Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.1999.45.52AgujaSocorro E. MohammadPear ShiraishiMasaya 1199921The development of chloroplasts in the mesophyll cells of control and urea-applied satsuma mandarin leaves were studied. At 20 days after budding (DAB) active differentiation of chloroplasts in urea-applied trees was evident. However, on a length times width basis, chloroplasts were small in both palisade (1.99 × 0.70 μm2) and spongy (2.78 × 1.50 μm2) layers that contained few small (0.53 - 0.72 × 0.39 - 0.57 μm2) starch grains. The thylakoid layers per chloroplast were lesser (2.80) in this treatment compared to control (3.72). At 40 DAB, both control and urea-applied trees reached chloroplast maturity, but control trees had bigger chloroplast (4.87 × 2.39 μm2) in the palisade layer cells which contained extremely large and numerous starch grains with few dilated thylakoid layers. Degenerating chloroplasts in the spongy layer cells of control trees were characterized by the disappearance of the outer membrane. While urea-applied trees had smaller chloroplast (4.56 × 2.39 μm2) in the palisade layer. Further, few small starch grains, thylakoid-filled stroma and many lipid droplets were found. Moreover, thylakoid layers were about to dilate but outer membrane of the chloroplasts remained intact in both palisade and spongy layer cells. Compared to the palisade layer cells, chloroplasts in the spongy were bigger (5.32 x 1.95 μm2).]]>Carmi, A. and I. Shomer,1979Phaseolus vulgaris L.).]]>44479484Chonan, N., H. Kawahara and T. Matsuda,197746387392Embleton, T.W., W.W. Jones, C.K. Labanauskas and W. Fleuther,19731973pp: 183-211pp: 183-211Feigenbaum, S., H. Bielorai, Y. Erner and S. Dasberg,198715N labeled nitrogen applied to mature citrus trees.]]>97179187Harrak, H., T. Lagrange, C. Bisanz-Seyer, S. Lerbs-Mache and R. Mache,1995108685692Kirchanski, S.J.,1975Zea mys L.]]>62695705Leon, P., A. Arroyo and S. Mackenzie,199849453480Makino, A. and B. Osmond,199196355362Mullet, J.E.,1993103309313Nelson, T. and J.A. Langdale,19891313Nii, N., M. Kato, Y. Hirano and T. Funaguma,199362547554Possingham, J.V.,198031113129Pyke, K.A. and R.M. Leech,1992Arabidopsis thaliana.]]>9910051008Pyke, K.A. and A.M. Page,1998116797803Reiter, R. S., S.A. Coomber, T.M. Bourett, G.E. Bartley and P.A. Scolnik,1994Pale cress.]]>612531264Thomson, W.W. and T.E. Weier,1962Phaseolus vulgaris.]]>4910471055Thomson, W.W. and J.M. Whatley,198031375394Whatley, J.M.,1971Phaseolus vulgaris during development under conditions of nutrient deficiency.]]>70725742Wykoff, D.D., J.P. Davies, A. Melis and A.R. Grossman,1998Chlamydomonas reinhardtii.]]>117129139