INFLUENCE OF POTASSIUM ON PLANT GROWTH AND 86Rb+-LABELED LIVE ROOTS OF DROUGHT-STRESSED HIBISCUS ROSA SINENSIS L. cv. LEPRECHAUN

• Published in: HortScience Vol. 28; no. 5; p. 535
• Main Authors: Egilla, Jonathan N, Davies, F. T., Jr, Drew, M. C
• Format: Journal Article
• Language: English
• Published: 01.05.1993
• ISSN: 0018-5345; 2327-9834
• DOI: 10.21273/HORTSCI.28.5.535d

Rooted cuttings of Hibiscus rosa sinensis L. cv. Leprechaun were grown in fine sand and irrigated with full strength Hoaglands solution containing 0, 2.5, or 10 mM K + . Half of the plants at each K + level were subjected to a 21-day slowly developing drought stress cycle (DS) and the other half were non-drought stressed (NDS), which yielded a midday leaf water potential (Ψ leaf ) at day 21 of -1.5 to -1.6 MPa and -0.5 MPa, respectively. Drought stress reduced leaf area (LA), leaf area ratio (LAR), shoot, root, leaf and total dry weights of 2.5 and 10 mM plants and increased the root:shoot ratio of all K + treatments. Increasing K + , increased all growth parameters measured in both DS and NDS plants, except for LAR, which was greatest at 0 mM K + . At 0 mM K + , drought stress did not affect LA, LAR, shoot, root and total dry weights. Neither drought nor K + treatments affected specific leaf area (SLA). In NDS plants, K + had no effect on percent live root ratio (PLR) as indicated by translocation of 86 Rb + from leaves into living roots, determined by autoradiography. Although drought stress reduced PLR at all K + levels, PLR was greatest at the higher K + levels.