中文摘要：

为了解外来入侵植物紫茎泽兰（Eupatorium adenophorum L.）与本地土著植物艾草（Artemisia argyi Levl）在UV-B辐射增强条件下生长形态和竞争关系的变化,以这两种植物为试验材料,以自然光为对照进行5周UV-B辐射增强实验和2周恢复实验,并测定和分析植株形态指标（株高、叶片鲜重、叶长、叶宽和叶面积）、叶片解剖结构（上下表皮、栅栏组织和海绵组织）和竞争能力指标（株高、叶生物量和茎生物量）.结果显示：艾草叶片鲜重和叶面积在辐射前两周显著减小（P〈0.05）和极显著减小（P〈0.01）,株高没有差异,而紫茎泽兰的株高、叶鲜重和叶面积在辐射期间都明显减小,且恢复实验时仍差异显著.艾草叶片厚度在UV-B辐射下极显著增大（上表皮、栅栏组织和海绵组织极显著增大）,紫茎泽兰叶片变厚但不明显,恢复实验时显著减小,叶片解剖结构表明UV-B辐射使两类杂草叶片细胞间隙变大.UV-B辐射对紫茎泽兰生物量的抑制比较显著,对艾草生物量的抑制在混种时显著;在UV-B辐射下,紫茎泽兰和艾草的相对生物量分别为1.03和0.81,在自然状态下分别为0.91和0.97,两者的相对生物量总和不变,为0.94.本研究表明艾草对UV-B辐射的形态抗性较强,UV-B辐射刺激了紫茎泽兰的种内竞争,也降低了艾草的种间竞争能力,但无论在自然条件下还是UV-B辐射增强条件下艾草的种间竞争能力都比紫茎泽兰强,但不足以淘汰对方.

英文摘要：

bstract This research investigated the differences of plant morphology,leaf anatomical structure and competitive effects of the invasive weed Eupatorium adenophorum L.and the native weed Artemisia argyi Levl under the condition of enhanced UV-B radiation and compared them with those in the natural sunlight environment.The plant morphological indexes（including plant height,fresh leaf weight and leaf size）,leaf anatomical structure（including upper epidermis,back epidermis,palisade tissue and spongy tissue） and competitiveness indicators（including plant height,leaf and stem biomass） were measured and analyzed based on a five-week UV-B radiation experiment followed by a two-week recovery experiment.The results showed significant decrease in fresh leaf weight and leaf area of A.argyi Levl during the first 2 weeks of UV-B radiation,and in all the plant morphological indexes of E.adenophorum L.throughout the UV-B radiation experiment and recovery experiment.The blade thickness of both weeds increased during the radiation experiment and decreased after the radiation stopped,with significant thickening of upper epidermis,palisade tissue and spongy tissue in the native weed.Besides,changes of leaf anatomical structure showed that the intercellular space in leaf tissue of both weeds increased after radiation.The UV-B radiation significantly inhibited the biomass of E.adenophorum L.,but for A.argyi Levl such inhibition occurred only in mixed culture.The relative yield of the two weeds was 1.03 and 0.81 respectively under UV-B radiation,compared with 0.91 and 0.97 in natural sunlight.The results suggested that A.argyi Levl is more tolerant of UV-B radiation than E.adenophorum L.in plant morphology;UV-B radiation provokes the intraspecific competition of E.adenophorum L.and weakens the interspecific competition of A.argyi Levl.;under both natural sunlight and UV-B radiation,A.argyi Levl is stronger in interspecific competition than E.adenophorum L.,but not strong enough to eliminate the other.