Ultrastructure of Citrus Leaves Infected by Huanglongbing (Greening) Disease
Article Sidebar
Main Article Content
Abstract
Observation of Huanglongbing; HLB (Greening) disease in Chiang Mai and Chiang Rai citrus orchards were found that diseased leaves shown vein yellowing, severe chlorosis with green main vein and yellow blochting, Sometime the symptom that resembles zinc deficiencies. Fruit is small and fall prematurely. Studying the ultrastructure of citrus HLB disease under transmission electron microscope (TEM), leaf samples were cut the midrib and prefixed with 2.5% glutaraldehyde in 0.1 M phosphate buffer. After a postfixation in 1 % osmium tetroxide then the samples were dehydrated in ethanol and acetone then embedded in Spurr’s resin. Ultrathin section were prepared with ultramicrotome and stained with uranyl acetate, lead citrate and observed under TEM. Electron micrographs of ultrathin sections revealed that fastidious bacterium was found in the phloem cells or in adjacent phloem cells of the midribs of HLB symptom leaf but no pathogenic body in healthy leaf.
Article Details
References
Anonymous. 2001. Food and Agricultural Organization Committee. (Online). Available: http://www.fag.org/es/ESC/esce/cmr/cmmo ts/CMRCIRE.htm (June 30, 2003).
Murray, R.G.E. and K.H. Schleifer. 1994. Taxonomic notes: a proposal for recording the properties of putative taxa of procaryotes. International Journal of Systematic Bacteriology. 44:174 –176.
Ohtsu , Y., M. Prommintara, S. Okuda, T. Goto, T. Kano, K. Nakashima, M. Koizumi, J. Imada and K. Kawashima. 2002. Partial purification of Thai isolate of citrus Huanglongbing (Greening) bacterium and antiserum production for serological diagnosis. Journal of General Plant Pathology. 68: 372-377.
Ruangwong, O. and A. Akarapisan. 2006. Detection of Candidatus Liberobacter asiaticus causing citrus huanglongbing disease. Journal of Agricultural Technology. 2(1): 111-120.
Su, H. –J. 2001. Citrus greening disease. (Online). Available: http://www.agnet.org/library/ article/tn2001002.html. (March 26, 2003).
Su, H. –J. and A.-L. Huang. 1990. The nature of likubin organism, life cycle morphology and possible strains. pp. 106-110. In: B. Aubert, S. Tontyaporn and D. Buangsuwon (eds.). Rehabilitation of Citrus Industry in the Asia Pacific Region. Proceedings of the Asia Pacific International Conference on Citriculture, Chiang Mai.
Timmer, L.W., S.M. Garnsey and J.H. Gerham (eds.). 2000. Compendium of Citrus Disease. 2nd ed. APS Press, St. Paul, Minnesota. 90 pp.
Whiteside, J.O., S.M. Gernsey and L.W. Timmer (eds.). 1988. Compendium of Citrus Disease. APS Press, St. Paul, Minnesota. 80 pp.
