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Picea mongolica is a conifer with a limited distribution in China and its taxonomic status is controversial. In order to explore genetic differences between P. mongolica and other nearby Picea species and to investigate its taxonomic status, phylogenetic relationships were analyzed between P. mongolica and Picea koraiensis, Picea meyeri and Picea wilsonii by three chloroplast gene sequences matK, chlB and atpA. The length of joint chloroplast sequence is 2379 bp. The fifteen haplotypes were identified by haplotype network analysis, among which two were major haplotypes and nine were unique. In addition, the genetic diversity of the sample collection species was inferred. Based on the haplotype network and Neighbor Joining phylogenetic tree analysis, P. mongolica was located on the basal clade of the phylogenetic tree which had more primitive taxa, and the genetic diversity of P. mongolica was highest. The significant differences between P. mongolica and these other Picea species were identified by this research.

Gibberellin (GA) is known to play an important role in low red/far-red (R:FR) light ratio-mediated hypocotyl and petiole elongation in Arabidopsis. However, the regulatory relationship between low R:FR and GAs remains unclear, especially in gymnosperms. To increase our understanding of the molecular basis of low R:FR-mediated shoot elongation in pines and to determine whether there is an association between low R:FR and GAs action, we explored the morphological and transcriptomic changes triggered by low R:FR, GAs, and paclobutrazol (PAC), a GAs biosynthesis inhibitor, in Pinus tabuliformis seedlings. Transcriptome profiles revealed that low R:FR conditions and GAs have a common set of transcriptional targets in P. tabuliformis. We provide evidence that the effect of low R:FR on shoot elongation in P. tabuliformis is at least partially modulated by GAs accumulation, which can be largely attenuated by PAC. GAs are also involved in the crosstalk between different phytohormones in the low R:FR response. A GA biosynthesis gene, encoding ent-kaurenoic acid oxidase (KAO), was strongly stimulated by low R:FR without being affected by GAs feedback regulation or the photoperiod. We show that GA signaling is required for low R:FR-induced shoot elongation in P. tabuliformis seedlings, and that there are different regulatory targets for low R:FR-mediated GA biosynthesis between conifers and angiosperms.

Background Seasonal flowering time is an ecologically and economically important trait in temperate trees. Previous studies have shown that temperature in many tree species plays a pivotal role in regulating flowering time. However, genetic control of flowering time is not synchronised in different individual trees under comparable temperature conditions, the underlying molecular mechanism is mainly to be investigated. Results In the present study, we analysed the transcript abundance in male cones and needles from six early pollen-shedding trees (EPs) and six neighbouring late pollen-shedding trees (LPs) in Pinus tabuliformis at three consecutive time points in early spring. We found that the EPs and LPs had distinct preferred transcriptional modules in their male cones and, interestingly, the expression pattern was also consistently maintained in needles even during the winter dormancy period. Additionally, the preferred pattern in EPs was also adopted by other fast-growing tissues, such as elongating new shoots. Enhancement of nucleic acid synthesis and stress resistance pathways under cold conditions can facilitate rapid growth and maintain higher transcriptional activity. Conclusions During the cold winter and early spring seasons, the EPs were more sensitive to relatively warmer temperatures and showed higher transcriptomic activity than the LPs, indicating that EPs required less heat accumulation for pollen shedding than LPs. These results provided a transcriptomic-wide understanding of the temporal regulation of pollen shedding in pines.

Additional file 3: Figure S3. EP- and LP-preferred transcriptomic pattern shifts during male cone development.

Additional file 2: Figure S2. Expression levels of Pinus tabuliformis EBB1 homologues in male cones from early pollen-shedding trees (EPs) and late pollen-shedding trees (LPs).

Additional file 4: Figure S4. Comparison of transcriptomic activity between male cones and needles of EPs and LPs in the spring.

Additional file 5: Figure S5. mRNA accumulation was significantly decreased at the transcriptome-wide level in the winter.

Additional file 6: Figure S6. Comparison of the expression profiles of the top 12 most abundant genes in mid-winter between male cones and needles from EPs and LPs.

Additional file 1: Figure S1. Expression profiles of genes highly abundant in male cones from early pollen-shedding trees (EPs) and late pollen-shedding trees (LPs).

Gibberellin (GA) is known to play an important role in low red/far-red (R:FR) light ratio-mediated hypocotyl and petiole elongation in Arabidopsis (Arabidopsis thaliana). However, the regulatory relationship between low R:FR and GAs remains unclear, especially in gymnosperms. To increase our understanding of the molecular basis of low R:FR-mediated shoot elongation in pines and to determine whether there is an association between low R:FR and GAs action, we explored the morphological and transcriptomic changes triggered by low R:FR, GAs, and paclobutrazol (PAC), a GAs biosynthesis inhibitor, in Pinus tabuliformis seedlings. Transcriptome profiles revealed that low R:FR conditions and GAs have a common set of transcriptional targets in P. tabuliformis. We provide evidence that the effect of low R:FR on shoot elongation in P. tabuliformis is at least partially modulated by GAs accumulation, which can be largely attenuated by PAC. GAs are also involved in the cross talk between different phytohormones in the low R:FR response. A GA biosynthesis gene, encoding ent-kaurenoic acid oxidase (KAO), was strongly stimulated by low R:FR without being affected by GAs feedback regulation or the photoperiod. We show that GA signaling is required for low R:FR-induced shoot elongation in P. tabuliformis seedlings, and that there are different regulatory targets for low R:FR-mediated GA biosynthesis between conifers and angiosperms.

