极端高温对冬小麦冠层碳同化的影响  

Effect of extreme heat on winter wheat canopy carbon assimilation

作　　者：姜雨萌 赵风华[2] 刘金秋[3] 任传友[1] 

机构地区：[1]沈阳农业大学,沈阳110866 [2]中国科学院地理科学与资源研究所/中国科学院生态系统网络观测与模拟重点实验室,北京100101 [3]山东农业大学,泰安271018

出　　处：《中国生态农业学报》2015年第10期1260-1267,共8页Chinese Journal of Eco-Agriculture

基　　金：国家重点基础研究发展计划(973计划)课题(2012CB955904);"十二五"农村领域国家科技计划课题(2013AA102903);国家自然科学基金项目(31000207)资助

摘　　要：以涡度相关通量观测系统对山东禹城冬小麦农田碳通量进行11年（2003—2013年）连续观测,定义该11年内灌浆期日最高气温（Ta_max）的第95百分位数（30.58℃）为极端高温（EH）阈值。选择2004年和2012年中两个典型EH日和非极端高温（non-EH）日,对比分析EH对净生态系统生产力（NEP,白天）的影响特征与机理。结果表明：2004年EH日Ta_max比non-EH日高3.10℃,白天NEP总量低3.25 mg（CO2）·m^-2·s^-1,降低比率19.77%;2012年EH日Ta_max比non-EH日高3.17℃,白天NEP总量低6.04 mg（CO2）·m^-2·s^-1,降低比率19.17%。两年中,EH日与non-EH日的光合有效辐射（PAR）与NEP均呈显著二次曲线关系,但在PAR〉1 000μmol·m^-2·s^-1时段（该时段NEP总量占白天NEP总量的52.31%以上）则没有显著相关关系。随着PAR的增强,EH日和non-EH日的NEP差距有扩大趋势;在PAR〉1 000μmol·m^-2·s^-1时段,两者差异显著。无论全天还是仅PAR〉1 000μmol·m^-2·s^-1时段,空气相对湿度（RH）与NEP均没有显著相关关系。在4个观测日中,0~20 cm土壤含水量（SWC）均为田间持水量的80%左右,在冬小麦灌浆期适宜的土壤含水量范围内,对冠层碳同化无抑制作用。从全天看,EH日和non-EH日的气温（Ta）与NEP相关性均不显著,但在PAR〉1 000μmol·m^-2·s^-1时段,Ta与NEP则有显著负相关关系,Ta上升1℃,NEP降低7.28%~9.53%（2004年）和6.94%~10.42%（2012年）。因此华北平原冬小麦灌浆期极端高温（30.58℃）对冠层碳同化有显著抑制作用,在EH日,Ta对NEP抑制的贡献率为59%~83%,Ta升高1℃,白天NEP总量降低6.05%~6.37%。Canopy carbon flux was continuously measured in 2003–2013 using the eddy covariance system in a winter wheat field in Yucheng station, Shandong Province, to explore the effect of extreme heat on winter wheat canopy carbon assimilation. The extreme heat （EH） threshold was determined as the 95th percentile of daily maximum temperature （Ta_max）, which was 30.58℃ during grain-filling stage in 2003–2013 in the study area. Two typical couples of EH and non-EH days in 2004 and 2012 were selected and compared to determine the characteristics and mechanism of the effects of EH on net ecosystem productivity （NEP, daytime）, which was used to denote winter wheat canopy carbon assimilation rate. The results showed that Ta_max in the EH days were 3.10℃ and 3.17℃ higher than those in the non-EH days respectively in 2004 and 2012. Then total amounts of daytime NEP in EH days decreased by 3.25 mg（CO2）.m-2.s-1 （with decreasing rate of 19.77%） and 6.04 mg（CO2）.m-2.s-1 （with decreasing rate of 19.17%）, respectively, compared with that in non-EH days in 2004 and 2012. NEP had a significant quadratic curve correlation with PAR, but no significant when PAR was greater than 1 000μmol.m-2.s-1, at that time NEP accounted for over 52.31% of total daytime NEP for both EH and non-EH days. The difference in NEP between EH and non-EH days increased with increasing PAR, especially when PAR was greater than 1 000μmol.m-2.s-1. There were no significant correlations between relative humidity of atmosphere （RH） and NEP, whether during whole day or when PAR was more than 1 000μmol.m-2.s-1. In the four observed days, 0-20 cm soil water content （SWC） was about 80% of field capacity. This was the appropriate soil water content at grain-filling stage of winter wheat, which had no negative effect on NEP. For the whole days, NEP had no significant correlation with air temperature （Ta） in both EH and non-EH days. However, during the daytime with PAR 〉 1 000μmol.m-2.s-1, NEP had significant negative co

关 键 词：全球变暖 极端高温 冠层碳同化 光合有效辐射 净生态系统生产力 环境因素 冬小麦 

分 类 号：S512.1[农业科学—作物学]