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Interference of phytohormones (jasmonic, gibberellic, and abscisic acids) and synthetic growth regulator melafen on Ca2+ translocation across the membrane of plasma membrane vesicles prepared from dormant potato ( Solanum tuberosum L.) tubers was studied. The activity of plasma membrane Ca2+, Mg2+-ATPase was stimulated by melafen and jasmonic and gibberellic acids and suppressed by abscisic acid. These substrances did not change the passive membrane permeability for Ca2+. The pattern of the effect of melafen on the activity of Ca2+,Mg2+-ATPase depended on the presence of phytohormones in incubation medium. When melafen and each phytohormone were simultaneously added to incubation medium, their effects were not additive, which indicates that the effects of the tested compounds on the Ca2+ uptake into the plasma membrane vesicles are interdependent. Apparently, the interaction between the phytohormones and plasma membrane components modulates the response to melafen. [ABSTRACT FROM AUTHOR]

Technology is developed for manufacturing dispensing nozzles made of zirconium dioxide. Test-industrial batches of objects, manufactured using separate and combined stabilization of ZrO2, are produced and tested under industrial conditions. Dispensing nozzles differ in open porosity. The service behavior for the objects developed and imported analogs is compared. The efficiency of using dispensing nozzles made of zirconium dioxide with porosity less than 12% during operation in a CBCM is demonstrated. [ABSTRACT FROM AUTHOR]

The rate of Ca2+ accumulation in plasmalemma vesicles isolated from quiescent and sprouting potato ( Solanum tuberosum L.) tubers and the effect of 10−5–10−10 M jasmonic acid on the accumulation of Ca+2 in plasmalemma vesicles and its efflux were studied. It was found that potato tuber plasmalemma contains a Ca+2,Mg+2-ATPase whose activity decreases upon the transition from forced quiescence to growth. The direction of the effect of jasmonic acid on Ca+2,Mg+2-ATPase (stimulation or suppression) depends on the physiological state of tubers and the phytohormone concentration. [ABSTRACT FROM AUTHOR]

The mechanism of the stimulatory effect of melafen on potato tuber sprouting was studied. The treatment with 10−8 M melafen intensified division and stretching and activated granular endoplasmic reticulum of apical meristem cells. An increase in the activity of membrane-bound H+-ATPase in the plasmalemma of parenchymal cells of melafen-treated potato tubers and enhancement of passive proton permeability of the plasmalemma was observed. In vitro studies showed that melafen at concentrations of 10−5−10−12 M stimulated the activity of plasmalemmal H+-ATPase in a concentration-dependent manner. [ABSTRACT FROM AUTHOR]

The introduction of the thaumatin gene into potato plants was accompanied by a decrease in the activity of H+-ATPase in the plasmalemma ( PL) of tuber cells. When tubers were released from dormancy, the enzyme was activated in the tuber cells of both the original and transgenic plants. Experiments performed in vitro demonstrated that sensitivities to ambiol ( AM) and jasmonic acid (JA) of H+-ATPase in the PL of tubers from the original plants were lower after the release from a period of deep dormancy. In preparations from the tubers of transgenic plants, the situation was reversed. The differences between the activities of H+-ATPase in the PL preparations produced from the original and transgenic tubers that sprouted under the action of AM and JA were detected. Thus, the overexpression of the thaumatin gene in potato plants changed the properties of H+-ATPase from PL. [ABSTRACT FROM AUTHOR]

Abscisic acid (ABA) fully suppressed the development of the hypersensitive necrosis of potato tuber slices to crude elicitor from Phytophthora infestans and arachidonic acid (AA) if supplied before or up to 6 to 8 h after elicitor treatments. Later application of ABA only reduced the necrotic response. Added to highly purified plasma membrane preparation from tuber tissue, ABA eliminated the AA-induced inhibition of the plasma membrane-bound (K+ + Na+ + Mg2+) ATPase. It is suggested that ABA counteracts AA in the membrane. [ABSTRACT FROM AUTHOR]