It has long been known that the pollen shedding time in pine trees is correlated with temperature, but the molecular basis for this has remained largely unknown. To better understand the mechanisms driving temperature response and to identify the hub regulators of pollen shedding time regulation in Pinus tabuliformis Carr., we identified a set of temperature-sensitive genes by carrying out a comparative transcriptome analysis using six early pollen shedding trees (EPs) and six late pollen shedding trees (LPs) during mid-winter and at three consecutive time points in early spring. We carried out a weighted gene co-expression network analysis and constructed a transcription factor (TF) collaborative network, merging the common but differentially expressed TFs of the EPs and LPs into a joint network. We found five hub genes in the core TF module whose expression was rapidly induced by low temperatures. The transcriptional activity of this TF module was strongly associated with pollen shedding time, and likely to produce the fine balance between cold hardiness and growth activity in early spring. We confirmed the key role of temperature in regulating flowering time and identified a transcription factor module associated with pollen shedding time in P. tabuliformis. This suggests that repression of growth activity by repressors is the main mechanism balancing growth and cold hardiness in pine trees in early spring. Our results provide new insights into the molecular mechanisms regulating seasonal flowering time in pines.

The development of new energy industry is one of the important breakthroughs to solve energy and environmental issues and fulfill commitment to the international community for China. SWOT analysis was used to study the new energy industrial upgrading in Tianjin in this paper. By analyzing the strengths, weaknesses, opportunities and threats of the development of new energy industry in Tianjin, the current situations and problems were summarized, in order to provide reference for the practice of new energy industrial upgrading in Tianjin.

The leakage magnetic field and equivalent circuit model of OLTC double-winding power transformer has been established by electromagnetic field Finite Element analysis software. The method of field-circuit coupled method has been used to calculate its magnetic field leakage, the short circuit impedance obtained by the calculation of formula and compared with the experimental data. At the same time, based on the calculation method for the Visual Basic language as a tool for MAGNET software for secondary development, obtain the software to calculate the short-circuit impedance of power transformer simulation software, and is verified by using the typical products, proves the validity of this software.

In this paper, the size of winding electromagnetic force after short circuit has been acquired through leakage field calculation and analysis on power transformer, and based on the computation results, the radial stability experimental results of large capacity power transformer inner winding short-circuit model were compared to the simulation values to guide actual product analysis and checking. With the accumulated simulation experience on this model, then a type of sfz9-80MVA power transformer inner coil static and dynamic stability has been checked to confirm the radial instability phenomenon could whether or not occur on this product.

In this paper, based on the modal analysis combined with power transformer product structure, using the empirical formula calculation method and finite element simulation analysis software calculates the natural vibration frequency of power transformer core, respectively, while making the VB language as a tool to develop the calculation software of natural vibration frequency of power transformer, provides a strong support for product tenders, design and optimization.

Analyzed about the present situation of energy logistics service quality, and combined with related literature at home and abroad, select “energy logistics tracking information timeliness”, “accuracy of energy logistics tracking information”, ”energy delivery time accuracy”, “energy distribution accuracy “, “energy integrity “, “error handling” six elements as a measure factors of the energy logistics service quality, establish research model. Through questionnaire investigation and quantitative analysis verify this research model. The Conclusions: energy distribution of accuracy have significant positive effects on sustainable development, and influence degree; Energy delivery time accuracy, integrity have significant positive effects on sustainable development, but the impact is relatively small; While energy logistics tracking information timeliness, accuracy and error of energy logistics tracking information treatment had no significant influence to the sustainable development of economy and society. Energy logistics is an important part of the logistics industry, also is an important support of economic society and people's life. Improve the quality of energy logistics service, to play an important role in promoting sustainable development.

Due to inclement weather in recent years, the short-circuit fault cannot be ruled out in a short time on power system, and this make the transformer as the main components of the system will withstand the impact of two consecutive short-circuit current in a short time, which makes the winding disks in the initial short circuit without damage, its residual deformation and vibration situation can meet the requirements of stability of transformer. But with the impact effect of the second short circuit, the coil disks residual deformation and vibration amplitude has increased in order to destroy the coil insulation eventually to make the instability phenomenon occurred as a result the transformer has been damaged. So it is necessary to study coils stability after reclosing occurred in power transformer.

The transformer is one of the most important equipment of the power system, the accident that the lightning impact damages the transformer insulation often happens[1]. The main design method of transformer longitudinal insulation structure design is the wave process calculation which is basis on the transformer electromagnetic optimization design[2] [3]. So research the wave process of the transformer windings under the effect of shock wave is very necessary. For the finite element simulation technology is used widely in the engineering design, this paper uses the lumped parameter equivalent circuit calculate and analysis the winding wave process of large power transformer, can reduce the calculation time, improve the efficiency of calculation, and also can write general computing applications, which is convenient for calculating various types of large transformer.