Orthotrichum revolutum， an endemic to China, has not been re-found since its original collection made 123 years ago. It is recorded from a new locality: Baihuashan Nature Reserve, Beijing, China. The plants morphologically agree well with the type specimens. Orthotrichum revolutum is firstly well photoed and its distribution is firstly mapped. Four records of this species from China’s Gansu, Xinjiang and Japan, Kyrgyzstan are all misidentifications in previous studies. We also discuss its main differences from close species and re-evaluate its threat status in the field.
Based on the field investigation and literature analysis， this paper pointed out the problems in the description of flower characteristics of Maianthemum japonicum（A. Gray） LaFrankie（Liliaceae） in Flora Reipublicae Popularis Sinicae and Flora of China， and provided the suggestions for revision. In addition， its scientific name was briefly discussed.
Non-structural carbohydrate was the main intermediate storage between photosynthesis and growth of plants， and played an important role in the growth and metabolism of plants. To explore the distribution and seasonal variation of non-structural carbohydrates and the relationship between soluble sugar and starch in roots. The root sample of Larix gmelinii was collected from May to October in 2018， and the samples were divided into 1， 2， 3， 4， and 5 rank by root order method. The concentration of soluble sugar and starch were measured using the phenol-sulfuric acid method and enzymatic hydrolysis method respectively. The results showed that the concentration of soluble sugar was a significant difference between root order， month， and their interaction（P<0.001）. The concentration of soluble sugar in 1-5 orders ranged from 4.42%~14.90%， 4.35%~16.40%， 5.67%~19.70%， 5.91%~33.10% and 6.95%~37.80%， respectively. There was no significant difference in the concentration of starch among different root orders（P>0.05）. However， the concentration of starch was a significant difference among months（P<0.001）. It was ranged 23.36%~48.65% and decreased from May to July， and then increased， peaked in August， and there was no significant difference between October and May in 2018. The results could provide data for explaining the carbon metabolism and growth adaptation strategies of roots and understanding the internal structure and functional heterogeneity of fine root system.
By using the spatial replacement time and the typical sampling as methods， taking Eucalyptus robusta plantation in Weiyuan County， Sichuan Province as materials， we comprehensively analyzed the composition of the understory vegetation species and important value， and the aboveground， underground and whole plant biomass of the shrub and herb layers and species diversity index（Shannon-Wiener diversity index H， Simpson dominance index H′， richness index D and Pielou evenness index JSW）， and explored the dynamic changes of species diversity and biomass of undergrowth vegetation at five different forest ages（4， 5， 6， 7， 8 years） and the correlation between them respectively. The results showed that： A total of 210 species were found， belonging to 79 families and 151 genera， with more species in the herb layer than in the shrub layer. The herb layer of Miscanthus floridulus， Dicranopteris pedata and shrub layer of Melastoma malabathricum and Rubus hastifolius all occupied the dominant position at different ages respectively. With the forest age increasing， the density canopy increased， the D value， H value and H′ value of shrub layer all increased first and then decreased respectively； The D， H and H′ values of the herb layer showed a trend of change of the bimodal curve after increased， then decreased， then increased and then decreased. The biomass of the herb layer increased first and then decreased and then increased， the biomass of shrub layer increased first and then decreased. There was a significant positive correlation between species diversity and biomass， the D and H indices of herb layer were the direct factors affecting biomass. The species distribution， composition， species diversity and biomass of undergrowth vegetation in Eucalyptus robusta plantation were different in response to changes in forest age， showing different dynamic characteristic rules， the results provided data support for Eucalyptus robusta forest management in southwest China.
