Using transgenic Nicotiana plumbaginifolia seedlings in which the calcium reporter aequorin is targeted to the chloroplast stroma, we found that darkness stimulates a considerable flux of Ca(2+) into the stroma. This Ca(2+) flux did not occur immediately after the light-to-dark transition but began approximately 5 min after lights off and increased to a peak at approximately 20 to 30 min after ...

The plant plasma membrane H+-ATPase (EC 3.6.1.3) had been shown to be essential for generating the membrane potential and concomitant electrochemical gradient, the means for translocating various solutes such as cations, anions, amino acids, and sugars across the plasma membrane by secondary transport systems (6, 7, 9, 10). Two cDNAs, OSA1 and OSA2, which encode H+-ATPase from rice cali (Oryza ...

In plants, as in all organisms, the plasma membrane serves two main roles: (1) the transport of solutes, both into and out of each cell, and (2) sensory transduction, i.e., the sensing and initiation of the cellular response to changing environmental conditions. Recently, considerable progress has been made in elucidating the role of specific plasma membrane proteins in these two processes. His...

INTRODUCTION. ........ .............................. ......................... 311 The types used.. ................................................................. 311 The work of the early hybridizers Experimental work.. ............ .............................. The parental strains and their beha;ior ............................ Nicotiana rustica humililis crossed with Nicotiana panicula...

Activated oxygen or oxygen free radicals have been implicated in a number of physiological disorders in plants including freezing injury. Superoxide dismutase (SOD) catalyzes the dismutation of superoxide into O2 and H2O2 and thereby reduces the titer of activated oxygen molecules in the cell. To further examine the relationship between oxidative and freezing stresses, the expression of SOD was...