| 摘要: |
| 为探求不同行距配置下高密夏玉米群体光合性能及产量形成对群体光环境变化的响应,本试验在75 000 (D1)和90 000 (D2)株/hm2 2个种植密度下,研究了3个行距配置(等行距S1:60 cm+60 cm;大宽窄行S2:80 cm+40 cm;小宽窄行S3:60 cm+45 cm)对夏玉米(郑单958)群体光分布、全株叶片光合特性及产量的影响。结果表明:1)随着种植密度增加,夏玉米群体上层光截获显著增加,下层光截获显著降低。与等行距相比,大宽窄行处理中下层透光率增加,但群体光总截获降低。小宽窄行处理显著增加了穗位层的光截获。2)全株叶片SPAD值、最大光能转换效率(Fv/Fm)和同一光照水平下净光合速率(Photosynthetic rate,Pn)随冠层垂直深入呈现出单峰曲线变化,峰值出现在穗位层;随密度增加全株叶片SPAD值、Fv/Fm和Pn呈现降低趋势,下部叶片降低显著,行距配置之间全株叶片光合生理活性总体上表现为小宽窄行 >大宽窄行 >等行距。叶片Pn与冠层内光照强度具有极显著正相关关系,表明光照强度是限制玉米冠层中下部叶片Pn的主要原因。3)密度增大后产量增加,但未达显著水平。同一密度处理下,小宽窄行处理产量显著增加。随着密度增加,宽窄行增产效应增加。总体表明,密植条件下,小宽窄行处理下玉米冠层内光分布比较合理,群体穗位层截获光合有效辐射较多,光合能力和干物质生产能力增强,更有利于夏玉米产量提高。 |
| 关键词: 夏玉米 光照强度 光分布 叶绿素荧光 净光合速率 |
| DOI：10.11841/j.issn.1007-4333.2015.06.02 |
| 投稿时间：2015-03-08 |
| 基金项目:国家现代产业技术体系建设专项(CARS-02-26); 公益性行业(农业)科研专项(201203031) |
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| Effects of high planting density and row spacing on canopy light distribution and photosynthetic characteristics of summer maize |
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GAO Ying-bo, TAO Hong-bin, HUANG Shou-bing, TIAN Bei-jing, WANG Li-jun, Li Yun, REN Jian-hong, WANG Pu
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| (College of Agronomy and Biotechnology/Key Laboratory of Farming System, Ministry of Agriculture, China Agricultural University, Beijing 100193, China) |
| Abstract: |
| The plant distribution within the field determined the canopy characters and light interception of canopy,which directly related to photosynthesis capacity and affect the grain yield of summer maize in the end.A 2-year field trial was conducted at Wuqiao Experimental Station of China Agricultural University in Hebei Province to clarify the effect of canopy character on light interception and yield formation of summer maize.The experiment was a split-plot design with planting density as main factor and row spacing as minor factor.Two planting densities were 75 000 and 90 000 plant/hm2 respectively.Under each planting density,three row spacing were set up as uniform row spacing of 60 cm,un-even row spacing of 80 cm+40 cm,and un-even row spacing of 60 cm+45 cm.Light distribution,leaf photosynthesis of whole plant,and yield were measured.The results indicated that:1) light interception at upper canopy layer was significantly increased with the increase of planting density.Moreover,light interception of whole canopy was less in un-even row spacing of 80 cm+40 cm with an increment of transmittance,while light interception from 14th to 17th leaf was greater in uneven row spacing of 60 cm+45 cm as compared with uniform row spacing; 2) SPAD value,Fv/Fm,and Pn of single leaf in whole plant were decreased except top leaf and ear leaf.In addition,all these parameters decreased with the increase of planting density,specifically for lower leaf positions.Generally,whole plant photosynthesis under uneven row spacing of 60 cm+45 cm was the greatest,while that under uniform row spacing of 60 cm was the least;3) Grain yield slightly increased with the increase of planting density.Grain yield increased significantly under uneven row spacing of 60 cm+45 cm as compared to uniform row spacing of 60 cm under both plant densities.In conclusion,uneven row spacing of 60 cm+45 cm is suitable for improving yield at high plant density,as a consequence of reasonable light distribution and interception by canopy. |
| Key words: summer maize light intensity light distribution chlorophyll fluorescence photosynthetic rate |