To explore the photosynthetic characteristics of Sassafras tzumu Hemsl. under Cd stress ， the potted method was used. With 5 cadmium concentration levels（CK：0 mg·kg-1， T1：5 mg·kg-1， T2：20 mg·kg-1， T3：50 mg·kg-1， T4：100 mg·kg-1） were set， Chlorophyll content， photosynthetic gas exchange parameters and photosynthetic-light response curve of S. tzumu leaves matching each treatment were measured respectively. The results showed that：①As the concentration of Cd increased， chlorophyll a， chlorophyll b and the total amount of chlorophyll in S. tzumu leaves increased first and then decreased， the maximum was in T2. ②With the Cd concentration increased， the net photosynthetic rate（Pn） and stomatal conductance（Gs） of leaves showed a downward trend. There were no significant differences in the intercellular carbon dioxide concentration（Ci） and transpiration rate（Tr） between treatments. The photosynthetic rate of S. tzumu leaves was mainly limited by non-stomatal factors. ③With the Cd concentration increased， Pnmax（maximum net photosynthetic rate） of S. tzumu leaves decreased significantly. Under T1 processing conditions， the initial quantum efficiency（α） of S. tzumu leaves got maximum value； The dark respiration rate（Rd）， light compensation point（LCP） and light saturation point（LSP） of S. tzumu leaves decreased respectively. In conclusion， under the stress of different concentrations of Cd， the chlorophyll content of S. tzumu first increased and then decreased， which was higher than that of CK at T1 and T2， reflecting the “low promoting and high suppressing” effect of Cd stress. With the Cd concentration increased， photosynthetic gas exchange parameters and photosynthetic-light response parameters showed a downward trend compared with CK， indicating that Cd stress had an obvious inhibitory effect on S. tzumu photosynthesis.
In vitro shoots of Phalaenopsis Aphrodite ‘Mantianhong’ which were infected by Cymbidium mosaic virus（CymMV） were used as initial materials in the study. Droplet vitrification protocol of shoot tips was established by screening sucrose concentrations in preculture medium， preculture time and time of exposure to PVS2 （Plant vitrification solution 2， PVS2）. The regenerative shoot tips were induced to form protocorm-like-body（PLB） and differentiated to shoots. After detection by RT-PCR for CymMV， negative shoots were micropropagated and induced to form roots. The results showed that shoot tips being precultured on BM+0.6 mol·L-1 sucrose for 1-2 days was the optimal， resulting 70%-76.7% survival rate and 53.3%-56.7% regeneration rate of cryopreserved shoot tips. The optimal time duration of PVS2 was 60-90 minutes， resulting 73.3%-76.7% survival rate and 50.0%-56.7% regeneration rate of cryopreserved shoot tips. Being tested by RT-PCR， half of the regenerated shoots were negative. The CymMV eradication frequency was 50% by droplet vitrification protocol， which laid a technical and theoretical foundation for CymMV eradication of orchids.
MicroRNAs（miRNAs） are a class of non-coding small RNAs that negatively regulate gene expression. Through high-throughput sequencing miRNAsof Salvia miltiorrhiza， a mature sequence miR858 named Sm-miR858 was obtained. The sequence alignment showed that the Sm-miR858 was highly conserved with the identified miR858 sequences in other plants， and the result of Small RNA northern blotting showed that the Sm-miR858 was expressed in the root， stem and leaf tissues of S. miltiorrhiza， especially relatively high in leaves. To explore the function of Sm-miR858 in S. miltiorrhiza， the Sm-miR858 was predicted first online using biological software. The result of psRNATarget analysis showed that there were 13 potential target genes of Sm-miR858. One was SmPAP1， an important transcription factor， participated in the metabolic regulation on phenolic acid active substances of S. miltiorrhiza. To further verify the targeting effect of Sm-miR858 on SmPAP1， the correlation of co-expression between Sm-miR858 and SmPAP1 was analyzed and verified by Real-time qPCR in the tobacco transient expression system and S. miltiorrhiza tissues and organs. The Real-time qPCR results showed that there was a significant negative correlation co-expression between SmPAP1 and Sm-miR858 in S. miltiorrhiza. Then the Sm-miR858 and SmPAP1 over-expressing plant vectors were constructed， and the transient co-expression of the Sm-miR858 and SmPAP1 was subsequently assayed in tobacco. The results showed that the sm-mir858 overexpression resulted in a significant decrease of the SmPAP1 mRNA expression level， compared with the control， and this indicated that sm-mir858 did actually target and negatively regulate the expression of SmPAP1 in S. miltiorrhiza. Above results laid a solid foundation for elucidating the role of sm-mir858 in the regulation phenolic acids biosynthesis in S. miltiorrhiza.
DELLA protein is a negative regulator of gibberellin signaling pathway， which inhibits plant growth and development. Analyzing the structure and function of DELLA family members will be helpful to elucidate the mechanism by which the DELLA protein regulates the growth and development of rubber trees. In this study， the full-length cDNA sequence of HbRGA1 was cloned from the leaves of rubber tree cultivar Reyan73397. HbRGA1 is 2 136 bp long， contains 1 839 bp ORF， and encodes 613 amino acids. The HbRGA1 protein sequence contains DELLA and GRAS superfamily conserved domains， which are 82.5% like the DELLA genes of poplar， cassava and rubber trees. qRT-PCR analysis showed that the expression level of HbRGA1 was high in the leaf of rubber tree， but very low in the bark and latex. The expression of HbRGA1 in leaves was significantly up-regulated by gibberellin and abscisic acid spraying. These results indicated that HbRGA1 was closely related to gibberellin and other hormone signals in rubber trees， which laid a good foundation for further study of HbRGA1’s structure and function in the growth and development of rubber trees.
