Fault rupture propagation in soil with intercalation using nonlocal model and softening modulus modification

Fault rupture propagation is more complex in the overlying soil with intercalation than in homogeneous soil,and it is challenging to simulate this phenomenon accurately using the finite element method.To address this issue,an improved nonlocal model that incorporates softening modulus modification is proposed.The methodology has the advantage that the solutions are independent of both mesh sizes and characteristic lengths,while maintaining objective softening rates of materials.Using the proposed methodology,a series of numerical simulations are conducted to investigate the effects of different mechanical parameters,such as elastic modulus,friction angle and dilation angle of the soil within the intercalation,as well as the impact of geometries,such as the depth and thickness of the intercalation,on the fault rupture progress.This study not only provides significant insights into the mechanisms of fault rupture propagation,specifically in relation to intercalations,but also shows a great value in promoting the current research on fault rupture.

Overexpression of the LcPIN2 and LtPIN2 Gene in Arabidopsis thaliana Promotes Root Elongation

The auxin polar transporter,PIN-FORMED 2(PIN2)plays an important role in root development.However,it remains unclear whether PIN2 genes form two Liriodendron species,L.chinense(LcPIN2)and L.tulipifera(LtPIN2),are both involved in root development and whether and to what extent these two genes diverge in function.Here,we cloned and overexpressed LcPIN2 and LtPIN2 in Arabidopsis thaliana wild-type(WT)and Atpin2 mutant.Phylogenetic and sequence analysis showed a small degree of differentiation between these two Liriodendron PIN2 genes.Tissue-specific gene expression analysis indicated that both Liriodendron PIN2 genes were highly expressed in roots,implying a potential role in root development.Finally,heterologous overexpression of LcPIN2 and LtPIN2 in Arabidopsis both significantly increased the root length compared to wild-type and empty vector.Furthermore,the root length defect in Atpin2 was complemented both by LcPIN2 and LtPIN2.However,heterologous overexpression of LcPIN2 and LtPIN2 cannot rescue the defect in root gravitropism of Atpin2 mutants.Taken together,ourfindings unravel PIN2 genes from the magnoliids plant Liriodendron were functionally conserved with AtPIN2 in the dicotyledonous plant Arabidopsis in regard to the regulation of root length,but not root gravitropism.This study also provides a potential target for genetic improvement of the root system in these valuable forest trees Liriodendron.

Genome-wide identification and cold stress-induced expression analysis of the CBF gene family in Liriodendron chinense

Cold-resistance pathways that operate in model plants such as Arabidopsis thaliana and Oryza sativa have been studied extensively.It has been found that CBF genes play an important role in plant cold resistance.Liriodendron chinense,a tree known for its graceful tree shape and widely spread in south China,has weak cold tolerance.However,little is known about its response to cold.To further study the function of L.chinense CBF gene family,we started by characterizing all members of this gene family in the L.chinense genome and their expression profiling.Phylogenetic analysis found that 14 CBF genes in L.chinense are more closely related to their homologues in woody plants and A.thaliana than those in O.sativa.Cis-acting elements and GO analysis showed that some LcCBF genes participated in the biological process of cold stress response.The transcriptomic and RT-qPCR data showed that most of LcCBF genes displayed an initially increasing and subsequently decreasing trend during cold stress course and the expression profile of each member was different.Some LcCBF genes exhibited a different abundance in callus,root,stem and leaf tissues.The structure and expression characteristics of LcCBF genes imply that they may have similar and different functions in response to cold stress conditions.The identification and analysis of LcCBF gene family have laid the foundation for future studies into L.chinense cold stress mechanisms and for the cultivation of cold-resistance cultivars.

Transcriptome analysis and metabolic profiling reveal the key role of carotenoids in the petal coloration of Liriodendron tulipifera

