Fry Ellen L, Evans Amy L, Sturrock Craig J, Bullock James M, Bardgett Richard D
1School of Earth and Environmental Sciences, Michael Smith Building, The University of Manchester, Oxford Road, Manchester, M13 9PT UK.
2School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD UK.
Plant Soil. 2018;433(1):189-200. doi: 10.1007/s11104-018-3824-1. Epub 2018 Oct 25.
Root characteristics are important for predicting plant and ecosystem responses to resource scarcity. Simple, categorical traits for roots could be broadly applied to ecosystem function and restoration experiments, but they need to be evaluated for their role and behaviour under various stresses, including water limitation. We hypothesised that more complex root architectures allow more plastic responses to limited water than do tap roots.
We carried out two greenhouse experiments: one with a range of grassland plant species; the other with only species of Asteraceae to test the responsiveness of root architectural classes to location of limited water in the soil column. Using trait screening techniques and X-ray tomography, we measured the plasticity of the roots in response to water location.
Plasticity of root biomass was lowest in tap rooted species, while fibrous and rhizomatous roots allocated biomass preferentially to where the soil was wettest. X-ray tomography indicated that root morphology was least plastic in rhizomatous species.
Our results provide a starting point to effective categorisation of plants in terms of rooting architecture that could aid in understanding drought tolerance of grassland species. They also demonstrate the utility of X-ray tomography in root analyses.
根系特征对于预测植物和生态系统对资源稀缺的响应至关重要。简单的根系分类性状可广泛应用于生态系统功能和恢复实验，但需要评估它们在包括水分限制在内的各种胁迫下的作用和行为。我们假设，与直根系相比，更复杂的根系结构对有限水分具有更强的可塑性响应。
我们进行了两项温室实验：一项涉及一系列草原植物物种；另一项仅使用菊科物种，以测试根系结构类型对土壤柱中有限水分位置的响应。使用性状筛选技术和X射线断层扫描，我们测量了根系对水分位置的可塑性。
直根系物种的根生物量可塑性最低，而须根系和根茎型根系则优先将生物量分配到土壤最湿润的地方。X射线断层扫描表明，根茎型物种的根系形态可塑性最小。
我们的结果为根据根系结构对植物进行有效分类提供了一个起点，这有助于理解草原物种的耐旱性。它们还证明了X射线断层扫描在根系分析中的实用性。
