土壤杀菌剂对木霉根际竞争的影响及木霉对玉米生长作用的初步研究

Competitive Effects of Fungicide on Rhizosphere of Trichoderma spp.in Soil and Maize Growth

利用木霉对五氯硝基苯的天然抗性，在土壤中施用4-12μg·g^-1土五氯硝基苯。结果表明，哈茨木霉T7在用4μg·g^-1土五氯硝基苯处理的玉米根际土中的根际竞争指数为4．332，明显高于对照（RC=3．758）。表明适量浓度的土壤杀菌剂，能提高其在玉米根际土中的种群密度，从而提高其根际竞争；但在6-12μg·g^-1土五氯硝基苯处理的玉米根际土中均低于对照，表明过高浓度的杀菌剂会因影响木霉的生长而降低其在根际的竞争能力。盆栽试验表明，用哈茨木霉T7处理土壤，对玉米的出苗无明显作用，但对玉米植株后期的生长有明显的促进作用。

A soil was treated with a resistant fungicide pentachloronitrobenzene （PCNB） at dosages of 4- 12 μg per gram in consideration of its natural resistance. The results indicated that rhizosphere competence index （RC） of Trichoderma harzianum T7 for the treatment at close of 4 μg PCNB was 4. 332, higher than the control; while the treatments at doses of 8- 12 μg PCNB, rhizosphere competence index were lower than the control. The experiment data showed that proper consistence of PCNB may enable Trichoderma spp. to grow more readily along the developing root. The pot experiments showed, Trichoderma harzianum T7 could not affect on rate of germination of maize, hut promote seeding growth of maize subsequently.