Effects of nitrogen fertilizer application amount and ratio of base to topdressing fertilizer on physiological traits and assimilate distribution of root of quinoa
探究了滴灌模式下藜麦根系生理及农艺性状对氮肥不同施用量及氮肥不同基追比(基追肥施用比例)的响应，旨在为藜麦生产中氮肥的有效利用提供科学依据。结果显示，在 60 kg/hm2施氮量条件下高的基追比提高了根系活力，60 kg/hm2施氮量的根系超氧阴离子产生速率和丙二醛含量都显著低于对照；但高施氮量(90 kg/hm2)高基追比(2∶1)条件时丙二醛含量最高，发挥活性氧清除功能的超氧化物歧化酶活性降低，根系活性氧积累。整体而言，60 kg/hm2施氮量的抗氧化酶活性较低。高氮(60和 90 kg/hm2)、高基追比(2∶1)条件促进了藜麦根系的延伸；60 kg/hm2施氮量的藜麦根系总根长和根系表面积整体上高于 30 kg/hm2施氮量。60 kg/hm2施氮量的根直径和根体积整体高于其他处理。在 60 kg/hm2施氮量条件下的产量和单株重整体上均高于其它处理，并且在 2∶1、1∶1和 1∶2基追比分别较不施肥增产74.6%、40.3%和86.8%。施氮 60 kg/hm2、基追比为 1∶2的处理的株高适中，茎秆较粗壮，单株重量最大。综上所述，增施适量氮肥(60 kg/hm2)，并根据藜麦生育阶段给予适当比例的追肥，可通过根系生理代谢、根系形态适应性调整，减轻藜麦根系的脂质过氧化程度及细胞膜损伤等伤害，促进生长发育；施氮 60 kg/hm2，基追比为 1∶2处理的藜麦农艺形状及产量表现最好。
To provide a basis for the effective utilization of fertilizer in the growth and production ofquinoa，the effect ofdifferent amount of nitrogen(N)fertilizer and different base to topdressing ratio on the root morphological characteristics，physiological metabolism，agronomic trait as well as tuber weight of quinoa were studied under drip irrigation mode. Theresults showedthat，with 2∶1 base to dressingratio，60 kg/hm2N fertilizer application improved the rootvigor，the production rate of O2 ?-and MDA content were significantly lower than that of control(C1)，while the MDA content peaked under 90 kg/hm2N fertilizerapplication，SOD activity reduced with a reactive oxygen metabolism disorder. As awhole， under the condition of 60 kg/hm2N fertilizerapplication，the accumulation of reactive oxygen was relatively low. High levelof N fertilizer(60 and 90 kg/hm2)with low ratio of N topdressing promoted the extension of quinoa root system. The total root length and root surface area of quinoa under 60 kg/hm2 N fertilizer were higher than that of 30 kg/hm2. The root diameter and root volume of quinoa under 60 kg/hm2 N fertilizer were higher than that of other treatments. The yield and single plant weight of quinoa under 60 kg/hm2N application were higher than other treatments and tuber weight was74.6%，86.8% and 40.3% higherthan the control respectively. Under the same N application amount and 1∶2 base to topdressingratio，the comprehensiveperformance of quinoa plant was the best，with a moderate plantheight，relatively thick stalk and largest plant weight. Inconclusion，a moderate amount of N fertilizer application(60 kg/hm2)along with an appropriate ratio of topdressing fertilizer applying during quinoa fertility stage could alleviate the osmotic stress caused by imbalance between the concentration of soilsolution and the infiltration potential of root cells through the adjustment in physiological metabolism and root morphology，consequently，reduce the degree of lipid peroxidation and cell membrane damage of quinoa rootsystem，improve the plant growth and development. With 60 kg/hm2N application amount and 1∶2 base to topdressingratio，the comprehensive economic characters were the best.