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作 者 ：周宇飞1,史振声1,吕德贵2,王艺陶1,王 娜1*

期 刊 ：西北植物学报 2013年 3期 页码：518~526

关键词：玉米；密度；维管束；伤流；

Keywords:maize, density, vascular bundle, root bleeding sap,

摘 要 ：选用不同耐密性玉米品种‘郑单958’（密植品种）和‘辽单526’（稀植品种）为材料,设置4个不同的密度水平,分别在拔节期和乳熟期采用徒手切片显微观测基部茎秆内部维管束结构变化,采集茎基部伤流液测定其主要成份含量并计算伤流强度,以期为春玉米的密植高产提供理论依据。结果显示:（1）在拔节期,‘郑单958’维管束结构对密度变化反应相对敏感,而‘辽单526’维管束结构在各密度间并无显著差异;当密度最大时,‘辽单526’伤流强度的下降程度要大于‘郑单958’,但两品种伤流液成分对密度反应无明显变化。（2）在乳熟期,密度对‘郑单958’维管束结构无显著影响,而‘辽单526’在密度增加后维管束结构各指标明显下降且与对照（适宜密度）差异显著;各密度‘郑单958’的伤流强度均大于‘辽单526’,增加密度会提高两品种伤流液中可溶性糖的含量,尤其以‘辽单526’增加更显著。（3）在高于对照密度条件下,两品种的籽粒产量都不同程度低于对照,但‘辽单526’产量降低程度要大于‘郑单958’。研究表明,密植性玉米对密度压力的反应要早于稀植性玉米,其在高密度表现出的适应性也要优于稀植性玉米,这从茎基部的结构和功能上揭示了玉米品种耐密性差异的生理基础。

Abstract:Effects of plant densities on basal stem vascular bundles and root bleeding sap of different density-tolerant maize cultivars were studied in order to provide theoretical basis for high-density planting.The density experiment was conducted in the field with a high density-tolerant maize cultivar (‘Zhengdan 958’) and a low density-tolerant maize cultivar (‘Liaodan 526’) as the experimental materials.The vascular bundle structure of the basal stem internodes was observed by microscope through the hand-sliced method.Moreover,the bleeding sap quantity and the main composition content were also analyzed.The results indicated that:(1)At the jointing stage,the structure of vascular bundle in ‘Zhengdan 958’ was relatively sensitive to changes of density,but there was no significant difference of vascular bundle in ‘Liaodan 526’ among densities.The bleeding sap quantity of ‘Liaodan 526’ decreased in larger extents than did ‘Zhengdan 958’ at the highest density and there was no regular changes in composition content of both cultivars with the density increased.(2)At the milking stage,densities significantly affected the structure of vascular bundle in ‘Liaodan 526’ but had no significant effects on it of ‘Zhengdan 958’.With the density increased,indicators of vascular bundle in ‘Liaodan 526’ decreased in evidence compared with the contrast.The bleeding sap quantity of ‘Zhengdan 958’ was larger than that of ‘Liaodan 526’ at all densities.Soluble sugar in root bleeding sap of both cultivars enhanced,especially in ‘Liaodan 526’.(3)The decreasing extents of yield in ‘Liaodan 526’ were larger than that in ‘Zhengdan 958’ when the density exceeded the contrast.Consequently,the response of high density-tolerant maize to changes of plant density was earlier and expressed a better adaptability than density-intolerant maize,which illuminated physiological mechanism for the difference of density tolerance.

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