Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2009.246.251AhmedOmer Khidir 32009123The inhibition by sucrose of chromoplast reversion to
chloroplast in citrus epicarp was studied by observing the effects of
several sugars, sugar metabolites and 1-iodoacetate on chlorophyll reaccumulation
in cultured Citrus paradisi Macf. pericarp segments. Pericarp segments
of 1 cm in diameter were cut from yellow fruits and cultured on modified
medium plus the indicated metabolites and kept under continuous fluorescent
light. Accumulation of chlorophyll in the segments was measured with a
spectrophotometer fitted with sphere reflectometer. Respiration was determined
via., an infrared gas analyzer. Inhibition of regreening was not specific
to a particular sugar. The organic acids malate, citrate, succinate, 2-oxoglutarate
and especially malonate elicited effects similar to sucrose, but at much
lower concentrations. However, malonate inhibition of chlorophyll accumulation
was overcome by increased concentrations of glutamine. At concentrations
that usually inhibited chlorophyll, malonate did not reduce CO2
production in the presence of glutamine or KNO3. Sucrose effects
on regreening were reduced by 1-iodoacetate. These results indicate that
sugar regulation of plastid reversion during regreening in citrus epicarp
is not directly due to sugars, but is instead mediated through metabolism
of sugars to organic acids, especially malonic acid.]]>Alexander, L. and D. Grierson,20025320392055An, J.H. and Y.S. Kim,1998Rhizobium trifolii.]]>257395402Cheung, A.Y., T. McNellis and B. Piekos,199310112231229Davydov, V.V.,1993658588Domingo, J.I., R.T. Francisco, L. Francisco, P.M. Edwardo and T. Manuel,2001In vivo sucrose stimulation of colour change in citrus fruit epicarps; Interaction between nutritional and hormonal signals.]]>112244250Fedotcheva, N.I., A.P. Sokolov and M.N. Kondrashova,2006414145Hortensteiner, S., J. Chinner, P. Matile, H. Thomas and I.S. Donnison,2000Chlorella protothecoides: Characterization of degreening and cloning of degreening-related genes.]]>42439450Hortensteiner, S.,2006575577Jacob-Wilk, D., D. Holland, E.E. Goldschmidt, J. Riov and Y. Eyal,199920653661Kim, Y.S.,200235443451Matile, P., S. Hortensteiner and H. Thomas,1999506795Mayfield, S.P. and A. Huff,1986Citrus sinensis Epicarp.]]>813035Pruzinska, A., I. Anders, S Aubry, N. Schenk, E. Tapernoux-Luthi, T. Muller, B. Krautler and S. Hortensteiner,2007In vivo participation of red chlorophyll catabolite reductase in chlorophyll breakdown.]]>19369387Puntel, R.L., C.W. Nogueira and J.B.T. Rocha,2005in vitro.]]>30225235Puntel, R.L., D.H. Roos, D. Grotto, S.C. Garcia, C.W. Nogueira and J.B.T. Rocha,2007in vitro: A comparative study using the colorimetric method and HPLC analysis to determine malondialdehyde in rat brain homogenates.]]>815162Thomas, H., H.J. Ougham, C. Wagstaff and A.D. Stead,20035411271132