海岛植被修复中的耐旱植物筛选及抗旱技术研究

Drought-tolerant plants screening and drought-resistant technology research for island vegetation restoration

针对海岛地理缺水、季节性干旱等造成海岛植被修复工作困难的问题,采用室外模拟实验的方法,研究3种典型的海岛植被修复常用植物——木麻黄、台湾相思和夹竹桃的耐旱能力及使用保水剂、覆盖凋落物对其耐旱能力的影响.结果表明:(1)3种苗木都具有一定的耐旱能力,在长时间干旱胁迫下,耐旱能力从强到弱依次为夹竹桃、台湾相思和木麻黄;(2)在植被修复期间,应根据植物的耐旱能力,适当调整浇水间隔期.为保持良好的生长状态,木麻黄、夹竹桃和台湾相思的浇水间隔期分别是20、15 d和10 d;而在极度缺水的野外,只为保证成活率的情况下,夹竹桃、台湾相思和木麻黄的浇水间隔可以分别延长至60、40 d和30 d;(3)施加土壤保水剂和土壤表面覆盖凋落物均可提高植物成活率,其中,覆盖凋落物效果优于施加保水剂;(4)施加土壤保水剂需控制合理比例,以保水剂与土壤质量比例为1∶500为宜.相关研究成果已在海岛植被修复中得到应用,取得良好效果,可为我国海岛植被修复提供参考.

For island vegetation restoration,geographical water shortage and seasonal drought were tough difficulties. Outdoor experiments were conducted to simulate natural processes to investigate 3 typical plants usually chosen for island vegetation restoration. These plants are Casuarina equisetifolia,Acacia confuse and Nerium indicum.Drought resistant ability of each plant was compared. Impacts of water retention agent and the drought resistant ability by litter coverage on each plant were examined. Results show that（ 1） 3 plants all had certain drought resistant ability. The drought-resistant ability under a long-time drought stress is higher for Nerium indicum than Acacia confusa and Casuarina equisetifolia.（ 2） When there was a water shortage,watering intervals should be adjusted according to the drought-resistant ability of the plant. in order to keep good growth situation,Casuarina equisetifolia,Nerium indicum and Acacia confusa should be watered once every 20,15 and 10 days,respectively. However,when extremely water shortage occurred judged by the plants withering time under drought stress,watering intervals can be prolonged to 60,40 and 30 days to guarantee the survival of Nerium indicum,Acacia confuse and Casuarina equisetifolia,respectively.（ 3） Soil water retention agent and litter coverage can enhance the survival rate of plants and the later has better effect by comparison.（ 4） When using the soil water retention agent,the ratio of water retention agent and soil quantity should be controlled,and the advisable ratio is 1 ∶ 500. Our results have been applied in situ and promising results were observed. Thus,the work can provide experiences for island vegetation restoration in our country.