化肥有机肥配施对油菜营养生长期根系分泌物的影响

Effects of chemical fertilizers combined with organic fertilizers on root exudates of rape during vegetative growth period

探讨油菜营养生长期根系分泌有机酸和氨基酸对不同施肥处理的响应,为油菜安全高效生产提供理论依据。盆栽试验设置5个化肥有机肥不同配施比例,分析油菜根系和地上部的干重及其根系分泌的有机酸和氨基酸的种类和含量。研究结果表明,油菜根系分泌有机酸以丙二酸、乙酸和柠檬酸为主,其中丙二酸和乙酸受施肥影响最为显著,有机肥配施显著降低二者分泌量。与单施化肥相比,有机肥配施显著减少了油菜根系分泌有机酸总量,并不同程度降低了地上部和根系生物量。化肥有机肥配施比例为1∶3时有机酸总量降低最明显,但生物量与单施化肥无明显差异。油菜根系分泌氨基酸以谷氨酸和γ-氨基丁酸为主,不同配施比例对油菜根系分泌35种氨基酸种类的影响不大,但对氨基酸分泌总量影响显著。随有机肥配比的增加,氨基酸总量呈现先减少后增加的趋势。根系干重与有机酸分泌总量呈极显著正相关关系,但与氨基酸分泌总量无关,后者与土壤可溶性有机碳含量和细菌数量显著相关。油菜根系分泌有机酸和氨基酸所起的生态作用可能不同,前者可能是植物受到养分胁迫时的应激反应,后者可能是为了增强土壤活性。化肥有机肥1∶3配比为油菜生长提供最均衡养分,为油菜施肥管理提供参考。

The responses of organic acids and amino acids secreted by roots during the vegetating period of rape to different fertilization treatments were explored to provide a theoretical basis for safe and efficient production of rape.The dry weight of roots and above-ground parts in rape and the types and contents of organic acids and amino acids secreted by the roots were analyzed in pot experiment with five different proportioned fertilizers.The results showed that malonic acid,acetic acid and citric acid were the main organic acids secreted by the roots of rape,among which malonic acid and acetic acid were the most significantly affected by fertilization,and organic fertilizer combined application significantly reduced their secretion.Compared with single application of chemical fertilizer,combined application of organic fertilizer significantly reduced the total amount of organic acids secreted by the roots of rape,and reduced the biomass of above-ground and root in different degrees.When the proportion of chemical fertilizer and organic fertilizer application was 1∶3,the total organic acid decreased most obviously,but there was no significant difference in biomass compared with single chemical fertilizer application.Glutamic acid andγ-aminobutyric acid were the main amino acids secreted by the roots of rape.Different ratios of combined application had little effect on the 35 amino acids species secreted by the rape roots,but had significant effect on the total amino acid secretion.With the increase of organic fertilizer ratio,the total amount of amino acids showed a trend of decreasing first and then increasing.The dry weight of the root was extremely significantly positively correlated with the total amount of organic acid secretion,but not with the total amount of amino acid secretion,which was significantly correlated with the content of soluble organic carbon and the number of bacteria in the soil.We speculated that the ecological effects of organic acids and amino acids secreted by the root of rape may be different,the former may be the stress response of plants under nutrient stress,while the latter may be to enhance soil activity.The suitable ratio of chemical fertilizer to organic fertilizer is 1∶3,which can provide the most balanced nutrition for the growth of rape and provide reference for the fertilization management of rape.