Contrasting Effects of Plant-Soil Feedbacks on Growth and Morphology of Two Clonal Plants

Abstract

AimSoil abiotic and biotic conditions are often spatially variable, challenging plants with a heterogeneous environment consisting of favorable and unfavorable patches of soil. Many stoloniferous clonal plants can escape from unfavorable patches by elongating stolon internodes, but aggregate in favorable ones through shortening stolon internodes. However, whether these plants can use their stolons to respond to plant-soil feedbacks (PSFs) is largely unknown. MethodsIn the conditioning phase, we grew either Hydrocotyle vulgaris or Glechoma longituba clonal plants separately in mesocosms to condition bulk soil. In the feedback phase, we grew connected mother and daughter ramets of each species in soil inoculated with the unsterilized or sterilized soil conditioned by conspecifics. We grew the plants for 12 weeks and measured the growth of the mother and daughter ramets separately. ResultsThe daughter ramets of H. vulgaris produced more biomass but shorter stolon internodes when grown in soil with sterilized inocula than with unsterilized inocula. However, no difference was found between the daughter ramets of G. longituba grown in soil with unsterilized and sterilized inocula. For both species, no significant difference was found between the mother ramet or between the daughter ramets when the mother ramet was grown in soil with sterilized and unsterilized inocula. ConclusionsThe daughter ramets rather than the mother ramet of H. vulgaris experienced negative biotic PSFs. However, PSF had no effects on the daughter or mother ramet of G. longituba. Moreover, physiological integration or plasticity in stolon internode lengths cannot help H. vulgaris alleviate the negative PSFs.