Time-course transcriptome landscape of achene development in lettuce

Lettuce(Lactuca sativa L.),which belongs to the large Asteraceae(Compositae)family,breeds by sexual reproduction and produces seeds.Actually,lettuce seeds are achenes,which are defined as fruits.However,few studies have described the morphological characteristics of the lettuce achenes,and genes essential for achene development are largely unknown in lettuce.To investigate the gene activity during achene development and determine the possible mechanisms that influence achene development in lettuce,we performed a time-course transcriptome analysis of lettuce achenes.A total of 27,390 expressed genes were detected at the five achene development stages.We investigated the gene expression patterns during achene development and identified the enriched biological processes at the corresponding stages.Kyoto Encyclopedia of Genes and Genomes and Gene Ontology analyses revealed a variety of transcriptomic similarities and differences at different achene development stages.Further,transcription factors and phytohormones were found to play important roles during achene development.Finally,we proposed a working model to illustrate the gene expression modules and possible molecular mechanisms underlying achene development.Our time-course transcriptome data also provide a foundation for future functional studies to reveal the genetic control of achene development in lettuce.

LsAP2 regulates leaf morphology by inhibiting CIN-like TCP transcription factors and repressing LsKAN2 in lettuce

Leaf size and flatness directly affect photosynthesis and are closely related to agricultural yield.The final leaf size and shape are coordinately determined by cell proliferation,differentiation,and expansion during leaf development.Lettuce(Lactuca sativa L.)is one of the most important leafy vegetables worldwide,and lettuce leaves vary in shape and size.However,the molecular mechanisms of leaf development in lettuce are largely unknown.In this study,we showed that the lettuce APETALA2(LsAP2)gene regulates leaf morphology.LsAP2 encodes a transcriptional repressor that contains the conserved EAR motif,which mediates interactions with the TOPLESS/TOPLESS-RELATED(JPL/TPR)corepressors.Overexpression of LsAP2 led to small and crinkly leaves,and many bulges were seen on the surface of the leaf blade.LsAP2 physically interacted with the CINCINNATA(CIN)-like TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR(TCP)transcription factors and inhibited their transcriptional activation activity.RNA sequencing analysis showed that LsAP2 affected the expression of auxin-and polarity-related genes.In addition,LsAP2 directly repressed the abaxial identity gene KANAD12(LsKAN2).Together,these results indicate that LsAP2 regulates leaf morphology by inhibiting CIN-like TCP transcription factors and repressing LsKAN2,and our work provides insights into the regulatory mechanisms of leaf development in lettuce.

A Swarm Intelligence Networking Framework for Small Satellite Systems

Recent development of technologies and methodologies on distributed spacecraft systems enable the small satellite network systems by supporting integrated navigation, communications and control tasks. The distributed sensing data can be communicated and processed autonomously among the network systems. Due to the size, density and dynamic factors of small satellite networks, the traditional network communication framework is not well suited for distributed small satellites. The paper proposes a novel swarm intelligence based networking framework by using Ant colony optimization. The proposed network framework enables self-adaptive routing, communications and network reconstructions among small satellites. The simulation results show our framework is suitable for dynamic factors in distributed small satellite systems. The proposed schemes are adaptive and scalable to network topology and achieve good performance in different network scenarios.

青藏高原多年冻土地区涵洞基础稳定性调查及分析

本文通过对于国道G109线(青藏公路)路段的公路工程概况和该地区的自然地质条件的调查结果的分析,以及青藏公路涵洞使用状况调查方法与调查结果的探讨,在此基础上论述了多年冻土区涵洞破损类型与特征,并对其发生的深层次原因进行了较为详尽的总结,提出针对多年冻土地区涵洞破坏原因,应从4个方面入手,采取措施进行病害防治:减小工程对多年冻土的热扰动;消除或削弱季节活动层的冻胀和融沉;增强涵洞结构抵抗和适应冻融变形的能力;消除或减小涵底渗流。

The Effect of Crop Rotation on Soil Nematode Community Composition in a Greenhouse

[Objective] The aim was to identify changes in a nematode community in response to crop rotation and to determine the appropriate catch crop for a greenhouse. [Method] The experiment was carried out in a typical 6-year-old greenhouse,in which cucumber crops were cultivated twice each year(in spring and autumn),and catch crops were planted in summer. The total number of nematodes was counted and nematode community indices were calculated after collecting soil samples in different stages. [Result] Total nematode abundance was decreased in the soils of catch crop in contrast with former crops(cucumber crops). The abundance of the nematode community was reduced in the treatment of crop rotation compared to the soils of catch crop. In addition, the number of nematode taxa was significantly reduced by the treatment of crown daisy compared to the treatments of following crops. Crop rotation regulated the functional composition of the nematode community by increasing the omnivores-predators functional group and decreasing the relative abundance of root herbivores. [Conclusion] These results indicate that crop rotation affects the nematode community in abundance, diversity and functional composition of the nematode community and crown daisy can be served as the most appropriate catch crop in the greenhouse.

Reconfiguring perovskite interface via R4NBr addition reaction toward efficient and stable FAPbI3-based solar cells

Defect states in perovskite films restrict the interfacial stability and open-circuit voltage of perovskite solar cells.Here,aiming at superior interfacial passivation,we investigate the reconfiguration of perovskite interface by the interaction between a series of quaternary ammonium bromides(QAB)and lead—halide(Pb—X)octahedrons.Bromide—iodide substitution reaction or R4NBr addition reaction may occur on the perovskite surface,which is related to the steric hindrance of quaternary ammonium cations.On this basis,the perovskite surface morphology,band structure,growth orientation and defect states are reconstructed via the R4NBr addition reaction.This ordered lead—halide adduct could effectively repair the imperfect perovskite/hole transportation layer interface to suppress non-radiative recombination and ion migration toward ultralong carrier lifetime surpassing 10µs.The resulting perovskite solar cells yield the efficiency of 23.89%with steady-state efficiency of 23.70%.The passivated cells can sustain 86%of initial efficiency after 200-h operation,which is attributed to the passivation effect and hydrophobic characteristics.This work provides an avenue for reconfiguring perovskite surface by QABs.