Jin Jian, Li Yansheng, Liu Xiaobing, Wang Guanghua, Tang Caixian, Yu Zhenhua, Wang Xiaojuan, Herbert Stephen J
Key Laboratory of Mollisols Agroecology, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Harbin, China.
Centre for AgriBioscience, La Trobe University, Melbourne Campus, Bundoora, Vic, Australia.
PLoS One. 2017 May 1;12(5):e0176688. doi: 10.1371/journal.pone.0176688. eCollection 2017.
Understanding how elevated CO2 affects dynamics of nodal leaf growth and N assimilation is crucial for the construction of high-yielding canopy via breeding and N management to cope with the future climate change. Two soybean cultivars were grown in two Mollisols differing in soil organic carbon (SOC), and exposed to ambient CO2 (380 ppm) or elevated CO2 (580 ppm) throughout the growth stages. Elevated CO2 induced 4-5 more nodes, and nearly doubled the number of branches. Leaf area duration at the upper nodes from R5 to R6 was 4.3-fold greater and that on branches 2.4-fold higher under elevated CO2 than ambient CO2, irrespective of cultivar and soil type. As a result, elevated CO2 markedly increased the number of pods and seeds at these corresponding positions. The yield response to elevated CO2 varied between the cultivars but not soils. The cultivar-specific response was likely attributed to N content per unit leaf area, the capacity of C sink in seeds and N assimilation. Elevated CO2 did not change protein concentration in seeds of either cultivar. These results indicate that elevated CO2 increases leaf area towards the upper nodes and branches which in turn contributes yield increase.
了解高浓度二氧化碳如何影响主茎节间叶片生长和氮同化动态，对于通过育种和氮管理构建高产冠层以应对未来气候变化至关重要。在两种土壤有机碳（SOC）含量不同的软土中种植了两个大豆品种，并在整个生长阶段将其暴露于环境二氧化碳（380 ppm）或高浓度二氧化碳（580 ppm）环境中。高浓度二氧化碳诱导多出4 - 5个节间，枝条数量几乎翻倍。无论品种和土壤类型如何，在高浓度二氧化碳条件下，从R5到R6阶段主茎上部节间的叶面积持续时间比环境二氧化碳条件下大4.3倍，枝条上的叶面积持续时间大2.4倍。结果，高浓度二氧化碳显著增加了这些相应位置的荚果和种子数量。高浓度二氧化碳对产量的响应在品种间存在差异，但在土壤间无差异。品种特异性响应可能归因于单位叶面积氮含量、种子碳库容量和氮同化能力。高浓度二氧化碳并未改变两个品种种子中的蛋白质浓度。这些结果表明，高浓度二氧化碳增加了主茎上部节间和枝条的叶面积，进而有助于提高产量。
