Abstract:In Arabidopsis thaliana, IQM family is a calmodulin-binding protein family containing IQ motifs, IQM3 mutation can increase main root length, CO (CONSTANS) is an important member of photoperiodic floral regulation pathway, CO mutation can shorten taproot length. The genetic relationship between IQM3 and CO gene was studied by constructing double mutants of IQM3 and CO. The results showed that the first exon in co-12 sequence of the new CO mutant was missing 9 base ACTTGCTAG, which contains the restriction endonucrenase BfaI restriction site CTAG. A molecular marker was established to identify the mutant. When the cross-coding PCR product was cleaved by BfaI enzyme, four fragments were obtained from wild-type Col because it had three sites, three fragments were obtained from co-12 because it had only two sites, and five fragments were obtained from CO/co-12 heterozygote. Under long sunshine, the main root length of co-12 was shorter than that of wild type Col, and that of iqm3-2 was longer than that of wild type, while the phenotype of double mutant co-12 iqm3-2 was more favorable to iqm3-2. Therefore, IQM3 acts downstream of CO to regulate main root length under long day in Arabidopsis.

Abstract:Calcium (Ca²⁺)/calmodulin (Cam) signals are involved in the regulation of plant growth and development and response to external stimuli. The Arabidopsis thaliana contains seven genes in CaM family, which encoding proteins with highly conserved amino acid sequence. The protein binding activities of CaM5 splicosomes CaM5.1 and CaM 5.3 were analyzed by yeast two-hybrid and bioinformatics analysis. The results showed that the Arabidopsis calmodulin-binding protein (CaMBP) IQM3 (IQ motif-containing protein 3) could bind to members of CaM family except CaM5.3 in yeast. The bioinformatic analysis revealed that CaM5.3 had one more C-terminal domain (CTD) consisting of 35 amino acid residues than CaM5.1 and other CaM subtypes, which might affect the binding of CaM5.3 to IQM3. CTD of CML10 was added to the C-terminal of CaM5.1, the recombinant protein was binded to IQM3, confirming that CTD of CaM5.3 was the key sequence affecting its binding to IQM3. Therefore, different splicing modes of CaM5 in A. thaliana affect its protein-binding activity, which providing reference for studying the binding activities of calmodulin and calmodulin-binding proteins.

Abstract:In order to select the gerplasm resources with strong tolerance in the abandoned land of ionic rare earth mine, twenty Canavalia ensiformis germplasms derived from more than 10 countries or regions were potted, the growth traits were observed and evaluated by variance analysis, membership function analysis and cluster analysis, variance analysis, membership function analysis and cluster analysis. The results showed that there were significant differences in plant height, ground diameter, stem thick, main stalk pitch number and aboveground biomass among different germplasms at seedling stage and initial flowering stage (P<0.05). The membership function analysis showed that comprehensive evaluation value of 20 germplasms were in the order of PI 279593>PI 362193>NT 576>BN-13474-63>PI 470242>PI 358592>B2>PI 181048>PI 364355>CHN3>PI 470931> PI 337078>CHN4>PI 164695>PI 276655>CPI 50103>B1>PI 338584>PI 404610>PI 308540. The cluster analysis showed that 20 germplasms could be divided into 5 categories, among which the fourth category had the best growth characteristics, followed by the fifth category, which was consistent with the result of membership function. The secondary screening experiment showed that the comprehensive evaluation value of the top five germplasms with good growth characteristics on ionic rare earth mine soil were in the order of PI 362193>NT 576>PI 279593>BN-13474-63>PI 470242. Therefore, PI 362193 had the strongest tolerance, which could be used as the best choice for ecological restoration of ionic rare earth mine, while NT 576 and PI 27959 can be used as candidate germplasms.

