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水稻化感品种能从根系分泌释放化感作用物质 ,长期以来 ,酚酸类物质被认为是水稻根分泌的主要化感物质 ,但这一结论常常被质疑。利用连续循环和直接树脂吸收两种方法采集典型的水稻化感品种 PI31 2 777幼苗的根分泌物 ,并用液相色谱 /质谱(L C/ MS)联用技术鉴定了根分泌物中的非酚酸类物质。结果显示 ,水稻 PI31 2 777幼苗根系能分泌释放 7-甲氧基羟基肟酸、羟基肟酸、3-异丙基 - 5 -乙酰氧基环己烯酮 - 1、5 ,7,4′-三羟基 - 3′,5′-二甲氧基黄酮、二萜内酯 A和二萜内酯 B6个非酚酸类化合物。经液相色谱 (HPL C)定量分析 ,这些化合物在水稻生长 1 0 d的根分泌物中的浓度为 5～ 1 9μmol/ L。进一步的生测结果显示 ,这些化合物在其释放的浓度范围能对稻田常见的稗草和异型莎草有抑制活性 ,尤其是这些化合物的等摩尔混合物的抑草活性增加 ,同时水稻根分泌物的抑草活性与土壤载体显著相关。表明羟基肟酸、环己烯酮、黄酮和二萜内酯四类非酚酸类物质是水稻的主要化感物质 ,这与近期愈来愈多的研究结果一致
Rice allelochemicals can release and release allelochemicals from roots. For a long time, phenolic acids were considered as the major allelochemicals secreted by rice roots, but this conclusion is often questioned. The root exudates of PI31 2 777 seedlings, a typical rice susceptible cultivar, were collected by continuous circulation and direct resin absorption. The non-phenolic acids in root exudates were identified by liquid chromatography / mass spectrometry (LC / MS) Substances. The results showed that the root system of rice seedling PI31 2 777 could secrete 7 - methoxyhydroxamic acid, hydroxamic acid, 3 - isopropyl - 5 - acetoxycyclohexenone - 1,5,7,4’- Trihydroxy-3 ’, 5’-dimethoxyflavone, diterpene lactone A and diterpene lactone B6 non-phenolic compounds. Quantitative analysis by liquid chromatography (HPL C) showed that the concentration of these compounds in root exudates at 10 days of rice growth ranged from 5 to 19 μmol / L. Further bioassay results showed that these compounds could inhibit the activity of barnyardgrass and cross sedge which are common in paddy fields in the range of their release concentration. Especially, the equimolar mixture of these compounds had increased weatherability, The weed control activity was significantly correlated with soil support. This indicates that the four non-phenolic acids such as hydroxamic acid, cyclohexenone, flavone and diterpene lactone are the main allelochemicals in rice, which is consistent with more and more recent studies