The growth characters of 15-year-old Space Mutation families of Betula platyphylla（HT-1， HT-2， HT-3， HT-4） and ground controls（CK-1， CK-2， CK-3， CK-4） were analyzed， and the growth characters of 2-year-old， 5-year-old and 15-year-old B. platyphylla were used to fit the growth curve. The results showed that the heights of 15-year-old HT-1 and HT-4 were significantly different from the ground control， respectively. The HT-1 height was higher than the ground control， while the HT-4 height was lower than the ground control. The heights of the other two families after Space mutagenesis were also higher than those of the control， but did not show a significant level. With the growing， some characters of the Space mutagenesis Birch families compared to the ground controls changed from significant differences to nonsignificant differences， but the overall trend of differences remained consistent with the seedling stage. The value of repeatabilities of the Space mutagenesis families and ground controls were high（>0.5）， except the 98-3 family. The favorable mutation on height trait of the HT-1 was the highest， which was 7.31%. Using xˉ+S as the standard， 4 excellent individual plants were selected from HT-1， and the optimal individual height increased by 35.29% compared to the ground control family. The growth trend of tree height was predicted by fitting the tree height growth curve.
To explore the classification and identification and interspecific relationship of Calanthe， the floral phenotypes and pollen morphological characteristics of 13 species of Calanthe in Tibet were studied. The results showed that： ①the floral color was divided into yellow， yellow-green， yellow-brown and pink， with pink flowers in the majority； ②the inflorescence was raceme， and length and width of various parts of the flower（sepal， petal， labellum， ovary， stigma） showed the difference. The difference of sepal length， petal width， labellum width， and stigma length was the largest， and the P value showed significant differences among various species； ③the pollen masses of these 13 Calanthe species were composed of thousands of single grains， which has no germination hole found， the obvious sticky substance between pollen grains of some species was found. The different size pollen blocks vary shaped mostly oval， oblong， and pear； ④the surface morphological characteristics of pollen blocks in different species were different， the pollen grains were stacked vertically or horizontally， and the shape of the pollen grains were also different； ⑤the appearance differences of pollen grains of different species were obvious， divided into concave type， smooth type， small hole type and perforated type. The results above showed that the flower phenotype and pollen morphological characteristics refer for identification of 13 species of Prairie Calanthe， and played the supplementary role in determining their phylogeny and systematic classification.
In order to optimize somatic embryo induction system of Syringa reticulata var. mandshurica， callus induction and somatic embryogenesis from mature zygotic embryo were conducted by adjusting the type and concentration of plant growth regulators. The morphological observation and physiological analysis of the explants in the culture process were carried out. The results showed that： ①Somatic embryo regenerate from mature zygotic embryo explant 30 d cultured later and cotyledonous somatic embryo can be obtained cultured 60 d later； ②BA played a leading role in callus induction， the callus induction rate was reached 100% in the combinations of 0.5 mg·mL-1 BA with 5-6 mg·mL-1 NAA， and the somatic embryo induction rate reached 8% in the combination of 0.5 mg·mL-1 BA and 5 mg·mL-1 NAA； ③Polyphenol content increased sharply at the primary stage of callus formation and kept a relatively high level in the process of culture. The PAL and POD activity increased and the MDA and SOD activity decreased in cotyledonous stage of somatic embryo.
To explore the transmission mode of target gene in hybrid offspring of transgenic birch for further follow-up investigation， it is helpful to realize polymerization breeding for study on transgenic birch. In this study， the growth traits including thousand-seed weight，germination rate，germination potential and vigor index for offspring of transgenic birch were measured respectively. The offspring included families of T1 cross generation of 1-year-old BpAP1 and TabZIP transgenic birch， 5-year-old BpGH3.5 and BpCCR transgenic birch and half-sibling families of open pollination. The results showed that thousand-seed weight， seed vigor index and seedling height were all significantly different at 0.01 level among those families respectively， and family heritability of each trait was higher than 85.00%. Results showed that the transmission mode of target gene in T2 generation population does not accord with mendelian inheritance. The transfer efficiency of target genes of female and male gametes was about 30.00% and 50.00% respectively， however T2 hybrid polymerized with the 3 target genes was unattained. The random insertion of target gene reduced the seed vigor of T2 generation hybrid. We did not obtain birch hybrids with the 3 target genes. The polymerization of the target gene had an adverse effect on the growth and development of the hybrid offspring， and even death.
