Root foraging in response to heterogeneous soil moisture in two grapevines that differ in potential growth rate

Authors


Author for correspondence:
David M. Eissenstat
Tel:+1 814 863 3371
Fax: +1 814 863 6139
Email: dme9@psu.edu

Summary

  • • Linkages between plant growth rate and root responses to soil moisture heterogeneity were investigated.
  • • Root dynamics were studied using genetically identical shoots (Vitis vinifera cv. Merlot) with genetically distinct root systems that promote higher (HSV) and lower (LSV) shoot growth rates (1103P and 101–14 Mgt, respectively). Three quantities of irrigation replenished different amounts of evapotranspiration (0, 40 and 100%ETc) in a California vineyard.
  • • Roots of HSV vines exhibited more plasticity, as indicated by greater preferential growth in irrigated soil during the summer, and a larger shift in root diameter with a change in soil moisture than LSV vines. Higher tolerance of low soil moisture was not observed in LSV roots – root survivorship was similar for the two rootstocks. LSV vines produced a large fraction of its roots during the winter months and increased root density over the study, while HSV vines produced roots mainly in summer and only exhibited a high initial peak in root biomass in the first year.
  • • These results demonstrated that a plant of higher vigor has greater morphological plasticity in response to lateral heterogeneity in soil moisture but similar tolerance to moisture stress as indicated by root survivorship in dry soil.

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