It should be remembered that a single complete defoliation of a herbaceous annual may so incapacitate the assimilation that no stores are available for seeds, tubers, &c., for another year, or at most so little that feeble plants only come up. In the case of a tree matters run somewhat differently; most large trees in full foliage have far more assimilatory surface than is immediately necessary, and if the injury is confined to a single year it may be a small event in the life of the tree, but if repeated the cambium, bud-stores and fruiting may all suffer.
Warming (1909: 220) quotes Griffon (1898), to the effect that the assimilatory activity is less in the halophytic form than in the ordinary form of the same species.
Hence during the day the assimilatory processes of these cells are overbalanced by their wear and tear, and the end-result is that the cell attains an atomic condition less favourable to further disintegration than to reintegration.
It is more probably abeyance of external function during a periodic internal assimilatory phase.
Two processes conjoin to initiate the assimilatory phase.