Potassium deficiency reduces grapevine transpiration through decreased leaf area and stomatal conductance

Or Sperling, Aviad Perry, Alon Ben-Gal, Uri Yermiyahu, Uri Hochberg

Research output: Contribution to journalArticlepeer-review

Abstract

Plants require potassium (K) to support growth and regulate hydraulics. Yet, K's effects on transpiration are still speculated. We hypothesized that K deficiency would limit grapevine water uptake by limiting canopy size and stomatal conductance (gs). Hence, we constructed large (2 m3) lysimeters and recorded vine transpiration for three years (2020–2022) under three fertilization application rates (8, 20, or 58 mg K L−1 in irrigation). Maximal K availability supported transpiration up to 75 L day−1, whereas K-deficient vines transpired only 60 L day−1 in midsummer. Limited vine growth and canopy size mainly accounted for reduced transpiration under low K conditions. Hence, considering K demand in addition to supply, we compared K deficiency effects on vines bearing 20 or 50 fruit clusters and found that reduced gs further limited transpiration when yields were high. Although fruits were strong K sinks, high yields did not alter K uptake because lower vegetative growth countered the additional K demands. Potassium deficiency leads to lower transpiration and productivity. Yet, internal mineral allocation compensates for fruit K uptake and masks biochemical indices or physiological proxies for K deficiency. Thus, decision support tools should integrate mineral availability, seasonal growth, and yield projections to determine grapevine water demands.

Original languageEnglish
Article number108534
JournalPlant Physiology and Biochemistry
Volume208
DOIs
StatePublished - 1 Mar 2024

Keywords

  • Fertilization
  • Leaf area
  • Mass balance
  • Mineral sinks
  • Solute transport

ASJC Scopus subject areas

  • Genetics
  • Physiology
  • Plant Science

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