摘要:
烟草生产过程中会产生大量烟草残体,为了研究烟草残体对烟草生长的影响,将烟根、水稻土和无菌水按一定比例混合后,在适当条件下培养得到烟根腐解物。将烟根腐解物按不同的施用量设置6个处理组,并以未施用烟根腐解物组作为对照,分别在烟草生长的团棵期、旺长期和成熟期测定烟草的农艺性状、根系活力、硝酸还原酶(nitrate reductase,NR)和过氧化物酶(peroxidase,POD)活性以及丙二醛(malondialdehyde,MDA)含量。结果表明:在团棵期,烟根腐解物能显著抑制烟草的生长,增加烟草中MDA含量和POD活性,使根系活力和NR活性先升高后降低,叶鲜质量、根鲜质量及植株干质量明显降低,表现出较强的化感效应;随着处理时间的延长,在旺长期和成熟期,这种化感抑制效应逐渐减弱并转变为促进作用。此外,在添加烟根腐解物土壤中生长的烟株发生了较强的烟草花叶病毒(tobacco mosaic virus,TMV)引起的病害,且随施用量的增大和处理时间的延长发病率增加。实验结果表明:烟根腐解物对烟草生长呈现出前期抑制,后期促进的效应;从各生长时期的农艺性状、相关酶活性及病害发生情况综合来看,以施用量50 g/盆效果最好。
Abstract:
As lots of tobacco residues remain in the soil during tobacco production, in order to study the decomposition of tobacco residues on the growth of tobacco, tobacco root, paddy soil and water were mixed together in certain proportion to form the decomposition of tobacco root under suitable conditions. Experiments were divided into 6 treatment groups with the application of different dosages of root decomposition, and the group treated with none of root decomposition was used as the control group. The physical property, the activities of root, nitrate reductase (NR) and peroxidase (POD) and the content of malondialdehyde (MDA) were measured in the extending stage, budding stage and mature stage. The results indicated that the decomposition of root restrained the growth of tobacco (nicotiana tobacum) during the period of extending stage, showing a strong allelopathic inhibition effect. In the extending stage, the content of MDA and the activity of POD increased; the activity of root and NR increased first and then decreased; the mass of fresh leaves, fresh root and the whole dry plant all decreased significantly. However, during the budding stage and mature stage, the allelopathic inhibition weakened gradually and the tobacco root decomposition turned to serve as a catalyst for tobacco growth. Besides, the decomposition of root could cause the tested tobacco to be infected by tobacco mosaic virus (TMV), the morbidity exhibited a tendency of increase with the extension of treatment time and the increase of dosage. It is demonstrated that the decomposition of root inhibited the growth of tobacco in the early stage, but promoted its growth in the latter period. The best application dosage of tobacco root decomposition was 50 g per pot in terms of the physical property and physiology index of tobacco and its infection rate by TMV.
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