Abstract:

【Objective】To study the effects of nitrogen forms and variety on root morphology and nitrogen accumulation of cotton, and explore the interaction mechanism between variety and nitrogen forms in the hope of providing a theoretical basis for the rational selection of nitrogen fertilizer form and variety in cotton.【Methods】The experiment was conducted in the incubation room of the Agricultural Science Building of Xinjiang Agricultural University in 2020. Two varieties (Xinluzao 45 and Xinluzao 48 ) and four fertilization treatments ( no nitrogen fertilizer (CK), urea (N₁ ), ammonium sulfate (N₂), and calcium nitrate (N₃) ) were set in the completely randomized root-box culture experiment. The nitrogen fertilizer application rate was 300 kg/hm². Samples were collected 90 days after sowing to determine the root morphological parameters and nitrogen accumulation.【Results】The order of cotton root morphology and nitrogen accumulation was N₃ > N₁ > N₂ > CK. The root morphology parameters (total root length, dry matter weight (P<0.05), surface area, volume), root, stem, leaf (P<0.05) and plant nitrogen accumulation of N₃ treatment were significantly higher than those of N₂ and CK treatment (P<0.01), which increased by 24.66%, 33.93%, 19.61%, 18.57% and 52.64%, 50.95%, 16.20%, 28.09%, respectively. Compared with CK treatment, the average increase was 40.57%, 61.09%, 38.65%, 33.31% and 103.02%, 119.59%, 57.40%, 76.12%, respectively, and there was no significant difference between processing ways of N₁ and N₃. There were no remarkable differences between interactive function of root forms and nitrogen accumulation which are acted by cotton variety and nitrogen form. The total root length and root volume of Xinluzao 48 were significantly higher than those of Xinluzao 45 (P<0.01), with an average increase of 9.16% and 7.01%, respectively. The nitrogen accumulation in roots, stems (P<0.05), leaves and plants was also significantly higher than that of Xinluzao 45 (P<0.01), with an average increase of 15.28%, 7.75%, 9.55% and 9.86%, respectively. Xinluzao 45 root-shoot ratio of CK treatment and specific root length of N₂ treatment, was significantly lower than other treatments, Xinluzao 48 root-shoot ratio and specific root length were not significantly different between the treatments.【Conclusion】Nitrate nitrogen fertilizer is more conducive to cotton root morphological development and nitrogen accumulation than urea and ammonium nitrogen fertilizer. The total root length, root volume and plant nitrogen accumulation of Xinluzao 48 are significantly higher than those of Xinluzao 45, and there is no significant difference in root-shoot ratio and specific root length among different treatments, indicating that the variety had obvious advantages.

Key words: nitrogen forms; varieties; cotton; roots; nitrogen accumulation

摘要：

【目的】研究氮肥形态和品种对棉花根系形态与氮素积累量的影响,分析品种与氮肥形态的互作机制,为棉花合理选择氮肥形态和品种提供理论基础。【方法】试验于2020年设在新疆农业大学农科楼培养室,设置2个品种(新陆早45号和新陆早48号)与4个施肥处理(不施氮肥(CK)、施尿素(N₁)、施硫酸铵(N₂)、施硝酸钙(N₃))双因素完全随机根箱培养试验,氮肥施用量为300 kg/hm²,播种后90 d采样,测定根系形态参数指标和氮素积累量。【结果】棉花根系形态和氮素积累量变化规律为N₃>N₁>N₂>CK,N₃处理的根系形态参数(总根长、干物质质量(P<0.05)、表面积、体积)和根部、茎部、叶部(P<0.05)和植株氮素积累量显著高于N₂和CK处理(P<0.01),比N₂分别平均提升24.66%、33.93%、19.61%、18.57%和52.64%、50.95%、16.20%、28.09%,比CK处理分别平均提升40.57%、61.09%、38.65%、33.31%和103.02%、119.59%、57.40%、76.12%,与N₁处理无显著性差异。棉花品种和氮素形态对根系形态与氮素积累的交互作用无显著性差异。新陆早48号的根系总根长、根系体积显著高于新陆早45号(P<0.01),分别平均提升9.16%和7.01%,根部、茎部(P<0.05)、叶部和植株的氮素积累量也显著高于新陆早45号(P<0.01),分别平均提升15.28%、7.75%、9.55%和9.86%。新陆早45号根冠比的CK处理和比根长的N₂处理,显著低于其他处理,新陆早48号根冠比和比根长各处理之间无显著性差异。【结论】硝态氮肥比尿素和铵态氮肥更利于棉花根系形态发育和氮素积累量的增加。新陆早48号根系总根长、根系体积和植物氮素积累量显著高于新陆早45号,且根冠比与比根长在不同处理间无显著性差异,品种优势明显。

关键词: 氮肥形态, 品种, 棉花, 根系, 氮素积累