| Echium vulgare L.is a plant of Echium belonging to Boraginaceae family.Plant extract contain abundant secondary metabolites such as phenolics,terpenoids,and alkaloids.It has been reported that extract of E.vulgare showed strong allelopathic effect on seed germination of field crops and on five common garden plants of Compositae.In order to explore the allelopathic potential and application prospect of E.vulgare,Echinochloa crusgalli(L.)Beauv,Viola philippica,Elsholtzia ciliata(Thunb.)Hyland.)and Amaranthus retroflexus L.four representative field weeds in Jilin Province were selected.Experiment studied the allelopathic effects of E.vulgare extract on the seed germination and growth.The result showed that E.vulgare extract inhibited the seed germination and growth of weeds which provided a certain scientific theoretical basis for further research on the weed inhibitory substances and mechanism contained in E.vulgare plant extract.The results were presented as the following:1.Seed sprouting: Set the concentration of E.vulgare extract as(0.01 g/m L,0.02g/m L,0.03 g/m L,0.04 g/m L,0.06 g/m L),control(CK is 0 g/m L),compared with the control group(ck).The germination potential,germination rate,germination index and vigor index of the four kinds of weeds were inhibited by the E.vulgare extract.The inhibitory effect became stronger with increased extract concentrations.When the concentration of the E.vulgare extract was 0.06 g/m L,the greatest inhibitory effect showed on the germination rate of E.crusgalli,Viola philippica,Elsholtzia Cilita and A.retroflexus.Compared with the control(ck),they were reduced by 54%,72%,44%,and 60%,respectively.2.Seed stage shoots and root growth :When the concentration of the extract was0.06 g/m L,the inhibitory effect on the seedling length and root length of E.crusgalli,Viola philippica,Elsholtzia Cilita and A.retroflexus was the strongest,compared with the control group(ck),the seedling length was reduced by 54.66%,42.42%,39.70% and 45.50%,respectively,root length decreased by 41.96%,50.30%,41.18%,51.61%,it could be seen that the 0.06g/m L extract has the strongest inhibition on the growth of E.crusgalli,the strongest inhibition on the root growth of A.retroflexus.At a concentration of 0.01 g/m L,The E.vulgare extract had a certain promoting effect on the root growth of E.crusgalli seedlings,compared with the control(ck),the seedling length and root length of E.crusgalli increased by 5.48% and4.90%.At a concentration of 0.04 g/m L,the E.vulgare extract had a certain promoting effect on the root growth of Elsholtzia Cilita,compared with the control(ck),the root length of Elsholtzia Cilita increased by 2.61%.3.Potted plant growth:When the concentration of the E.vulgare extract was from0.01 g/m L to 0.06 g/m L,the three measurement periods of the 4 weeds showed a suppressed effect.Basically,it gradually decreased with the increase of the concentration of the water extract in the shoots of E.vulgare(The normal growth period after transplanting was measured once every 14 days,the first time was set as T1,the second was T2,and the last was T3).The chlorophyll and nitrogen contents of the four weeds were also the strongest when the concentration of the water extract of the shoots of E.vulgare was 0.06 g/m L.In three measurement periods,The E.vulgare extract had the most significant inhibitory effect on the photosynthetic rate of the four receptor weeds,including E.crusgalli,Viola philippica,Elsholtzia Cilita and A.retroflexus at a concentration of 0.06 g/m L,and with the strengthening of the watering time of the water extract of the shoots of E.vulgare,the inhibition efficiency gradually increased,Among them,the highest inhibition rate was 74.97%in the T3 period of Elsholtzia Cilita,and 72.79% in Viola philippica.In addition,the above-ground water extract of E.vulgare was in T1 period,at the concentration of 0.01g/m L,the photosynthetic rate and stomatal conductance of Viola philippica were increased by 8.37%and 11.11%,respectively,compared with the control group,however,with the regular watering of the extract,the accumulation of allelochemicals turned into an inhibitory effect in T2 and T3 periods.4.Correlation analysis of potted period : From T1 to T3,the chlorophyll content,nitrogen content,photosynthetic rate and stomatal conductance of A.retroflexus had a very significant negative correlation with the concentration of the extract(P<0.01),while Elsholtzia Cilita was in the T1,only the photosynthetic rate had a very significant negative correlation with the concentration(P<0.01),during the T2 period,there was a significant negative correlation between photosynthetic rate and stomatal conductance and concentration(P<0.05),during the T3 period,the chlorophyll,nitrogen content,photosynthetic rate and concentration were significantly negatively correlated(P<0.01),stomatal conductance was significantly negatively correlated with concentration(P<0.05),the degree of correlation was deepened with the extension of the watering period of the extract.Chlorophyll and nitrogen content consistently showed a very significant positive correlation in each measurement period of the four recipient weeds(P<0.01),photosynthetic rate and stomatal conductance had been positively correlated(P<0.01),except E.crusgalli showed a significant positive correlation at T1 period(P<0.05).5.The comprehensive allelopathic effect index(SE)showed during seed germination,the shoots intensity order of the allelopathic effect by the E.vulgare extract was as follows:Viola philippica > E.crusgalli > A.retroflexus > Elsholtzia Cilita.In potted period,The allelopathic effect on the receptor weeds was in the order of A.retroflexus > Viola philippica > E.crusgalli > Elsholtzia Cilita.Above all,E.vulgare ecteact got the best inhibitory effect on the Viola philippica seed germination and growth.E.vulgare extract inhibition of plant growth was the most pronounced in A.retroflexus.In the concentration range of 0.01 g/m L-0.06 g/m L,the comprehensive allelopathic effect index of the E.vulgare extract on the four receptor weeds was negative,and with the increase of the concentration,the absolute value of the comprehensive allelopathic effect index gradually increased.Above all,the E.vulgare ectract had strong inhibitory effect on four kinds of grass,and as the concentration of the extract increased,the inhibitory effect increased continuously. |
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