TY - JOUR N2 - Abstract During greening, excised etiolated barley leaves and cucumber cotyledons that were depleted of exogenous Ca2+ by a chelating agent (ethylene glycol-bis (beta aminoethyl ether)-N,N,N`N`-tetraacetic acid, EGTA) showed ∼50% reduced chlorophyll (Chl) accumulation and ∼30% accumulation of apoprotein of the light-harvesting chlorophyll a/b-binding protein complex of photosystem II (LHCPII). The Ca2+ channel blocker lanthanum chloride (LaCl3) applied to cucumber cotyledons reduced LHCPII accumulation more than EGTA did. In both plant mate-rials, cytokinins enhanced chlorophyll accumulation by 50-60% and this effect was completely canceled by EGTA application. Hormones significantly increased LHCPII accumulation but EGTA application reduced that effect in barley leaves by ∼30% and in cucumber cotyledons by ∼80%. A similar effect was observed in LaCl3-treated cotyledons. CaCl2 application boosted chlorophyll accumulation in both plant materials. CaCl2 applied together with cytokinin reduced the hormonal effect on chlorophyll accumulation by ∼38% in barley leaves and 23% in cucumber cotyledons, but almost totally inhibited cytokinin-stimulated LHCPII accumulation. Our results indicate that calcium variously mediates the effect of cytokinin on chlorophyll and LHCPII accumulation. Cytokinin-induced enhancement of chlorophyll accumulation seems totally dependent on the exogenous pool of Ca2+, while Ca2+-dependent and Ca2+-independent pathways are involved in the hormonal effect on LHCPII accumulation. The effect of cytokinin on the increase of light-induced LHCPII accumulation appears to be sensitive to exogenously applied Ca2+, which almost totally blocked the hormonal effect. Our results give indirect evidence that the responses to cytokinin and light act on different events leading to Chl and LHCPII accumulation. L1 - http://www.czasopisma.pan.pl/Content/81828/PDF/03_legocka.pdf L2 - http://www.czasopisma.pan.pl/Content/81828 PY - 2014 IS - No 2 DO - 10.2478/abcsb-2014-0017 A1 - Legocka, Jolanta A1 - Sobieszczuk-Nowicka, Ewa PB - Biological Commission of the Polish Academy of Sciences – Cracow Branch VL - vol. 56 DA - 2015[2015.01.01 AD - 2015.12.31 AD] T1 - Calcium Variously Mediates the Effect of Cytokinin on Chlorophyll and LHCPII Accumulation During Greening in Barley Leaves and Cucumber Cotyledons UR - http://www.czasopisma.pan.pl/dlibra/publication/edition/81828 T2 - Acta Biologica Cracoviensia s. Botanica ER -