本省三十種冬裡作田雜草水溶萃取液之相剋潛勢。紫花霍香薊、看麥娘、野莧、白花霍香薊、小葉碎米薺、昭和草、鼠麴草、畔茅、廣東蒿藶、假吐金菊和鵝兒腸等11種雜草，其高度濃度10%(w/v)水溶萃取液可完全抑制萵苣種子萌芽及胚軸生長。其中野莧、白花霍香薊、假吐金菊和鵝兒腸低濃度1%(w/v)水溶萃取液，對萵苣胚軸生長仍具有70%以上之抑制率效果。對高粱胚軸生長之影響，僅以野莧低濃度水溶萃取液，具62%之抑制率，其餘處理之抑制率皆低於50%。三十種雜草水溶萃取液濃度增加，其抑制活性亦增加，但此等水溶萃取液的酸鹼值與滲透壓並不會影響測試植物的萌芽和生長。土壤中野莧植物生物量增加為1.2%(w/v)以上，對萵苣、水稻的萌芽與幼苗生長具顯著之抑制現象。

Allelopathic activity of thirty upland weeds of Taiwan was determined using aqueous extracts of the weeds. Germination and seedling growth of lettuce (Lectuce sativa) ere completely inhibited by IO%(w/v) aqueous extracts of Ageratum boustonienun, Alopecurus eequslis var. amurensis, Amaranthus viridis. Ageratum conyzoides, Csrdsmine parvifJora, Brechtites vslcrianstolis, GnBphalium affine, Leptocblou chinesis, Rorippe csntoniensis, Soliv« enthemitolis or Stellaria squetice. Aqueous extracts of Amaranthus viridis, Ageratum conyzoides, Saliva enthemitolia or Stellsri« aquatics at l%(w/v) level resulted in more than 70% inhibition of radicle growth of lettuce. Radicle growth of sorghum (Sorghum bicolor) were less affected by aqueous extracts at l%(w/v) level. Phytotoxicity severally increased with raising concentration of the extracts obtained from all 30 weeds tested. Osmotic pressure and pH in the range that of the extracts did not affect germination and radicle growth of lettuce. Litter of Amaranthus viridis, at 1.2%(w/w) level significantly inhibited germination and seedling growth of lettuce and rice (Oryza satuva) in pot test.