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Global climate changes have led to frequent and recurrent heat stress, which has seriously affected the world maize production. The experiment presented in this paper was carried out during the maize‐growing season in 2021 and 2022 at the Huang–Huai–Hai Region Maize Science and Technology Innovation Center (36°09′N, 117°09′E) in Tai'an, Shandong province, China. The test site is located in the semi‐humid warm temperate continental monsoon climate zone, soil is brown loam. We selected different heat‐sensitive maize varieties: heat‐tolerant variety Zhengdan 958 (ZD958) and heat‐sensitive variety Xianyu335 (XY335) to study the stress effects of high temperature on the development of tassel in the key stage of its differentiation (the 12‐leaf stage, V12). We found that exposure to heat stress during the V12 stage significantly reduced the tassel size and the anther dehiscence area, making it difficult to disperse pollen, thus effectively reducing pollen production. In addition, heat stress had significant negative effects on pollen development, resulting in deformed pollen and lower pollen viability and germination rate. Our results also showed that heat stress significantly increased the activities of key reactive oxygen species‐scavenging enzymes including superoxide dismutase, peroxidase and catalase, and that the malondialdehyde and H2O2 content in tassels exposed to heat stress were significantly higher than those control group, where it should be noted that for the XY335, these effects were more pronounced than for the ZD958. The endogenous hormone content of tassels exhibited a variety of responses. After heat stress, the zeatin and salicylic acid content in tassels of both maize varieties were significantly lower than those in the respective control groups, while the abscisic acid and gibberellin acid content were significantly higher. With respect to the jasmonic acid and 3‐indoleacetic acid content, the two maize varieties exhibited opposite responses: in tassels from ZD958 plants subjected to heat stress were higher than those in the respective control group, while in tassels from XY335 plants, they were lower. The observed changes in protective enzyme activities and endogenous hormone contents induced by heat stress significantly affected the development of maize tassels and significantly reduced the amount, activity and germination rate of pollen. [ABSTRACT FROM AUTHOR]

In recent years, rapid urbanization in China has led to land transformation and unequal social and economic development among rural collective land in different regions. Although there has been considerable research on land development in China, there is a lack of studies on the socioeconomic impacts of unequal collective land development on rural elders. This research investigates collective land support, family support, and social support among the elderly in three types of villages—urban, suburban, and remote—in China's Pearl River Delta. The findings show that land support retains an important factor for supporting the rural elderly, while family support is in steep decline, and social elderly support offers low coverage. However, land support differs greatly with location, and only urban villages in central locations with high land values are found to provide adequate land support for the rural elderly. The key influential factor of land income has shifted from land quantity to land location, and there now appears to be a need to adjust relevant land, fiscal, and taxation policies for collective land in different locations. [ABSTRACT FROM AUTHOR]

The coronavirus disease 2019 (COVID-19) outbreak became the worst epidemic in decades. Since its inception, COVID-19 has had a dramatic impact on chronic obstructive pulmonary disease (COPD) patients. This study explores explore the current status, hot spots, and research frontiers of COVID-19 and COPD based on a bibliometric approach. The Web of Science Core Collection was used to search the literature related to COPD and COVID-19, and VOSviewer and CiteSpace software were applied to analyze the distribution characteristics, research hotspots, and research frontiers of literature in related fields and to map the scientific knowledge domains. A total of 816 valid publications were included, among which USA, China, and England are the core countries/regions publishing related literature, and the research institutions are concentrated in Huazhong University of Science and Technology (18 papers), University College London (17 papers), and Imperial College London (16 papers). Guan WJ is the most prolific author with the most articles. The journals with the most publications are PLOS ONE, JOURNAL OF CLINICAL MEDICINE, and FRONTIERS IN MEDICINE. The main research hotspots in this field are clinical features, disease management, and mechanism research. By constructing COPD and COVID-19 research network diagrams, we reveal the hot spots, frontiers, and development trends of relevant research fields, which provide a reference for subsequent researchers to quickly grasp the current status of related research fields., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)