Nitrogen fertilization and 18O of CO2 have no effect on 18O-enrichment of leaf water and cellulose in Cleistogenes squarrosa (C4) - is VPD the sole control?
Nitrogen fertilization and 18O of CO2 have no effect on 18O-enrichment of leaf water and cellulose in Cleistogenes squarrosa (C4) - is VPD the sole control?
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DOI：
10.1111/pce.12824
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发表时间：
2016-12-01
影响因子：
7.3
通讯作者：
Schnyder, Hans
中科院分区：
文献类型：
--
作者：
Liu, Hai Tao;Gong, Xiao Ying;Schnyder, Hans
纤维素（O-18（Cel））的氧同位素组成档案水文和生理信息。在这里，我们评估以前未探索的直接和相互作用的影响O-18的二氧化碳（O-18（CO2））、氮肥供应和水汽压亏缺（VPD）对O-18（Cel）、O-18（LW）和纤维素的影响（O-18（Cel））和p（ex）p（x），在纤维素合成位点与未富集水交换的纤维素中氧的比例，在C-4草（糙隐子草）中。O-18（CO2）和N供应及其与VPD的交互作用对O-18（Cel）、O-18（LW）、O-18（Cel）和p（ex）p（x）没有影响。O-18（Cel）和O-18（LW）随VPD增加而增加，p（ex）p（x）降低。对O-18（LW）变化和羰基氧与水之间平衡分馏因子的敏感性试验支持VPD对p（ex）p（x）的影响。氮供应改变了生长和形态特征，但不O-18关系;相反，VPD对生长或形态没有影响，但控制O-18关系。这项工作意味着，从O-18（Cel）重建VPD将高估VPD变化的幅度，至少在这个物种中，如果VPD对p（ex）p（x）的影响被忽略。要进一步了解O-18（LW）和O-18（Cel）之间的关系，就需要分别研究p（ex）和p（x）及其对环境条件的响应。
The oxygen isotope composition of cellulose (O-18(Cel)) archives hydrological and physiological information. Here, we assess previously unexplored direct and interactive effects of the O-18 of CO2 (O-18(CO2)), nitrogen (N) fertilizer supply and vapour pressure deficit (VPD) on O-18(Cel), O-18-enrichment of leaf water (O-18(LW)) and cellulose (O-18(Cel)) relative to source water, and p(ex)p(x), the proportion of oxygen in cellulose that exchanged with unenriched water at the site of cellulose synthesis, in a C-4 grass (Cleistogenes squarrosa). O-18(CO2) and N supply, and their interactions with VPD, had no effect on O-18(Cel), O-18(LW), O-18(Cel) and p(ex)p(x). O-18(Cel) and O-18(LW) increased with VPD, while p(ex)p(x) decreased. That VPD-effect on p(ex)p(x) was supported by sensitivity tests to variation of O-18(LW) and the equilibrium fractionation factor between carbonyl oxygen and water. N supply altered growth and morphological features, but not O-18 relations; conversely, VPD had no effect on growth or morphology, but controlled O-18 relations. The work implies that reconstructions of VPD from O-18(Cel) would overestimate amplitudes of VPD variation, at least in this species, if the VPD-effect on p(ex)p(x) is ignored. Progress in understanding the relationship between O-18(LW) and O-18(Cel) will require separate investigations of p(ex) and p(x) and of their responses to environmental conditions.