No abstract

To uncover the transcriptomic mechanism of lignin accumulation caused by boron deficiency (BD), Nanlin895 (Populus × euramericana “Nanlin895”) was subjected to control (CK, 0.25 mg·L−1) and BD (0 mg·L−1) treatments for 3 days. RNA-Seq was carried out to survey the expression patterns of the lignin-regulated biosynthetic genes in response to BD. The results showed that 5946 genes were identified as differentially expressed genes (DEGs), 2968 (44.2%) of which were upregulated and 3318 (55.8%) of which were downregulated in response to BD. Among them, the expression of lignin monomer biosynthetic (PAL, CCR, CAD, COMT, F5H, PER/LAC) and modulated genes, for example, transcription factors (MYBs) and hormone signal regulating genes (GIDs, histidine kinase 1, coronatine-insensitive protein 1), were upregulated, and some hormone signal regulating genes, such as AUXs and BR-related (sterol methyltransferases), were downregulated under BD treatment. There are also some genes that were screened as candidates for an association with wood formation, which will be used for the further analysis of the function of lignin formation. These results provide an important theoretical basis and reference data in plant for further research on the mechanism of lignin accumulation under BD.

Hurricane Ida recently became one of the strongest hurricanes to hit Louisiana on record, with an estimated landfalling maximum sustained wind of 130 kt. Although Hurricane Ida made landfall at a similar time of year and landfall location as Hurricane Katrina (2005), Ida’s postlandfall decay rate was much weaker than Hurricane Katrina. This manuscript includes a comparative analysis of pre- and post-landfall synoptic conditions for Hurricane Ida and other historical major landfalling hurricanes (Category 3+ on the Saffir-Simpson Hurricane Wind Scale) along the Gulf Coast since 1983, with a particular focus on Hurricane Katrina. Abundant precipitation in southeastern Louisiana prior to Ida’s landfall increased soil moisture. This increased soil moisture along with extremely weak overland steering flow likely slowed the storm’s weakening rate post-landfall. Offshore environmental factors also played an important role, particularly anomalously high nearshore sea surface temperatures and weak vertical wind shear that fueled the rapid intensification of Ida just before landfall. Strong nearshore vertical wind shear weakened Hurricane Katrina before landfall, and moderate northward steering flow caused Katrina to move inland relatively quickly, aiding in its relatively fast weakening rate following landfall. The results of this study improve our understanding of critical factors influencing the evolution of the nearshore intensity of major landfalling hurricanes in the Gulf of Mexico. This study can help facilitate forecasting and preparation for inland hazards resulting from landfalling hurricanes with nearshore intensification and weak post-landfall decay.

Hurricanes undergoing intensification immediately before landfall can cause devastating losses of both life and property. For example, Hurricane Audrey in 1957 intensified from maximum sustained winds (MSW) of 80 kt to 110 kt in less than 20 h, causing more than 400 deaths in Louisiana and Texas due to inadequate preparation for coastal areas (Blake et al., 2011). At nearly the identical landfall location, Hurricane Laura in 2020 underwent a 40 kt rapid intensification in the 24 h prior to landfall (Pasch et al., 2021), bringing heavy damage to southwestern Louisiana (NOAA, 2021). Meanwhile, the deadly reach of hurricanes can also penetrate far inland. For example, Hurricane Michael in 2018 not only underwent rapid intensification, from 100 kt to 140 kt in the 24 h before landfall but maintained tropical storm-force winds even 24 h after landfall, resulting in devastating damage to inland infrastructure (Beven et al., 2019). Hurricane Isaias in 2020 caused widespread damage along the U.S. East Coast due to its slow decay (Latto et al., 2021). Therefore, understanding hurricane MSW change rates before landfall and intensity dissipation rates after landfall are of critical importance for improved hurricane risk mitigation.For hurricanes impacting the continental United States, high ocean heat content along with deep mixed layers in the Gulf are favorable for hurricane intensification prior to landfall (Rappaport et al., 2010), while hurricanes located in the western Atlantic near southeast Florida may intensify when encountering the warm Gulf Stream (Nguyen & Molinari, 2012).

This study examines risk perceptions and evacuation planning for those residents affected by Hurricane Laura–the first major hurricane evacuation during the COVID-19 pandemic–and Hurricane Sally, prior to the widespread availability of vaccines. Research on hurricane evacuation behavior and risk perceptions during a pandemic is critical for quantifying the intersect of these compounding threats. Analyses captured how people perceive public shelters and whether evacuation choices changed in light of the pandemic. Many study participants considered themselves vulnerable to COVID-19 (39.4%) and two-thirds believed it would be “very serious” if they or their loved ones contracted COVID-19, but this had no impact on their actual evacuation decision-making. Approximately 75% of the sample stayed at home during Hurricanes Laura or Sally, and of these, just over 80% indicated that COVID-19 was a somewhat important deciding factor. This reflects the partial role that COVID-19 played in balancing individual and household protective action decision-making during complex disasters. Whereas 15.5% wanted to evacuate but waited until it was too late. For those who evacuated to a hotel, many found that staff and guests wore masks and socially distanced in common spaces. Of particular interest is that individuals have a continued negative perception of public shelters’ ability to safeguard against COVID-19 which was coupled with a significant decrease in the number of respondents that would potentially use shelters in 2020 compared to before the COVID-19 pandemic. These results have and will inform future hazard mitigation planning during the current or future pandemic, or infectious disease outbreaks.