Abstract: | Factors affecting the uptake and distribution of calcium (Ca)by detached tomato (Lycopersicon esculentum Mill.) fruit wereinvestigated in seven cultivars with different susceptibilitiesto blossom-end rot (BER), a physiological disorder caused byCa deficiency. Plants were grown with different levels of salinityin the root zone or under shade to induce BER. In addition,fruit grown at different salinities were treated with CME, aninhibitor of auxin transport to alter IAA movement. The basipetalmovement of indole-3-acetic acid (IAA) out of detached fruit(i.e. IAA efflux) was determined concurrently with 45Ca uptaketo assess the possible involvement of IAA in Ca import or theincidence of BER. High salinity in the root zone during fruitdevelopment decreased both the uptake and distribution of 43Cato the blossom-end of the detached fruit. Shading and the applicationof CME reduced 45Ca uptake to a lesser extent. IAA efflux, however,was not consistently reduced by these treatments. Neither theuptake and transport of 45Ca within, nor the efflux of IAA from,detached fruit was related to the cultivar susceptibility toBER. The proposed role of IAA on the uptake and distributionof Ca by tomato fruit is assessed. Key words: Tomato, calcium, IAA, blossom-end rot, salinity |