Aim: The safety and toxicity outcomes in a group of patients with advanced haematological diseases undergoing reduced intensity allogeneic stem cell transplantation using Fludarabine (30 mg/m2) and Melphalan (140 mg/m2) conditioning was examined. The majority (62%) of these heavily pre-treated patients had failed previous transplantation (22 autologous, and 1 allogeneic). Method: Thirty-seven patients underwent Sibling (Full Match) - 19; Mismatch Sibling/Other Family – 4, Matched Unrelated Donor – 13 or Umbilical Cord Blood – 1 transplantation. The median patient age was 50 years (range, 29 – 64 years). Disease at time of transplant was: 6 primary acute leukaemia, 3 secondary acute leukaemia, 3 secondary MDS, 1 primary MDS, 11 multiple myeloma, 12 NHL and 1 myelofibrosis. Results: The median follow-up period was 21 months (range, 0.2 – 84 months. Median survival was 9 months (range 0.2 – 68 months) with 32% (12 patients) remaining alive at time of analysis. Sustained donor engraftment (neutrophils) occurred in 33 (89%) patients. The median time to neutrophil engraftment was 14 days (range 9–27); and for platelet engraftment 19 days (range 13–67). The median length of stay in hospital was 28 days (range 15–71). Twenty eight out of 37 patients (76%) were discharged from hospital post transplant. Nine patients (24%) required an Intensive Care admission. Seventeen out of the 37 patients (46%) had severe mucositis requiring opiates, with 6 requiring total parental nutrition. Graft vs Host Disease (GVHD) occurred in 24 individuals; 42% had acute GVHD (50% had >= Grade 3 severity) and 55% had chronic GVHD (44% moderate to severe). The day 100 transplant-related mortality (TRM) was 32%, with the overall (all cause) mortality at 1 year of 51%. GVHD accounted for 6 (24%) deaths, primary disease 7 (28%) and sepsis 12 (48%). Conclusion: The combination of Fludarabine/Melphalan as a reduced intensity conditioning regime in this group of patients with advanced haematological malignancies can lead to prolonged disease control in up to one third of patients. However, it is not without its short term and long term toxicity, and is associated with a high day 100 transplant related mortality.

Information on the relative efficiency of fertilizer N at different landscape positions is needed to develop variable rate N fertilizer recommendations and to optimize crop yield with precision agriculture. The objective of this study was to determine the effect of landscape position on yield, N uptake, recovery of applied fertilizer N in plant and soil, and % of plant N derived from fertilizer (% Ndff) in heads, straw and roots of wheat. Field experiments (2 years on a Dark Brown Chernozemic soil at Watrous and 3 years on a Black Chernozemic soil at Prince Albert) were conducted in Saskatchewan, Canada. The N-15-labelled fertilizer technique was used to compare the results from microplots (45 x 45 cm) located at lower and upper slope positions. At Watrous, yield, N uptake, and recovery of applied N in heads, straw and roots of wheat were greater in 1 year and tended to be greater in the second year at lower slope positions compared to upper slope positions. The opposite was true for % Ndff, which was less in heads, straw and roots in 1 year and tended to be less in the second year at lower slope positions compared to upper slope positions. The recovery of applied N in soil or plant plus soil was less at lower slope positions than at upper slope positions in 1 year. At Prince Albert, the influence of slope position was not significant in most cases, but there was a consistent trend of slightly greater yield and N uptake, and somewhat smaller recovery of applied N in heads, % Ndff in heads, straw and roots, and recovery of fertilizer N in soil or plant plus soil at lower slope positions compared to upper slope positions. The differences between the two slope positions were relatively large and significant in many cases at Watrous, due to relatively drier soil conditions at the upper slope position than at the lower slope position in 1998. However, the differences were usually small and not significant at Prince Albert, due to relatively adequate soil moisture conditions on both slope positions.

The literature, and previously unpublished data from the authors' laboratories, shows that the δ13C of organic matter in marine macroalgae and seagrasses collected from the natural environment ranges from -3 to -35‰. While some marine macroalgae have δ13C values ranging over more than 10‰ within the thallus of an individual (some brown macroalgae), in other cases the range within a species collected over a very wide geographical range is only 5‰ (e.g. the red alga Plocamium cartilagineum which has values between -30 and -35‰). The organisms with very negative δ13C (lower than -30‰) are mainly subtidal red algae, with some intertidal red algae and a few green algae; those with very positive δ13C values (higher than -10‰) are mainly green macroalgae and seagrasses, with some red and brown macroalgae. The δ13C value correlates primarily with taxonomy and secondarily with ecology. None of the organisms with δ13C values lower than -30‰ have pyrenoids. Previous work showed a good correlation between δ13C values lower than -30‰ and the lack of CO2 concentrating mechanisms for several species of marine red algae. The extent to which the low δ13C values are confined to organisms with diffusive CO2 entry is discussed. Diffusive CO2 entry could also occur in organisms with higher δ13C values if diffusive conductance was relatively low. The photosynthesis of organisms with δ13C values more positive than -10‰ (i.e. more positive than the δ13C of CO2 in seawater) must involve HCO3- use.

