Decreased wheat grain yield stimulation by free air CO2 enrichment under N deficiency is strongly related to decreased radiation use efficiency enhancement
Decreased wheat grain yield stimulation by free air CO2 enrichment under N deficiency is strongly related to decreased radiation use efficiency enhancement
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DOI：
10.1016/j.eja.2018.08.007
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发表时间：
2018-11-01
影响因子：
5.2
通讯作者：
Manderscheid, Remy
中科院分区：
文献类型：
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作者：
Dier, Markus;Sickora, Jan;Manderscheid, Remy
大气CO2浓度升高对小麦增产的影响程度和机制尚不确定。特别是，在严重缺氮的田间试验中，e[CO2]效应的数据很少。为了研究e[CO2]和N施肥对决定谷物产量并经常用于作物模拟模型的重要变量的相互作用，例如冠层辐射吸收（AR）、辐射利用效率（芸香）和比叶氮重量（SLNW），进行了一项为期两年的自由空气CO2富集（FACE）实验，（393和600 ppm）和三个N水平（严重缺氮（Nd），40（第一年）和35公斤氮公顷（-1）（第2年）;充足的N供应，180（第1年）和200公斤氮公顷（-1）（第二年）;过量供氮320 kg/ha（-1）地上生物量为816 ~ 2012 g/m2，籽粒产量为417 ~ 973 g/m2。在Nd、NAD和Nex处理下，eCO 2分别使地上生物量增加13%、18%和14%，籽粒产量增加10%、17%和17%。产量刺激主要是由于增加的粒数。随着氮素供应量的增加，绿色面积指数的峰值在e[CO2]下增加了4至22%，而AR不受影响。氮素供应和e[CO2]的增加均提高了RUE，Nad（+20%）和Nex（+18%）处理的芸香提高幅度大于Nd（+6%）处理。SLNW被e[CO2]降低，并且这种降低在N水平之间非常相似（类似于-6%）。然而，如果叶面积指数包括作为协变量，那么只有在Nd下发现一个E[CO2]诱导的SLNW下降。本研究表明，产量刺激由E[CO2]是小的严重缺氮相比，高氮供应小麦。与另一项FACE研究的结果相反，这种减少不是由于AR减少，而是由于芸香减少，这可能是由于对源活性（即光合能力）和库大小（即穗生长）的限制。
Uncertainty still exists about the extent and mechanisms of yield stimulation by elevated atmospheric CO2 (e[CO2]) in wheat. Particularly, data of the e[CO2] effect under severe N deficiency from field experiments are scarce. To investigate the interaction of e[CO2] and N fertilization on important variables that determine grain yield and are often used in crop simulation models, e.g. radiation absorption by the canopy (AR), radiation use efficiency (RUE) and specific leaf N weight (SLNW), a two-year Free Air CO2 Enrichment (FACE) experiment was conducted with two [CO2] (393 and 600 ppm) and three N levels (severe N deficiency (Nd) with 40 (1st year) and 35 kg N ha(-1) (2nd year); adequate N supply with 180 (1st year) and 200 kg N ha(-1) (2nd year); and excess N supply with 320 kg N ha(-1) (1st and 2nd year).Final aboveground biomass ranged from 816 to 2012 g m(-2) and grain yield from 417 to 973 g m(-2). e[CO2] increased aboveground biomass by 13, 18 and 14% and grain yield by 10, 17 and 17% under Nd, Nad and Nex, respectively. Yield stimulation was primarily due to enhanced grain number. With increasing N supply, peak values of green area index were increased under e[CO2] by 4 up to 22%, while AR was unaffected. RUE was increased by both rising SLNW, which depended on N supply, and e[CO2] and the RUE increase was larger under Nad (+20%) and Nex (+18%) than under Nd (+6%). SLNW was decreased by e[CO2] and this decrease was very similar among N levels (similar to -6%). However, if leaf area index was included as covariable, then a e[CO2] induced decrease of SLNW was only found under Nd.The present study demonstrates that yield stimulation by e[CO2] is smaller under severe N deficiency compared to high N supply in wheat. In contrast to the results of another FACE study, this decrease was not due to reduced AR but reduced RUE, which might be attributed to both restrictions on source activity, i.e. photosynthetic capacity and sink size, i.e. ear growth.