Linking tree genetics and stream consumers: isotopic tracers elucidate controls on carbon and nitrogen assimilation
Linking tree genetics and stream consumers: isotopic tracers elucidate controls on carbon and nitrogen assimilation
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DOI：
10.1002/ecy.2224
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发表时间：
2018-08-01
期刊：
影响因子：
4.8
通讯作者：
Marks, Jane C.
中科院分区：
文献类型：
--
作者：
Compson, Zacchaeus G.;Hungate, Bruce A.;Marks, Jane C.
落叶提供了一个重要的营养补助源流，但很少有人知道树木遗传学如何影响能源途径，从垃圾到更高的营养水平。尽管对分解凋落物的碳（C）和氮（N）途径进行了量化，但凋落物分解与水生消费者之间的关系仍未得到解决。我们测量了凋落物的偏好（附件凋落物），C和N同化率，和增长率的切碎石蛾（Hesperophylax magnus，Limnephilidae）响应于不同的化学和物理表型的落叶杨树杂交类型（P. fremontii，P. angustifolia，和F-1杂种）和基因型P. angustifolia。我们结合实验室围隔研究，使用来自一个共同的花园，使用双标记的垃圾（C-13和N-15）在温室中生长，并在橡树溪，亚利桑那州，美国孵化的实地研究。我们发现，在实验室中，碎纸机最初选择相对不稳定（低木质素和缩合单宁浓度，快速分解）的交叉型凋落物，但在4天内改变的偏好，以相对不稳定的柠檬（高木质素和缩合单宁浓度，缓慢分解）凋落物类型。此外，在实验室中，切碎机的增长率较高，相对不稳定的交叉型凋落物。在为期三周的田间试验的过程中，碎纸机也吸收了更多的C和N从比较不稳定的交叉型凋落物。在沙枣各基因型中，切碎机对氮的同化作用与凋落物木质素和C：N呈正相关，与缩合单宁和分解速率呈负相关。C同化同样与凋落物C：N和凋落物%N呈正相关。C同化与缩合单宁或木质素无关。总的来说，这些研究结果表明，杨属杂交类型的相对较硬的凋落物提供了更多的营养效益，在N通量和生长方面，比不稳定的凋落物，但在P.狭叶基因型之间的凋落物较硬的具体性状（木质素或单宁）决定对C或N同化的影响。由于粉碎机提供营养和能量，以更高的营养水平，这些遗传为基础的植物分解途径粉碎机的偏好和性能的影响可能会影响社区和食物网结构。
Leaf litter provides an important nutrient subsidy to headwater streams, but little is known about how tree genetics influence energy pathways from litter to higher trophic levels. Despite the charge to quantify carbon (C) and nitrogen (N) pathways from decomposing litter, the relationship between litter decomposition and aquatic consumers remains unresolved. We measured litter preference (attachments to litter), C and N assimilation rates, and growth rates of a shredding caddisfly (Hesperophylax magnus, Limnephilidae) in response to leaf litter of different chemical and physical phenotypes using Populus cross types (P. fremontii, P. angustifolia, and F-1 hybrids) and genotypes within P. angustifolia. We combined laboratory mesocosm studies using litter from a common garden with a field study using doubly labeled litter (C-13 and N-15) grown in a greenhouse and incubated in Oak Creek, Arizona, USA. We found that, in the lab, shredders initially chose relatively labile (low lignin and condensed tannin concentrations, rapidly decomposing) cross type litter, but preference changed within 4d to relatively recalcitrant (high lignin and condensed tannin concentrations, slowly decomposing) litter types. Additionally, in the lab, shredder growth rates were higher on relatively recalcitrant compared to labile cross type litter. Over the course of a three-week field experiment, shredders also assimilated more C and N from relatively recalcitrant compared to labile cross type litter. Finally, among P. angustifolia genotypes, N assimilation by shredders was positively related to litter lignin and C:N, but negatively related to condensed tannins and decomposition rate. C assimilation was likewise positively related to litter C:N, and also to litter %N. C assimilation was not associated with condensed tannins or lignin. Collectively, these findings suggest that relatively recalcitrant litter of Populus cross types provides more nutritional benefit, in terms of N fluxes and growth, than labile litter, but among P. angustifolia genotypes the specific trait of litter recalcitrance (lignin or tannins) determines effects on C or N assimilation. As shredders provide nutrients and energy to higher trophic levels, the influence of these genetically based plant decomposition pathways on shredder preference and performance may affect community and food web structure.