Phytochrome-mediated germination control of maize caryopses.

Maize caryopses sown in water germinate equally well either in darkness or under any light regime. However, when they are imbibed in mannitol solutions, continuous far-red light proves to be strongly inhibitory on the final germination as compared to darkness. Similar but less pronounced inhibition is also exhibited by continuous red or blue light.

On the differential divisions and preprophase microtubule bands involved in the development of stomata of Vigna sinensis L.

The manifestation of premitotic cell polarity and the resultant structural asymmetry of the differential divisions participating in the development of stomata of Vigna sinensis vary considerably. However, two morphologically distinct types of differential division were distinguished: (a) 'asymmetrical differential divisions', in which the premitotic polarization of the cell, the eccentric position of the nucleus during division and the differences in size and organization of the daughter cells are obvious; and (b) differential divisions in which the above features are inconspicuous or almost absent. The former occur in the ordinary protodermal cells, the latter in some meristemoids.

Phytochrome effect on free amino acid metabolism of higher plants.

Activated phytochrome lowers the free amino acid pools of all plants investigated by about 15%. The action of red light is preferentially directed to Asp, Glu and Phe. Exogenously supplied Leu-U-(14)C is incorporated more quickly into protein of red-light-treated samples compared with dark controls.

Red-light effect on tracer distribution in etiolated leaf tissue.

A survey of the distribution of tracer in preparations from etiolated corn leaf sections which had been fed with uniformly labeled glucose (glucose-U-C(14)) and then exposed to ten minutes of red light, failed to show the presence of any new or specifically labelled metabolite. The earliest consequence of the light-treatment was a loss of tracer from the soluble sugars accompanied by an accumulation of C(14) in the cell-wall polysaccharides. Other light effects were reduced labelling of amino acids and higher phosphate turnover rates.