Low winter temperature is generally recognized as the chief factor limiting the northward distribution of Osmanthus fragrans. O. fragrans has been cultivated in Kaifeng for nearly two decades, yet little is known rega...Low winter temperature is generally recognized as the chief factor limiting the northward distribution of Osmanthus fragrans. O. fragrans has been cultivated in Kaifeng for nearly two decades, yet little is known regarding how well this plant has adapted to the city＇s cold winter. In a city-wide survey, we periodically examined O. fragrans leaves for visible symptoms of freeze damage, then measured leaf soluble sugar content, leaf electric conductivity, palisade layer thickness/leaf thickness ratio, and spongy layer thickness/leaf thickness ratio of several cultivars. The data thus collected were assessed to determine the cultivars＇ cold resistance levels. Our results indicate that the northward distribution of O. fragrans may be limited primarily by low spring temperatures rather than low winter temperatures. O. fragrans Sijigui and Huangchuan Jingui are the most cold resistant O. fragrans cultivars in Kaifeng, China.展开更多
基金This research was supported by The National Natural Science Foundation of China （Grant No. 30970176） and The Innovation Scientists and Technicians Troop Construction Projects of Henan Province （Grant No. 094100510018）. The authors thanked Yuanji Han, Xueyan Yan, Wangjun Yuan, and Meifang Dong for their assistance.
文摘Low winter temperature is generally recognized as the chief factor limiting the northward distribution of Osmanthus fragrans. O. fragrans has been cultivated in Kaifeng for nearly two decades, yet little is known regarding how well this plant has adapted to the city＇s cold winter. In a city-wide survey, we periodically examined O. fragrans leaves for visible symptoms of freeze damage, then measured leaf soluble sugar content, leaf electric conductivity, palisade layer thickness/leaf thickness ratio, and spongy layer thickness/leaf thickness ratio of several cultivars. The data thus collected were assessed to determine the cultivars＇ cold resistance levels. Our results indicate that the northward distribution of O. fragrans may be limited primarily by low spring temperatures rather than low winter temperatures. O. fragrans Sijigui and Huangchuan Jingui are the most cold resistant O. fragrans cultivars in Kaifeng, China.
