Callose

Huhner-auge, . corn (the callosity), -eiweiss, n. white of egg. 

Brundrett MC, Enstone DE, Peterson CA. A herherine-aniline blue fluorescent staining procedure for suberin, lignin and callose in plant tissues. Protoplasma 1988 146 133-142. 

The pollen tube walls contain callose-like polysaccharides that absorb aniline blue. That is why this method is very useful to detect pollen tube elongation and to understand how the tube penetrates the inside of the pistil tissue. The pollen tubes grow from the surface ofthe stigma through... 

The medium for maceration (HC1 or NaOH) depends on the material and purpose of staining. If fresh material is at hand, NaOH is best. It keeps material at the proper pH even after washing a few times in water. It is very important to achieve a pH of 9.0-10.0 to obtain the proper fluorescence of callose after staining with aniline blue. 

The fixed material is already acidic and can be macerated in HC1. After maceration, material has to be rinsed in distilled water and left in phosphate buffer for a few hours to achieve a pH of about 9.5. If the pH is lower in the specimen, the fluorescence of callose disappears. 

This method gives a bright fluorescence of callose but also a side effect due to the presence of chlorophyll. Chlorophyll dispersed in the specimen yields a red fluorescence all around the tissue, especially a red layer on the surface of the organs due to chlorophyll deposition in any lipid substances, such as a cuticle. 

In many plant species compatible pollen tubes grow directly down inside the style as a bundle of long smooth tubes with bright callose plugs. Only in female sterile plants of Oenothera mut. brevistylis was branching of pollen tubes found in the style and ovary (7). 

Dumas C, Knox RB. Callose and determination of pistil viability and incompatibility. Theor Appl Genet 1983 67 1-10. 

Vishnyakova M A. Callose as an indicator of sterile ovules. Phytomorphology 1991 41 245-252. 

Currier HB, ShihCY. Sieve tubes and callose in Elodea leaves. AmJBot 1968 55 145-152. 

Currier HB, Strugger S. Aniline blue and fluorescence microscopy of callose in bulb scales of Allium cepa L. Protoplasma 1956 4 552-559. 

Evert RE, Derr WF. Callose substance in sieve elements. Am JBot 1964 51 552-559. 

Most of the biochemical studies on polysaccharide synthesis to date have been concerned with the formation of homopolymers even when it is known that the synthesis of the homopolymer chain occurs in vivo as part of a heteropolysaccharide (4-6). Cytochemical investigations have made no such distinctions and the polymers located by these studies have nearly always been sites at which heteropolymers were present and where deposition in the wall occurred. The bulk of the polysaccharides that occur in the wall, with the exception of cellulose and callose, are heteropolymers. Generally the polysaccharides of the hemicelluloses and pectins are composed of poly-... 

Innocenti, G.M. (1981) Growth and reshaping of axons in the establisment of visual callosal connections. Science 212 824-827. 

MacMaster, F.P., Keshavan, M.S., Dick, E.L., and Rosenberg, D.R. (1999) Corpus callosal signal intensity in treatment-naive pediatric obsessive compulsive disorders. Prog Neuropsychopharma-col Biol Psychiatry 23 601-612. 

In classical genetic self-incompatability systems, the site of pollen tube inhibition is on the stigma surface or somewhere in the style. A pollen grain may fail to genninate, or produces a tube that grows abnonnally and is soon occluded by callose, or... 

EmbrYOSTEGA The caplike callosity near the hilum of certain seeds, which is detached by the radicle in germination. 

Attempts to produce cellulose from UDP-Glc using enzymes of isolated plasma membranes from higher plants have usually yielded the ( -1,3-linked glucan (callose) instead. This is a characteristic polysaccharide of plant wounds which, as healing occurs, is degraded and replaced by cellulose.140144 Callose... 

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