Response of seedlings of radish (Raphanus sativus) to osmotic shock and external hydrostatic pressure

Abstract

Response of seedlings of radish (Raphanus sativus) fo osmotie shock and external hydrosfafic pressure. -Physiol. Plant. 87: 609-615.The effeefs of an osmotie shoek (300 mA/ mannitol, -0.67 MPa) or/and increased external hydrostatic pressure on seedlings (42-h-germinated seeds) of radish (Raphanus sativus L. cv, Tondo Rosso Quarantino) were invesfigated. The osmotic shock did not inhibit H* extrusion and net K* upfake, and did nof affect the levels of malic aeid, reducing sugars, sucrose or amino acids or of the energy eharge (i.e. the synthesis of energy-rich phosphafe bonds), buf inhibited the synthesis of proteins, RNA and DNA, measured as incorporation of labelled precursors. When the osmotic shoek was applied together with an increased external hydrostafic pressure of the same magnitude (+0.67 MPa), fhe same metabolic parameters and the inhibition of synthesis of RNA and DNA were not substantially affected, while the inhibition of protein synthesis was practically reversed and the energy charge decreased; the recovery of protein synthesis was nof due to a change in labelled leueine upfake capability. Increased external hydrostatic pressure alone decreased fhe energy eharge withouf affecting the other parameters considered. The possibility that protein synthesis activity is directly controlled by eell furgor pressure (internal hydrostatic pressure) is discussed.

Ma2± and water stress effects on germination and growth of Nicotiana tabacum var. BEL W3

“…Germination inhibition by osmotic stress is a well known phenomenon in a great number of species (HEGARTY & Ross, 1978;COCUCCI et al, 1993) and many metabolic alterations have been studied (JONES & ARMSTRONG, 1971). Few are knowledges upon the effect of heavy metals on the seed germination (ARDUINI et al, 1995).…”

The rice Mybleu transcription factor increases tolerance to oxygen deprivation in Arabidopsis plants

“…Extraction and determination of adenylate nucleotide levels were performed on samples from three independent experiments according to Cocucci et al (1993) with minor modifications. Frozen samples (0.2 g FW) of untreated and treated WT and high expressing (HE) transgenic plants were ground in liquid nitrogen and extracted with ice-cold 0.6 M perchloric acid.…”