增温和土壤肥力对大豆光合特征和产量的影响

Effects of Elevated Temperature and Soil Fertility on Photosynthetic Characteristics and Yield of Soybean

面对全球变暖的大背景,研究增温对大豆生长的影响,以期为大豆生产应对未来气候变化提供理论依据。选取高肥力和低肥力2个土壤类型,采用开放式增温系统,设置常温(aT)和增温(eT)处理,以‘金大豆626’为供试品种,探究增温对大豆三叶期、开花期和鼓粒期叶绿素含量、光合特性和产量的影响。结果表明:在三叶期,增温使高肥力土壤上大豆叶片P(n光合速率)、G(s气孔导度)和T(r蒸腾速率)较对照分别下降了21.3%、36.7%、17.4%,低肥力土壤上大豆SPAD值(叶绿素)较对照提高了15.1%,而Pn下降了11.4%;在开花期,增温使高肥力土壤上叶片SPAD值提高了24.0%,而Pn、G_(s)、C(i胞间CO_(2)浓度)和T(r蒸腾速率)较对照均显著下降,低肥力土壤上大豆叶片G_(s)、C_(i)和T_(r)较对照也均显著下降;在鼓粒期,与对照相比,增温使高肥力土壤上的大豆叶片Pn、G_(s)和T_(r)分别提高了25.6%、55.5%和33.8%,而低肥力土壤上分别下降了42.4%、58.7%和56.1%。增温使高肥力土壤上的大豆较对照增产23.3%,而低肥力土壤上却减产10.9%。总体表明,大豆鼓粒期的光合能力是限制产量形成的关键要素,尤其在高肥力土壤上可以弥补生育前中期光合速率的不足,最终提高产量。因此,可以通过适当提高土壤肥力来增强大豆对未来气候变暖的适应能力。

In face of global warming,the effect of elevated temperature on soybean growth was studied to provide theoretical basis for soybean production responding to future climate change.Two soil types,high and low fertility,were selected to study the effects of elevated temperature on chlorophyll content,photosynthetic characteristics and soybean yield at three leaf stage,flowering stage and bulking stage under ambient temperature(aT)and elevated temperature(eT)treatments by using an open warming system.The results showed that at the three leaf stage,eT decreased the Pn(photosynthetic rate),G_(s)(stomatal conductance)and T_(r)(transpiration rate)of soybean leaves by 21.3%,36.7%and 17.4%on high fertility soil,respectively,while increased the SPAD value by 15.1%and decreased Pn by 11.4%on low fertility soil,respectively,compared to control.At flowering stage,leaf SPAD value was increased by 24.0%on high fertility soil,while Pn,G_(s),C_(i)(intercellular CO_(2) concentration)and T_(r)(transpiration rate)were decreased significantly on low fertility soil at eT than that of control,and eT decreased leaf G_(s),C_(i) and T_(r) on low fertility soil compared with the control.At the bulking stage,in contrast to control,leaf Pn,G_(s) and T_(r) at eT were increased by 25.6%,55.5%and 33.8%on high fertility soil,but were decreased by 42.4%,58.7%and 56.1%on low fertility soil,respectively.The increased temperature resulted in a 23.3%yield increase of soybean on high fertility soils compared to the control,while a 10.9%yield reduction on low fertility soils.The photosynthetic capacity of soybean at bulking stage was the key factor in limiting yield formation,especially on high fertility soil,which can offset the insufficient photosynthesis at early growth stage,and finally improved yield.Therefore,adjusting soil fertility would be a potential strategy to improve the adaptability of soybean production to future global warming.