Galls


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Related to Galls: Gallstones, gallbladder, Gauls, Plant galls

Galls

 

(or cedicia), local pathological neoplasms on the organs of plants caused by special species of irritants and providing these irritants with a dwelling place and a source of food. Galls caused by invertebrate animals are sometimes called zoocecidia; those caused by fungi are called mycocecidia. The formation of galls is called gallogenesis and the irritants are called gallogens. The latter include viruses, bacteria (for example, Agrobacterium tumefaciens, which causes crown galls and goiters on the roots of apple trees), fungi (such as the irritant that causes bubble smut in corn), nematodes (especially rootknot nematodes), mites (quadrupeds), and insects (mainly gall wasps, gall midges, sawflies, aphids, and jumping plant lice); all of these lead a parasitic existence. Gallogenesis takes place in several steps and is stimulated by secretions from the salivary glands of the female irritants while they are laying the eggs, from the salivary glands of the larvae, and from the growing tubes of germinating spores, which contain certain free amino acids, compounds of an indol nature, and so forth. The further progress of gallogenesis is associated with local changes in the synthesis and metabolism of certain amino acids, phenol compounds, and proteins. The origin of crown galls, used as models in the study of tumor growth in animals and man, is linked to changes in the DNA in the infected cells of the organism. The structure of a gall depends on the type of the irritant, the nature of its localization in the infected organ, the number of individual irritants in the developing gall, the degree of mobility of the irritant, and the morphological structure of the infected tissues. The pathogens of many galls cause considerable damage to agriculture and forestry. They include the pathogens of potato canker, cabbage carina, bubble smut in corn, warts in geraniums, silver fir tree canker, and phylloxera in grapes. The pathogens of certain galls are used in the biologist’s fight against weeds. The galls on oaks, sumac, and pistachio trees contain a considerable amount of tannin.

E. I. SLEPIAN

References in periodicals archive ?
Forty-five days after the commencement of the test, all the galls were removed from the plants and counted (Table 2).
Ball-shaped galls are created by the fly and appear midway down on goldenrod stems beginning in late June to early July.
bedeguaris was found in the galls collected from Shahrestanak, Tabriz and Nazlou.
The researchers sampled soldiers from galls late in the summer.
Some saplings appear to be covered in the galls while adjacent trees are completely free of them.
The numbers of vein galls correlated negatively with the numbers of discoid and spherical galls per leaflet as well as the number of spherical galls correlated negatively with the numbers of discoid galls on C.
EMTs have been calling for more user-friendly products that still fit into the realities of their budgets," said Gary Christensen, president of Galls.
umbilicatus, galls from each of the 3 host plants within their respective overlapping ranges in 2 distant geographic and noncontiguous locations in Florida at a distance of approximately 350 km were compared.
The Gaels made a better show of things after the restart and three times they narrowed the gap to four points, but it was a game that St Galls never looked like losing.
They are all phytophagous thrips inducing leaf-fold and leaf-roll galls, where they breed and develop.
Galls with Eamon Trimble and son of former Down player of the same name, Ambrose Rodgers taking second half goals.