摘要:

AbstractRetention of K, Ca and PbyPseudoscleropodium purumgrowing under oak in Windsor Forest was examined following treatment, over 9 days, with 10 mol m−3CaCl2or KH2PO4Concentrations of the added elements and Mg were determined in the intercellular, exchangeable (cell wall) and intracellular fractions of the green tissues before nutrient addition and at intervals (0–205 days) afterwards.Increases of cations in the intercellular fraction of treated shoots were transient. Addition of K and Ca markedly increased levels of these cations in the exchangeable fraction and significantly reduced the concentration of exchangeable Mg. The changes in exchangeable cations were progressively reversed under field conditions indicating that their levels are in dynamic equilibrium with element concentrations in precipitation and/or throughfall rather than the result of a continuousaccumulation process.Net uptake of K and Ca into the protoplasts of treatedP. purumwas slight but substantial net gain (+178%) of P occurred in KH2PO4treated plants. One-third of the additional P was lost within 15 days due, either, to redistribution within the shoot, or, to leakage. Intracellular Mg fell significantly below controls 2 weeks after treatment with CaCl2suggesting that Mg uptake involves prior adsorption onto the cell wall exchange sites. Fluctuations in K, Ca and Mg levels of untreatedP. purumindicated that appreciable net uptake of natural inputs occurred, particularly during autumn when leachates from the senescing tree canopy may be received.Element concentrations, including Mg, were highest at a shaded site where the moss remained moist for long periods suggesting that either ion absorption is favoured by protracted contact times or that metabolic nutrient requirement increases with increasingly mesic conditions.

ISSN:0373-6687    

DOI:10.1179/jbr.1989.15.3.589

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

摘要:

AbstractSeasonal patterns of reproductive development are reported for the five British mossesAtrichum undulatum, Bryum argenteum, Grimmiapulvinata, Polytrichum alpestreandTortula muralis, and vegetative phenology is also described forB. argenteumandP. alpestre. Clearly defined seasonal cycles of gametangial and sporophytic development characterize P. alpestre, and the cycles in Britain resemble those previously reported for polar populations of this species. The seasonal timing of the later stages of sporophytic development, and of spore release, was shown to be relatively constant within each species but the gametangial cycles and fertilization periods appear to be more variable than inP. alpestrein the weedy colonist,B. argenteum, and particularly in the lithophytes,G. pulvinataandT. muralis.

ISSN:0373-6687    

DOI:10.1179/jbr.1989.15.3.607

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1989.15.3.623

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1989.15.3.624

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1989.15.3.626

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1989.15.3.629

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1989.15.3.635

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor

ISSN:0373-6687    

DOI:10.1179/jbr.1989.15.3.ii

出版商:Taylor&Francis    

年代:1989

数据来源: Taylor