ABSTRACTWe grew a non‐bicarbonate using red seaweed, Lomentaria articulata (Huds.) Lyngb., in media aerated with four O2 concentrations between 10 and 200% of current ambient [O2] and four CO2 concentrations between 67 and 500% of current ambient [CO2], in a factorial design, to determine the effects of gas composition on growth and physiology. The relative growth rate of L. articulata increased with increasing [CO2] up to 200% of current ambient [CO2] but was unaffected by [O2]. The relative growth enhancement, on a carbon basis, was 52% with a doubling of [CO2] but fell to 23% under 5× ambient [CO2]. Plants collected in winter responded more extremely to [CO2] than did plants collected in the summer, although the overall pattern was the same. Discrimination between stable carbon isotopes (Δ13C) increased with increasing [CO2] as would be expected for diffusive CO2 acquisition. Tissue C and N were inversely related to [CO2]. Growth in terms of biomass appeared to be limited by conversion of photosynthate to new biomass rather than simply by diffusion of CO2, suggesting that non‐bicarbonate‐using macroalgae, such as L. articulata, may not be directly analogous to C3 higher plants in terms of their responses to changing gas composition.

Recent work has focused on a possible relationship between marine organic delta(13)C and the concentration of carbon dioxide dissolved in seawater [CO2(aq)]. This relationship is based on the general assumption that diffusive CO2 uptake is the main pathway of photosynthetic carbon acquisition by phytoplankton. This study found an inverse linear relationship between [CO2(aq)] and organic delta(13)C in the marine diatoms Chaetoceros calcitrans and Ditylum bright-wellii. However, the relationship was not a function of diffusive CO2 use by these diatoms, which have previously been shown to be HCO3- users. Our findings underline the importance of understanding the mechanisms of phytoplankton carbon acquisition in interpreting carbon isotope data.

Carbon and nitrogen contents of two intertidal fucoid species, Fucus serratus and Himanthalia elongata, were investigated with respect to variations in seasonal resource availability, growth and reproductive requirements. The linear growth rate of F. serratus peaked in spring at 2 . 3 cm 28 d(-1), compared with < 0 . 1 cm 28 d(-1) in the winter. In H. elongate, the button diameter increased slowly throughout the year (< 0 . 22 cm 28 d(-1)); in contrast, the receptacle had an elongation rate of up to 7 . 8 an 28 d(-1) in the spring months. There was no difference in the nitrogen content (% dry weight, dwt) of the vegetative tissue of both non-reproductive and fertile thalli and receptacle tissue of F. serratus, but the nitrogen content of all three tissue types varied seasonally. Reproductive development was initiated in May when nitrogen content was at its peak (3 % dwt). Tissue nitrogen content decreased rapidly through reproductive development to a minimum of less than 1 . 5% dwt in August; this decrease also occurred in non-reproductive thalli. Tissue nitrogen varied between 0 . 5 and 1 . 75% dwt in the vegetative buttons on both non-reproductive and fertile H. elongata, but not in a distinct seasonal manner. Receptacle development in H. elongata was initiated in October/November. The nitrogen content of the receptacle tissue increased rapidly in the first two months of reproductive development (up to 2 . 5 % dwt) then progressively decreased throughout the remaining period of reproductive development. There was no evidence of carbon storage in the vegetative tissues of either F. serratus or H. elongata.

