Pear psylla (Cacopsylla pyricola Foërster) is the most serious pest of the European pear (Pyrus communis L.) in the production regions of Europe and North America. Nine plant germplasm introductions of pear from Central Europe recently released from plant quarantine were evaluated for nymphal feeding antixenosis, a primary mode of resistance known to be correlated with ovipositional antixenosis...

Uptake of Ca(2+) by suspension-cultured pear (Pyrus communis L. cv Passe Crassane) cells and protoplasts was significantly enhanced by exposure to 38 degrees C compared to 25 degrees C. The increased uptake was specific for Ca(2+) and was not due to cell wall binding. Tissues pretreated at 38 degrees C showed increased uptake even upon return to 25 degrees C. Treatment with carbonylcyanide m-ch...

Ripening reactions in pears (Pyrus communis L.) were differentially affected by an aminoethoxy analog of rhizobitoxine (l-2-amino-4-[2-aminoethoxy]-trans-3-butenoic acid) (AAR). Ethylene production of both ;Anjou' and ;Bartlett' pears was inhibited by AAR. Decrease in firmness, increase in protein N and soluble pectin were delayed by AAR in ;Anjou' but not in ;Bartlett' pears. While loss in mal...

Polysome profiles were examined from lyophilized peel tissue of ripening pear (Pyrus communis, L. var. Passe-Crassane). Messenger RNA chains bearing up to eight ribosomes (octamers) were resolved and exhibited the highest absorption peak when ribonuclease activity was eliminated during extraction. Neither normal ripening nor the increase of large polyribosomes that normally accompanies ripening...

The aerial parts of Stachys laxa Boiss. and Buhse. from Siah-bishe in Mazandaran province, Stachys trinervis Aitch. and Hemsl. from Karaj in Alborz province, Stachys subaphylla Rech. F. and Stachys turcomanica Trautv. from Golestan province have been collected in May 2008. Total extracts were obtained through MeOH/H2O (80/20) and then partitioned between CHCl3, EtOAc and MeOH. These fractions a...