High-quality cucumber seedlings are a prerequisite for ensuring high yield of cucumbers.With the continuous increase of cucumber planting area in China,the demand for high-quality cucumber seedlings is also increasing...High-quality cucumber seedlings are a prerequisite for ensuring high yield of cucumbers.With the continuous increase of cucumber planting area in China,the demand for high-quality cucumber seedlings is also increasing.One of the important ways to improve the quality of cucumber seedlings is to improve the light environment by using artificial light source.In this study,three cucumber seedlings(cv.Jintong,cv.Yunv and cv.Xiazhiguang)were grown for 23 d under eight levels of daily light integral(DLI)at 4.3 mol/(m^(2)·d),8.6 mol/(m^(2)·d),10.1 mol/(m^(2)·d),13.0 mol/(m^(2)·d),5.8 mol/(m^(2)·d),11.5 mol/(m^(2)·d),14.4 mol/(m^(2)·d)and 17.3 mol/(m^(2)·d),respectively.The results showed that when DLI was 14.4 mol/(m^(2)·d),the seedling height,stem diameter,total leaf area and shoot dry/fresh weight of all three cucumber cultivars reached the maximum,while hypocotyl length decreased with the increase of light intensity.When DLI was 14.4 mol/(m^(2)·d),Jintong and Xiazhiguang had the highest health index,which were 49.29 and 28.56,respectively,while that of Yunv was 81.59(DLI=14.4 mol/(m^(2)·d)).With the increase of DLI,the photosynthetic capacity of cucumber increases gradually.The highest net photosynthetic rate was shown at DLI of 14.4 mol/(m^(2)·d),while the chlorophyll content of cucumber seedlings of all three cultivars were less affected by DLI.Jintong and Yunv had the highest chlorophyll content when DLI was 8.6 mol/(m^(2)·d)because they were adapted to low-light environment.In conclusion,the DLI of 14.4 mol/(m^(2)·d)for Jintong and Xiazhiguang,while that of 17.3 mol/(m^(2)·d)for Yunv are suggested for the light environment design of factory-cultivated seedling for cucumber.展开更多
亚历山大数字图书馆项目（Alexandria Digital Library，ADL）是美国最大的、持续时间最长的数字图书馆研究项目之一，自1994年起连续得到了美国国家科学基金会（NSF）的美国数字图书馆倡导计划（Digital Library Initiative，DLI）长...亚历山大数字图书馆项目（Alexandria Digital Library，ADL）是美国最大的、持续时间最长的数字图书馆研究项目之一，自1994年起连续得到了美国国家科学基金会（NSF）的美国数字图书馆倡导计划（Digital Library Initiative，DLI）长达十年的资助。该项目的重点在于设计并运行其颇有特色的地理参考数字图书馆。ADL是一个分布式参考资料数字图书馆，以各种数据来源的地图、图像和地理定位文献为主要收集对象，实现公众对地理空间信息对象的访问和搜索，是互联网上的地理信息资源中心。文章对该数字图书馆的项目背景、信息资源组织、服务和技术特点等进行了介绍和评价。展开更多
国家声音展馆（the National Gallery of the Spoken Word，NGSW），美国国家科学基金（NSF）资助的数字图书馆先导研究计划二期的项目之一，是记录20世纪重要历史声音的数字图书馆，旨在实现20世纪的重要讲演、广播和录音等历史声音的...国家声音展馆（the National Gallery of the Spoken Word，NGSW），美国国家科学基金（NSF）资助的数字图书馆先导研究计划二期的项目之一，是记录20世纪重要历史声音的数字图书馆，旨在实现20世纪的重要讲演、广播和录音等历史声音的数字化储存、全文检索与在线使用。文章首先介绍该项目的基本情况，然后在资源建设与组织、技术手段和服务特征等三个方面对其进行概要的评述，最后提出评价和建议。展开更多
基金This work was supported by the National Key Research and Development Program of China(2017YFB0403901).
文摘High-quality cucumber seedlings are a prerequisite for ensuring high yield of cucumbers.With the continuous increase of cucumber planting area in China,the demand for high-quality cucumber seedlings is also increasing.One of the important ways to improve the quality of cucumber seedlings is to improve the light environment by using artificial light source.In this study,three cucumber seedlings(cv.Jintong,cv.Yunv and cv.Xiazhiguang)were grown for 23 d under eight levels of daily light integral(DLI)at 4.3 mol/(m^(2)·d),8.6 mol/(m^(2)·d),10.1 mol/(m^(2)·d),13.0 mol/(m^(2)·d),5.8 mol/(m^(2)·d),11.5 mol/(m^(2)·d),14.4 mol/(m^(2)·d)and 17.3 mol/(m^(2)·d),respectively.The results showed that when DLI was 14.4 mol/(m^(2)·d),the seedling height,stem diameter,total leaf area and shoot dry/fresh weight of all three cucumber cultivars reached the maximum,while hypocotyl length decreased with the increase of light intensity.When DLI was 14.4 mol/(m^(2)·d),Jintong and Xiazhiguang had the highest health index,which were 49.29 and 28.56,respectively,while that of Yunv was 81.59(DLI=14.4 mol/(m^(2)·d)).With the increase of DLI,the photosynthetic capacity of cucumber increases gradually.The highest net photosynthetic rate was shown at DLI of 14.4 mol/(m^(2)·d),while the chlorophyll content of cucumber seedlings of all three cultivars were less affected by DLI.Jintong and Yunv had the highest chlorophyll content when DLI was 8.6 mol/(m^(2)·d)because they were adapted to low-light environment.In conclusion,the DLI of 14.4 mol/(m^(2)·d)for Jintong and Xiazhiguang,while that of 17.3 mol/(m^(2)·d)for Yunv are suggested for the light environment design of factory-cultivated seedling for cucumber.
文摘亚历山大数字图书馆项目（Alexandria Digital Library，ADL）是美国最大的、持续时间最长的数字图书馆研究项目之一，自1994年起连续得到了美国国家科学基金会（NSF）的美国数字图书馆倡导计划（Digital Library Initiative，DLI）长达十年的资助。该项目的重点在于设计并运行其颇有特色的地理参考数字图书馆。ADL是一个分布式参考资料数字图书馆，以各种数据来源的地图、图像和地理定位文献为主要收集对象，实现公众对地理空间信息对象的访问和搜索，是互联网上的地理信息资源中心。文章对该数字图书馆的项目背景、信息资源组织、服务和技术特点等进行了介绍和评价。
文摘国家声音展馆（the National Gallery of the Spoken Word，NGSW），美国国家科学基金（NSF）资助的数字图书馆先导研究计划二期的项目之一，是记录20世纪重要历史声音的数字图书馆，旨在实现20世纪的重要讲演、广播和录音等历史声音的数字化储存、全文检索与在线使用。文章首先介绍该项目的基本情况，然后在资源建设与组织、技术手段和服务特征等三个方面对其进行概要的评述，最后提出评价和建议。