Seasonal variations and the effect of reproductive development on resource acquisition by two intertidal fucoid species, the iteroparous Fucus serratus L. and the semelparous Himanthalia elongata (L.) S. F. Gray were examined. The oxygen-exchange characteristics of vegetative apical tissue of both non-fertile and fertile plants and receptacle tissue were compared at monthly intervals throughout reproductive development. Respiratory rates in non-fertile F. serratus varied seasonally between 1.5 and 8.0 μmol g−1 fresh wt h−1; in fertile plants the receptacle had a significantly lower respiratory rate than the vegetative tissue. The respiratory rate of the vegetative button of fertile H. elongata displayed less seasonal variation and was lower than that of the receptacle, which varied from a maximum of 9.5 μmol g−1 fresh wt h−1 at receptacle initiation in October to a minimum of 2.0 μmol g−1 fresh wt h−1 in February. The maximum photosynthetic rate (P max) of non-fertile plants of both species did not vary in a distinct seasonal manner (∼60 μmol g−1 fresh wt h−1 for F. serratus and ∼12 μmol g−1 fresh wt h−1 for H. elongata). In fertile plants, the P max of the receptacle tissue was (∼50% lower in F. serratus, and at its peak three times higher in H. elongata, than that of vegetative tissue. The stable carbon-isotope ratio (δ13C) did not differ between different tissue types in F. serratus, but values did vary seasonally, being less negative in the summer than in the winter (−13.5‰ compared to −18‰). The receptacle tissue of H. elongata also displayed a distinct seasonal variation in δ13C values (−12‰ in summer, −16‰ in winter), whilst the δ13C of the vegetative button did not vary seasonally. The rate of uptake of inorganic nitrogen by the vegetative thallus was lower in H. elongata than in F. serratus. The receptacle tissue of F. serratus had lower uptake rates than the vegetative tissue, whilst the uptake rate by H. elongata receptacle tissue was higher than that of the vegetative button.

ABSTRACTThe utilization of inorganic carbon by three species of marine diatom, Skeletonema costatum (Grev.) Cleve. Ditylum brightwellii (West) Grun., and Chaetoceros calcitrans Paulsen was investigated using an inorganic carbon isotopic disequilibnum technique and inorganic carbon dose‐response curves. Stable carbon isotope data of the diatoms are also presented. Observed rates of photosynthetic oxygen evolution were greater than could be accounted for by the theoretical rate of CO2 supply from the uncatalyzed dehydration of HCO3− in the external medium, suggesting use of HCO3− as an inorganic carbon source. Data from the isotopic disequilibrium experiment demonstrate the use of both HCO3− and CO2 for photosynthesis. Carbon isotope discrimination values support the use of HCO3− by the diatoms.

The effects that environmental variables, other than dissolved CO2, have on C-13 discrimination by marine phytoplankton were studied. Two selected species showed different responses. The delta(13)C values of the marine diatiom Phaeodactylum tricornutum grown in a range of temperatures with a constant dissolved [CO2] were more negative as the growth temperature decreased. delta(13)C values of P. tricornutum showed little response to changes in growth photon flux density (except at low PFD <10 mu mol m(-2) s(-1)) and growth pH. delta(13)C values of the prymnesiophyte Emiliania huxleyi were more negative with decreased growth temperature, more negative with decreased growth PFD and less negative with decreased growth pH. The distinct effects which environmental variables have on the delta(13)C values of 2 contrasting algal species suggest that species-specific responses to environmental change may be important in understanding the variability of delta(13)C values found in particulate organic carbon obtained from oceanic and coastal waters. The role of environmental variables in hindcasting dissolved [CO2] is discussed.

The ability of the diatom Phaeodactylum tricornutum to accumulate inorganic carbon was investigated using the silicone oil centrifugation technique. At internal inorganic carbon concentrations less than 0.2 mol m(-3) the internal inorganic carbon concentration was always greater than expected assuming CO2 assimilation based on diffusion. When tested at 2.0 mol m(-3) the normal inorganic carbon concentration of seawater, the internal inorganic carbon concentration was less than the external concentration. Apparently this alga has the ability to accumulate inorganic carbon. When grown in poorly aerated media P. tricornutum is able to reduce the inorganic carbon concentration of the media to a greater extent than during growth in well-aerated media. Cells that have experienced inorganic carbon depletion are able to accumulate inorganic carbon to a greater extent than cells from well-aerated cultures when tested at low external inorganic carbon concentrations. Inorganic carbon photosynthesis dose-response curves showed that carbon-depleted cells have a higher affinity for inorganic carbon than cells from well-aerated cultures. delta(13)C values of carbon-depleted cultures were less negative than those of well-aerated cultures. These results are discussed in relation to previously reported inorganic carbon-photosynthesis dose-response curves. This alga is able to alter the mechanism of inorganic carbon acquisition in response to changes in the external inorganic carbon concentration.

