Phylogeny and biogeography of Fagus (Fagaceae) based on 28 nuclear single/low-copy loci

Fagus L. is a key component in temperate deciduous broadleaf forests of the Northern Hemisphere. However, its biogeographic history has not been examined under the framework of a fully resolved and reasonably time-calibrated phylogeny. In this study, we sequenced 28 nuclear single/low-copy loci (18 555 bp in total) of 11 Fagus species/segregates and seven outgroups. Phylogenetic trees were reconstructed using both concatenation-based (maximum parsimony, maximum likelihood, and Bayesian inference) and coalescent-based methods (StarBEAST2, ASTRAL). The monophyly of two subgenera (Fagus and Engleriana) and most sections was well supported, except for sect. Lucida, which was paraphyletic with respect to sect. Longipetiolata. We also found a major phylogenetic conflict among North American, East Asian, and West Eurasian lineages of subgen. Fagus. Three segregates that have isolated distribution (F. mexicana, F. multinervis, and F. orientalis) were independent evolutionary units. Biogeographic analysis with fossils suggested that Fagus could have originated in the North Pacific region in late early Eocene. Major diversifications coincided with a climate aberration at the Eocene/Oligocene boundary and the global cooling since mid-Miocene. The late Miocene accelerated global cooling and the Pleistocene glaciations would have driven beeches into East Asia, North America, and West Eurasia. Meanwhile, range reduction and extinction in high latitudes, central Asia, and western North America converged to form the beech modern distribution pattern. This study provides a first attempt to disentangle the biogeographic history of beeches in the context of a nearly resolved and time-calibrated phylogeny, which could shed new insights into the formation of the temperate biome in the Northern Hemisphere.This work was supported by the National Natural Science Foundation of China (Grant Nos. 31770236, 30760016, and 31560064) and the Strategic Priority Research Program of Chinese Academy of Sciences (XDB31000000).1 Introduction 2 Material and Methods 2.1 Taxon sampling 2.2 Screening of nuclear single/low-copy orthologous locus 2.3 DNA extraction, PCR protocol, and sequencing 2.4 Phylogenetic analyses and molecular dating 2.5 Ancestral area reconstruction 3 Results 3.1 Concatenated tree 3.2 Species tree and molecular dating 3.3 Ancestral area reconstruction 4 Discussion 4.1 Nearly resolved and well supported phylogeny of Fagus 4.2 Species delimitation of three segregates within Fagus 4.3 Biogeographic history of beech species Acknowledgement

Practical calculation of asymmetric short circuit current of DFIG connected to distribution network

In view of the existing complex analytic calculations of DFIG short-circuit current are hardly applied in engineering projects, a practical calculation of asymmetric short-circuit current of DFIG is proposed. According to the complex sequence and their Thevenin equivalent model of DFIG network, the composition of each sequence component of DFIG short-circuit current is analysed. Moreover, considering the low-voltage ride through strategy of DFIG, the negative sequence periodic components of short circuit current are well analysed during the crowbar activation and deactivation, and the formula of the negative sequence periodic components of short circuit current are derived. On the basis of positive and negative sequence open circuit voltage, calculating impedance and rotor current, the judgement of crowbar activation is established. The pre-calculated surfaces of negative sequence periodic components of short circuit current are proposed, and the procedure for calculating the asymmetric short-circuit current of DFIG is designed. Finally, the proposed method is verified by simulation

Exogenous Diethylaminoethyl Hexanoate Highly Improved the Cold Tolerance of Early <i>japonica</i> Rice at Booting

