| 摘要: |
| 【目的】探究深松增密对不同类型玉米品种冠层结构及其光合特性的影响，为进一步提升玉米综合生产力提供理论依据。【方法】2015-2016年，在大田条件下，采用再裂区试验设计，以耕作方式（常规浅旋15 cm(RT)和深松40 cm(SS)）为主区，密度（82 500株/hm2(D1)，105 000株/hm2(D2)）为副区，不同类型玉米品种为副副区，测定了不同类型玉米品种群体叶面积指数和冠层透光率、植株形态、光合特性、产量等指标，研究不同耕作方式和种植密度条件下上述指标的变化情况。【结果】深松增密显著提高耐密玉米品种产量，增产11.9%～14.7%，非耐密品种增产-8.1%～0.6%；耐密品种产量对深松增密的响应程度显著高于非耐密品种，耐密品种主要通过增穗数、保粒数、稳粒重来实现增密增产。深松耕作能有效缓解增密产生的簇拥效应，提高植株叶片的自我调节能力；降低增密后茎粗变小的趋势，增加穗上茎节长度，缓解株型的变化，耐密品种缓解作用高于非耐密品种。增密后，深松耕作能延缓玉米生育后期LAI和穗位层透光率的下降速率以及叶片衰老程度，降低净光合速率的下降幅度，吐丝期后耐密品种叶片叶绿素相对含量和Pn高于非耐密品种。【结论】耐密玉米品种对增密后产生的形态和生理上的变化有更强适应能力，增密后深松耕作使耐密玉米品种能长时间维持较高的LAI，延缓叶片衰老程度，保证充足的光合面积，稳定较高的净光合速率，有利于植株进行光合生产，获得较高产量。 |
| 关键词: 春玉米 耐密性 冠层结构 光合特性 深松耕作 种植密度 |
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| 基金项目:国家自然科学基金项目(31560360)；国家玉米产业技术体系项目(CARS-02-63)；华北黄土高原地区作物栽培科学观测实验站项目(25204120)；国家重点研发计划项目(2017YFD0300800，2017YFD0300804) |
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| Response of canopy structure and photosynthetic characteristics of different maize varieties to subsoiling tillage and increasing density |
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WANG Fugui,YU Xiaofang,GAO Julin,et al
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| Abstract: |
| 【Objective】This experiment studied the effect of subsoiling and increasing density on canopy structure and photosynthetic characteristics of spring maize varieties to provide basis for further raising overall productivity of spring maize varieties.【Method】The field experiment was designed based on split-split plot with 2 main tillage practices (15 cm deep,conventional rotary tillage (RT) and 40 cm deep,strip-subsoiling(SS)),2 split plant densities (82 500 plant/hm2 (D1) and 105 000 plant/hm2(D2)),and different sub-split for maize varieties.LAI,canopy percent transmittance,plant morphological trait,photosynthetic characteristic and yield were determined in 2015 and 2016,and the changes of these indexes were analyzed.【Result】Strip-subsoiling and increasing density improved the yield of density tolerant maize varieties by 11.9%-14.7%,while changed the yield of density sensitive varieties by -8.1%-0.6% yield increasing.The response of density tolerant varieties was much larger than that of density sensitive varieties.The density tolerant varieties increased yield mainly by increasing spike number,preserved grain number,and stabled grain weight.Subsoiling tillage can effectively alleviate the crowding effect,and improve leaf self-adjustment ability.It also reduced tendency of stem diameter decreasing after density increase,increased the internode length above ear,and relieved plant morphological changing.The density tolerant varieties had larger relieving ability than other varieties.After density increase,subsoiling can alleviate the decrease of LAI and canopy percent transmittance in ear position,delay leaf senescence,and slow the decreasing rate of Pn.After the silking stage,the density tolerant varieties had higher SPAD and Pn than density sensitive varieties.【Conclusion】Density tolerant maize varieties had stronger adaptable ability of morphological and physiological changes after density increase.Subsoiling tillage after density increase can increase maize yield by maintaining high LAI for longer time,delaying leaf senescence,ensuring photosynthetic area,and stabilizing high net photosynthesis. |
| Key words: spring maize density tolerance canopy structure photosynthetic characteristics subsoiling tillage planting density |
