Publications - Faculty - Recently Submitted Faculty Publications 2010
<- Back
Syvertsen - Proc. Florida State Horticultural Society
Salinity Tolerance of Cleopatra Mandarin Seedlings and Two of its Trifoliata Hybrids, US-897 and x639
J. P. Syvertsen and Wije Bandaranayake
Abstract.In a greenhouse study, we evaluated growth, leaf Cl- and Na+ concentrations along with physiological responses of seedlings of the relatively salt tolerant citrus rootstock Cleopatra mandarin (Cleo) and two of its commercial hybrids, Cleo x Flying Dragon trifoliata (US-897) and Cleo x Rubidoux TF (x639). These hybrids have some horticultural advantages over Cleo but their relative tolerance to salinity is not known. Well-fertilized and well-watered 4 month old seedlings were grown in a high peat soilless potting mix and salinized with 0, 30 or 60 mM NaCl (max. TDS = 5,000 ppm) for 9 weeks. Both hybrids grew more than Cleo regardless of salinity level. At the end of the experiment, total plant dry weight (TPDW) was reduced by salinity in Cleo and US-897 but growth of x639 was not reduced by salinity. Final total leaf area was greatest x639 followed by Cleo and US-897. Seedlings of x639 also had the highest root to shoot dry weight ratio as x639 allocated relatively more growth to roots than to shoots. Seedlings x639 accumulated higher concentrations of Cl in roots while Cleo accumulated the highest Na in roots. Both hybrids accumulated more Cl in leaves than Cleo and leaf Na concentrations were highest in x639. High salinity reduced leaf photosynthesis and water use efficiency most in US-897. The greater growth and higher leaf Cl levels support the idea that both hybrids were more salt tolerant than Cleo at least at moderate salinity. At high salinity, seedlings of x639 grew more and had higher leaf water use efficiency than US-897.
