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At least 667 records · Page 37Linked to original sources
PubMed1993

Release of active cytokinin by a beta-glucosidase localized to the maize root meristem.

A beta-glucoside encoded by a cloned Zea mays complementary DNA (Zm-p60.1) cleaved the biologically inactive hormone conjugates cytokinin-O-glucosides and kinetin-N3-glucoside, releasing active cytokinin. Tobacco protoplasts that transiently expressed Zm-p60.1 could use the inactive cytokinin glucosides to initiate cell division. The ability of protoplasts to sustain growth in response to cytokinin glucosides persisted indefinitely after the likely disappearance of the expression vector. In the roots of maize seedlings, Zm-p60.1 was localized to the meristematic cells and may function in vivo to supply the developing maize embryo with active cytokinin.

Adenine↗
PubMed1978

Cytological effects of phenothiazine tranquilizing agents on barley meristems.

A growth reduction of 30--40% was noted in barley plants grown in two phenothiazine tranquilizers. Similar reductions were noted in the number of mid-anaphase cells, indicating the reduced growth could have been the result of a reduced mitotic rate. Also observed were several types of chromosomal aberrations. Electron microscopy revealed less endoplasmic reticulum and cytoplasmic organelles in the treated cells than in untreated cells. Various sized discontinuities in the nuclear membrane was the most frequent abnormality observed in the electron micrographs. The abnormal nuclear membrane was possibly a result of enzyme degradation.

Antipsychotic Agents↗
PubMed1984

The subcellular concentration of ions and elements in thin cryosections of onion root meristem cells. An electron-probe EDS study.

Quantitative electron-probe energy dispersive X-ray microanalysis has, for the first time, been accomplished at a subcellular level in plant tissue using cryofixed and thin freeze-dried cryosections. The subcellular concentrations of Na+, Cl-, K+, P, S, Mg2+ and Ca2+ were measured in mol/kg dry weight in two types of root meristematic cells of the onion, Allium cepa. The cell wall of the meristematic cells had much higher concentrations of K+ and Ca2+ than was found in the intracellular compartments. Storage granules in the protoderm cells were about 6-12 times lower in P and were about four times higher in S as compared to other intracellular compartments. Comparison between the concentrations of ions and other elements in meristematic plant cells and in mouse cardiac myocytes confirms that major differences in cytoplasmic Na+ and Cl- concentrations do indeed exist between these cell types.

Animals↗