Desiccation Injury in Mosses

Abstract

SUMMARYIntra-speclfic differences in desiccation injury are shown in collections of Acrocladium cuspidatum, Climadum dendroides and Hypnum cupressiforme from habitats subjected to a wide range o moisture stresses. The degree of desiccation tolerance is correlated with degree of moisture stress in the habitat. Desiccation injury was measured as the decline in the initial rate of photosynthesis on remcistening. Collections of species from habitats in which severe moisture deficits occur show a slower decline in photosynthesis on desiccation and a more rapid recovery of function on wetting than collections from hahitats with no appreciable moisture deficits. The results are discussed in terms of their ecological and physiological significance.

Desiccation Effects and Cation Distribution in Bryophytes

“…The same species obtained from a water seepage on a stone wall showed a desiccation resistance index of 21-6, a recovery index of 63-8 and contained 517 /^mol g~p otassium (compared to values of 76*1, 110-7 and 196 for the dry habitat sample). Lee and Stewart (1971) and Stewart and Lee (1972) have also reported that races of mosses from wet and dry habitats show differences, after desiccation, in terms of their ability to show recovery of photosynthesis and the degree to which NADP+-linked glyceraldehyde 3-phosphate dehydrogenase is stimulated by glutathione.…”

“…Work on the sensitivity of bryophytes to desiccation stress has included studies of changes in photosynthetic and respiratory capacity (see Lee and Stewart, 1971;Proctor, 1974, 1976, and references therein) and the stabiHty of polyribosomes (e.g. Tucker and Bewley, 1976;Dhindsa and Bewley, 1977) in relation to depth and duration of desiccation.…”

The Water Relations of the Alga Cyanidium caldarium in Soil

“…The distributions of the lichen symbiotic association (Rogers, 1971) and of mosses (Lee & Stewart, 1971) have been correlated in at least some cases with desiccation tolerance. In lichens, it may be the fungal partner which is responsible for the desiccation resistance of the thallus, since fungi are able to tolerate lower water potentials than any other organisms This work was supported by a research grant from the U.S. National Science Foundation (Scott, 1957).…”

EFFECT OF DESICCATION ON DNA SYNTHESIS AND THE CELL CYCLE OF THE MOSS POLYTRICHUM FORMOSUM

“…Several studies have been carried out on this phenomenon, and shown that, on rehydration, the gametophytes are able to recover most of their metabolic activities. Respiration and photosynthesis have been shown to resume either immediately, or a short time after the addition of water (Hinshiri and Proctor, 1971;Lee and Stewart, 1971;Bewley, Tucker and Gwozdz 1974;Bewley and Gwozdz, 1975;Bewley et al, 1978;Proctor, 1974, 1979;Peterson and Mayo, 1975;Gupta, 1976, 1977 andreferences therein). Concerning RNA metabolism, Bewley (1972Bewley ( , 1973, Tucker and Bewley (1976), Dhindsa and Bewley (1977) have pointed out, that polyribosomes are conserved during desiccation of the terrestrial moss Tortula ruralis.…”