Soil nitrogen fertilization reduces relative leaf nitrogen allocation to photosynthesis
Soil nitrogen fertilization reduces relative leaf nitrogen allocation to photosynthesis
复制标题
土壤氮肥减少了叶向光合作用的相对氮分配
DOI：
10.1093/jxb/erad195
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发表时间：
2023
影响因子：
6.9
通讯作者：
Rogers, ed., Alistair
中科院分区：
文献类型：
--
作者：
Waring, Elizabeth F.;Perkowski, Evan A.;Smith, Nicholas G.;Rogers, ed., Alistair
土壤氮素有效性、叶片氮素和光合能力之间的联系尚不完全清楚。由于这三种成分在大的空间尺度上趋于正相关，一些人认为土壤氮正驱动叶片氮，而叶片氮正驱动光合能力。另一种观点认为，光合作用能力主要是由地面条件驱动的。在这里，我们研究了一种非固氮植物（棉）和一种固氮植物（甘氨酸）在光和土壤氮有效性的全因子组合中的生理反应，以帮助调和这些相互矛盾的假设。土壤氮刺激了两种植物的叶片氮，但在所有光效处理中，土壤氮含量升高导致叶片氮含量的增加大于叶绿素和叶片生化过程速率的增加，导致叶片氮用于光合过程的相对比例降低。叶片含氮量与生化过程速率[j]。地草对土壤氮素变化的响应强于禾草。max，可能是由于强g。低氮条件下根系结瘤投资最大。尽管如此，两种植物的全株生长都因土壤氮的增加而显著提高。光可用性持续增加叶片氮分配给叶片光合作用和整个植物生长，这种模式在物种之间相似。这些结果表明，在不同土壤氮水平下，叶片氮与光合作用的关系是不同的，随着土壤氮的增加，这些物种优先将更多的氮分配给植物生长和叶片非光合过程，而不是光合作用。
The connection between soil nitrogen availability, leaf nitrogen, and photosynthetic capacity is not perfectly understood. Because these three components tend to be positively related over large spatial scales, some posit that soil nitrogen positively drives leaf nitrogen, which positively drives photosynthetic capacity. Alternatively, others posit that photosynthetic capacity is primarily driven by above-ground conditions. Here, we examined the physiological responses of a non-nitrogen-fixing plant (Gossypium hirsutum) and a nitrogen-fixing plant (Glycine max) in a fully factorial combination of light by soil nitrogen availability to help reconcile these competing hypotheses. Soil nitrogen stimulated leaf nitrogen in both species, but the relative proportion of leaf nitrogen used for photosynthetic processes was reduced under elevated soil nitrogen in all light availability treatments due to greater increases in leaf nitrogen content than chlorophyll and leaf biochemical process rates. Leaf nitrogen content and biochemical process rates inG. hirsutumwere more responsive to changes in soil nitrogen than those inG. max, probably due to strongG. maxinvestments in root nodulation under low soil nitrogen. Nonetheless, whole-plant growth was significantly enhanced by increased soil nitrogen in both species. Light availability consistently increased relative leaf nitrogen allocation to leaf photosynthesis and whole-plant growth, a pattern that was similar between species. These results suggest that the leaf nitrogen–photosynthesis relationship varies under different soil nitrogen levels and that these species preferentially allocated more nitrogen to plant growth and non-photosynthetic leaf processes, rather than photosynthesis, as soil nitrogen increased.