中文摘要：

采用田间试验方法，研究了连续两年大田条件下，增强UV-B辐射（UV-B，280～310nm，5．0kJ·m^-2）对两个割手密（Saccharum spontaneum L．）无性系（Ⅰ91-48和Ⅱ91-81）形态和生理的影响，以及两个割手密无性系对UV-B辐射响应的种内差异。结果表明，两年中，在增强UV-B辐射下，Ⅰ91-485个生育时期的株高（除2004年成熟后期外）和分蘖数，以及分蘖期和伸长初期的茎径显著增加，而Ⅱ91-81株高在伸长初期和伸长后期，分蘖数在伸长初期、伸长后期、成熟初期和成熟后期（除2004年伸长后期外），以及茎径在分蘖期、伸长初期和伸长后期显著降低。两年的成熟后期，UV-B辐射导致Ⅰ91-48生物量、叶面积指数和节间长显著增加，Ⅱ91-81生物量、叶面积指数和节间长显著降低，而两个无性系节数无显著变化。两年中，UV-B辐射显著降低两个割手密无性系伸长后期和成熟初期叶展开角度。在UV-B辐射下，两年的5个生育时期中，Ⅰ91-48的类黄酮含量显著增加，丙二醛含量无显著变化，而Ⅱ91-81的类黄酮含量显著降低（除2003成熟后期外），丙二醛含量显著增加。总体上，UV-B辐射导致Ⅰ91-48叶绿素a、叶绿素b和叶绿素（a＋b）含量在两年的分蘖期、伸长初期和伸长后期显著增加，而Ⅱ91-81叶绿素a、叶绿素b和叶绿素（a＋b）含量在两年的分蘖期、伸长初期、伸长后期和成熟初期显著降低。割手密无性系Ⅰ91-48和Ⅱ91-81对UV-B辐射的响应具有种内差异。

英文摘要：

Effects of enhanced UV-B radiation （UV-B, 280-310 nm, 5.0 kJ·m^-2）on morphology and physiology of two wild sugarcane （Saccharum spontaneum L.）clones （ Ⅰ91-48 and Ⅱ91-81 ）and intraspecific differences of two wild sugarcane clones to enhanced UV-B radiation were investigated under field conditions for two consecutive years. In 2003 and 2004, under UV-B radiation, plant height （except ripening in 2004）, tiller number in five development stages and stem diameter in tillering and initial growth of Ⅰ 91-48 increased significantly, while plant height in initial growth and late growth, tiller number in initial growth, late growth, ripening and later ripening （except late growth in 2004）, and stem diameter in tillering, initial growth and late growth of Ⅱ 91-81 decreased significantly. UV-B radiation increased significantly shoot biomass, LAI and internode length of Ⅰ 91-48, and decreased significantly that of Ⅱ91-81, whilst no effect on node number of two wild sugarcane clones. UV-B radiation decreased significantly leaf expanding angle of two wild sugarcane clones in late growth and ripening in 2003 and 2004. In five development stages of 2003 and 2004, UV-B radiation increased significantly flavonoid contents and no effect on MDA contents of Ⅰ 91-48, whilst decreased significantly flavonoid contents （except late ripening of 2003）and increased significantly MDA contents of Ⅱ91-81. In general, UV-B radiation increased significantly contents of chlorophyll a, chlorophyll b and chlorophyll （a＋b）in tillering, initial growth and late growth of Ⅰ 91-48 in 2003 and 2004, whilst those of Ⅱ 91-81 decreased significantly in tillering, initial growth, late growth and ripening in two years. Intraspecific differences existed in responses of two wild sugarcane clones to enhanced UV-B radiation.