提高密度对根冠发育及其产量的影响研究

Studies on the Effect of Density on the Root-shoot Relationship and Yield in Maize

试验于2009-2010年在吉林省中国农科院公主岭试验站进行。以耐密玉米品种郑单958(ZD)和先玉335(XY)为材料,采用2种密度(52 500株/hm2(LD)和82 500株/hm2(HD))研究了不同处理单株和群体形态和生理指标的变化动态,通过田间根系挖掘的方法研究了根系性状在不同土层的分布状况和根冠比例关系。结果表明,随着密度增高单株性状变劣而群体质量提高,群体的叶面积和干物量显著增加。与低密度相比,高密度下根系分布呈现"横向紧缩、纵向扩展"的趋势。高密度下根长密度(RLD)显著增加,对各土层的水肥资源利用能力增强。根冠比是品种的特征性状,在同一时期不随密度改变而改变,不同品种有其适合的密度,先玉335的耐密性优于郑单958。根据研究结果,将东北春玉米从目前的52 500株/hm2提高到82 500株/hm2是可行的。研究阐明了高密度下高产玉米的生理基础,并对高产玉米栽培具有重要意义。

Experiment was conducted at Gongzhuling experimental station of Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Gongzhuling, Jilin Province during 2009 -2010. Changes of plant and population morphological and physiological index were measured using maize hybrids Zhengdan958 （ZD）and Xianyu335 （XY） as experimental materials under 52500 plants/ha （LD） and 82500 plants/ha （HD） conditions. Root characteristics distribution among soil layers and the relationships between shoot and roots were also studied by the field root dig- ging method. The results showed that plant character index decreased but the population quality increased with the densities. There were significant increases in population leaf areas and biomass. Root distribution showed a trend of horizontal contraction and vertical extension under high density conditions compared with low density. Root length density （RLD） was significantly bigger than that of low density population, so the water and nutrition resources could be absorbed more efficiently under high density conditions. Shoot-root ratio was a character of hybrid and it did not change with density at a certain growing stage. Different varieties had their own optimal density, Xianyu335 was more suitable to high density than Zhengdan958 under this experimental conditions. Based on the result of the ex- periment it was possible to improve the current maize planting density of 52500 plants/ha to 82500 plants/ha in North-east maize production area. This experiment elucidated the mechanism of high-yield under high density condi- tions,and it is also of a great meaning for high-yielding maize production.