01478naa a2200169 a 450000100080000000500110000800800410001910000220006024501490008226000090023152009440024065300170118465300230120170000200122470000150124477300490125916469412023-05-30       1988    bl uuuu     u00u1 u    #d1 aBERETTA, M. J. G.  aA comparison of histochemical staining reactions of the xylem occlusions in trees affected by citrus blight and declinio.h[electronic resource]  c1988  aDeclinio of citrus trees in Brazil, a vascular disorder of unknown cause, is similar to citus blight in Florida. Both diseases are characterized by zinc accumulation in trunk wood and xylem plugging, which results in restricted water flow in diseased trees. This dysfunetion is caused by the presence of xylem plugging. Amorphous and filamentous occlusions have been detected and reduced water flow has been correlataed with amorphous plugs. The histochemical staining reactions of plugs found in xylem vessels in trees with declinio and blight were compared. With both diseases the amorphous plugs reacted positively for callose, lignin, peactic substances, gums, proteins, and lipids. Filamentous plugs stained positively for lignins, gums, proteins, and lipids. These results showed that similar xylem plugs (amorphous and filamentous) were found in both declinio and blight, but the two plug types differ in their chemical composition.  aSweet orange  aYoung tree decline1 aBRLANSKY, R. H.1 aLEE, R. F.  tPlant Diseasegv.72, n.12, p.1058-1060, 1988