Original article Plasticity in R/S ratio, morphology and fitness-related traits in response to reciprocal patchiness of light and nutrients in the stoloniferous herb, Glechoma longituba L Mingjun Liao, FeihaiYu, Minghua Song, Shumin Zhang, Jinzheng Zhang, Ming Dong * Laboratory of Quantitative Vegetation Ecology, Institute of Botany, The Chinese Academy of Sciences, 20 Xiangshan nanxincun, District Haidian, Beijing 100093, China Received 6 November 2002; accepted 15 July 2003 Abstract Clonal fragments of the stoloniferous herb Glechoma longituba were subjected to a complementary patchiness of light and soil nutrients including two spatially homogeneous treatments (SR–SR and IP–IP) and two spatially heterogeneous treatments (IP–SR and SR–IP). SR and IP indicate patches (shaded, rich) with low light intensity (shaded, S), high nutrient availability (rich, R) and patches (illuminated, poor) with high light intensity (illuminated, I) and low nutrient availability (poor, P), respectively. Plasticity of the species in root–shoot ratio, fitness-related traits (biomass, number of ramets and dry weight per ramet) and clonal morphological traits (length and specific length of stolon internodes, area and specific area of laminae, length and specific length of petioles) were experimentally examined. The aim is to understand adaptation of G. longituba to the environment with reciprocal patches of light and soil nutrients by plasticities both in root–shoot ratio and in (clonal) morphology. Our experiment revealed performance of the clonal fragments growing from patches with high light intensity and low soil nutrient availability into the adjacent opposite patches was increased in terms of the fitness-related characters. R/S ratio and clonal morphology were plastic. Meanwhile, the capture of light resource from the light-rich patches was enhanced while the capture of soil nutrients from either the nutrient-rich or the nutrient-poor patches was not. Analysis of cost and benefit disclosed positive effects of clonal integration on biomass production of ramets in the patches with low light intensity and high soil nutrient availability. These results suggest an existence of reciprocal translocation of assimilates and nutrients between the interconnected ramets. The reinforced performance of the clonal fragments seems to be related with specialization of clonal morphology in the species. © 2003 Éditions scientifiques et médicales Elsevier SAS. All rights reserved. Keywords: Clonal plant; Complementary patchiness; Cost-benefit analysis; Glechoma longituba; Fitness-related traits; Light; Morphological plasticity; R/S ratio; Soil nutrients 1. Introduction Essential resources for plants such as light and soil nutri- ents are usually patchily distributed in horizontal space under field conditions (Frankland et al., 1963; Stuefer, 1997). In some cases the availability of the different resources can be negatively correlated with each other within the patches (Alpert and Stuefer, 1997). The property of such a distribu- tion pattern of resources is named “reciprocal patchiness of resources (RPR)” (Alpert and Stuefer, 1997;Yu et al., 2002). For example, a patch abundant in sunlight may at the same time be scarce of soil nutrients, while patches with the oppo- site resource conditions (abundant of soil nutrients and scarce of light) may happen to exist in adjacent microhabitats (Cook, 1983; Alpert and Stuefer, 1997). Since ramets of single clonal fragments or genets can be connected through stolon and/or rhizome segments during a certain period of time and spread over a relatively large area (Hartnett and Bazzaz, 1983; Pitelka and Ashmun, 1985), the connected ramets may experience a heterogeneous environment with RPR. For instance, single ramets or groups of ramets of a clonal fragment or genet may be placed in a patch in which light intensity is high and soil nutrient availability is low, and their connected ramets may be put in a nearby patch of low light intensity and high soil nutrient availability at the same time (Alpert and Mooney, 1986; Friedman and Alpert, 1991; Stuefer and Hutchings, 1994; Stuefer, 1996). * Corresponding author. E-mail address: dongming@95777.com (M. Dong). Acta Oecologica 24 (2003) 231–239 www.elsevier.com/locate/actoec © 2003 Éditions scientifiques et médicales Elsevier SAS. All rights reserved. doi:10.1016/j.actao.2003.07.001