Combinations Of Trichoderma-Oilrape And Its Function For Absorbing Cadmium From Soil

Trichoderma spp. ,one of the most commonly used biocontrol fungi, has been shown to be able to degrade and transform heavy metals, DTT etc. Oilseed rape is one of the most important crops, and Brassica napus which is widely planted in the northern district of China has been proven to have the Cadmium degradation ability. However, research has been limited to Trichoderma or oilseed rape. Absorption of heavy metals from the soil by the combined effect of Trichoderma - Oilrape has great significance. There have been little related reports on the combination of oilseed rape and Trichoderma REMI mutants, so it is possible for us to use Trichoderma mutants and oilseed rape to remediate soils contaminated with the heavy metal. In this study Trichoderma REMI mutants and oilrape which has high tolerance and absorption capacities of heavy metal were screened separately, and then the best combination of trichoderma– oilrape which has the highest absorption capacity of heavy metal was chosen. It is showed that Trichodema mutants could not only stimulate the heavy metal absorption in oilrape, but also could prevent Sclerotinia sclerotiorum infection. According to greenhouse pot trails using artificial Zinc and Cadmium contaminated loam soil, we detected the tolerance and ability of absorbing Zinc and Cadmium in 12 different oilseed rapes and selected one Zinc and Cadmium accumulating oilseed rape Huyou20 which could be widely grown in Yangtze river delta and had markedly higher above-ground biomass, relative biomass, Zinc, Cadmium uptake amount and soil remediation rate than other oilseed rape varieties. The result indicated that Huyou20 was a potential phytoremediation cultivar for phytoremediating Zinc and Cadmium contaminated soil. Oilrape Huyou 20 seedlings were treated with wild Trichoderma soil remediation agents in soil with or without cadmium stress. A set of parameters including height, dry weight, relative biomass and cadmium removal rate of oilrape seedlings was compared. Results suggested that the cadmium uptake ability by Huyou 20 in the presence of mutants P6 and H6 soil remediation agents in soil was improved greatly and the prevention rate of Sclerotinia sclerotiorum also increased above 80%. The preliminary study on the mechanism of the combination of Trichoderma mutants-oilrape showed that cadmium could be found in the cell wall and the chloroplasts of the leaves. Cell wall absorbed more cadmium, maybe the effect of Trichoderma stimulate cadmium absorption and it lead to more destroy of the nuclear of the oilrape.A set of parameters including height, dry weight, relative biomass and cadmium removal rate of oilrape seedlings treated with different soil repair agents was compared. Results suggested that Huyou 20-P6+H6 is the best combination, it could improve the cadmium uptake ability by Huyou 20 in the presence of mutants P6+ H6 soil remediation agents in soil were improved greatly, and prevent the Sclerotinia sclerotiorum infection, make sure that the Trichodema-oilrape could grow safely in the contaminated soil, the study also lay a foundation for the implication and mechanism of the remediation of heavy metal contamination in farmland by the interaction of plant-microbe.