Effects of cell size and/or specific growth rate were studied in 2 species of marine diatom, the large-celled Ditylum brightwellii and the smaller Chaetoceros calcitrans. Cells were grown as light-limited continuous cultures to produce a wide range of specific growth rates from 0.12 d(-1) in D. brightwellii to 1.01 d(-1) in C. calcitrans. Carbon isotope discrimination (Delta) values, relative to source delta(13)C Of dissolved inorganic carbon (DIG), showed no relationship to specific growth rate within species. When examined interspecifically there was some evidence that growth rate or cell size affected the C-13/C-12 ratios of the diatoms. At each photon flux density (PFD) used for growth, the specific growth rate of C. calcitrans was at least twice that of D. brightwellii. Values of Delta were greater in D. brightwellii at PFDs of 5, 20 and 40 pmol photon m(-2) s(-1). These data are in agreement with a hypothesis stating that faster-growing diatoms should be enriched in C-13. However, at the highest growth irradiance of 60 mu mol m(-2) s(-1), Delta values were higher in C. calcitrans than in D. brightwellii. Source delta(13)C values varied between individual cultures and demonstrated the importance of directly measuring the delta(13)C of DIC. The value of physiological data in fully interpreting the stable carbon isotope ratios of diatoms is also discussed.

Marine macroalgae and seagrasses collected from Penguin Island, Western Australia, and red marine macroalgae from Australasia and Europe were analysed for the natural abundance of stable isotopes in their organic matter. These measurements revealed 1 species of green macroalgae and 9 species of red macroalgae with a delta(13)C below -30 parts per thousand. These new observations bring the total of reports of wild-collected marine macrophytes with delta(13)C values below -30 parts per thousand to 3 species of ulvophycean chlorophytes and 22 species of florideophycean rhodophytes. The 22 rhodophyte species are in 18 genera in 10 families of 4 orders. Marine algae with very negative delta(13)C values have been shown in other work to be unable to use HCO3- and rely on CO2 diffusion into the thallus for photosynthesis. The quantitative implications of the low C-13/C-12 ratio and the inability to use HCO3- were analysed to predict the maximum in situ rate of photosynthesis. The relatively low predicted rates agree with measured rates (by other workers) of C assimilation in photosynthesis and growth. These low potential rates of C acquisition can be related to the low mean photon flux density required for growth in 17 of the 22 species of red algae and all 3 species of green algae. Low mean photon flux densities are characteristic of habitats in the subtidal (18 species of red algae, 3 species of green algae) and shaded microhabitats in the intertidal (1 species of red algae). Even the 5 other algae, littoral and infralittoral, seem from the literature to have low photosynthetic and relative growth rates, although it is not clear whether the low metabolic rates result from dependence on CO2 diffusion or whether diffusive CO2 entry as the sole means of inorganic C supply is permitted by a low metabolic rate imposed by some other cause.

Measurements of parameters related to photosynthesis, with particular reference to the mechanism of inorganic C acquisition, were made on the obligate epiphyte Notheia anomala Harvey et Bailey (Phaeophyta: Fucales) and on its most usual basiphyte, Hormosira banksii (Turner) Decaisne (Phaeophyta: Fucales). The work on Hormosira banksii included a comparison of specimens which are normally emersed at low tide on rock platforms with specimens which are normally submersed in rockpools at low tide; the rockpool specimens are those which most commonly bear Notheia anomala. No significant differences were detected for any of the characteristics tested, i.e. photosynthetic rate as a function of incident photon flux density, external inorganic C concentration and plant N content; capacity to use HCO3-; diel changes in titratable acidity of cell contents ('CAM-like' behaviour); rates of dark C-14-inorganic C fixation; delta(13)C values of plant organic C. These data are consistent with there being no significant genotypic and, probably, phenotypic differences in inorganic C acquisition between the two populations. The inorganic C acquisition properties of Hormosira banksii resemble more closely those of other Fucaceae than those of other members of the Fucales and of the Laminariales and Durvillaeales which have been investigated. Notheia anomala has a higher photosynthetic capacity on a fresh or dry weight basis than its basiphyte Hormosira banksii, possibly due to its larger surface area per unit mass and/or to a smaller allocation of resources to chemical defences in Notheia than in Hormosira. Overgrowth of Hormosira by Notheia may be a function of the delay of Notheia infestation until the basiphyte is reproductively active, and of more grazing of the Notheia than of the better defended Hormosira. The photosynthetic characteristics of Notheia were examined; photosynthesis resembles those of Fucales 'emersed at low tide' (including Hormosira) rather than those of brown algae 'invariably submersed at low tide'. The high photosynthetic rates of Notheia and Hormosira on a tissue N basis may relate to their low N status as a result of living in a lower N-supply habitat than those of many other brown algae examined.