Liriodendron tulipifera,also known as tuliptree,is a popular ornamental horticultural plant with extraordinary tulipshaped flowers characterized by an orange band near their base.The mechanisms underlying petal band-specific pigmentation during L.tulipifera flower development are unclear.Here,we combined nontargeted and targeted metabolomics and transcriptomics to identify a pathway cascade leading to carotenoid biosynthesis that is specifically activated in the petal band.The comparative analysis of carotenoid metabolites between L.tulipifera and Liriodendron hybrids indicates thatγ-carotene,a rare carotene in plants,is the most likely orange pigment responsible for the coloration of the petal band.Phenotypic and transcriptomic analyses of developing petals reveal that the band area is first predefined by the loss of green color.Later,the band is maintained by locally activating and repressing carotenoid and chlorophyll biosynthesis genes,respectively.Two rate-limiting genes of carotene biosynthesis,carotenoid isomerase(CRTISO)and epsilon lycopene cyclase(ε-LCY),encode the core enzymes responsible for petal band-specific orange pigmentation in L.tulipifera.In particular,a putative additionalε-LCY copy specific to L.tulipifera may contribute to the distinct petal coloration pattern,compared with L.chinense.Taken together,our work provides a first glimpse of the metabolome and transcriptome dynamics in tuliptree flower coloration and provides a valuable resource for flower breeding or metabolic engineering as well as for understanding flower evolution in an early woody angiosperm.

Spatial analysis increases efficiency of progeny testing of Chinese fir

We used spatial, global trend and post-blocking analysis to examine the effectiveness of a progeny trial in a tree breeding program for Chinese fir （Cunninghamia lanceolata （Lamb.） Hook） on a hilly site with an environmental gradient from hill top to bottom. Diameter at breast height （DBH） and tree height data had significant spatial auto-correlations among rows and columns. Adding a firstorder separable autoregressive term more effectively modelled the spatial variation than did the incomplete block （IB） model used for the experimental design. The spatial model also accounted for effects of experimental design factors and greatly reduced residual variances. The spatial analysis rel- ative to the IB analysis improved estimation of genetic parameters with the residual variance reduced 13 and 19% for DBH and tree height, respectively; heritability increased 35 and 51% for DBH and tree height, respectively; and genetic gain improved 3-5%. Fitting global trend and postblocking did not improve the analyses under IB model. The use of a spatial model or combined with a design model is recommended for forest genetic trials, particularly with global trend and local spatial variation of hilly sites.

Inheritance of growth and survival in two 9-year-old, open-pollinated progenies of an advanced breeding population of Chinese firs in southeastern China

Tree growth traits （tree height, DBH and stem volume） and survival from two 9-year-old, open-pollinated progeny tests of Chinese fir were investigated for heri- tability, genotype × environment interaction, age-age genetic correlation and selection efficiency. The 97 and 79 families planted at two sites were collected from the thirdcycle seed orchard. Individual heritability was estimated between 0.05 and 0.21 for tree height, DBH, and volume and between 0.45 and 1.0 for survival. Family heritability was between 0.20 and 1.14. Significant genotype x envi- ronment interaction was observed for the three growth traits. Type B genetic correlation was between 0.41 and 0.67 with an increasing trend as tree grows. High age-age genetic correlation was observed with correlation reaching 0.9 after age 4 for height, DBH, and volume. The genetic gains were estimated at 3.26, 3.39 and 5.98 % for tree height, DBH, and volume with 10 % selection intensity. The implication for advanced tree breeding in Chinese fir is discussed.

The role of γ-aminobutyric acid in aluminum stress tolerance in a woody plant, Liriodendron chinense×tulipifera

The aluminum(Al)cation Al^(3+)in acidic soil shows severe rhizotoxicity that inhibits plant growth and development.Most woody plants adapted to acidic soils have evolved specific strategies against Al^(3+)toxicity,but the underlying mechanism remains elusive.The four-carbon amino acid gamma-aminobutyric acid(GABA)has been well studied in mammals as an inhibitory neurotransmitter;GABA also controls many physiological responses during environmental or biotic stress.The woody plant hybrid Liriodendron(L.chinense×tulipifera)is widely cultivated in China as a horticultural tree and provides high-quality timber;studying its adaptation to high Al stress is important for harnessing its ecological and economic potential.Here,we performed quantitative iTRAQ(isobaric tags for relative and absolute quantification)to study how protein expression is altered in hybrid Liriodendron leaves subjected to Al stress.Hybrid Liriodendron shows differential accumulation of several proteins related to cell wall biosynthesis,sugar and proline metabolism,antioxidant activity,cell autophagy,protein ubiquitination degradation,and anion transport in response to Al damage.We observed that Al stress upregulated glutamate decarboxylase(GAD)and its activity,leading to increased GABA biosynthesis.Additional GABA synergistically increased Al-induced antioxidant enzyme activity to efficiently scavenge ROS,enhanced proline biosynthesis,and upregulated the expression of MATE1/2,which subsequently promoted the efflux of citrate for chelation of Al^(3+).We also showed similar effects of GABA on enhanced Al^(3+)tolerance in Arabidopsis.Thus,our findings suggest a function of GABA signaling in enhancing hybrid Liriodendron tolerance to Al stress through promoting organic acid transport and sustaining the cellular redox and osmotic balance.

