Aims

Plant stoichiometry is known to influence ecological processes and element cycles in ecosystems, which in turn can all be affected by ongoing climate change. While previous studies mainly focused on warming, drought or species invasion, effects of changing water supply on plant stoichiometry have not been well explored.

Methods

To study how water supply affects plant stoichiometry (here C:N, N:P), and whether such effects differ among plant species, a manipulative experiment was conducted in which four grass species (Leymus chinensis, Stipa grandis, Artemisia frigida and Potentilla acaulis) dominant in the Inner Mongolia steppe were subjected to a gradient of water supply via changes in growing-season rainfall.

Results

Water supply significantly impacted C:N and N:P, and these effects differed among grass species. Specifically, while C:N of A. frigida and P. acaulis was unaffected by water supply, C:N of L. chinensis and S. grandis increased with increasing precipitation. Furthermore, N:P of A. frigida showed a unimodal pattern along the imposed precipitation gradient. Whereas aboveground and belowground N:P showed similar trends (but different patterns) with changing water supply, this was not the case for aboveground and belowground C:N. As a result, plant stoichiometry between aboveground and belowground parts followed an allometric pattern.

Conclusions

Changes in water supply can significantly modulate plant stoichiometry. These results could improve our understanding of the dynamics of grasslands under climate change.

中文翻译：

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供水对内蒙古草原植物C、N、P化学计量的影响

目标

众所周知，植物化学计量会影响生态系统中的生态过程和元素循环，而这反过来又会受到持续的气候变化的影响。虽然以前的研究主要集中在变暖、干旱或物种入侵，但尚未很好地探索改变供水对植物化学计量的影响。

方法

为了研究供水如何影响植物的化学计量（此处为 C:N、N:P），以及这种影响是否因植物物种而异，进行了一项操纵性实验，其中四种草种（羊草、大针茅、冷蒿和委陵菜） ）在内蒙古草原占主导地位的地区受到生长季节降雨量变化的供水梯度影响。

结果

供水对 C:N 和 N:P 有显着影响，这些影响因草种而异。具体来说，虽然冷杉和紫锥菊的 C:N 不受供水影响，但L. chinensis和S. grandis的 C:N随着降水的增加而增加。此外，A. frigida的 N:P沿施加的降水梯度显示出单峰模式。尽管随着供水的变化，地上和地下 N:P 显示出相似的趋势（但模式不同），但地上和地下 C:N 的情况并非如此。结果，地上和地下部分之间的植物化学计量遵循异速生长模式。

结论

供水的变化可以显着调节植物化学计量。这些结果可以提高我们对气候变化下草原动态的理解。