摘要:

AbstractSix bryophyte species were investigated:Plagiochila spinulosa, Hylocomium splendens, Scorpiurium circinatum, Tortula ruraliformis, Rhacomitrium aquaticum and Andreaea rothii.Of these, all exceptA. rothiishowed clear evidence of seasonal variation in desiccation tolerance, as measured by net assimilation following 24 h remoistening.(2) In general these species showed low desiccation tolerance in autumn (October) and winter (January) and increased tolerance in spring and summer.Hylocomium splendenswas a partial exception in showing relatively high tolerance in January and little change from then until July.(3) On the whole, the seasonal pattern of desiccation response accords well with what might be expected from conditions in the habitats of the plants. The results are briefly discussed in relation to distribution of rainfall and some microenvironmental factors, and compared with some data from the literature.

ISSN:0373-6687    

DOI:10.1179/jbr.1976.9.2.239

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

摘要:

Abstract(1) Gas exchange measurements onRhytidiadelphus loreusandAnomodon viticulosusfollowing re-moistening after a period of desiccation showed an initial stimulation of respiration, followed immediately by progressive recovery of photosynthesis within the first 1–6 h. A. viticulosus after 48 h dry reached the compensation point within a few minutes of re-moistening; R. lore us after 7 days dry reached the compensation point after about 4 hours.(2)Hylocomium splendens,R. loreusand Tortula ruraliformiswere subjected to the following patterns of alternating wet and dry periods over a period of 18 weeks: continuous dry, 1 day wet/6 days dry, 6 days wetll day dry, 1 day wet/1 day dry, 7 days wet/7 days dry, continuous wet.(3) OnlyT. ruraliformisstill attained a positive net assimilation rate after the continuous dry treatment for the duration of the experiment. All three species retained a positive net assimilation rate throughout after all the remaining treatments.(4) A moist period of 24 h allowed substantially complete recovery from the after-effects of preceding desiccation.(5) Experiments in which two dry periods were separated by moist periods of 6 h, 24 hand 7 days showed that recovery inH. splendensandR. loreuswas incomplete in 6 h but confirmed that it was complete in 24 h.(6)H. splendensshowed constant or slightly increased desiccation-tolerance in successive dry periods.R. loreusshowed a well marked increase in tolerance (hardening) following a previous dry/wet cycle.(7) The effect of intermittent desiccation can be predicted approximately from the successive effect of the individual dry periods.(8) It is doubtful whether there is any specific deleterious effect of drying and re-moistening; any such effect that does exist can only be small.

ISSN:0373-6687    

DOI:10.1179/jbr.1976.9.2.249

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

摘要:

AbstractThe widespread occurrence of a number of bryophytes on British saltmarshes is reported. The communities in which bryophytes are most frequently found are discussed. These communities are more common on marshes on the west coast of Britain. Differences between moss assemblages on salt marshes in England and Wales and in Scotland are emphasised and the greater range of habitat preference demonstrated byGrimmia maritimain Scotland is commented upon.

ISSN:0373-6687    

DOI:10.1179/jbr.1976.9.2.265

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1976.9.2.275

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1976.9.2.279

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1976.9.2.281

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1976.9.2.282

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1976.9.2.283

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1976.9.2.i

出版商:Taylor&Francis    

年代:1976

数据来源: Taylor