摘要：【目的】通过比较分析不同钼氮配比处理下两种小麦茎秆形态特征，基部茎节粗细胞壁组分及茎秆力学特征变化，探究钼氮配施对小麦抗倒伏性的影响机制。【方法】以97003（小麦钼高效品种）和97014（小麦钼低效品种）为材料，采用随机区组试验设计，设置4个施氮水平(N 0 kg/hm2，N 120 kg/hm2，N 210 kg/hm2，N 300 kg/hm2) ，3个施钼水平((NH4)2MoO4 0kg/hm2，(NH4)2MoO4 0.75 kg/hm2，(NH4)2MoO4 1.50kg/hm2)，比较不同处理的倒伏率，并从生理学、形态学和力学指标等方面，分析小麦倒伏差异的原因。【结果】1)小麦钼低效品种97014在相同的氮、钼水平下折断处到顶端的距离和弯曲力矩均高于小麦钼高效品种97003；相比不施氮，施氮三水平均可提高两品种小麦上部鲜重和弯曲力矩，其中在氮水平为210 kg N/hm2下差异较为明显，施氮对断面系数和弯曲应力有显著影响，在施氮水平0 kg N/hm2和210 kg N/hm2时，折断弯矩会随着施钼量的增加而增加；2)小麦钼高效品种97003基部节长在各个钼、氮施肥水平下均高于小麦钼低效品种97014，而上部节长和穗长均低于小麦钼低效品种97014；小麦钼高效品种97003的茎秆长短轴外径及长轴内径和穗长均随着施氮水平的增高而增加，小麦钼低效品种97014的茎秆长短轴外径及长轴内径、基部茎长和穗长均随着施氮水平的增高而增加；3)随着氮肥用量的增加，小麦茎秆非结构性碳水化合物显著降低，小麦钼高效品种97003施0.75 kg 钼酸铵/hm2可减少小麦茎秆非结构性碳水化合物量；4)两品种小麦基部纤维素、木质素含量有所差异。小麦钼高效品种97003纤维素、木质素含量在各个处理水平下基本不变，小麦钼低效品种在4个氮水平下配施1.5 kg 钼酸铵/hm2均增加了纤维素含量，在施氮水平210 kg N/hm2和120 kg N/hm2下配施0.75 kg/hm2钼酸铵，基部节间木质素含量下降。【结论】不同钼氮配施量下的2品系冬小麦茎秆主要物理性状优化组合不同，基部节间短而粗，茎壁厚度大，结构性碳水化合物总量增大，茎秆充实程度好，是冬小麦抗折力大、倒伏指数小、增强抗倒伏能力的直接原因。
Abstract: 【Objective】By comparing and analyzing the 2 varieties winter wheat changes of stem morphological characteristics, basal node coarse cell wall composition and stem mechanical characteristics under different molybdenum-nitrogen ratio treatments, to explore the effect of molybdenum and nitrogen combined application on lodging resistance of winter wheat. 【Method】 By using 97003 and 97014 as materials, four nitrogen application levels (N 0 kg/hm2, N120 kg/hm2, N 210 kg/hm2, N 300 kg/hm2) and three Mo application levels ((NH4)2MoO4 0 kg/hm2, (NH4)2MoO4 0.75 kg/hm2 and (NH4)2MoO4 1.5 kg/hm2 were set up to compare the lodging rate of different, and the reasons of wheat lodging difference were analyzed from physiological, morphological and mechanical indexes. 【Result】 1) The distance from the break to the top and the bending moment of the wheat molybdenum low-efficiency cultivar 97014 at the same nitrogen and molybdenum levels were higher than those of the wheat molybdenum high-efficiency cultivar 97003; compared with no nitrogen application, the three levels of nitrogen application could increase both varieties of wheat the upper fresh weight and bending moment, the difference was more obvious when the nitrogen level was 210 kg N/hm2, nitrogen application had a significant effect on the section coefficient and bending stress. The nitrogen level was 0 kg N/hm2 and 210 kg N/hm2 , the bending moment would increase as the amount of molybdenum applied increases; 2) The basal node length of wheat variety 97003 was higher than that of wheat variety 97014 under all Mo and N fertilization levels, while the upper node length and ear length were lower than that of wheat variety 97014; the outer diameter of long axis and the inner diameter of long axis and ear length of wheat molybdenum efficient variety 97003 increased with the increase of nitrogen application level In addition, the outer diameter and inner diameter of long axis, basal stem length and ear length of wheat variety 97014 increased with the increase of nitrogen application level; 3) With the increase of nitrogen application rate, the non structural carbohydrate of wheat stem decreased significantly, and the application of (NH4)2MoO4 1.5 kg/hm2 efficient wheat variety 97003 was observed Ammonium Molybdate / hm2 can reduce the amount of non structural carbohydrate in wheat stem; 4) The cellulose and lignin content in the base of two wheat varieties were different. The cellulose and lignin contents of 97003 wheat variety with high molybdenum efficiency were basically unchanged under all treatment levels. The cellulose content of wheat variety 97003 with low molybdenum efficiency was increased by applying (NH4)2MoO4 1.5 kg/hm2 under four nitrogen levels. The lignin content of basal internode decreased when 0.75 kg/hm2 (NH4)2MoO4 was applied at 210 kg N/hm2 and 120 kg N/ hm2 . 【Conclusion】 The optimal combination of the main physical properties of the two winter wheat lines under different Mo and N application rates were different. The short and thick basal internode, large stem wall thickness, increased total amount of structural carbohydrates and good stalk plumpness were the direct reasons for the high bending resistance, small lodging index and enhanced lodging resistance of winter wheat.