不同施肥模式对桃幼树根系生长与氮素吸收分配的影响

Effects of Different Fertilization Mode on Root Growth,Nitrogen Uptake and Distribution of Young Peach Trees

采用盆栽试验,应用15 N同位素示踪技术,研究了不同施肥模式对桃幼树根系生长与氮素吸收分配的影响。结果表明,与不施肥(CK)相比,单施化肥(MF)、生化黄腐酸钾配施化肥(BFA)及有机肥配施化肥(OF)3种施肥模式均显著提高了根系总长度、平均直径、根系表面积、根系体积、根尖数、分枝数和交叉数,其中BFA处理显著提高了根系平均直径,OF处理增加根系生物量的效果最好,并且OF处理更有利于诱导细根(d≤2mm)的发生和生长,而BFA处理更有利于诱导根系的加粗生长,增加中粗根(2mm<d≤4.5mm)和粗根(d>4.5mm)的长度。BFA处理的根系活力显著高于其它各处理,且根系SOD、POD、CAT酶活性显著高于其它处理,MDA含量显著低于其它处理,表现为BFA处理延缓根系衰老效果最好。不同施肥模式处理的桃幼树各器官Ndff%差异显著,BFA处理各器官Ndff%显著高于其它处理。BFA处理的15 N利用率为13.53%,显著高于OF(11.77%)和MF(10.60%)处理。不同施肥模式处理均在一定程度上促进了桃幼树地上部的生长,且BFA处理更能显著促进地上部新梢的加粗和加长生长,这与BFA处理对根系加粗生长的影响表现出一致性。综上可见,生化黄腐酸钾配施化肥(BFA)能显著促进根系生长,促进根系加粗生长,增加粗根的长度,提高根系活力,延缓根系衰老进程,同时还能显著提高根系氮素利用效率,促进桃幼树地上部的生长。

A pot experiment was conducted to study the influence of different fertilization mode on root growth,nitrogen uptake and distribution of young peach trees by using 15 N-isotope tracer technique.The results showed that compared with no fertilizer treatment（CK）,treatments of chemical fertilizers（MF）,biochemical fulvic acid potassium and inorganic fertilizers（BFA）,and organic and inorganic fertilizers（OF）could significantly improve the total length,average diameter,surface area,volume,tip number,branch number and cross number of root of peach tree.Compared with CK treatment,BFA treatment significantly increased root average diameter,and was more favorable to promote thickening growth of root system and to increase the length of middle thick root（2 mmd≤4.5 mm）and thick root（d4.5 mm）,while OF treatment had the most significant positive effects on root biomass,and showed more beneficial effects on induction of fine roots（d≤2mm）.In BFA treatment,the root activity,and enzyme activities of SOD,POD,and CAT of root were significantly higher,while root MDA content was significantly lower,than those in other treatments,showing that BFA treatment had the most significant effects on slowing down root senescence.The Ndff% values in peach tree organs were significantly different among different fertilizer treatments,which were significantly higher in BFA treatment than in other treatments.The utilization rate of 15 N in BFA treatment was 13.53%,which was significantly higher than those in OF treatment（11.77%）and MF treatment（10.60%）.To a certain extent,different fertilization modes promoted the growth ofaboveground young peach tree,and in BFA treatment,new shoots of peach trees grew thicker and longer,which was consistent with the influence of BFA treatment on root growth.In conclusion,the results indicated that the combined application of biochemical fulvic acid potassium and inorganic fertilizers could significantly promote thickening growth of root,increase thick root length and root activity,and slow down root senescence process.At the same time,it could also significantly increase the nitrogen use efficiency of root system,and promote the growth of aboveground peach tree.