gall

views updated May 18 2018

gall1 / gôl/ • n. 1. bold, impudent behavior: the bank had the gall to demand a fee.2. the contents of the gallbladder; bile (proverbial for its bitterness). ∎  an animal's gallbladder. ∎  used to refer to something bitter or cruel: accept life's gall without blaming somebody else.gall2 • n. 1. annoyance; irritation: he imagined Linda’s gall as she found herself still married and not rich.2. (esp. of a horse) a sore on the skin made by chafing.• v. [tr.] 1. make (someone) feel annoyed: he knew he was losing, and it galled him.2. make sore by rubbing: the straps galled their shoulders.gall3 • n. an abnormal growth formed on plants and trees, esp. oaks, in response to the presence of insect larvae, mites, or fungi. ∎  [as adj.] denoting insects or mites that produce such growths: gall flies.

gall

views updated Jun 08 2018

gall (cecidium) An abnormal growth or swelling in a plant. The formation of a gall may be induced by infection of the plant with bacteria or fungi, or by attack from certain mites, nematodes, or insects. Galls may be formed on roots, stems, or leaves. Some galls (e.g. clubroot and crown gall) are symptoms of disease; others appear to do little harm to their hosts, while some may actually be beneficial to the plant (e.g. nitrogen-fixing root nodules of legumes). Galls are variously structured, ranging from a simple outgrowth to a large and histologically complex structure with up to 5 distinct tissue layers with nutritive zones. Most gall-forming species are members of the insect family Cynipidae (Hymenoptera), and often have complex, heterogynous life cycles, utilizing different parts of the same host or different hosts, which are generally Quercus species. The mechanism of gall initiation and development is little understood, and the study of galls offers an unparalleled opportunity for physiological and ecological research. The gall community supports a large number of parasitoids, hyperparasitoids, and inquilines (species which use the gall but do not kill its occupant).

gall

views updated May 23 2018

gall(cecidium) An abnormal growth or swelling in a plant. The formation of a gall may be induced by infection of the plant with bacteria or fungi, or by attack from certain mites, nematodes, or insects. Galls may be formed on roots, stems, or leaves. Some galls (e.g. clubroot and crown gall) are symptoms of disease; others appear to do little harm to their hosts, while some may actually be beneficial to the plant (e.g. nitrogen-fixing root nodules of legumes). Galls are variously structured, ranging from a simple outgrowth to a large and histologically complex structure with up to five distinct tissue layers with nutritive zones. Most gall-forming species are members of the insect family Cynipidae (Hymenoptera), and often have complex, heterogynous life cycles, utilizing different parts of the same host or different hosts, which are generally Quercus species. The mechanism of gall initiation and development is little understood, and the study of galls offers an unparalleled opportunity for physiological and ecological research. The gall community supports a large number of parasitoids, hyperparasitoids, and inquilines (species which use the gall but do not kill its occupant).

gall

views updated May 18 2018

gall (cecidium) An abnormal growth of a plant tissue or organ elicited by a foreign organism. Galls can take a wide variety of forms, but most frequently occur as swellings or pits in stems, roots, leaves, and buds. Organisms responsible for their formation include bacteria, viruses, fungi, nematodes, mites, and insects. The gall structure can be quite complex, with several distinct cell layers, or relatively simple and undifferentiated, but is typically very distinct from surrounding normal tissue and often is characteristic of the eliciting organism. It can involve cell enlargement (hypertrophy) and/or cell proliferation (hyperplasia). The mechanisms underlying gall formation are known in only a few cases. The bacterium Agrobacterium tumefaciens, which is responsible for crown galls, induces a genetic change in infected host tissue by transfer of a plasmid bearing tumour-forming genes. Insects may secrete substances in their saliva that induce gall formation, or in some cases may transmit viruses or other genetic carriers that affect the plant genome.

gall

views updated May 23 2018

gall1 bile; bitterness. XII. — ON. gall, corr. to OE. ġealla, OS., OHG. galla (Du. gal, G. galle) :- Gmc. *ʒallam, *ʒallan-, -ōn, f. IE. *ghol- *ghel- (repr. by Gr. kholé, L. fel bile); cf. YELLOW.

gall

views updated May 17 2018

gall2 swelling, pustule XIV; bare spot XVI. — MLG., MDu. galle (Du. gal), corr. to OE. ġealla sore on a horse, (M)HG. galle, ON. galli fault, flaw, perh. identical with prec.
Hence galled sore from chafing XIV (cf. OE. ġeallede); whence gall vb. chafe, fret XIV.

gall

views updated Jun 27 2018

gall bile; proverbial for its bitterness, and in biblical allusion associated with wormwood; the gall of bitterness is the extremity of bitterness.

gall

views updated May 23 2018

gall Abnormal swelling of plant tissue stimulated by an invasion of any of a wide variety of parasitic or symbiotic organisms, including bacteria, fungi, insects and nematodes. Most gall organisms stunt but do not kill the affected plants.

gall

views updated May 29 2018

gall3 excrescence growing on the oak, etc. XIV. — (O)F. galie :- L. galla.