Aims

Data on the decomposition of fine roots are scarce for the Mediterranean basin. This work aims to compare chemical traits, decomposition rate, and temperature sensitivity (Q10) for root and leaf litter of 43 Mediterranean species.

Methods

We carried out a two-years litterbag decomposition experiment using 43 fine roots litter and leaf litter types incubated in laboratory conditions at three different temperatures, i.e. 4 °C, 14 °C, and 24 °C. Litter was characterized for carbon (C), nitrogen (N), lignin and cellulose concentration, C/N, and lignin/N ratios.

Results

Fine root litter had lower N content but higher lignin concentration, lignin/N, and C/N ratios compared to leaf litter. The decay rate of fine root litter was slower than leaf litter. For both tissues, the decay rate was negatively associated with lignin concentration, lignin/N, and C/N ratios but positively with N concentration. Q10 was higher for fine root than leaf litter, with a positive correlation with lignin while negative with N concentration.

Conclusions

Our findings demonstrate a higher Q10 accompanied by a slower decomposition rate of fine root litter compared to leaf litter in Mediterranean ecosystems. These results must be considered in modeling organic C at the ecosystem scale.

中文翻译：

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43种地中海植物细根和凋落物的分解和温度敏感性

目的

地中海盆地缺乏有关细根分解的数据。这项工作旨在比较43种地中海物种的根和叶凋落物的化学特性，分解速率和温度敏感性（Q 10）。

方法

我们进行了为期两年的垃圾袋分解实验，使用了43种细根凋落物和叶片凋落物类型，它们在实验室条件下在3个不同的温度（即4°C，14°C和24°C）下孵育。凋落物的特征在于碳（C），氮（N），木质素和纤维素浓度，C / N和木质素/ N比。

结果

细根凋落物与叶凋落物相比，氮含量较低，但木质素浓度，木质素/氮和碳氮比更高。细根凋落物的腐烂速率比叶子凋落物慢。对于这两个组织，衰减速率与木质素浓度，木质素/ N和C / N比值呈负相关，而与N浓度呈正相关。细根Q 10高于叶片凋落物，与木质素呈正相关，而与N浓度呈负相关。

结论

我们的研究结果表明，与地中海生态系统中的落叶凋落物相比，较高的Q 10伴随着细根凋落物的分解速率降低。在生态系统规模的有机碳建模中必须考虑这些结果。