谷子茎秆水浸提液对其种子萌发及幼苗生长的自毒作用

为探明谷子连作障碍机理,采用完全随机设计开展发芽和盆栽试验,分析谷子茎秆水浸提液对其种子萌发和幼苗生长的影响。结果表明:不同浓度谷子茎秆水浸提液对谷子种子的萌发表现为"低促高抑"。与对照相比,原液处理下的种子发芽率分别比对照降低73.2%和56.6%,根长、芽长、鲜重、干重也均显著低于对照,表明原液显著抑制谷子种子的萌发和根芽的生长;稀释10、50和100倍液处理下的谷子种子的化感综合效应指数均为正值,表明其对谷子种子的萌发和根芽的生长起到促进作用。谷子茎秆水浸提液原液处理下,谷子幼苗株高、叶面积、生物量、叶绿素含量、净光合速率和蒸腾速率均显著低于对照,且化感效应指数均为负值;稀释10倍液处理下的幼苗株高、叶面积、生物量均显著高于对照,且化感效应指数均为正值;不同浓度茎秆水浸提液处理下的幼苗叶片光合作用与对照相比均受到了抑制作用;谷子苗期叶片的SOD、POD活性经不同浓度谷子茎秆水浸提液处理,随着浓度的增加,分别表现为先增加后减少、先增加后减少再增加的趋势。谷子茎秆中的化感物质在高浓度(原液)下对谷子自身有较强的自毒作用,抑制了种子的萌发和幼苗的生长;在适当浓度(稀释10、50和100倍液)下,表现出促进作用,研究结果可为谷子高效生产提供理论参考。

Autotoxicity effect of the water extracts of foxtail millet straw on seed germination and seedling growth

In order to explore the mechanism of foxtail millet continuous cropping obstacle and investigate the effects of foxtail millet straw water extracts on the seed germination and seedling growth of foxtail millet,germination and pot experiments were completely randomly designed and conducted.The results displayed that the water extracts showed promoting effect at low concentrations while showed inhibition effect at high concentrations on the seed germination of foxtail millet.Compared with the control,the germination rates of the foxtail millet seeds treated with the undiluted water extracts were decreased by 73.2% and 56.6%,respectively.The root and bud length,fresh and dry weight of foxtail millet seedlings were significantly lower than those of the control.It indicated that the undiluted water extracts significantly inhibited the germination of the foxtail millet seeds and growth of the foxtail millet roots and buds.The allelopathic indexes of foxtail millet seeds treated with 10,50 and 100 fold diluted water extracts were all positive suggesting their promoting effects on the seeds germination and the root and bud growth of foxtail millet.After treated by the water extract,the plant height,leaf area,biomass,chlorophyll content,net photosynthetic rate and transpiration rate of foxtail millet seedling were significantly lower than those of the control,and their allelopathic indexes were all negative.In contrast,the plant height,leaf area and biomass of the seedlings under the treatment with 10 fold dilution were significantly higher than those of the control,and all with positive allopathic indexes.Compared with the control,the photosynthesis of the foxtail millet seedlings treated with water extracts at different concentrations was inhibited.With the increase of water extract concentration,the SOD and POD activity in the leaves of foxtail millet seedlings treated with water extracts were increased at first and then decreased,and increased at first,then decreased and finally increased again,respectively.In conclusion,the allelopathic substances in foxtail millet straws had strong autotoxic effects on foxtail millets at high concentration (undiluted water extracts),which inhibited the seeds germination and the seedlings growth,whereas it showed promoting effects at appropriate concentrations (10 fold,50 fold and 100 fold dilution).This study provided theoretical references for the efficient production of foxtail millet.