Correlation Analysis between Well-cellar Early Transplanting of Robust Seedlings and Diseases in Shiyan Tobacco-growing Area

[Objectives]The paper was to investigate the relationship between the well-cellar early transplanting of robust seedlings and the prevalence of diseases in the Shiyan tobacco-growing area.[Methods]The relationship between disease occurrence and meteorological factors during the field growth period was examined by analyzing the prevalence of flue-cured tobacco virus diseases,brown spot,and total disease in the Shiyan tobacco-growing area before(2013-2017)and after(2018-2022)the well-cellar early transplanting of robust tobacco seedlings.[Results]The implementation of a well-cellar early transplanting technique of robust seedlings resulted in a reduction in the average incidence of tobacco virus disease,brown spot,and total disease by 0.83%,8.85%,and 7.91%,respectively,in comparison to the incidence observed prior to early transplanting.These findings suggest that early transplanting can significantly reduce the incidence of flue-cured tobacco diseases.Prior to the well-cellar early transplanting of robust tobacco seedlings,there was a significant(including highly significant)positive correlation between the incidence of brown spot and total disease and precipitation in August and September.The incidence of brown spot and total disease in tobacco plants was found to be significantly positively correlated with May precipitation and significantly negatively correlated with May sunshine hours following the well-cellar early transplanting of robust seedlings.The advancement of the transplanting period by 20 d resulted in a reduction in the growing period of tobacco plants in the field under autumn rains(late August to November)in western China.This effectively circumvented the suitable conditions for disease occurrence and can reduce the incidence of disease.[Conclusions]This study offers a framework for enhancing the quality and efficiency of flue-cured tobacco production in the northwest tobacco-growing area of Hubei.

The first two leading modes of the tropical Pacific and their linkage without global warming

A discrepancy remains in the first two leading empirical orthogonal function(EOF) modes of the tropical Pacific sea surface temperature anomaly(SSTA) based on observations since the 1980s. The EOF1 mode, representing the El Ni?o-Southern Oscillation(ENSO), is a robust result. However, the EOF2 features either El Ni?o Modoki(EM) or ENSO evolution during different periods, which is probably associated with the impacts of global warming. The underlying question is what the EOF2 mode of the tropical Pacific would be without global warming. Using the CMIP5 preindustrial scenario to exclude the influence of global warming, we find that the EOF1 mode of the tropical Pacific SSTA represents ENSO and that the EOF2 mode is not EM. According to the lead–lag correlation between the ENSO and EOF2 modes, the linkage between these two modes is as follows: …El Ni?o → EOF2 → La Ni?a →–EOF2 → El Ni?o…. By analyzing the evolution of sea surface temperature, surface wind, and subsurface ocean temperature anomalies, we find the mechanism linking the ENSO and EOF2 modes is the air–sea interaction associated with the ENSO cycle. This result suggests that the EOF2 mode represents an aspect of ENSO evolution under preindustrial conditions. Therefore, this study further indicates that the EM is probably due to the influence of global warming.

The increasing predominance of extreme precipitation in Southwest China since the late 1970s

Extreme precipitation events cause severe environmental and societal damage worldwide.Southwest China(SWC)is sensitive to such effects because of its overpopulation,underdevelopment,and fragile ecosystems.Using daily observations from 108 rain-gauge stations,the authors investigated the frequency of extreme precipitation events and their contribution to total precipitation in SWC since the late 1970 s.Results indicate that total precipitation is decreasing insignificantly,but rainfall-events frequency is decreasing significantly,whereas the region is experiencing more frequent and intense extreme precipitation events.Note that although fewer stations are statistically significant,about 60%of the rain-gauge stations show an increasing trend in the frequency and intensity of extreme precipitation.Furthermore,there is an increasing trend in the contribution of total extreme precipitation to total precipitation,with extreme precipitation becoming dominant in the increasingly arid SWC region.The results carry important implications for policymakers,who should place greater emphasis on extreme precipitation and associated floods and landslides when drafting water-resource management policies.

Pore plugging effects on the performance of ZSM-5 catalyst in MTP reaction using a discrete model

Coke is an important medium for connecting reaction and regeneration of the methanol to propylene process on the ZSM5 catalyst.Coke grows in the meso and macro pores,it gradually worsens the diffusion inside the catalyst particle.Furthermore,pore plugging is inevitable which causes the deactivation of ZSM5 catalyst.However,current continuum model cannot reflect the changes in pore structure with clear physical concepts.A discrete model that is verified by the carbon deposition experiments is introduced to indicate the behavior of pore plugging effects.Results show that the pore plugging has a significant effect on the performance of the catalyst.The time varying profile of effectiveness factor is obtained,indicating a regular reduction with the increase of the pore plugging effect.Spatial distributions of pore size that would significantly enhance the plugging effect are also identified.

檀香烯与檀香醇生物合成研究进展

檀香烯和檀香醇是名贵香料檀香精油的主要组成成分,具有较好的抗菌、抗氧化和抗肿瘤等药理活性。市售檀香精油主要从檀香树提取,但檀香树生长缓慢及培育难度大,檀香精油的提取率低,难以满足市场需求,导致檀香精油价格居高不下。利用基因工程及分子生物学手段,在微生物体内异源生物合成檀香烯和檀香醇是缓解这种供需矛盾的途径之一。文中对檀香烯和檀香醇合酶的研究现状,以及对宿主甲羟戊酸代谢路径的改造进行总结,并提出利用蛋白质工程技术对檀香烯合酶进行定向改造的思路,为檀香烯和檀香醇的生物合成优产研究提供参考。