施氮量对不同藜麦品种幼苗生长的影响

通过盆栽试验,研究5个水平的施氮量(N₀,0 g·kg^-1;N₁,0.05 g·kg^-1;N₂,0.1 g·kg^-1;N₃,0.15 g·kg^-1;N₄,0.2 g·kg^-1)对8个不同藜麦品种幼苗生长的影响。结果表明: 1)不同施氮量处理下,藜麦品种GB22和OY的生物量最大,而品种B2的生物量最小。品种B2的花质量比最大,品种GB22的茎质量比最大,品种R1的根质量比最大,品种W23的叶质量比最大。2)施氮显著影响藜麦幼苗的生长。在较低施氮量(N₁、N₂)下,叶片最大净光合速率、植株生物量积累都比对照(N₀)明显增加;在较高施氮量(N₃、N₄)下,藜麦叶片光合速率出现降低趋势,生物量积累减少。品种和施氮量对植株生物量有显著的交互作用,表明不同藜麦品种对施氮量的响应不同。品种R1、MY11、GB22、OY的最佳施氮量为0.05 g·kg^-1,品种GB11、DB、B2的最佳施氮量为0.1 g·kg^-1,品种W23的最佳施氮量小于0.05 g·kg^-1。3)品种和施氮量之间的交互作用显著影响藜麦幼苗的生物量分配。在达到0.2 g·kg^-1施氮量前,随着施氮量增加,藜麦将更多的生物量分配到花和叶。4)不同品种和施氮量下,幼苗生物量与最大净光合速率、苗高、地径、比叶面积呈显著正相关。本研究可为不同藜麦品种的养分管理提供参考。

Effects of nitrogen application rate on the growth traits in seedlings of different quinoa cultivars

Effects of five different nitrogen application rates (i.e., N₀, 0 g·kg^-1; N₁, 0.05 g·kg^-1; N₂, 0.1 g·kg^-1; N₃, 0.15 g·kg^-1; N₄, 0.2 g·kg^-1) on the growth of seedlings of eight different quinoa cultivars were investigated in a pot experiment. The results showed that: 1) Across different nitrogen application rates, cultivar GB22 and OY had the highest biomass, but cultivar B2 had the lowest value. The highest flower mass ratio, stem mass ratio, root mass ratio, and leaf mass ratio were found in cultivar B2, GB22, R1, and W23, respectively. 2) The rate of nitrogen application significantly affected seedling growth. Compared with the control (N₀), the maximum net photosynthetic rate and biomass accumulation were significantly higher in the lower nitrogen applications (i.e., N₁ and N₂ treatments), but were lower in the higher nitrogen applications (i.e., N₃ and N₄ treatments). The significant interactions between cultivar and nitrogen application rate on plant biomass indicated that different quinoa cultivars responded differently to nitrogen rate. The optimum nitrogen application rate (Nopt) required for cultivar R1, MY11, GB22 and OY was 0.05 g·kg^-1; while that of cultivar GB11, DB, and B2 was 0.1 g·kg^-1; but for cultivar W23, Nopt was less than 0.05 g·kg^-1. 3) The interactions between cultivar and nitrogen application rate significantly affected biomass allocation. Below the highest nitrogen rate used (i.e., less than 0.2 g·kg^-1), the flower and leaf biomass allocation increased with the increasing nitrogen rates. 4) Across different cultivars and nitrogen application rates, plant biomass was positively correlated to the maximum net photosynthetic rate, plant height, ground diameter, and specific leaf area, respectively. These results provided valuable information for the nutrition management of different quinoa cultivars.