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Photosynthetic Control in Chloroplasts Suspensions Frozen in Liquid Nitrogen in the Presence of Glycerol
- Kaminski, K.
- Zeitschrift für Naturforschung 2014 v.32 no.3-4 pp. 254-256
- Spinacia oleracea, adenosine diphosphate, chloroplasts, electron transfer, freezing, glycerol, nitrogen, oxidants, photosynthesis, spinach, thawing
- Type A complete spinach chloroplasts (photosynthetic control ratio ≅ 5) were frozen in liquid nitrogen, in the presence or absence of 50 percent glycerol (v/v). By considering five parameters related to the non cyclic electron transfer in the light (oxidant : K-ferricyanide) it was shown that the uncoupling due to freezing and thawing was partially prevented by glycerol. However glycerol was responsible for a slight uncoupling in fresh chloroplasts. The clearest uncoupling effect of freezing, and chiefly of glycerol, concerned the inhibition of the electron flow which follows the stimulation caused by a limiting quantity of ADP (state 4).The relative decrease of the photosynthetic control and of related parameters due to the use of this method of preservation, has to be balanced with the improved homogeneity and convenience resulting from it.