不同供氮条件下水稻的化感抑草作用与资源竞争分析

为探讨化感水稻在不同氮素水平下的生物干扰现象，提出了一种新的测试方法——化感 竞争分离法（allelopathy and competition separation-based bioassay,ACS），成功地区分了在稻/稗共生系统中水稻化感作用与资源竞争及其在不同N条件下的反应特性.结果表明,水稻PI312777具有较强的生物干扰能力.在不同N水平下，其资源竞争能力较强且表现稳定，但化感作用潜力则随供N水平的下降而明显增强.水稻Lemont不具化感作用潜力，在供N水平正常或充足条件下，其资源竞争能力减弱，但在N胁迫下却明显增强.这是在环境资源贫乏时，稻/稗共生系统中生态位竞争加剧的结果.

Allelopathy and resources competition of rice under different nitrogen supplies

In order to explore the bio-interference of allelopathic rice with barnyardgrass under different nitrogen supplies,a new bioassay method,i.e.,allelopathy-competition separation based (ACS) approach was recommended in this study.The results indicated that ACS could be successfully used to distinguish the rice allelopathy from its resources competition in rice-weed co-culture system,and to evaluate its response characteristics under different N supplies.The test rice accession PI312777 had a higher ability in interfering target weed barnyardgrass (BYD),represented by its stable and higher ability in resources competition,as well as its increasing allelopathic potential in suppressing companion weed BYD when the N supply decreased in the co-cultured system.The reverse was true in the case of rice accession Lemont,which had a lower allelopathic potential under all N supply levels,and a lower ability in resources competition under normal or rich N supply.But,Lemont had an obviously increased ability in resources competition under lower N supply,which was considered as the result of econiche competition in rice-weed system.