Functional differences in seasonally absorbed nitrogen in a winter-green perennial herb
Functional differences in seasonally absorbed nitrogen in a winter-green perennial herb
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冬绿多年生草本植物季节性吸收氮的功能差异
DOI：
10.1098/rsos.190034
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发表时间：
2020
影响因子：
3.5
通讯作者：
Kachi N.
中科院分区：
文献类型：
--
作者：
Nishitani S.;Ishida A.;Nakamura T.;Kachi N.
氮 (N) 的吸收量与其可用性和氮的有效利用对于确定植物的适应性非常重要，因为氮是主要的限制资源，其可用性随季节和年度变化。诸如球茎之类的储存器官被认为是植物氮利用策略的适应性特征。众所周知，氮从储存器官中被重新调动，以满足新生长的高需求，而仅靠外部吸收并不能完全满足这一需求。然而，人们对不同季节吸收的氮如何影响植物性能知之甚少。通过控制冬绿多年生石蒜科盆栽石蒜的季节性氮素利用率，我们发现不同季节吸收的氮素对叶片生长和叶片氮素浓度有不同的影响，有效提高了植物的生长和成活。夏季（无叶期；因此，氮储存在球茎中）吸收的氮通过增加叶子生长来促进植物生长。与秋季（叶盛期）供应氮的植物相比，尽管后者的面积光合能力较低，但叶类植物也表现出单位叶面积的更大生长。相比之下，秋季吸收的氮增加了叶子的氮浓度，从而提高了光合能力，这被认为可以通过减少低温下吸收光子引起的潜在致命风险来增强植物在冬季的生存和生长。我们的发现对于估计植物对环境变化的反应具有重要意义。我们预测，季节性氮可用性的变化会通过改变氮对不同功能的相对投资来影响植物的性能，甚至是具有大型储存器官的多年生植物的性能。
Nitrogen (N) uptake in response to its availability and effective N-use are important for determining plant fitness, as N is a major limiting resource and its availability changes both seasonally and annually. Storage organs such as bulbs are considered an adaptive trait with respect to plant N-use strategies. It is well known that N is remobilized from storage organs to satisfy the high demand for new growth that is not completely satisfied by external uptake alone. However, little is known about how this N absorbed during different seasons contributes to plant performance. By manipulating seasonal N availability in pottedLycoris radiatavar.radiata(Amaryllidaceae), a winter-green perennial, we found that the N absorbed during different seasons had different effects on leaf growth and leaf N concentrations, effectively increasing the growth and survival of the plants. N absorbed during the summer (leafless period; N was thus stored in the bulb) enhanced plant growth by increasing leaf growth. Compared with the plants supplied with N during autumn (leaf flush period), the leafy plants also showed greater growth per unit leaf area despite the lower area-based photosynthetic capacity of the latter. By contrast, N absorbed during the autumn increased the leaf N concentration and thus the photosynthetic capacity, which was considered to enhance survival and growth of the plant during winter by reducing the potentially fatal risk caused by the absorption of photons under low temperature. Our findings have important implications for estimating plant responses to environmental changes. We predict that changes in seasonal N availability impact the performance of plants, even that of perennials that have large storage organs, via an altered relative investment of N into different functions.