Abstract: Alien plants and their ecological invasion have negative impacts on indigenous species diversity and ecosystems, being one of the hotspots in current ecological research. Based on literature consultation and field survey, the database of alien plants in Shandong Province was established, with their components, geographical flora and spatial distribution patterns statistically analyzed. The results showed that there were 827 species of alien plants, belonging to 122families and 416 genera, among which, 348 species were imported from other countries. The alien plant species had a higher proportion, occupying 39.03% of the flora in the province, and were of the obvious dominant families and typical families. The diverse geographic distribution patterns of genera were characterized by 52.51% of temperate zone components and 44.06% of tropical zone components. The relatively centralized origins and distribution of alien species suggested the co-impacts of environment factors and human actions. Alien plants originated from temperate zone were more invasive in Shandong Province than those from other origins.

Key words: Poplar clone seedlings, Osmotic stress, Photo inhibition of photosynthesis, Reactive oxygen species, Protecting enzymes