Flowering pattern and seedling establishment of umbrella bamboo (Fargesia murieliae (Gamble) Yi) were studied in its native habitat, Mount Shennongjia in Central China. Here in 1996-2000, over 95% of the bamboo pl...Flowering pattern and seedling establishment of umbrella bamboo (Fargesia murieliae (Gamble) Yi) were studied in its native habitat, Mount Shennongjia in Central China. Here in 1996-2000, over 95% of the bamboo plants simultaneously flowered and died, extending from lower elevations to the higher mountains along the altitude and from southwest to northeast along the mountain settings. Bamboo seedlings emerged after the simultaneous flowering, achieving an average density of 5 460 seedlings·m^-2 in the autumn of the year following the flowering. After a high mortality throughout the first winter, bamboo seedlings remained a stable density in following 2-4 years (1130-1230 seedlings·m^-2). Seedling density positively related to the coverage of parent bamboo, but negatively to the herb layers.展开更多
In this article, authors describe how to use the project-based learning (PBL) pedagogy to enhance students' Calculus learning based on the first author's experimental teaching experience. The "2014 BMCC Polar Art...In this article, authors describe how to use the project-based learning (PBL) pedagogy to enhance students' Calculus learning based on the first author's experimental teaching experience. The "2014 BMCC Polar Art Calendar" project was completed by Calculus students at Borough of Manhattan Community College (BMCC) during the fall 2013 semester. Students were requested to apply graphs of polar equations to create computer-generated images with a variety of flower patterns by using the Maple technology in a math lab. At the end of this project, students were requested to submit and present their written reports to express their mathematical thinking. Authors also explain in details how to create projects compatible with textbook knowledge learning objectives, how to prepare scaffolding materials for students to use, how to utilize a math lab and to work with lab technicians in Maple Software, and how to design a rubric for project evaluations. Students' artwork created in the Polar Art Calendar are presented. Students' positive outcomes have proven a success of this project design as well as its execution as an example of PBL. Benefits to students and challenges to teachers on the use of PBL approach have been discussed at the end of this article.展开更多
Heat waves induced by climate warming have become common in food-producing regions worldwide,frequently coinciding with high temperature(HT)-sensitive stages of many crops and thus threatening global food security.Und...Heat waves induced by climate warming have become common in food-producing regions worldwide,frequently coinciding with high temperature(HT)-sensitive stages of many crops and thus threatening global food security.Understanding the HT sensitivity of reproductive organs is currently of great interest for increasing seed set.The responses of seed set to HT involve multiple processes in both male and female reproductive organs,but we currently lack an integrated and systematic summary of these responses for the world’s three leading food crops(rice,wheat,and maize).In the present work,we define the critical high temperature thresholds for seed set in rice(37.2℃±0.2℃),wheat(27.3℃±0.5℃),and maize(37.9℃±0.4℃)during flowering.We assess the HT sensitivity of these three cereals from the microspore stage to the lag period,including effects of HT on flowering dynamics,floret growth and development,pollination,and fertilization.Our review synthesizes existing knowledge about the effects of HT stress on spikelet opening,anther dehiscence,pollen shedding number,pollen viability,pistil and stigma function,pollen germination on the stigma,and pollen tube elongation.HT-induced spikelet closure and arrest of pollen tube elongation have a catastrophic effect on pollination and fertilization in maize.Rice benefits from pollination under HT stress owing to bottom anther dehiscence and cleistogamy.Cleistogamy and secondary spikelet opening increase the probability of pollination success in wheat under HT stress.However,cereal crops themselves also have protective measures under HT stress.Lower canopy/tissue temperatures compared with air temperatures indicate that cereal crops,especially rice,can partly protect themselves from heat damage.In maize,husk leaves reduce inner ear temperature by about 5℃compared with outer ear temperature,thereby protecting the later phases of pollen tube growth and fertilization processes.These findings have important implications for accurate modeling,optimized crop management,and breeding of new varieties to cope with HT stress in the most important staple crops.展开更多
The grand cloth screen with a phoenix pattern comprised of 1.008 pieces, embroidered bu 1.000 women from Shaanxi Province. on display in the Hall of Arts and Crafts during the FWCW.
