Experiment was conducted at the Gongzhuling Experimental Station of Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Jilin Province, China, during 2009-2010. Six representative varieties of maize ...Experiment was conducted at the Gongzhuling Experimental Station of Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Jilin Province, China, during 2009-2010. Six representative varieties of maize （Baihe in the 1950s, Jidan 101 in the 1960s, Zhongdan 2 in the 1970s, Yedan 13 in the 1980s, Zhengdan 958 in the 1990s, and Xianyu 335 in the 2000s） were each planted under two different densities （52 500 and 82 500 plants ha-~） and two different nitrogen application levels （150 and 300 kg ha-l）. Root characteristics and distribution among soil layers were studied by the field root digging method. The results showed that root mass increased with the process of the growth and development of the plant, and it peaked at kernel filling stage, and decreased at maturity due to the root senesces. Root mass of different maize varieties from the 1950s to 1980s had a trend of increase, while it decreased for the modern varieties. Root length and root surface areas had the similar changing trend. The study suggested that early maize varieties may have root redundancy, and reducing root redundancy may be a direction for variety improvement for high yield. Root characteristics were affected by nitrogen application level and density; modern varieties were more suitable for higher fertilizer application level and density conditions. Root characteristics distribution among soil layers decreased by an exponent equation, but the regression coefficients of different varieties were different. Though the root length density （RLD） of every soil layer of different varieties also decreased by an exponent equation, there were large variations of RLD in every part of a layer.展开更多
为了明确不同年代玉米品种的光合和灌浆特性对增加种植密度的响应差异,为玉米合理增密增产提供理论依据。本研究以我国1970s—2010s五个在生产中大面积种植的玉米品种为材料,设置了4.5万株hm^(-2)和10.5万株hm^(-2)两个种植密度,进行3...为了明确不同年代玉米品种的光合和灌浆特性对增加种植密度的响应差异,为玉米合理增密增产提供理论依据。本研究以我国1970s—2010s五个在生产中大面积种植的玉米品种为材料,设置了4.5万株hm^(-2)和10.5万株hm^(-2)两个种植密度,进行3年大田试验。对不同种植密度下,各年代玉米品种的产量及其构成因素、叶片光合性能和籽粒灌浆特性等指标进行对比分析。结果表明,在低种植密度下,2010s品种(登海618,Denghai 618,DH618)吐丝后穗位叶SPAD值、吐丝–吐丝后50 d穗位叶Pn和籽粒平均灌浆速率均较1970s—2000s品种显著提高了2.18~12.05、0.57~4.88μmol CO_(2)m^(-2)s^(-1)和0.02~0.09 g kernel^(-1)d^(-1),活跃灌浆期显著延长了2.62~4.74 d,从而使其粒重和产量显著增加(P<0.05)。增密后,1970s和1980s品种产量降低,1990s品种产量变化不显著,而2000s和2010s品种产量显著增加,且2010s品种产量增加幅度最大,达到2.11 t hm^(-2)。进一步对光合性能、灌浆特性与百粒重和产量等指标的相关分析表明,高种植密度下2010s品种的百粒重对活跃灌浆期依赖程度增大(r=0.70),其在吐丝期、乳熟期和成熟期均较1970s—2000s品种保持相对高的SPAD(提高了6.42%~41.92%),延缓了叶片衰老,使花后玉米叶片仍维持较高的光合势(leaf area duration,LAD)和吐丝后30~50 d的Pn(提高了1.09%~88.95%),从而积累了较多的光合产物,促使活跃灌浆期延长8.73%~15.80%,平均灌浆速率增加了3.39%~24.33%,进而维持了相对稳定的百粒重。展开更多
基金supported by the National Basic Research Program of China (2009CB118605)the National Natural Sciences Foundation of China (31071362)the Key Technologies R&D Program of China during the 12th Five-Year Plan period (2011BAD16B08)
文摘Experiment was conducted at the Gongzhuling Experimental Station of Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Jilin Province, China, during 2009-2010. Six representative varieties of maize （Baihe in the 1950s, Jidan 101 in the 1960s, Zhongdan 2 in the 1970s, Yedan 13 in the 1980s, Zhengdan 958 in the 1990s, and Xianyu 335 in the 2000s） were each planted under two different densities （52 500 and 82 500 plants ha-~） and two different nitrogen application levels （150 and 300 kg ha-l）. Root characteristics and distribution among soil layers were studied by the field root digging method. The results showed that root mass increased with the process of the growth and development of the plant, and it peaked at kernel filling stage, and decreased at maturity due to the root senesces. Root mass of different maize varieties from the 1950s to 1980s had a trend of increase, while it decreased for the modern varieties. Root length and root surface areas had the similar changing trend. The study suggested that early maize varieties may have root redundancy, and reducing root redundancy may be a direction for variety improvement for high yield. Root characteristics were affected by nitrogen application level and density; modern varieties were more suitable for higher fertilizer application level and density conditions. Root characteristics distribution among soil layers decreased by an exponent equation, but the regression coefficients of different varieties were different. Though the root length density （RLD） of every soil layer of different varieties also decreased by an exponent equation, there were large variations of RLD in every part of a layer.
文摘为了明确不同年代玉米品种的光合和灌浆特性对增加种植密度的响应差异,为玉米合理增密增产提供理论依据。本研究以我国1970s—2010s五个在生产中大面积种植的玉米品种为材料,设置了4.5万株hm^(-2)和10.5万株hm^(-2)两个种植密度,进行3年大田试验。对不同种植密度下,各年代玉米品种的产量及其构成因素、叶片光合性能和籽粒灌浆特性等指标进行对比分析。结果表明,在低种植密度下,2010s品种(登海618,Denghai 618,DH618)吐丝后穗位叶SPAD值、吐丝–吐丝后50 d穗位叶Pn和籽粒平均灌浆速率均较1970s—2000s品种显著提高了2.18~12.05、0.57~4.88μmol CO_(2)m^(-2)s^(-1)和0.02~0.09 g kernel^(-1)d^(-1),活跃灌浆期显著延长了2.62~4.74 d,从而使其粒重和产量显著增加(P<0.05)。增密后,1970s和1980s品种产量降低,1990s品种产量变化不显著,而2000s和2010s品种产量显著增加,且2010s品种产量增加幅度最大,达到2.11 t hm^(-2)。进一步对光合性能、灌浆特性与百粒重和产量等指标的相关分析表明,高种植密度下2010s品种的百粒重对活跃灌浆期依赖程度增大(r=0.70),其在吐丝期、乳熟期和成熟期均较1970s—2000s品种保持相对高的SPAD(提高了6.42%~41.92%),延缓了叶片衰老,使花后玉米叶片仍维持较高的光合势(leaf area duration,LAD)和吐丝后30~50 d的Pn(提高了1.09%~88.95%),从而积累了较多的光合产物,促使活跃灌浆期延长8.73%~15.80%,平均灌浆速率增加了3.39%~24.33%,进而维持了相对稳定的百粒重。