The Regulatory Roles of microRNAs and Associated Target Genes during Early Somatic Embryogenesis in Liriodendron Sino-Americanum

Somatic cells respond to considerable stress,and go through a series of phytohormone pathways,then forming an embryo.The developmental process is recorded as somatic embryogenesis(SE).One of the key components regulating SE are the microRNAs(miRNAs).Despite previous studies,it is still not clear exactly how miRNAs exert their function of regulating targets during conditionally activated early SE.Here,we use Liriodendron sino-americanum as a model system and perform a combined analysis of microfluidic chips and degradome sequencing to study this process.We identified a total of 386 conserved miRNAs and 153 novel miRNAs during early SE.According to the ANOVA test,239 miRNAs showed 12 distinct expression patterns.Through degradome sequencing,419 targets and 198 targets were identified for 136 known miRNAs and 37 novel miRNAs,respectively.Gene Ontology(GO)and metabolism pathway enrichment analysis revealed that these targets were significantly involved in oxidation-reduction processes,calmodulin-mediated signal transduction pathways and carbohydrate metabolism.The genes that were related to stress responses,phytohormone pathways and plant metabolism were identified within the targets of miR319,miR395,miR408,miR472,miR482,miR390,miR2055,miR156,miR157,miR171,miR396,miR397,miR529,miR535 and miR159.According to promoter analysis,various cis-acting elements related to plant growth and development,phytohormones response and stress response were present in the promoter of the miRNAs.The differential expression patterns of 11 miRNA-target modules were confirmed by real-time quantitative PCR.The study demonstrated that the miRNA plays an important role in the early SE process by regulating its target and then participating in carbohydrate metabolism and stress response.It also provided a valuable resource for further research in determining the genetic mechanism of SE,and then facilitating breeding programs on plants.

Exogenous Spermidine Promotes Somatic Embryogenesis of Cunninghamia lanceolata by Altering the Endogenous Phytohormone Content

In order to study how exogenous hormones in C.lanceolata(gymnosperm)regulate somatic embryogenesis,we measured the endogenous phytohormones of two genotypes with different somatic embryogenesis efficiency and found that an increase in endogenous concentrations of IAA and ABA may be correlated to more efficient somatic embryogenesis.By applying exogenous spermidine,we found that exogenous hormones may affect somatic embryogenesis efficiency through affecting the endogenous phytohormone content.Based on these results,further studies can be conducted whereby the concentration of exogenous hormones or the levels of endogenous phytohormones by molecular methods are regulated to promote somatic embryogenesis.Our research may benefit the long-term economic output of the forestry industry and lays the foundation to studying the molecular mechanism that controls somatic embryogenesis efficiency.

Morphological, phenological, and transcriptional analyses provide in sight into the diverse flowering traits of a mutant of the relic woody plant Liriodendron chinense

Flowering is crucial to plant reproduction and controlled by multiple factors.However,the mechanisms underlying the regulation of flowering in perennial plants are still largely unknown.Here,we first report a super long blooming 1(slbl)mutant of the relict tree Liriodendron chinense possessing a prolonged blooming period of more than 5 months,in contrast to the 1 month blooming period in the wild type(WT).Phenotypic characterization showed that earlier maturation of lateral shoots was caused by accelerated axillary bud fate,leading to the phenotype of continuous flowering in slbl mutants.The transcriptional activity of genes related to hormone signaling(auxin,cytokinin,and strigolactone),nutrient availability,and oxidative stress relief further indicated active outgrowth of lateral buds in slbl mutants.Interestingly,we discovered a unique FT splicing variant with intron retention specific to slbl mutants,representing a potential causal mutation in the slbl mutants.Surprisingly,most slbl inbred offspring flowered precociously with shorter juvenility(~4 months)than that(usually 8-10 years)required in WT plants,indicating heritable variation underlying continuous flowering in slbl mutants.This study reports an example of a perennial tree mutant that flowers continuously,providing a rare resource for both breeding and genetic research.