Abstract:To explore the effects of nitrogen deposition and drought on plant growth in subtropical forests, the responses of four typical subtropical tree species, such as Pinus massoniana, Cunninghamia lanceolata, Ormosia pinnata and Schima superba, to different nitrogen levels and drought degrees were studied. The results showed that drought and nitrogen addition treatment for 2.5 years had different effects on the growth of different tree species. Nitrogen addition significantly increased the total biomass, plant height, and basal diameter of S. superba and C. lanceolata under the control and moderate drought treatment, but constrained the root and stem biomass and basal diameter of P. massoniana under moderate drought treatment, and had no significant effect on the growth of four tree species under severe drought treatment. Drought and nitrogen addition decreased height and total biomass of O. pinnata, P. massoniana and S. superba, and the inhibition effect became more obvious with the increase of drought degree. Without nitrogen addition, drought had no significant effect on the total biomass and plant height of S. superba. However, severe drought and nitrogen addition significantly reduced the basal diameter and total biomass of S. superba. Drought significantly increased the root-shoot ratio of C. lanceolata, but had no significant effect on other tree species. Furthermore, the effects of nitrogen addition and drought on the growth of non-leguminous species (e.g., S. superba) were more obvious than that of leguminous plants (e.g., O. pinnata). Therefore, it was that nitrogen deposition might exacerbate the inhibitory effect of extreme drought on the growth of some tree species in subtropical regions.

Abstract:In order to explore the adaptability of Dodonaea viscosa in coral sand environment, three light treatments, such as full light (FL), shade (HL) and dark (NL), and three water gradients, including normal water control (WW), moderate stress (MS) and severe stress (SS) were set up. The changes in physiological indexes of stress resistance of D. viscosa seedlings under both light and water treatment were studied. The results showed that light, water and their interaction had significant effects on contents of malondialdehyde (MDA), proline (PRO) and soluble protein (SP), and the activities of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) (P<0.05). The MDA content remaintained at a low level in HL and NL. SOD activity increased with the increase of dark degree. POD activity is the highest under FL×WW condition. With the decrease of light intensity, CAT activity increased gradually. The content of SP was the highest under HL and SS, and the content of Pro was the highest under HL and MS. Therefore, light and water had an interactive effects on the growth of D. viscosa seedlings. In the practice of ecological restoration in special habitats, appropriate shade and water would be helpful to the growth of D. viscosa seedlings.

Abstract:Dunnia sinensis is a rare and endangered plant unique to Guangdong Province. It has white metaseptic calyx segments with obvious veins and has good ornamental value. However, there is no genomic information about it. In order to understand the molecular regulation of calyx development and explore related functional genes, the expression of RNA-seq and differential genes in sepals, fruits, leaves and petals of D. sinensis were analyzed, to screening the specific expression genes or signaling pathways in sepals. The results showed that there were 3 972 differentially expressed genes in sepals compared with leaves, which were mainly concentrated in metabolic pathways, secondary metabolic biosynthesis, photosynthesis, phenyl-C biosynthesis, etc. Compared with petals, there were 9 680 differentially expressed genes (3 616 up-regulated, 6 024 down-regulated, FC>2) in sepals, which were mainly concentrated in plant hormones, phenyl-C biosynthesis, plant pathogen interaction, secondary metabolic biosynthesis and other pathways. Compared with fruit, there were 4 655 differentially expressed genes (1 827 up-regulated, 2 828 down-regulated, FC>2) in sepals, and the enrichment and regulation pathways of differential gene were similar to those of petal transcriptome. Cluster analysis showed that there were three types of transcription factors involved in the development of sepals with specific high expression: ERFs, MYBs and WRKYs. Among them, DsTMYB3 of the MYB family might be involved in the color regulation of sepals. Analysis of highly expressed genes in tissues showed that UBI11 promoter was widely expressed in all tissues, while CSLG2 promoter were specifically expressed in calyx, and the promoters of these genes would be used as genetic tools to drive the targeted genome forming expression or specific expression in calyx. Therefore, some of differentially expressed genes between calyx and the other tissues of D. sinensis, might be involved in the color regulation of sepals, which would provide a basis for the genetic transformation and functional study of D. sinensis.