SynopsisHyperoxia (O2in solution in excess of air-equilibrium values) occurs in certain photosynthesising cells which use inorganic C concentrating mechanisms, and as a result of abiological mechanisms. Geochemical evidence suggests that the atmosphere may have had significantly higher O2partial pressures in the past (e.g. the Upper Carboniferous) than occurs today. Biochemical effects of high O2concentrations in solution include inhibition of RUBISCO (competitive with CO2) and nitrogenase, as well as damage caused by higher levels of toxic O species (H2O2, O2and, especially,1O2and OH). The influence of high (twice the extant level) atmospheric O2on growth of non-N2-fixers is as predicted from the properties of RUBISCO and the occurrence of inorganic C concentrating mechanisms. Acclimation of N2-fixers to twice the extant O2level involves increased restriction on O2diffusion to nitrogenase so that growth is not inhibited (unless the high O2has access to the C3photosynthesis apparatus). Evidence as to the effect of hyperoxia on quenchers and scavengers of toxic O species is equivocal. Cells exposed to high O2probably have higher mutation rates as a result of higher levels of toxic O species, although the production and maintenance of ‘stem’ cells may occur in parts of the plants with relatively low O2levels.

SUMMARYThe 13C/12C ratio (expressed as δ13C) of benrhic photolithotrophs. in the Dighn Water (= Burn) were measured fur comparison with that of the potential inorganic carhun sources. CO2 and HCO3‐, in the Burn. The Burn water contains an average of 65.7 mmol m‐3 CO2 with δ13C of ‐14.7% and 1600 mmol m‐3 HCO3‐ with δ13C of ‐4.%. δ13C values of riparian vegetation were also measured as contributors, after respiration in the soil or the Burn, to the δ13C of inorganic carbon in the Burn. The potential range of differences in 13C/12C between dissolved CO2 and plant organic C is set by the intrinsic 13c/12C discrimination (α value) in CO2 fixation by Rubisco. Main results and conclusions are. as follows, (i) A literature survey suggests that there is no convincing evidence that the α, Values (rate constant for 12CO2 fixation relative to that for 13CO2 fixation by Rubisco in the absence of CO2 transport limitation) for the‘lower plants’in the Burn (diatoms, green and red algae, mosses) are significantly different from the well‐established αp values for the flowering plum enzyme. (ii) In confirmation of earlier work, the semi‐erect 'streamer’gametophytes of the red alga Lemanea mamillosa and the moss Fontinalis antipyetica have δ13C values which can only be interpreted in terms of diffusive CO2 entry with minimal limitation of photosynthesis by CO‐ diffusion, (iii) The serui‐erect grren alga Cladophora glomerata and the flowering plant Ranunculus penicillatus ssp. pseudofluitons (formerly var. calcareus) are‐ both able to use HCO3‐. Their δ13C values indicate that, if the HCO3‐ ‐use system does not (as is likely) discriminate significantly between 13C and 12C, then a substantial fraction of the inorganic C made available to Rubisco must return to the medium, carrying 13C‐inorganic C not fixed by Rubisco. (iv) Two sets of δ13C data from different hydrodynamic regimes distance from leading edge of a flat stone; different size of thalli) show that the attainable differences in situ in thickness of the diffusion boundary layer do not alter the fractional limitation of photosynthesis of Cladophora by external diffusion of inorganic C, considered with HCO3 use. (vi) The entrusting red alga Hildenbrandia rivularis has a δ13C value suggestive of CO2 as the inorganic C source, but not entirely ruling nut HCO3‐. Marine species of both Hildenbrundia and Cladophora have δ13C values which, even when corrected for source inorganic C δ13C values, are 10%, more positive than the freshwater species. (vii) Mats of pennate diatoms were shown by pH‐drift to by able to use HCO3‐; the relatively high (i.e. not very negative) δ12C value of these mats could relate to a relatively‘non‐leaky’HCO3‐ aequisition mechanism and/or to limitation by external diffusion (e.g. through the mat).

The 13C/12C fractionation associated with net transport fluxes and chemical conversions, and with equilibria, associated with inorganic C assimilation processes in marine phytoplankton are quite well understood, though some gaps remain. These values are used in models of overall 13C/12C fractionation in inorganic C assimilation involving the two major mechanisms involved in inorganic C entry, i.e. diffusion of CO2 and active transport of CO2 and/or HCO3−. The CO2 diffusion model predicts the observed decrease in the 13C/12C of plankton organic C relative to source CO2 when CO2 concentration increases and/or temperature decreases. The inorganic C active transport model is complicated by repression of the active transport mechanism at high inorganic C levels, but this model also predicts the observed effect on cell 13C/12C of changes in CO2 partial pressure or temperature for cell growth. More refined modelling and more input data are needed for both transport processes. Operation of either of the alternative mechanisms for inorganic C entry can be consistent with growth rate not being limited by inorganic C supply even when the photosynthetic rate is inorganic C-limited.