Efficient Evergreen Plant Regeneration of Cinnamomum japonicum Sieb.through in vitro Organogenesis

Cinnamomum japonicum Sieb.is an excellent roadside tree and medicinal tree species with considerable ornamental and economic value.In this study,we successfully developed a large-scale micropropagation protocol for C.japonicum for the first time.Sterilized shoots were excised and used as explants for shoot induction on several basal media,supplemented with different concentrations of plant growth regulators(PGRs),such as Thidiazuron(TDZ),N^(6)-Benzyladenine(6-benzylaminopurine)(BA),α-naphthaleneacetic acid(NAA)and Gibberellic acid(GA_(3)).After comparison,the most efficient medium for shoot regeneration was 1/2 Murashige and Skoog(MS)medium containing 0.5 mg L^(-1)BA,0.05 mg L^(-1)NAA and 0.2 mg L^(-1)GA_(3),which resulted in an average number of induced shoots per explant and shoot length of 5.2 and 1.62 cm at 28 d,respectively.Then,elongated adventitious shoots were transferred to induce roots.86.7%of shoots was able to root on 1/2 MS medium supplemented with 0.5 mg L^(-1)NAA and 0.1 mg L^(-1)BA.The earliest rooting time observed was after 21 d and the average root length was up to 3.3 cm after 28 d.Our study shows that C.japonicum can be successfully regenerated through de novo organogenesis,which lays a foundation for future transformation research on this tree.

The Chloroplast Genome of Cerasus Campanulata Diverges from Other Prunoideae Genomes

Cerasus Campanulata is one of several species belonging to the Prunoideae focke,a subfamily of the flowering plant Rosaceae.We investigated the details of its chloroplast genome which may reveal its genus independent of morphological determination.Here,we determined the complete chloroplast(cp)genome sequence of C.campanulata and performed sequence analysis to reveal the presence of 18 forward repeats,20 palindrome repeats,2 complement repeats,4 reverse repeats and 93 simple sequence repeats(SSRs).We additionally performed a comparative study of C.campanulata and seven other Prunoideae focke species.Then,maximum parsimony(MP)and maximum likelihood(ML)phylogenetic analyses were carried out in the little part of Rosaceae,respectively.The results strongly support a position of C.campanulata as a member of the Cerasus in the Rosaceae family.Moreover,the complete cp genome can be used for plant phylogenetic and evolutionary studies that will provide insight into the degree of gene conservation.

Tissue Culture and Rapid Propagation of Platanus occidentalis L.

[ Objective ] The aim was to carry out study on the tissue culture of Platanus occldentalis L. so as to provide suitable method for propagation and preser- vation of fine strains. [ Method ] Four lines of P. occidentalis were used as test materials to explore the proliferation conditions of them on different mediums. [ Re- suit] The difference on the proliferation culture conditions among four clones, four media as well as the interaction of clones and media is extremely significant. The multiple comparisons result showed that the optimal proliferation medium for SX4, SX12, SJ28 and DY18 are ？,4, A2, A2 and A4. SX4 shows the best proliferation result. [ Conclusion] The result in this study has provided suitable method for propagation and preservation of fine strains and the material basis for further studies an P ,~rvirl.,,n^nli~

Inner Envelope CHLOROPLAST MANGANESE TRANSPORTER 1 Supports Manganese Homeostasis and Phototrophic Growth in Arabidopsis

Manganese （Mn） is an essential catalytic metal in the Mn-cluster that oxidizes water to produce oxygen dur- ing photosynthesis. However, the transport protein（s） responsible for Mn2＋ import into the chloroplast re- mains unknown. Here, we report the characterization ofArabidopsis CMT1 （Chloroplast Manganese Trans- porter 1）, an evolutionarily conserved protein in the Uncharacterized Protein Family 0016 （UPFO016）, that is required for manganese accumulation into the chloroplast. CMT1 is expressed primarily in green tissues, and its encoded product is localized in the inner envelope membrane of the chloroplast. Disruption of CMT1 in the T-DNA insertional mutant cmtl-1 resulted in stunted plant growth, defective thylakoid stacking, and severe reduction of photosystem II complexes and photosynthetic activity. Consistent with reduced oxy- gen evolution capacity, the mutant chloroplasts contained less manganese than the wild-type ones. In sup- port of its function as a Mn transporter, CMT1 protein supported the growth and enabled Mn2＋ accumula- tion in the yeast cells of Mn2＋-uptake deficient mutant （3smfl）. Taken together, our results indicate that CMT1 functions as an inner envelope Mn transporter responsible for chloroplast Mn2＋ uptake.