Abstract:In order to investigate the changes in tree species composition and biomass storage of degraded forests, we selected the evergreen broad-leaved forests in Ailao Mountain, Yunnan Province, southwest China were selected as the objects, and the forest community structure, tree species diversity and biomass changes were compared at different succession stages. The results showed that the number of families of tree species decreased first and then increased from early successional stage (ES) to late successional stage (LS), while the numbers of genera and species gradually increased. Moreover, the Margalef richness index, Simpson dominance index, Shannon-Wiener diversity index, and Pielou evenness index all increased with succession process. The tree biomass showed an increasing trend, which at ES and middle successional stage (MS) were 9.87% and 65.98% of that at LS, respectively. Furthermore, the tree diversity index had significant positive correlation with the total biomass at plot level (P<0.05). Therefore, it was suggested that with the succession process, the growth of trees and the tree species diversity were the main factors affecting tree biomass storage, and the forest restoration in the Ailao Mountains was relatively slow because of moist and cold climate.

Abstract:The dominant tree species Acacia auriculiformis and Eucalyptus urophylla growing on two abandoned oil shale tailings with different restoration years and their root zone soil were used as objects, the influences of tree species and restoration years on the ecological restoration effect of waste lands were studied. The results showed that the heavy metal pollution coefficient of soil in the southern tailing mine after 31 years of restoration was 8, which was significantly lower than the 12.33 of the north tailing mine after 18 years of restoration, indicating that the current heavy metal pollution degree of soil in the southern tailing mine was lighter. The heavy metal concentration and enrichment coefficient in leaves of A. auriculiformis and E. urophylla in the southern tailing mine were significantly higher than those in the northern tailing mine, and the remediation effect of trees in the southern tailing mine was better than that in the northern tailing mine. In addition to the more manganese enrichment in E. urophylla leaves, A. auriculiformis leaves had higher concentration of carbon, zinc, and cadmium, suggesting that A. auriculiformis planted in oil shale tailing remediation with multiple pollution elements could achieve better ecological effects than E. urophylla. Therefore, both A. auriculiformis and E. urophylla had strong ability to remove heavy metals and other harmful elements from oil shale tailings and improve soil quality, and especially A. auriculiformis showed more advantages than E. urophylla under the coexisted stresses of site poverty and multi-element pollution.

Abstract:Iris narcissiflora is an endemic herb to western Sichuan Province, China, its current distribution range has been severely shrunk, and it was listed as a key national wild protected plant of grade II. However, the understanding of the population status and habitat characteristics of I. narcissiflora is very poor, which is not conducive to the study of its endangered mechanism and the formulation of conservation measures. The present distribution range of iris daffodil was investigated in detail to investigate the wild population status and habitat, especially the characteristics of the community. After extensive field surveys, I. narcissiflora was distributed in alpine shrubs or edge of spruce (Picea likiangensis var. rubescens) forests with the altitude of 3 779-4 100 m in Daofu County and Kangding City, Ganzi Prefecture, Sichuan Province, and the populations were small with 28 to 2 100 individuals. Based on current distribution, I. narcissiflora is reassessed as endangered (EN) according to the IUCN Threatened Species Assessment criteria B2ab(iii). The species composition of the community with I. narcissiflora was rich, the life type was mainly perennial herbs, with more temperate components. There was a significant negative correlation between species composition similarity and geographical distance between communities. A significantly negative relationship was observed between community similarity and geographic distance. The communities with I. narcissiflora could be divided into four types: spruce forest margin and alpine shrubs with Rhododendron websterianum, R. hippophaeoides and Salix myrtillacea as the dominant species, respectively. The habitat of I. narcissiflora was affected by road construction, grazing, natural succession and global climate change were also potential threats. According to the habitat conditions of different distribution sites, it was suggested to set up conservation areas, take appropriate measures to reduce the expansion of spruce in western Sichuan and the influence of human factors, and to carry out research on ex situ conservation technology.

