| Heavy metal contaminated soil will have an important impact on the growth and development of plants.Furthermore,when the pollution is serious enough,it will threaten the safety of agriculture and animal husbandry.Some turf plants can grow normally in heavy metal contaminated soil,the heavy metal ion content in the soil could be gradually reduced through frequent mowing and disposal of the clippings.By this means the purpose of plant restoration can be achieved.Trichoderma,as one of the important biocontrol fungi of plant diseases,not only has a growth promoting effect on a variety of crops,but also can induce plant resistance.Therefore,this paper studied the effects of different concentrations of Trichoderma harzianum on the germination of Festuca rubra and Poa pratensis seeds,and the growth,physiological characteristics,cadmium accumulation ability of two species of turfgrass under Cd2+ stress after treatment with T.harzianum.Preliminary discussion on the physiological mechanism of resistance to turfgrass by T.harzianum,and provide a scientific basis for the application of turfgrass in Cd2+ contaminated areas.The main results obtained are as follows.The concentration of T1 harzianum at 106 CFU·ml-1 promotes the seed germination of Poa pratensis and Festuca rubra.Seeds were germinated under Cd2+ stress after soaking seeds with 106 CFU ml-1 of T.harzianum.The concentration of Cd2+ was 0,100,200,300,400 ?mol·L-1.The germination rate,germination potential,germination index and vigor index of the seeds of Poa pratensis and Festuca rubra decreased significantly(P<0.05)with the increase of stress concentration,and the germination rate,germination potential,germination index and vigor index of the seed soaking(T)under the same stress were significantly higher than that of non seed soaking(non-T)plants,Cd2+ treatment concentration more than 200 ?mol·L-1,the Festuca rubra indexes were significantly reduced,Cd2+ treatment on the seed radicle and plumule growth has a significant inhibition,and the effect on the growth of the radicle is greater than the effect on the plumule,through the seeds soaked with Trichoderma can reduce the stress.The Cd2+ stress test was performed with 108 CFU·ml-1 extract of T.harzianum,the concentration of Cd2+ was 0(CK),10,40,80,100 mg·L-1.The results showed that regardless of the presence or absence of T.harzianum in soil,the growth of both turfgrasses was significantly affected by Cd2+,and the plant height was significantly reduced,the biomass of both grasslands showed a downward trend,and there was a significant difference among the Cd2+ concentration treatments.The total chlorophyll content of two turfgrasses decreased significantly with the increase of Cd2+ concentration 7 days after Cd2+ treatment,and the content of T group was higher than that non-T group.In addition,T.harzianum promoted the accumulation of cadmium on the shoots of the two turfgrass plants,while the underground part absorbed less cadmium after the cadmium concentration exceeded 80 mg·L-1.The content of proline was significantly increased,the content of soluble sugar increased with the increase of treatment concentration and the prolongation of stress time.At 7 days after treatment,the soluble protein content of both turfgrass decreased significantly with increasing treatment concentration.The content of MDA increased significantly,T.harzianum treatment can increase the content of osmoregulatory substances and reduce cell membrane damage.The activities of SOD and CAT in leaves of Poa pratensis and Festuca rubra under Cd2+ stress increased at first and then decreased compared with the control,and the activity of SOD and CAT could be enhanced by T.harzianum treatment,with the extension of stress time and the increase of the concentration of stress,the performance is obvious.The above results show that Trichoderma harzianum has a good potential to control soil metal pollution.Trichoderma harzianum addition to some kinds of turfgrass with strong ecological adaptability could be a new option to control heavy metal pollution in soil-plant system. |
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