夏玉米果穗不同部位小穗轴维管束显微结构特点及其对子粒发育的影响

Microstructure of Rachilla Vascular Bundles at Different Positions of the Summer Maize Ear and Its Influence on the Dry Weight of Grain

采用大田试验,设置不同种植密度,选用不同类型玉米品种,研究果穗小穗轴维管束的解剖结构变化及其与不同部位子粒干重的关系。结果表明,正常情况下,小穗轴维管束的韧皮部发达,且其"喇叭"结构十分有利于子粒灌浆,败育子粒的小穗轴维管束则发育不良;相同粒位,ZD958的小穗轴维管束面积显著大于ND08的小穗轴维管束面积;两个品种的小穗轴维管束面积均随密度增加而降低;小穗轴维管束的面积受密度影响较大,但受基因(品种)影响更大。耐密性品种在较高密度下小穗轴维管束的结构仍然正常,其面积虽然也减少但不足以成为灌浆障碍,这也是其获得高产的原因之一。因此,在品种选育上,应优选小穗轴维管束面积较大的材料。

The experiment adopted the field trials, set different planting density, and chose different types of maize varieties to study the mierostrueture of raehilla vascular bundles at different positions of the summer maize ear and its relationship with the dry weight of grain. The results showed that, normally, the phloem of rachilla vascu- lar bundle was developed, and the ＂horn＂ structure was conducive to the grain-filling, and the rachilla vascular bun- dle of abortive grain was stunted. The rachilla vascular bundle area of ZD958 significantly greater than the ND 108＇; Both varieties of rachilla vascular bundle area decreased with increasing density; The area of rachilla vascular bun- dle was greatly influenced by the density, but had been affected more by gene（varieties）. The structure of rachilla vascular bundle under the higher density was still normal, although the area was to reduce but not enough to be an obstacle to the grouting. This was one of the reasons for its high-yield. Therefore, in variety breeding, we should pre- fer the materials with larger rachilla vascular bundle.