Apple proliferation (AP) and pear decline (PD) are the most severe diseases in pome fruit growing areas. AP-infected trees show typical symptoms such as witches’ broom, enlarged stipules, tasteless, and dwarf fruits. PD-infected pears show a progressive weakening, reduced terminal growth, smaller fruits, and die within weeks (quick decline) or years (slow decline). The diseases are caused by th...

The necessity of controlling the vegetative growth fruit trees is a growing concern for farmers since vigorous plants tend to have lower yields. use chemicals that inhibit plants, such as prohexadione-calcium (PCa), an inhibitor gibberellins which currently used regulator apple trees, agricultural practice aimed help in reducing pruning time and cost. Pear grafted on rootstocks present high rat...

The response of suspension-cultured pear (Pyrus communis cv Bartlett) cells to heat stress was studied using three viability tests: regrowth (culture growth during 10 days after stress); triphenyltetrazolium chloride reduction; and electrolyte leakage. Critical (50% injury) temperatures for a 20-minute exposure were 42 degrees , 52 degrees , and 56 degrees C, respectively, for these viability t...

Salicylic acid inhibited ethylene formation from ACC in self-buffered (pH 3.8) pear (Pyrus communis) cell suspension cultures with a K(1) (app) of about 10 micromolar after 1 to 3 hours incubation. Inhibition appeared noncompetitive. Among 22 related phenolic compounds tested, only acetylsalicylic acid showed similar levels of inhibition. Inhibition by salicylic acid was inversely dependent on ...

Fractionation of pectic polysaccharides from the juice of ripening ;Bartlett' pears (Pyrus communis) gave two general types of polyuronides. The major type was a homogalacturonan (HGA) whose molecular weight decreased upon ripening. The other type comprised heteropolymers composed of various amounts of arabinose, rhamnose, and galactose. Treatment of the major arabinose-containing heteropolymer...