State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, China.
PLoS One. 2011;6(9):e25401. doi: 10.1371/journal.pone.0025401. Epub 2011 Sep 30.
When growing in reciprocal patches in terms of availability of different resources, connected ramets of clonal plants will specialize to acquire and exchange locally abundant resources more efficiently. This has been termed division of labour. We asked whether division of labour can occur physiologically as well as morphologically and will increase with patch contrasts.
METHODOLOGY/PRINCIPAL FINDINGS: We subjected connected and disconnected ramet pairs of Potentilla anserina to Control, Low, Medium and High patch contrast by manipulating light and nutrient levels for ramets in each pair. Little net benefit of inter-ramet connection in terms of biomass was detected. Shoot-root ratio did not differ significantly between paired ramets regardless of connection under Control, Low and Medium. Under High, however, disconnected shaded ramets with ample nutrients showed significantly larger shoot-root ratios (2.8∼6.5 fold) than fully-lit but nutrient-deficient ramets, and than their counterparts under any other treatment; conversely, fully-lit but nutrient-deficient ramets, when connected to shaded ramets with ample nutrients, had significantly larger shoot-root ratios (2.0∼4.9 fold) than the latter and than their counterparts under any other treatment. Only under High patch contrast, fully-lit ramets, if connected to shaded ones, had 8.9% higher chlorophyll content than the latter, and 22.4% higher chlorophyll content than their isolated counterparts; the similar pattern held for photosynthetic capacity under all heterogeneous treatments.
CONCLUSIONS/SIGNIFICANCE: Division of labour in clonal plants can be realized by ramet specialization in morphology and in physiology. However, modest ramet specialization especially in morphology among patch contrasts may suggest that division of labour will occur when the connected ramets grow in reciprocal patches between which the contrast exceeds a threshold. Probably, this threshold patch contrast is the outcome of the clone-wide cost-benefit tradeoff and is significant for risk-avoidance, especially in the disturbance-prone environments.
当克隆植物的连接分株在不同资源的可获得性方面以互惠斑块的形式生长时，它们将专门化以更有效地获取和交换局部丰富的资源。这被称为劳动分工。我们想知道劳动分工是否不仅可以在形态上，而且可以在生理上发生，并且随着斑块对比度的增加而增加。
方法/主要发现：我们通过操纵每对分株中的光照和养分水平，将连接和不连接的羊胡子草 Potentilla anserina 分株对置于对照、低、中、高斑块对比度下。在对照、低和中条件下，连接的分株之间的生物量几乎没有净收益。无论连接状态如何，在对照、低和中条件下，配对分株的茎叶比都没有显著差异。然而，在高对比度下，养分充足的遮光分株与完全光照但养分不足的分株相比，以及与其他任何处理下的分株相比，茎叶比显著更大（2.8∼6.5 倍）；相反，完全光照但养分不足的分株与养分充足的遮光分株相连时，茎叶比显著大于后者（2.0∼4.9 倍），也大于其他任何处理下的分株。只有在高斑块对比度下，如果完全光照的分株与遮光分株相连，它们的叶绿素含量比后者高 8.9%，比孤立的分株高 22.4%；在所有异质处理下，光合作用能力也呈现出类似的模式。
结论/意义：克隆植物中的劳动分工可以通过分株在形态和生理上的特化来实现。然而，在斑块对比度之间，分株的特化程度适中，尤其是在形态上，这表明当连接的分株在相互之间对比度超过阈值的互惠斑块中生长时，劳动分工就会发生。可能，这个阈值斑块对比度是克隆广泛的成本效益权衡的结果，对于避免风险很重要，尤其是在易受干扰的环境中。
