Yu Hongwei, Shen Nan, Yu Dan, Liu Chunhua
The National Field Station of Freshwater Ecosystem of Liangzi Lake, College of Life Sciences, Wuhan University, Wuhan, China.
Front Plant Sci. 2019 Jan 11;9:1987. doi: 10.3389/fpls.2018.01987. eCollection 2018.
Clonal plants may face various types of resource heterogeneity in their natural habitats; as such, spatial or temporal resource heterogeneity can affect the growth of clonal plants. Clonal plants can concentrate their organs in a smaller area where resources are high would cause heterogeneity to increase competition between plants. Most studies on resource heterogeneity have investigated the response of plants under a single density or by manipulating a single resource. Few studies have tested the effects of the heterogeneous distribution of two covariable resources on plant growth and intraspecific competition. A greenhouse experiment was therefore conducted to study plant responses to the spatial and temporal heterogeneity of the soil and water supply under a variety of plant densities (one, two, four, or six plants per container). The perennial clonal herb was grown under different combinations of water supply patterns, soil nutrient distribution types and plant densities while maintaining the total water and soil nutrient availability per container constant. Compared with that at a relatively high plant density, soil nutrient heterogeneity resulted in significantly less total plant biomass and less-modified morphological traits when the plant density is relative low. At the highest plant density, compared with the homogeneous soil treatments, the heterogeneous soil treatments significantly increased the total biomass and R/S ratio. Water supply patterns also clearly affected plant morphological traits at the highest plant density. Furthermore, soil heterogeneity significantly increased intraspecific competition intensity at low plant densities, but did not significantly affect intraspecific competition intensity at higher plant densities. Water heterogeneity had little impact on intraspecific competition. These results suggest that the growth performance and intraspecific competition of are more strongly affected by soil nutrient distribution rather than by water supply patterns and that competition for soil nutrients may increase plant sensitivity to soil heterogeneity.
克隆植物在其自然栖息地可能面临各种类型的资源异质性；因此，空间或时间资源异质性会影响克隆植物的生长。克隆植物可能会将其器官集中在资源丰富的较小区域，这会导致异质性增加植物间的竞争。大多数关于资源异质性的研究都调查了单一密度下植物的反应或通过操纵单一资源进行研究。很少有研究测试两种协变资源的异质分布对植物生长和种内竞争的影响。因此，进行了一项温室实验，以研究在各种植物密度（每个容器一株、两株、四株或六株植物）下植物对土壤和水分供应的空间和时间异质性的反应。将多年生克隆草本植物种植在不同的供水模式、土壤养分分布类型和植物密度的组合下，同时保持每个容器的总水分和土壤养分供应量不变。与相对较高的植物密度相比，当植物密度相对较低时，土壤养分异质性导致植物总生物量显著减少，形态特征变化较小。在最高植物密度下，与均匀土壤处理相比，异质土壤处理显著增加了总生物量和根冠比。供水模式在最高植物密度下也明显影响植物形态特征。此外，土壤异质性在低植物密度下显著增加了种内竞争强度，但在较高植物密度下对种内竞争强度没有显著影响。水分异质性对种内竞争影响很小。这些结果表明，[植物名称]的生长性能和种内竞争受土壤养分分布的影响比受供水模式的影响更大，并且对土壤养分的竞争可能会增加植物对土壤异质性的敏感性。
