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从甜瓜枯萎病发病植株及其根际病土中分离到8株真菌,以甜瓜品种“西甜1号”为材料,采用回接试验和种子萌发试验确定真菌分离物对甜瓜的致病性和生长抑制作用;通过测定盆栽幼苗根系诱导酶活性、抗性物质含量及细胞膜相对透性,研究两株有害真菌粗毒素对甜瓜幼苗的化感作用;根据形态学特征及ITS序列分析对两株有害真菌进行初步鉴定.结果表明:两株有害真菌TF和HF粗毒素对甜瓜种子萌发以及胚轴、胚根生长具有抑制作用,可导致甜瓜幼苗根系丙二醛(MDA)含量、可溶性蛋白含量及细胞膜相对透性增加,其中TF粗毒素原液处理下甜瓜幼苗根系MDA含量和细胞膜相对透性较对照分别增加108.6%和40.6%.两株有害真菌粗毒素可提高甜瓜幼苗根系保护性诱导酶活性,其中,TF粗毒素10倍稀释液处理下根系苯丙氨酸解氨酶(PAL)和过氧化物酶(POD)活性较对照分别增加25.6%和23.2%;HF粗毒素原液处理下根系PAL活性较对照提高30.0%.两株有害真菌TF和HF初步鉴定为木贼镰孢菌(Fusarium equiseti)和层出镰孢菌(F.proliferatum).两株镰孢菌虽然不能通过回接侵染甜瓜,但能通过分泌毒素影响甜瓜正常生长和生理生化代谢,同时提高甜瓜根系保护性诱导酶活性,具有有害和有益双重作用,其化感危害是引起甜瓜连作障碍的主要原因之一.
Eight fungi were isolated from the diseased plants of melon wilt and their rhizosphere soils. The melon variety “Xitantian ” was used as the material, and the pathogenic fungi Sexual and growth inhibition; the allelopathic effects of two harmful fungal crude toxins on melon seedling were studied by measuring the induced enzyme activity, the content of resistant substances and the relative permeability of cell membrane in the roots of potted seedlings. Based on the morphological characteristics and ITS sequence analysis, The results showed that the two harmful fungi TF and HF crude toxin inhibited the germination of the melon seeds and the growth of the hypocotyls and radicles, which could lead to malondialdehyde (MDA) content, soluble protein content And the relative permeability of the cell membrane increased, and the content of MDA and the relative permeability of the cell membrane increased by 108.6% and 40.6%, respectively, in the root system of melon seedlings treated with TF crude toxin.The two harmful fungal crude toxins could increase the protective enzyme activity , In which the activities of PAL and POD increased by 25.6% and 23.2% respectively compared with the control under the treatment of 10 times dilution of TF crude toxin; HF The activity of PAL in roots treated with crude toxin was increased by 30.0% compared with the control.The two harmful fungi, TF and HF, were initially identified as Fusarium equiseti and F.proliferatum.The two Fusarium Although melon can not be infected by the reciprocal connection, it can exert a dual role of harmful and beneficial effects by secreting toxins to affect the normal growth and physiological and biochemical metabolism of muskmelons, while increasing the protective enzyme activity induced by the roots of muskmelon. One of the main reasons.