Yield response to heat stress as affected by nitrogen availability in maize
Yield response to heat stress as affected by nitrogen availability in maize
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DOI：
10.1016/j.fcr.2015.07.010
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发表时间：
2015-11-01
影响因子：
5.8
通讯作者：
Slafer, Gustavo A.
中科院分区：
文献类型：
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作者：
Ordonez, Raziel A.;Savin, Roxana;Slafer, Gustavo A.
为了满足世界需求，今后几十年必须提高玉米产量。这种增长必须在气候变化的情况下实现，特别是在以热应激为特征的情况下。有必要采取若干农艺和遗传策略来提高对高温的耐受性。在其他作物中的一些结果表明高温胁迫和氮（N）有效性之间的相互作用。据我们所知，这种相互作用尚未在玉米中进行过测试。因此，本研究的目的是探索，在田间条件下，是否由冠层气温升高开花前后或在早期籽粒灌浆的产量惩罚的幅度是受氮供应。特别是，我们的目标是（i）量化开花前后和灌浆早期的热胁迫造成的产量损失的幅度，（ii）确定氮肥是否影响这些幅度，以及（iii）确定影响是间接的（通过影响生长）还是直接影响结实和/或籽粒生长能力。在西班牙东北部连续四年进行了四次田间试验。处理包括一个或两个杂种，两个或三个水平的N施肥和三个温度条件的因子组合。温度处理包括一个控制（在整个生长季节的自然温度下生长的地块）和两个处理，其中冠层的温度在相对较短的时间内增加。所有试验均充分浇水以避免水分胁迫，冠层气温升高处理仅使穗位最高温度增加了相对较小的幅度（穗位日平均温度增加了c. 1 ℃，每天治疗）。然而，当处理包括决定粒数的关键时期（吐丝前后）时，热胁迫造成的产量损失通常非常明显和显著。在长周期混合动力车中，这种损害要比短周期混合动力车中的损害大得多。在关键时期将植物暴露于升高的冠层空气温度降低了收获指数，从未加热条件下的约46%降低到升高的冠层空气温度下的20%，N200下的降低高于NO施肥处理。据我们所知，我们首次在田间条件下种植的玉米中显示，氮素有效性放大了冠层气温升高对产量的影响。氮素对加重惩罚的作用似乎不是直接作用，而是通过影响生长而间接作用。该效应是通过影响植物结粒的能力，并在较小程度上使粒重最大化;并且它独立于对解偶联开花和吐丝或对花粉量和活力的任何（潜在的额外）效应。(C)2015 Elsevier B. V.版权所有。
Maize yield has to be increased in the next decades in order to satisfy world demand. This increase has to be achieved in a scenario of climate change particularly characterised by heat stress. Several agronomic and genetic strategies for increased tolerance to high temperatures will be necessary. Some results in other crops showed interactions between high temperature stress and nitrogen (N) availability. To the best of our knowledge, this interaction has not been tested in maize. Therefore, the aim of this study was to explore, under field conditions, whether the magnitude of yield penalty imposed by elevated canopy air temperature around flowering or during early grain filling is affected by N availability. In particular we aimed to (i) quantify the magnitude of yield losses by heat stress around flowering and during early grain filling, (ii) determine whether N fertilisation affects these magnitudes, and (iii) identify whether the effects are indirect (through affecting growth) or directly on the grain set and/or grain growth capacity. Four field experiments were carried out during four consecutive years in NE Spain. The treatments consisted in a factorial combination of one or two hybrids, two or three levels of N fertilisation and three temperature conditions. The temperature treatments consisted of a control (plots grown under natural temperature throughout the growing season) and two treatments in which the temperatures of the canopy were increased in the field for relatively short periods. All experiments were well watered to avoid water stress.The elevated canopy air temperature treatment only increased the maximum temperature in a relatively small magnitude (mean daily temperature was increased at the ears height by c. 1 degrees C each day of treatment). However, yield penalty imposed by heat stress was in general very noticeable and dramatic when the treatment included the critical period for grain number determination, around silking. The damage was much stronger in the long- than in the short-cycle hybrid. Exposing the plants to elevated canopy air temperature during the critical period reduced harvest index, from values of around 46% in unheated conditions to 20% under elevated canopy air temperature, being the reduction higher under N200 than under NO fertilisation treatments.As far as we are aware, we showed for the first time in maize grown in field conditions, that the losses in yield in response to elevated canopy air temperature treatment were magnified by the N availability. The effect of N on emphasising the penalties seemed not to be a direct effect of this nutrient but and indirect effect through affecting growth. The effect was through affecting the capacity of the plants to set grains and to a lesser extent to allow grain weight to be maximised; and it was independent of any (potentially additional) effects on either uncoupling anthesis and silking or on pollen amount and viability. (C) 2015 Elsevier B.V. All rights reserved.