环境因子对空心莲子草出苗和生长的影响

Influence of environmental factors on emergence and growth of alligatorweed

空心莲子草出苗和生长的最适宜温度为20～30℃，5℃以下不能出苗。在土壤湿度为30％时，出苗率最大。且在变湿条件下有利于出苗和生长。它具有很强的抗涝能力，耐早性则较弱，出苗率和生长势随根茎含水量的降低而降低，当根茎含水量低于22．2％，则不能出苗、生长。其出苗和生长的适宜土深为0．5～1．0cm，并随着土壤深度的增大而减弱。光对其出苗和生长的影响则不显著。这些结果不仅为空心莲子草的分布和危害提供了分析依据，也为防除提供了有效的控制措施，可结合冬耕或伏耕，将根茎翻至土表，受冻或干旱而丧失活力，或以深耕将根茎埋至20cm以下，以阻止大量出苗和生长繁殖。

Laboratory and greenhouse studies were conducted to determine the effects of temperature, soil moisture, light, planting depth, and rhizome water content on the emergence and vegetative growth of alligatorweed. The results showed that the optimum temperature for the emergence and growth was 20-30℃, and no emergence occurred below 5℃. The emergence rate was maximum at soil moisture of 30%, and fluctuating soil moisture benefited the emergence and growth. Alligatorweed rhizomes had a strong waterlogging resistance but a rather weak drought resistance. The emergence rate and growth vigor decreased as the rhizome water content decreased, and no emergence occurred when the rhizome water content was below 22.2 %. The emergence rate was above 90.3 % when rhizomes were buried 0.5 - 1.0 cm deep, and the emergence rate and growth vigor decreased with burial depth increasing. Alligatorweed emergence and vegetative growth were not significantly influenced by light. According to the above results the rhizomes could be turned up and became surface stratum in winter or summer plowing, losing their vitality for cold or dry. Also the rhizomes could be buried beneath 20 cm soil layer in deep plowing to avoid the emergence and growth of large numbers of alligatorweeds.