| Acanthus ilicifolius L. seedlings were cultivated out of doors and treated with different levels of salinity and sediments. 6 levels of salinity were 0, 5, 10, 15, 25, 35. 5 levels of sediments were 100% sea mud(0% sandy), 70% sea mud+30% sand(30% sandy), 50% sea mud+50% sand(50% sandy), 30% sea mud+70% sand(70% sandy), red soil(RS). All seedlings in different sediments were treated with same salinity 5. The cultivating period lasted 365 days. Systemic study on Acanthus ilicifolius were carried on growth, biomass allocation, chlorophyll and MDA and free proline content, photosynthetic properties and the activity of CAT, POD, SOD and PAL, total flavonoids. The change of total flavonoids through different months in wild Acanthus ilicifolius was also studied. The results showed:Stems of plants under salinity 5 and 0% sediments were the highest, the stem height of higher salinity and sediments of lower nutrient content was restrained. As the salinity rose to 35, the number of leaf production and fallen leaves decreased by 62.1% and 39.6% respectively, number of leaves decreased by 65.5%. Leaf area per plant reached maximum under salinity 5, then decreased as the salinity went up. The leaf area per plant under salinity 35 decreased by 22.99 cm~2. Under low nutrient content sediments, both the numbers of leaf production and fallen leaves decreased. The number and area of leaves per plant under 70% sandy sediments were 43.9% and 52.2% of which under 0% sandy sediments respectively. Biomass and their distribution under different salinity and sediments changed significantly (p < 0.05). The maximum biomass of different parts appeared under salinity 5, then decreased as the increase of salinity; RMR and R/C value rose as the increase of salinity, which under salinity 0 were 56.3% and 87.9% of the value under salinity 35 respectively; LMR reached maximum under salinity 5, then decreased, the LMR under salinity 35 was only 63.0% of which under salinity 5. The results indicated that under high salinity stress, shoot of Acanthus ilicifolius was restrained more than root. Plants under 0% sandy sediments had largest biomass of different parts. RMR and R/C increased as the nutrient content of sediments went down, the minimum of them were 82.0% and 36.7% of the maximum respectively; LMR decreased as the nutrient content of sediments went down, which was 58.2% lower under RS sediments than under 0% sandy sediments. These results suggested that Acanthus ilicifolius intended to develop more roots in sediments of low nutrient content.Within the salinity range of 0～35, chlorophyll content first increased then decreased. The highest chlorophyll content was under salinity 5, and the lowest under salinity 35. But the carotene content was not so sensitive. Effects of salinity on photosynthesis characters were: Pn and Gs were steady within the salinity range of 0～10, but decreased at the salinity higher than 10. Ci first increased than went down, the highest Ci was under salinity 5, and the lowest under salinity 35. There were no significant effects on Tr within different salinity. That indicated that the reason for which Pn of Acanthus ilicifolius decreased at high salinity was limitation of stomotal. Study on different sediments plants showed: as the nutrient content went down, chlorophyll content of Acanthus ilicifolius decreased, while the carotene content kept steady. Pn decreased, Gs first increased then went down. The highest Gs was under 30% sandy sediments. Ci and Tr increased. The results indicated the reason for which Pn of Acanthus ilicifolius decreased under lower nutrient content sediments was limitation of physiochemical processes.As the salinity rose, root activity of Acanthus ilicifolius decreased, MDA and free proline content in leaves first went down than increased. Activity of CAT increased continually. But the activity of POD and SOD rose within the salinity range of 0～10, declined within 15～35. There was negative correlation (p < 0.05) between MDA content and POD activity, the same result was found between MDA content and SOD activity. The results indicated that under high salinity, there was more damage to Acanthus ilicifolius caused by lipid peroxidation. As the nutrient content of sediments went down, root activity of Acanthus ilicifolius decreased, MDA content increased, free proline content was steady. Activity of CAT and POD declined, SOD activity increased under 30% sandy sediments first, than declined under lower nutrient content sediments. The results indicated under low nutrient content sediments, the activity of antioxidant enzyme system declined, the resistance capability of the plant decreased.Through orthogonal test, the optimum operation conditions of soxhlet and ultrasonic extraction for total flavonoids from Acanthus ilicifolius were established as follow: ethanol content 60%, extraction temperature 85 and extraction time 2.5 h in soxhlet extraction process; ethanol content 50%, extraction time 50 min, ratio of liquid to material 40:1 in ultrasonic extraction. Total flavonoids content under former two conditions was 3.74% and 3.82% respectively. Take the extracting results and economic factors into consideration, ultrasonic extraction is better than soxhlet extraction.Effects of salinity on total flavonoids content in different parts of Acanthus ilicifolius were different. Total flavonoids content in leaves increased as the salinity rose, which under salinity 35 was 1.85 times of under salinity 0. In roots, total flavonoids content didn't change significantly within salinity 0～15, but increased significantly under salinity higher than 15. Total flavonoids in stems kept relatively steady. As the nutrient content of sediments went down, total flavonoids in leaves and roots first increased than decreased, the largest content was under 30% sandy sediments (in leaves: 11.22 mg/g, in roots: 3.91 mg/g), the lowest under RS sediments (in leaves: 4.73 mg/g, in roots: 1.86 mg/g). Total flavonoids content in stems decreased continually. Total flavonoids content of Acanthus ilicifolius in leaves > in stems > in roots. Activity of leaf PAL increased as the salinity rose, which under salinity 5 was 169.6% higher than under salinity 0. But as the nutrient content of sediments went down, activity of PAL first increased than decreased, which had the maximum under 30% sandy sediments (133.17 u/gFW·min), while the minimum under RS sediments (93.18 u/gFW·min). This trend was similar to which of total flavonoids content change. This result showed that different treatments may influence the total flavonoids content by influencing activity of certain enzyme which was essential to the synthesizing process.Study on total flavonoids content of wild Acanthus ilicifolius showed: total flavonoids content in leaves reached highest during reproductive period, and were lowest at vegetative period. That means the total flavonoids content in leaves was higher in summer, lower in autumn. The change of total flavonoids content in stems was similar with which in leaves, but the fluctuation was smaller. Total flavonoids content in bud was higher than in blossom. Seed contained more flavonoids than capsule. The content of flavonoids in different parts of Acanthus ilicifolius was: in leaves > in seeds > in buds > in blossom > in stems > in capsules.
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