Iron deficiency may result in interveinal chlorosis of Shamrock plant (Oxalis regnellii)

Oxalis regnellii is a geophytic ornamental pot plant grown primarily for its clover-like leaves. During greenhouse production, the leaves often become chlorotic for unknown reasons, possibly including virus infection, iron (Fe) and/or manganese (Mn) deficiencies, and improper greenhouse forcing temperatures. We conducted a series of experiments to address these hypotheses. Shamrock chlorotic ringspot virus (SCRV) has been reported before in Oxalis regnellii. Oxalis plants exhibiting virus-like symptoms were analyzed and a potyvirus was detected, although this virus was not further confirmed to be SCRV. To confidently test other hypotheses, any suspected viral infected material was discarded. Plants grown at 13°C exhibited slowed growth and development; however, the incidence of leaf chlorosis did not increase compared with plants grown at warmer temperatures of 21/16°C (day/night); 22°C constant; or 22 to 16°C (plants were moved to 16°C when 50% of the plants were in first flower). To assess the ability to correct an iron (Fe) deficiency, a media drench of ferric ethylenediaminedi (o-hydroxyphenylacetic) acid (Fe-EDDHA) was applied to chlorotic, Fe-deficient oxalis plants and plants successfully re-greened within 5 days.