施氮量对鲜食型甘薯根系生长与干物质积累分配的影响

Effects of Nitrogen Application Rate on Root Growth and Dry Matter Accumulation and Distribution of Fresh Edible Sweet Potato

在盆栽条件下,以济薯26和龙薯9号为供试品种,每个品种设置施氮量为0(N0)、100(N1)、200(N2)mg/kg 3个处理,研究施氮量对鲜食型甘薯根系生长与干物质积累分配的影响。结果表明,栽后10、25 d和40 d,与N0和N2处理相比,N1处理有利于两品种保持较高的根系长度、根系表面积、根系平均直径和根系总体积;有利于提高两品种栽后10 d直径≤2 mm、栽后25 d直径为>2~≤5 mm和栽后40 d直径为>5~≤20 mm和>20 mm的根系体积,促进生长前期纤维根生长及根系增粗分化为块根。随施氮量增加,两品种地上部鲜重显著提高,地上部分配比例与地上部鲜重变化趋势基本一致,N1处理有利于提高两品种块根干物质积累与分配比例,保持较高的块根鲜重和干重。施氮量为100 mg/kg是本试验条件下的适宜施氮量。

To examine the effects of different nitrogen （N） application rates on root growth and dry matter accumulation and distribution in fresh edible sweet potato, three N levels including 0 （N0）, 100 mg/kg （N1） and 200 mg/kg （N2） were set in the pot experiments with Jishu 26 （J26） and Longshu 9 （L9） cultivars as materials. The results showed that the root length, surface area, average diameter and total volume of the two varieties in N1 were higher than those in N0 and N2 on the 10th, 25th and 40th days after planting. The volume of roots with the diameter ≤2 mm on the 10th day, 〉2～≤5 mm on the 25th day, and〉5～≤20 mm and〉20 mm on the 40th day could be increased by N1, thereby facilitating the fibrous root growth and inducing the thickening and differentiation of roots into tuberous roots in the early growth periods. As the N application rate increased, the aboveground fresh weight of the two varieties increased significantly, and the variation of the aboveground distribution proportion was similar to that of the aboveground fresh weight. The N1 treatment was benefit to increasing the accumulation and distribution proportion of root dry matter of the two varieties, and maintaining higher root fresh and dry weight. Under the conditions of this experiment, 100 mg/kg was the optimal N application rate.