavonoid anabolism in the leaves of M. cauliflora, but the decrease of flavonoid content in mature leaves was due to several down-regulated genes.

Abstract:Molluginaceae is a taxonomically difficult family in Caryophyllales, and its circumscription was much controversial among different systems of angiosperm classification. Based on result from a recent molecular phylogenetic study, the circumscription of Molluginaceae was well-established and 11 genera within the family were accepted, and thus a taxonomic revision of Molluginaceae in China is revised accordingly. Finally, seven species belong to five genera of Molluginaceae were accepted, and the species Hypertelis umbellata (Forssk.) Thulin is newly recorded from China. Detailed morphological description of all genera and distribution maps of all species accepted, as well a key to all of relevant species, were provided.

Abstract:A new natural hybrid species, Paphiopedilum×ailaoshanense B. Liu & S. P. Chen, from Yunnan Province, China, is reported, it is related to its parents P. spicerianum and P. gratrixianum var. cangyuanense. It is different from the former by hairy pedicel and ovary, purple halo and purple spots in dorsal sepal, dark green upper petal with purple halo, and yellowish green lower petal; and from the latter by a broad purple-brown midvein in middle sepals and purple pistil. The new natural hybrid was similar to the natural hybrid P.×lushuiense, however, the lower edge of dorsal sepal of P.×ailaoshanense is not retrorbed, with purplish red halo near base, synsepal with 2 distinct purple thick veins, petal spatulate, upper edge wavy, 6.0-6.2 cm long, lip length 5.0-5.5 cm, obviously different. In order to clarify the relationship among P.×ailaoshanense, P. spicerianum and P. gratrixianum var. cangyuanense, the phylogenetic tree of some Paphiopedilum was constructed based on three chloroplast gene sequences (matK, rbcL and trnL). In consideration of the morphological and molecular evidence, Paphiopedilum×ailaoshanense is identified as a natural hybrid. The vouchers are kept in the herbarium of Fujian Agriculture and Forestry University (FAFU).

Abstract:The lichenized fungi genus Reimnitzia Kalb (Graphidaceae) is reported as new record to China. It is a monotypic genus, containing the single species R. santensis epiphytic on bark or bryophytes. Reimnitzia santensis is crustose; has no cortex structures; contains large columns of calcium oxalate crystals; has abundant isidia, which are concolorous to thallus, unbranched, first globular, then worm-like, with a length of up to 1.5 mm, and a black pore area or a single pore at the top. The species has chroodiscoid ascomata, brown submuriform ascospores sized 15-25 μm×8-12 μm, and pycnidia that occur on the tips of isidia-like structures and in thallus warts, with bacilliform conidia, and abscence of lichen compounds.

Abstract:To investigate the diversity of endophytics in medicinal plant Portulaca oleracea and explore potential biological resources to prevent and control crop diseases, the endophytes from its roots, stems and leaves were isolated by medium cultivation method, their bioactivities were evaluated against Ralstonia solanacearum, and they were identified by colonial morphology and ITS sequence. The results showed that the crude extracts of two endophytics Penicillium citrinum and P. polonicum displayed strong activities against the phytopathogen R. solanacearum. One of active metabolite (citrinin) was identified based on UPLC-QTQF-MS. Moreover, the activity of citrinin had more strong antibacterial property than that of streptomycin, which was a common agent in agriculture to prevent bacterial wilt. So, these would provide scientific basis for biological control of bacterial wilt.