大气CO2浓度和气温升高对谷子生长及产量的影响

Effects of Elevated Atmospheric CO2 Concentration and Temperature on the Growth and Yield of Millet

研究大气CO2浓度和气温升高对谷子的影响,有助于人们了解未来气候变化背景下谷子(Setaria italica)生产的变化,以提前采取必要的应对措施。采用控制系统来模拟气温升高2℃和CO2浓度增加200μmol·mol−1的未来气候情景,研究气候变化对谷子光合及产量的影响。试验设对照(与室外气温、CO2浓度一致,CK)、增温2℃(C0T1)、CO2浓度增加200μmol·mol−1(C1T0)和增温2℃+CO2浓度增加200μmol·mol−1(C1T1)4个处理,对谷子灌浆期的光合作用及成熟期形态指标、生物量和产量进行测定。结果表明,与对照相比,气温升高(C0T1)后,谷子叶片净光合速率无明显变化,气孔导度和蒸腾速率上升,水分利用率下降;大气CO2浓度升高(C1T0)谷子叶片净光合速率升高,气孔导度和蒸腾速率下降,水分利用率提高;大气CO2浓度和气温同时升高(C1T1)后,谷子净光合速率提高,气孔导度和蒸腾速率升高,水分利用率下降。与对照相比,气温升高(C0T1)显著增加谷子的株高、穗长、茎直径、叶质量、茎质量、穗质量、地上部分生物量和产量,分别增加了62.29%、63.51%、59.87%、73%、77%、70%、72.3%和76.6%;大气CO2浓度升高(C1T0)显著增加谷子的株高、穗长、茎直径、节数、叶质量、茎质量、穗质量和地上部分生物量,比对照分别增加35.18%、32.75%、25.80%、21.54%、21.5%、70.8%、19.4%和32.3%;升温和升CO2复合处理(C1T1)条件下,谷子株高、穗长、茎直径、叶质量、茎质量、穗质量、地上部分生物量和产量升高,与对照相比分别增加58.24%、42.69%、131.89%、34.8%、80%、77.6%和92.6%。未来气候变化对谷子生长发育将以正效应为主。

Research on millet response to elevated atmospheric CO2 concentration and temperature is critical for understanding the changes in millet yield under future climate change and designing appropriate adaptation measures.We examined the photosynthesis,growth and yield of millet using controlled gas chamber under elevated CO2 concentration by 200μmol·mol−1 and temperature by 2℃.There were four treatments with three replications:(1)CK:with the ambient temperature and CO2 concentration;(2)C0T1:with 2℃temperature increase and ambient CO2 concentration;(3)C1T0:with 200 ppm CO2 concentration elevation and ambient temperature;And(4)C1T1:with 2℃temperature increase and 200μmol·mol−1 CO2 concentration elevation.The photosynthetic parameters at the filling stage,morphological indexes,biomass and yield at the maturity stage of millet were measured.Under treatment C0T1,stomatal conductance(Gs)and transpiration rate(Tr),were significantly increased but water use efficiency(WUE)significantly decreased.Treatment C0T1 significantly increased stomatal conductance(Gs)and transpiration rate(Tr)but decreased water use efficiency(WUE),while the net photosynthetic rate(Pn)of millet remained similar to CK.Treatment C1T0 significantly increased the net photosynthetic rate(Pn)and water use efficiency(WUE),but decreased stomatal conductance(Gs)and the transpiration rate(Tr).Treatment C1T1 significantly increased the net photosynthetic rate(Pn),stomatal conductance(Gs)and transpiration rate(Tr),but decreased the water use efficiency(WUE).The plant height,panicle length,stem thickness,leaf mass,stem mass,panicle mass,biomass and yield of millet were 62.3%,63.5%,59.9%,73.0%,77.0%,70.0%,72.3%and 76.6%higher under treatment C0T1 than CK,respectively.Treatment C1T0 significantly increased the plant height,panicle length,stem diameter,node number,leaf mass,stem mass,panicle mass and above-ground biomass by 35.2%,32.8%,25.8%,21.5%,21.5%,70.8%,19.4%and 32.3%compared with CK,respectively.Compared with CK,treatment C1T1 significantly increased plant height,panicle length,stem thickness,leaf mass,stem mass,panicle mass,above-ground biomass and yield by 58.2%,42.7%,131.9%,34.8%,80.0%,77.6%and 92.6%.Future atmospheric CO2 level and temperature will positively affect the growth and development of millet.