摘要:

Abstract(1) Net assimilation and respiration rates were measured at intervals after re-moistening, following various periods of desiccation, inHookeria lucens, Hylocomium splendens, Neckera crispa, Plagiochila spinulosa, Plagiothecium undulatum, Rhacomitrium lanuginosum, Rhytidiadelphus loreus, Saccogyna viticulosa, Scorpiurium circinatum and Tortula ruraliformis.(2)Rhacomitrium lanuginosumwas extremely resistant, recovering apparently normally after 239 days' desiccation at 32% R.H.;Plagiochila spinulosaandHookeria lucenswere the most sensitive.(3)Rhacomitrium lanuginosumandTortula ruraliformiswere most quickly damaged at the highest humidity (76%) andPlagiothecium undulatumat the lowest humidity tested (32%).(4)Saccogyna viticulosaandScorpiurium circinatumcombined relatively rapid impairment and slow recovery of assimilation with the capacity to survive long dry periods.(5) Dark respiration was relatively slow (commonlyc. 5–20% of net assimilation). It usually showed a slight initial stimulation and a longer-term build-up following moderate or prolonged desiccation.(6) Desiccation responses of bryophytes can be characterized in terms of parameters defining rate of loss of photosynthetic capacity with desiccationtime, rate of recovery after short periods of desiccation, and survival.

ISSN:0373-6687    

DOI:10.1179/jbr.1974.8.1.97

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

摘要:

AbstractAn electron microscope study of experimental and environmental lead poisoning of leaf cells from the mossRhytidiadelphus squarrosus(Hedw.) Warnst. is described. Plants treated with lead acetate and lead chloride solutions, or collected from roadsides exposed to lead pollution from motor exhaust gases have been used. The results are compared with other studies of experimental lead poisoning in both plants and animals, with particular regard to uptake mechanisms and to lead accumulating at different sites in the cell. We have shown that lead may be bound within the cell wall, and that it may also enter the cytoplasm. Pinocytosis was observed in leaf cells from moss plants treated with lead salt solutions. Via pinocytotic vesicles within the cytoplasm the particles containing lead could then be discharged into the vacuole. In the leaf cells of mosses exposed to environmental pollution the protoplasmic lead was found to be bound within the nucleus, and was easily identified as electron-dense, nuclear inclusions.

ISSN:0373-6687    

DOI:10.1179/jbr.1974.8.1.117

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1974.8.1.123

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1974.8.1.131

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1974.8.1.139

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1974.8.1.141

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1974.8.1.161

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1974.8.1.177

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1974.8.1.iv

出版商:Taylor&Francis    

年代:1974

数据来源: Taylor