阔叶丰花草与2种菊科植物之间的化感作用

Allelopathic interactions between Borreria latifolia and two common Asteraceae species

阔叶丰花草是一种适用于华南果园生草控草的一年生植物。为了揭示阔叶丰花草与果园常见杂草之间的竞争关系,研究了阔叶丰花草与两种菊科植物(胜红蓟和白花鬼针草)之间的化感作用。结果表明:10~50 mg·mL^-1的阔叶丰花草水浸液处理显著抑制胜红蓟和白花鬼针草种子萌发和幼苗生长,胜红蓟和白花鬼针草的胚根长分别比对照降低57.4%~90.2%和57.3%~62.3%。胜红蓟和白花鬼针草水浸液对阔叶丰花草种子萌发也有较强的化感效应,在50 mg·mL^-1的浓度处理下,阔叶丰花草种子几乎不能萌发。经10 mg·mL^-1阔叶丰花草水浸液处理30 d后,胜红蓟播种苗的净光合作用、株高和生物量分别比对照降低15.2%、20.6%和41.5%,白花鬼针草播种苗的生物量也出现下降趋势;但胜红蓟和白花鬼针草水浸液处理对阔叶丰花草播种苗生长的影响均不显著。在混种条件下,阔叶丰花草的生物量与单种的水平相当,胜红蓟和白花鬼针草的生物量则分别比单种降低86.0%和27.1%。与胜红蓟和白花鬼针草相比,阔叶丰花草的化感优势在于除了能抑制对方的种子萌发,也能抑制其植株生长。

Borrelia latifolia is an annual herb suitable to be used as cover crop for weed control in orchards in southern China.To understand the competition between B.latifolia and common weeds in orchards,we investigated the allelopathic interactions between B.latifolia and two Asteraceae species,Ageratum conyzoides and Bidens alba.The results showed that the aqueous extracts of B.latifolia at 10-50 mg·mL^-1 significantly inhibited seed germination and seedling growth of A.conyzoides and B.alba,with the radicle length of A.conyzoides and B.alba being reduced by 57.4%-90.2%and 57.3%-62.3%,respectively.The aqueous extracts of A.conyzoides and B.alba also had strong allelopathic effects on seed germination of B.latifolia.Under the treatment of 50 mg·mL^-1 aqueous extracts,the two Asteraceae species almost entirely inhibited the germination of B.latifolia.After treated with 10 mg·mL^-1 aqueous extract of B.latifolia for 30 d,net photosynthesis,plant height and biomass of A.conyzoide were reduced by 15.2%,20.6%and 41.5%,respectively,compared with the control,while the biomass of B.alba also showed a decreasing trend.Instead,the growth of B.latifolia was not affected.Under mixed culture,biomass of B.latifolia was comparable to that under monoculture,whereas those of A.conyzoides and B.alba were reduced by 86.0%and 27.1%,respectively.Compared with A.conyzoides and B.alba,the allelopathic advantage of B.latifolia is that it can inhibit growth of the two Asteraceae species as well as inhibit seed germination.