Reproductive capacity and seed germination characteristics of Chromolaena odorata
Chromolaena odorata is an alien weed with strong invasiveness and spreading rapidly in southern China at present.The successful invasion of this weed might be related to its reproductive traits and strong adaptability of seed germination to environmental conditions.We studied the reproductive capacity and seed germination characteristics of C.odorata by employing both field investigations and laboratory experiments.The results showed that C.odorata could reproduce clonally.However, its sexual reproductive capacity was much stronger.A single mature plant could produce approximate 480 thousands of seeds.Its seed was small and there are more than 27 pappus on a single seed.Seed germination of C.odorata was affected by environment factors.The optimum temperature for germination was 28 ℃.It did not require any additional nutrition for germination and could endure drought stress to some extent during germination process.Acidic conditions could accelerate its seed germination, but the percentage of germination was significantly decreased when pH was below 2.Germination could be inhibited by the buried treatment and no seedling emerged when seeds were planted 3.0 cm deep.