Petal size was one of the main factors affecting the ornamental value of Camellia nitidissima， but its formation mechanism was unclear. In this study， the petal development process of C. nitidissima was divided into five developmental stages： young bud stage（S1）， early bud stage（S2）， turning yellow stage（S3）， semi-blooming stage（S4） and full bloom stage（S5） respectively. The dynamic changes of transcriptome during flower development were analyzed by RNA-seq technique. Using enrichment analysis and trend analysis of differentially expressed genes， it was found that the number of differentially expressed genes in auxin transduction pathway was the largest， and some auxin response genes such as AUX1/LAX cotransporters， AUX/IAA genes and SAURs were significantly up-regulated during flowering respectively， indicated that auxin was an important regulator of petal growth. Transcription factor genes such as MYB， bHLH and zinc finger protein genes were obviously up-regulated or down-regulated respectively， and some downstream functional genes such as xyloglucan endotransglucosylase/hydrolase（XTH）， pectin esterase（PE） and pectin lyase（PL） were also showed significant changes respectively. The results also suggested that these genes may be candidate genes involved in petal development. In addition， the expressions of some genes related to flowering regulation， such as FT， SOC1， AP3， PI， SEP3， etc.， were analyzed during the petal development of C. nitidissima， but the results showed that their expressions were mainly medium and low expression. Besides， the results of KEGG enrichment analysis of highly expressed genes revealed that the synthesis of secondary metabolites was accompanied by the whole petal development of C. nitidissima. All these results would lay a theoretical foundation for further researches of the regulation mechanism of petal development of C. nitidissima.
In this experiment， tobacco BY-2 suspension cells were used as materials to investigate the effects of extracellular ATP on the chitosan-induced changes of ROS（reactive oxygen species）level and PAL（phenylalanine ammonia-lyase）activity. The results showed that the tobacco suspension cells mixed with chitosan 5-20 μg·mL-1 increased the intracellular ROS level at adose-dependent manner， and the PAL activity also increased and reached to the maximum at 15 μg·mL-1 chitosan， and then decreased slightly. There was not significant difference in ROS levels and PAL activity in tobacco suspension cells by adding 10-40 μmol·L-1 exogenous ATP. The extracellular ATP（eATP） level gradually decreased with the concentration of chitosan increased. The effects of eATP on the chitosan-induced change of ROS level and PAL activity were further analyzed. The results showed that the exogenous ATP 20 μmol·L-1 added to chitosan-induced tobacco suspension cells effectively alleviated the increases of ROS level and PAL activity in cells. These results showed that effects of extracellular ATP can affect the chitosan-induced changes in ROS level and PAL activity in cells.
In order to explore the adaptability of Magnolia denudata Desr. to salt stress， nutrient solution was used to simulate salt stress， and the growth traits， the physiological and biochemical response characteristics were determined and analyzed under different stress levels respectively. During the whole stress process， the symptom level of salt damage was reached up to grade 2， the leaves appeared yellow and scorched. With the stress time longer， the relative electric conductivity and contents of MDA and proline in leaves increased respectively. The contents of chlorophyll b， soluble sugar， soluble protein， SOD and POD activity increased first and then decreased. The contents of chlorophyll and chlorophyll a increased first and then decreased under 100 and 200 mmol·L-1 of NaCl stress respectively， but decreased under 300 mmol·L-1 of NaCl stress. M. denudata had certain ability of salt tolerance， and it could be used in mild saline soil.
