Spatial covariance in resources affects photosynthetic rate and water potential, but not the growth of Glechoma longituba fragments

Glechom longituba is a widespread clonal plant and usually experiences diverse patchiness of its growing sites. The hypothesis was tested that spatial covariance in resources differentially affects the growth and physiology of G. longituba. Plants were exposed to two patchy habitats where above- and below-ground resources were either positively or negatively associated, and to four control habitats. When equal amounts of resources were given, G. longituba fragments from two patchy habitats had similar biomass, root weight ratio, leaf weight ratio, fluorescence yield, specific petiole length, and specific root length; fragments under reciprocal patchiness significantly increased photosynthetic rate and decreased leaf water potential. Biomass of clones grown in patchy habitats was equal or less than that of counterparts from the control habitats, not supporting the notion that clonal growth is more advantageous in patchy habitats than in uniform habitats. In addition, no evidence was detected for spatial division of labour because biomass allocation to roots and leaves was similar in patchy habitats compared with the control habitats.