HOSTING the United Nations Fourth World Conference on Women in Beijing in September 1995 was an important event tor China, especially for Chinese women. In order to enable as many women as possible to participate in t...HOSTING the United Nations Fourth World Conference on Women in Beijing in September 1995 was an important event tor China, especially for Chinese women. In order to enable as many women as possible to participate in the welcome activities, the Shaanxi Provincial Women’s展开更多
基金This research was financed by the National Natural Science Foundation (No. 30470284) and the Center for Development Research of the University of Bonn (P. 52015).
文摘Flowering pattern and seedling establishment of umbrella bamboo (Fargesia murieliae (Gamble) Yi) were studied in its native habitat, Mount Shennongjia in Central China. Here in 1996-2000, over 95% of the bamboo plants simultaneously flowered and died, extending from lower elevations to the higher mountains along the altitude and from southwest to northeast along the mountain settings. Bamboo seedlings emerged after the simultaneous flowering, achieving an average density of 5 460 seedlings·m^-2 in the autumn of the year following the flowering. After a high mortality throughout the first winter, bamboo seedlings remained a stable density in following 2-4 years (1130-1230 seedlings·m^-2). Seedling density positively related to the coverage of parent bamboo, but negatively to the herb layers.
文摘In this article, authors describe how to use the project-based learning (PBL) pedagogy to enhance students' Calculus learning based on the first author's experimental teaching experience. The "2014 BMCC Polar Art Calendar" project was completed by Calculus students at Borough of Manhattan Community College (BMCC) during the fall 2013 semester. Students were requested to apply graphs of polar equations to create computer-generated images with a variety of flower patterns by using the Maple technology in a math lab. At the end of this project, students were requested to submit and present their written reports to express their mathematical thinking. Authors also explain in details how to create projects compatible with textbook knowledge learning objectives, how to prepare scaffolding materials for students to use, how to utilize a math lab and to work with lab technicians in Maple Software, and how to design a rubric for project evaluations. Students' artwork created in the Polar Art Calendar are presented. Students' positive outcomes have proven a success of this project design as well as its execution as an example of PBL. Benefits to students and challenges to teachers on the use of PBL approach have been discussed at the end of this article.
基金supported by the National Science Foundation of China(32272214)the 2115 Talent Development Program of China Agricultural University,and the General Project of Chongqing Natural Science Foundation(cstc2021jcyj-msxmX0747).
文摘Heat waves induced by climate warming have become common in food-producing regions worldwide,frequently coinciding with high temperature(HT)-sensitive stages of many crops and thus threatening global food security.Understanding the HT sensitivity of reproductive organs is currently of great interest for increasing seed set.The responses of seed set to HT involve multiple processes in both male and female reproductive organs,but we currently lack an integrated and systematic summary of these responses for the world’s three leading food crops(rice,wheat,and maize).In the present work,we define the critical high temperature thresholds for seed set in rice(37.2℃±0.2℃),wheat(27.3℃±0.5℃),and maize(37.9℃±0.4℃)during flowering.We assess the HT sensitivity of these three cereals from the microspore stage to the lag period,including effects of HT on flowering dynamics,floret growth and development,pollination,and fertilization.Our review synthesizes existing knowledge about the effects of HT stress on spikelet opening,anther dehiscence,pollen shedding number,pollen viability,pistil and stigma function,pollen germination on the stigma,and pollen tube elongation.HT-induced spikelet closure and arrest of pollen tube elongation have a catastrophic effect on pollination and fertilization in maize.Rice benefits from pollination under HT stress owing to bottom anther dehiscence and cleistogamy.Cleistogamy and secondary spikelet opening increase the probability of pollination success in wheat under HT stress.However,cereal crops themselves also have protective measures under HT stress.Lower canopy/tissue temperatures compared with air temperatures indicate that cereal crops,especially rice,can partly protect themselves from heat damage.In maize,husk leaves reduce inner ear temperature by about 5℃compared with outer ear temperature,thereby protecting the later phases of pollen tube growth and fertilization processes.These findings have important implications for accurate modeling,optimized crop management,and breeding of new varieties to cope with HT stress in the most important staple crops.
文摘The grand cloth screen with a phoenix pattern comprised of 1.008 pieces, embroidered bu 1.000 women from Shaanxi Province. on display in the Hall of Arts and Crafts during the FWCW.
文摘HOSTING the United Nations Fourth World Conference on Women in Beijing in September 1995 was an important event tor China, especially for Chinese women. In order to enable as many women as possible to participate in the welcome activities, the Shaanxi Provincial Women’s