中文摘要：

【目的】研究群体密度对玉米茎秆可溶性碳水化合物及矿质元素含量的影响,探讨其与茎秆强度的相关性,以揭示玉米的抗倒伏机制,为玉米抗倒伏高产栽培和育种提供理论依据。【方法】以抗倒伏性能不同的2个玉米品种先玉420（抗倒伏性差）和益丰29（抗倒伏性强）为试验材料,设定5,6,7,8,9,10,11万株/hm2共7个群体密度处理,分别在抽雄期（07-23）和灌浆初期（08-05）,测定玉米基部向上第3、4、5节可溶性糖、淀粉、矿质元素（N、K、Si、Ca、Mg、Zn）和茎秆强度,同时分析茎秆强度与可溶性糖、淀粉和矿质元素含量的相关性。【结果】随着群体密度的增加,2个玉米品种第3~5节可溶性糖、淀粉、矿质元素含量和茎秆强度均呈现先增加后降低的变化趋势,茎秆各项指标的最高值因品种、节间和生育时期的不同而差异明显。在同一生育时期同一群体密度下,益丰29 3个节平均各项指标均高于先玉420,第3和4节各项指标随群体密度的变化较第5节敏感;各节间相比,2个玉米品种第3、4节矿质元素含量均高于第5节。相关分析表明,不同生育时期玉米各节间茎秆强度与可溶性糖、淀粉和矿质元素含量的相关性不同,但各节间茎秆强度均与Si含量呈极显著正相关。【结论】过高的群体密度会影响茎秆基部各节间可溶性碳水化合物和矿质元素的含量,进而影响其抗倒伏性能。在实际生产中,应在因地制宜、合理密植的基础上,于灌浆前期适当喷施叶面肥或追施微量元素肥料,以提高玉米的抗倒伏能力。

英文摘要：

[Objective] The influences of population density on carbohydrate and mineral elements con- tents in stalk of maize and the correlation with stalk strength were studied to reveal lodging mechanism for maize. [Method] In this research,Xianyu 420 and Yifeng 29 with different lodging-resistances were used as the test material and seven density treatments （5,6,7,8,9,10 and 11 ten thousand plants/hm2） were ap- plied. At the tasseling stage （07-23） and filling stage （08-05）, stalk strength,contents of soluble sugar, starch and mineral elements （nitrogen （N）, potassium （K）, silicon （Si）, calcium （Ca）, magnesium （Mg）, and Zinc （Zn）） were measured in different internodes above basal part of stalk. At last,the relation be- tween stalk strength and measured indexes were analyzed. [Result] Stalk strength, contents of soluble sug- ar,starch and mineral elements in 3th, 4th, and 5th internodes increased first and then decreased with the increase of population density. In the treatments with same density and growth stages,all indexes of Yifeng 29 were higher than those of Xianyu 420. Indexes of 3th and 4th internodes were more sensitive to popula- tion density than 5th internode. The mineral elements contents of the 3th and 4th internodes were higher than those of the 5th internode. Correlation analysis showed the relationship between the stalk strength and contents of soluble sugar,starch and mineral elements were different at different growth stages. The stalk strength was positively correlated with Si content. [Conclusion] High density could influence carbohydrate and mineral elements of stalk, and then the lodging-resistance. To improve the lodging-resistance, foliage fertilizer or additional trace elements should be applied.