Receptor-like protein kinase gene OsRPK1 plays an important role in the resistance signal transduction of rice. OsRPK2 gene， which is highly homologous to OsRPK1， was amplified and transformed into Arabidopsisthaliana by the overexpression vector p1300：35S：OsRPK2. The stress resistance analysis of 35S：OsRPK2Arabidopsis homozygous showed that the germination rate of OsRPK2 overexpressed Arabidopsis was significantly lower than that of the wild-type under salt， ABA and PEG stress. The root and plant growth of the OsRPK2 overexpressed Arabidopsis seedlings showed more obvious inhibition than that of wild-type. Physiological detection of 35S：OsRPK2Arabidopsis showed that the chlorophyll content decreased more significantly， proline increased less and malondialdehyde content increased more significantly than the wild-typeafter salt treatment. These physiological mechanisms of OsRPK2 overexpression Arabidopsis significantly reduce the stress resistance. Through qRT-PCR detection of the OsRPK2 overexpressed Arabidopsis， the overexpression of OsRPK2 inhibited the expression of SAD， SOS3 and FRY genes significantly. Therefore， OsRPK2 gene may affect Arabidopsis resistance through SOS and CDPK signaling pathway.
Lilium are perennial herbaceous plants with important ornamental value and some species are edible and medicinal. In the present study， the transcriptome of four species of Lilium（L. pumilum， L. davidii， L. lancifolium and L. brownii var. viridulum） was sequenced respectively， and the genes which involved in flower development were analyzed. Combined with the previous transcriptome data of L. brownii， the orthologous genes were selected by comparative transcriptome analysis. Positive selections were screened and their environmental adaptability were analyzed respectively. 44 565， 51 413， 41 638 and 44 716 unigenes were obtained from L. pumilum， L. davidii， L. lancifolium and L. brownii var. viridulum respectively by assembly. In order to understand the function of unigene， the unigenes were compared and annotated in the public database. 13 genes related to the development of flower were identified. A total of 8 247 orthologous genes were obtained in five species， and Ka， Ks and Ka/Ks values were calculated. 33 pairs of homologous genes were strongly positive selected in five species. Subsequently， GO and KEGG enrichment analysis and gene function annotation were carried out， and it was found that these genes were mainly related to plant defense and biosynthesis.
In order to optimize the process of polyphenols by macroporous resin from Empetrum nigrum aerial parts， moisture content， adsorption rate and desorption rate of six resins（HPD-100， X-5， AB-8， D101， HPD-600 and NKA-Ⅱ） were investigated， and the resin with the best effect was selected. Four factors（sample concentration， ethanol concentration， elution flow rate and elution volume） that have a great influence on the purification process were selected， and the response surface method was used to analyze the optimal process. HPD-600 macroporous resin had the best purification effect on polyphenols yield. The optimal extraction conditions were as follows： sample concentration was 0.84 mg·mL-1， ethanol concentration was 62.15%， elution flow rate was 0.67 mL·min-1， and elution volume was 2.71 BV. Under these conditions， the yield of polyphenols was 229.18 mg·g-1， the purity of polyphenols was increased from 8.11% to 22.56%， and the recovery rate was 67.78%.
In order to uncover the response of phenolic compounds of the Catharanthus roseus under salt stress regulated by exogenous nitric oxide（NO）， the ingredient and content of phenolic metabolites in roots， stems， leaves， flowers of the C. roseus were detected using Liquid Chromatography-mass spectrometry（LC-MS） technology after being treated with different concentrations of Sodium Nitroprusside（SNP） under salt stress respectively. The results showed that 5 kinds of C6C1 phenolic compounds including vanillic acid， p-Hydroxybenzoic acid， Syringic acid， Protocatechuic acids and Gallic acid， and 5 kinds of C6C3 phenolic compounds including trans-p-Hydroxycinnamic acid， Chlorogenic acid， Ferulic acid， Cinnamic acid and p-Coumaric acid and 8 kinds of C6C3C6（flavonoids） including Genistein， Petunidin， Naringenin， Quercetin-3-O-rhamnoside， Myricitrin， Quercetin， Kaempferol and Rutin and L- phenylalanine were identified respectively. Among them， quercetin， chlorogenic acid， protocatechuic acids were all in roots， stems， leaves and flowers. The responsive accumulation of the phenolic compounds in different tissues of C. roseus were significantly different under different concentrations of SNP treatment respectively. The small molecular phenolic acids including C6C1and C6C3 were mainly accumulated in roots and stems and C3C6C3 phenolic compounds were enriched mainly in surface leaves and flowers respectively. There were more L-phenylalanine in stem and leaf than in root and flower， and the relative content of L-phenylalanine in stem significantly increased under salt stress， but it showed a downward trend with the increase of NO concentration. Exogenous NO affected the accumulation and change of phenolic compounds in C. roseus under salt stress， and the roots and stems were more sensitive to the response. From the perspective of species and relative content， the stems and leaves were more suitable for the detection of phenolic compounds than others.
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