To elucidate the mechanisms underlying the differences in yield formation among two parents(P1 and P2) and their F1 hybrid of cucumber, biomass production and whole source–sink dynamics were analyzed using a functio...To elucidate the mechanisms underlying the differences in yield formation among two parents(P1 and P2) and their F1 hybrid of cucumber, biomass production and whole source–sink dynamics were analyzed using a functional–structural plant model(FSPM) that simulates both the number and size of individual organs. Observations of plant development and organ biomass were recorded throughout the growth periods of the plants. The GreenLab Model was used to analyze the differences in fruit setting, organ expansion, biomass production and biomass allocation. The source–sink parameters were estimated from the experimental measurements. Moreover, a particle swarm optimization algorithm(PSO) was applied to analyze whether the fruit setting is related to the source–sink ratio. The results showed that the internal source–sink ratio increased in the vegetative stage and reached a peak until the first fruit setting. The high yield of hybrid F1 is the compound result of both fruit setting and the internal source–sink ratio. The optimization results also revealed that the incremental changes in fruit weight result from the increases in sink strength and proportion of plant biomass allocation for fruits. The model-aided analysis revealed that heterosis is a result of a delicate compromise between fruit setting and fruit sink strength. The organlevel model may provide a computational approach to define the target of breeding by combination with a genetic model.展开更多
为客观全面地分析农业土壤N_(2)O排放影响因素领域的研究动态、热点及发展脉络,利用Web of Science数据库中1978~2018年的文献信息,结合R语言文献计量分析方法,从高被引论文、关键词及历史直接引文三个方面对农业土壤N_(2)O排放影响因...为客观全面地分析农业土壤N_(2)O排放影响因素领域的研究动态、热点及发展脉络,利用Web of Science数据库中1978~2018年的文献信息,结合R语言文献计量分析方法,从高被引论文、关键词及历史直接引文三个方面对农业土壤N_(2)O排放影响因素研究情况进行了系统的文献计量分析。结果表明:(1)农业土壤N_(2)O排放的影响因素主要有四大类:土壤性质包括土壤类型、质地、pH、温度、水分、容重、氧化还原电位、O2、矿质氮(硝态氮+铵态氮)、有机碳、酶活性(主要是硝酸还原酶和亚硝酸还原酶等)和微生物多样性等;农艺管理措施包括施肥管理(肥料类型、施肥量、施肥时间、施肥方式、肥料形态等)、种植作物类型、播种时间、耕作制度、灌溉制度、秸秆还田、生物炭和硝化抑制剂使用、土地利用方式及变化等;气候条件(雪、霜、降水、气温和太阳有效辐射等);地下水位和生态系统氮饱和度等。(2)该领域的研究热点在宏观层面上包括利用模型估算全球、国家、区域尺度上的N_(2)O排放清单,评价切实有效的农业N_(2)O减排措施效果;在中、微观尺度上,主要通过田间或室内培养试验用土壤理化性质及微生物指标反映、研究各影响因素变化(主要为单一因素研究)对N_(2)O排放的效应。(3)该领域研究经历了影响因素从土壤性质再到人为活动的过程,研究内容包括使用模型研究农业土壤N_(2)O排放过程、机制,估算大尺度多因素条件下的农业土壤N_(2)O排放清单及减排措施效果。(4)农艺管理措施包括施用硝化抑制剂、包膜肥料、生物炭和秸秆还田,这些措施均可有效地减少农业土壤N_(2)O排放,但每一措施的效果因具体条件而不同。(5)未来农业土壤N_(2)O排放研究将向整合多因素、多尺度、多层次方向发展,其重点仍为明确农业土壤N_(2)O排放机制、影响因素的相对重要性以及不同减排措施的效应,进而为因地制宜地制定科学有效的农业土壤N_(2)O减排措施提供支持。展开更多
基金This work was supported by the National Natural Science Foundation of China(31700315 and 61533019)the Natural Science Foundation of Chongqing,China(cstc2018jcyjAX0587)+1 种基金the Chinese Academy of Science(CAS)-Thailand National Science and Technology Development Agency(NSTDA)Joint Research Program(GJHZ2076)The authors thank Wang Qian and Mory Diakite for their assistance in the experiment.
文摘To elucidate the mechanisms underlying the differences in yield formation among two parents(P1 and P2) and their F1 hybrid of cucumber, biomass production and whole source–sink dynamics were analyzed using a functional–structural plant model(FSPM) that simulates both the number and size of individual organs. Observations of plant development and organ biomass were recorded throughout the growth periods of the plants. The GreenLab Model was used to analyze the differences in fruit setting, organ expansion, biomass production and biomass allocation. The source–sink parameters were estimated from the experimental measurements. Moreover, a particle swarm optimization algorithm(PSO) was applied to analyze whether the fruit setting is related to the source–sink ratio. The results showed that the internal source–sink ratio increased in the vegetative stage and reached a peak until the first fruit setting. The high yield of hybrid F1 is the compound result of both fruit setting and the internal source–sink ratio. The optimization results also revealed that the incremental changes in fruit weight result from the increases in sink strength and proportion of plant biomass allocation for fruits. The model-aided analysis revealed that heterosis is a result of a delicate compromise between fruit setting and fruit sink strength. The organlevel model may provide a computational approach to define the target of breeding by combination with a genetic model.
文摘为客观全面地分析农业土壤N_(2)O排放影响因素领域的研究动态、热点及发展脉络,利用Web of Science数据库中1978~2018年的文献信息,结合R语言文献计量分析方法,从高被引论文、关键词及历史直接引文三个方面对农业土壤N_(2)O排放影响因素研究情况进行了系统的文献计量分析。结果表明:(1)农业土壤N_(2)O排放的影响因素主要有四大类:土壤性质包括土壤类型、质地、pH、温度、水分、容重、氧化还原电位、O2、矿质氮(硝态氮+铵态氮)、有机碳、酶活性(主要是硝酸还原酶和亚硝酸还原酶等)和微生物多样性等;农艺管理措施包括施肥管理(肥料类型、施肥量、施肥时间、施肥方式、肥料形态等)、种植作物类型、播种时间、耕作制度、灌溉制度、秸秆还田、生物炭和硝化抑制剂使用、土地利用方式及变化等;气候条件(雪、霜、降水、气温和太阳有效辐射等);地下水位和生态系统氮饱和度等。(2)该领域的研究热点在宏观层面上包括利用模型估算全球、国家、区域尺度上的N_(2)O排放清单,评价切实有效的农业N_(2)O减排措施效果;在中、微观尺度上,主要通过田间或室内培养试验用土壤理化性质及微生物指标反映、研究各影响因素变化(主要为单一因素研究)对N_(2)O排放的效应。(3)该领域研究经历了影响因素从土壤性质再到人为活动的过程,研究内容包括使用模型研究农业土壤N_(2)O排放过程、机制,估算大尺度多因素条件下的农业土壤N_(2)O排放清单及减排措施效果。(4)农艺管理措施包括施用硝化抑制剂、包膜肥料、生物炭和秸秆还田,这些措施均可有效地减少农业土壤N_(2)O排放,但每一措施的效果因具体条件而不同。(5)未来农业土壤N_(2)O排放研究将向整合多因素、多尺度、多层次方向发展,其重点仍为明确农业土壤N_(2)O排放机制、影响因素的相对重要性以及不同减排措施的效应,进而为因地制宜地制定科学有效的农业土壤N_(2)O减排措施提供支持。