Rice (Oryza sativa L.) is highly sensitive to cold stress, which leads to large reductions in rice yield at the booting stage. In this study, Kongyu131 and Kenjiandao6 rice cultivars with different levels of cold stress sensitivity were sprayed with diethylaminoethyl hexanoate (DA-6) concentrations of 500, 200, 20, 2, 0.2, and 0 mg/L one day before undergoing cold water stress (CWS). We analyzed changes in yield and its factors, dry matter production, stem characteristics, and physiological and biochemical characteristics of the rice plants. The results showed that DA-6 increased peroxidase activity, delayed nitrogen and chlorophyll degradation, maintained soluble protein and potassium contents, and suppressed the accumulation of malondialdehyde in the leaves of both cultivars under CWS. DA-6 also increased the phosphorous content and superoxide dismutase activity in Kenjiandao6 under CWS; however, in Kongyu131, DA-6 increased the soluble sugar content. In addition, DA-6 treatment increased the weight of the panicle at maturity, and of the leaf, panicle, and stem-sheath at heading in both cultivars. The lengths of the panicle, the top first internode, the export rate of stem-sheath, translocation rate of stem-sheath, and export of stem-sheath from heading to maturity were increased in Kenjiandao6; however, in Kongyu131, DA-6 increased the dry weight ratio of panicle to total plant and reduced the dry weight ratio of stem-sheath to total plant at maturity. Furthermore, DA-6 improved yield in both cultivars, mainly by increasing the grain weight in the inferior grains (IG) and middle grains (MG) under CWS. DA-6 increased the grain weight in the IG and MG in Kenjiandao6 mainly by enhancing the seed setting rate and number of filled grains (NFG) in the IG and MG, and in Kongyu131 by improving the NFG in MG and IG. The optimal concentration of DA-6 to alleviate CWS was 2 mg/L. In conclusion, exogenous DA-6 was effective for maintaining dry matter production and physiology in two early japonica rice cultivars under CWS at booting, thereby improving cold tolerance and enhancing yield. The less cold-tolerant cultivar Kenjiandao6 was more sensitive to the effects of DA-6 and displayed better results than the more cold-tolerant cultivar Kongyu131

Design of Hierarchical NiCo2O4 Nanocages with Excellent Electrocatalytic Dynamic for Enhanced Methanol Oxidation

Although sheet-like materials have good electrochemical properties, they still suffer from agglomeration problems during the electrocatalytic process. Integrating two-dimensional building blocks into a hollow cage-like structure is considered as an effective way to prevent agglomeration. In this work, the hierarchical NiCo2O4 nanocages were successfully synthesized via coordinated etching and precipitation method combined with a post-annealing process. The nanocages are constructed through the interaction of two-dimensional NiCo2O4 nanosheets, forming a three-dimensional hollow hierarchical architecture. The three-dimensional supporting cavity effectively prevents the aggregation of NiCo2O4 nanosheets and the hollow porous feature provides amounts of channels for mass transport and electron transfer. As an electrocatalytic electrode for methanol, the NiCo2O4 nanocages-modified glassy carbon electrode exhibits a lower overpotential of 0.29 V than those of NiO nanocages (0.38 V) and Co3O4 nanocages (0.34 V) modified glassy carbon electrodes. The low overpotential is attributed to the prominent electrocatalytic dynamic issued from the three-dimensional hollow porous architecture and two-dimensional hierarchical feature of NiCo2O4 building blocks. Furthermore, the hollow porous structure provides sufficient interspace for accommodation of structural strain and volume change, leading to improved cycling stability. The NiCo2O4 nanocages-modified glassy carbon electrode still maintains 80% of its original value after 1000 consecutive cycles. The results demonstrate that the NiCo2O4 nanocages could have potential applications in the field of direct methanol fuel cells due to the synergy between two-dimensional hierarchical feature and three-dimensional hollow structure.</p

Breeding of the Long-Grain Restorer of <i>Indica</i>-<i>Japonica</i> Hybrid Rice by Using the Genetic Effects of Grain Shape QTLs

Grain shape improvement, which determines grain yield, quality traits and commercial value, is an extremely important aspect of rice breeding. Grain size is controlled by multiple genes, and Maker Assistant Selection (MAS) breeding is effective for breeders in developing stable and efficient markers to aggregate these genes in order to speed up the selection of new lines with desirable traits during the breeding process. In this study, functional markers were developed based on the sequence differences of five grain-shaped genes (GL7, GW6a, GS6, GW5 and TGW6) between the long-grain japonica rice variety Zhendao and the indica-japonica restorer R2027. We then constructed a population of recombinant inbred lines (RILs) based on their cross. The newly designed functional markers were used to genotype grain-size genes, and a genetic effect analysis was conducted to screen high-quality long-grain restorers. Our results reveal diverse effects of different genes on grain size, and the five genotypes were distributed in the 36 selected BC1F8 lines. Specifically, gw5 positively regulates grain width and 1000-grain weight, gl7 and gs6 positively regulate grain length but negatively regulate grain width and 1000-grain weight, tgw6 positively regulates grain length and gw6a positively regulates 1000-grain weight. The most outstanding outcome is that 5 of the 36 lines achieved in this study showing an excellent performance of long grain and yield characters are ideal materials not only for studying the interaction and genetic effects between polygenes but also as restorers or donors for dominant genes in indica-japonica hybrid rice breeding