Abstract:To elucidate the light response characteristics and the applicability of the light response model of Michelia chapensis under different light intensities, one-year-old M. chapensis seedlings were grown under five light intensities, including 100%, 70%, 50%, 30% and 10% of nature light. The light response curves were measured and fitted by five models, such as rectangular hyperbola model (RH), nonrectangular hyperbola model (NRH), exponential model (EM), modified rectangular hyperbola model (MRH) and modified exponential model (MEM). Then, the fitting effects of the five models were comprehensively evaluated by using R_a², MAE and MSE combined with the measured values and fitting values of photosynthetic parameters. The results showed that the light response curves of M. chapensis under different light intensities fitted by RH, NRH and EM model did not conform to its photosynthetic-light response characteristics. The photosynthetic parameters fitted by the MRH models were the closest to the measured values, followed by the MEM model. Therefore, the MRH model has high fitting accuracy and applicability and is the most suitable model for fitting the photosynthetic light response characteristics of M. chapensis under different light intensities.

Abstract:In order to understand the internal causes of endangerment of Michelia shiluensis, the morphological characteristics of flower organs, flowering dynamics and visiting insects were observed, and the pollen germination rate, stigma acceptability and breeding system characteristics were tested. The results showed that the stamen group and pistil group naturally form spatial isolation during flowering, and the perianth plate bends laterally to form a spherical space to protect the stamen group. The pistil stalk continues to extend, pushing the pistil out of the stamen and perianth. The main flower-visiting and pollinating insect of the nurseries are Apis mellifera. Stigma acceptability was strongest in stages VI and VII when the perianth was open to 50% of the maximum diameter. The pollen activity of stage VI was also the highest, and the germination rate in vitro was (66.96±11.28)%. The same flower or cross-flower pollination of the same plant could not bear fruit, but the fruit rate of cross-pollination was 100%. Therefore, Michelia shiluensis is a strictly hetero-pollinated plant, with outbreeding and self-incompatibility, and there is no apomixes, and there is also reproductive isolation with other species of Michelia. The dynamic changes in perianth and pistillation groups of M. shiluensis revealed the biological mechanism of cleverly avoiding self-mating.

Abstract:To investigate the chemical constituents from agarwood of Aquilaria walla from Sri Lanka, two new 2-(2-phenylethyl)chromone compounds were isolated from the ethanol extract by silica gel column chroma- tography, Sephadex LH-20 gel column chromatography and semi preparative high performance liquid chromate- graphy (HPLC). Based on spectral data, their structures were identified as (5R,6S,7S)-5,6,7-trihydroxy-5,6,7,8- tetrahydro-2-(2-phenylethyl)chromone (1) and (5R,6S,7S)-5,6,7-trihydroxy-5,6,7,8-tetrahydro-2-[2-(4-methoxy- phenyl)ethyl]chromone (2). Compounds 1 and 2 did not show inhibitory on the NO production induced by lipopolysaccharide (LPS) in mouse mononuclear macrophages RAW264.7, and cytotoxic activity against five common human cancer cell lines by MTT method. There was weak inhibitory effect of compound 2 on tyrosinase, with an inhibitory rate of (21.67±1.67)% at a concentration of 200 μg/mL.

Abstract:To study the isoquinoline alkaloids of Dactylicapnos scandens and their antibacterial activities, ten isoquinoline alkaloids were isolated from its roots. Based on physical and chemical properties and spectral data, their structures were identified as protopine (1), 1-methoxyberberine (2), allocryptopine (3), pseudoprotopine (4), palmatine (5), sinomenine (6), jatrorrhizine (7), sanguinarine (8), tetrahydropalmatine (9), isocorydine (10). Compounds 2-4 and 8 were isolated from this plant for the first time. Moreover, compound 4 exhibited significant antimicrobial activity against Escherichia coli with an MIC value of 6.25 μg/mL, which is better than the clinical antibacterial drug berberine (25.0 μg/mL).

Abstract:Silicon, as a non-metallic element, not only plays an important role in plant growth and development, but also involves in biotic and abiotic resistance. Silicon transporters are directly responsible for the absorption and transportation of silicon, which could be mainly classified into silicon influx transporters and silicon efflux transporters according to their transport properties. In this review, the structural characteristics, functions, and regulatory modes of the reported silicon transporters are summarized, the process of silicon uptake and transport in plants are described, the existing problems are put forward, and the future research directions is also prospected.