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This commentary considers the benefits of a new framework to incorporate ecological processes in Earth System Models (ESMs) to both Earth system science and to ecology. Adding ecological processes to ESMs skillfully will likely improve the long-term performance of these models. The rigor required to achieve this will prompt ecologists to test complex ecological hypotheses on regional and global scales. Some candidate processes are suggested.

BACKGROUND: To investigate whether meteorological factors (temperature, barometric pressure, relative humidity, ultraviolet index [UVI], and seasons) trigger flares in male and female urologic chronic pelvic pain patients. METHODS: We assessed flare status every two weeks in our case-crossover study of flare triggers in the Multidisciplinary Approach to the Study of Chronic Pelvic Pain one-year longitudinal study. Flare symptoms, flare start date, and exposures in the three days preceding a flare or the date of questionnaire completion were assessed for the first three flares and at three randomly selected non-flare times. We linked these data to daily temperature, barometric pressure, relative humidity, and UVI values by participants’ first 3 zip code digits. Values in the three days before and the day of a flare, as well as changes in these values, were compared to non-flare values by conditional logistic regression. Differences in flare rates by astronomical and growing seasons were investigated by Poisson regression in the full study population. RESULTS: 574 flare and 792 non-flare assessments (290 participants) were included in the case-crossover analysis, and 966 flare and 5,389 non-flare (409 participants) were included in the full study analysis. Overall, no statistically significant associations were observed for daily weather, no patterns of associations were observed for weather changes, and no differences in flare rates were observed by season. CONCLUSIONS: We found minimal evidence to suggest that weather triggers flares, although we cannot rule out the possibility that a small subset of patients are susceptible.

The response of terrestrial carbon uptake to increasing atmospheric [CO2 ], that is the CO2 fertilization effect (CFE), remains a key area of uncertainty in carbon cycle science. Here we provide a perspective on how satellite observations could be better used to understand and constrain CFE. We then highlight data assimilation (DA) as an effective way to reconcile different satellite datasets and systematically constrain carbon uptake trends in Earth System Models. As a proof-of-concept, we show that joint DA of multiple independent satellite datasets reduced model ensemble error by better constraining unobservable processes and variables, including those directly impacted by CFE. DA of multiple satellite datasets offers a powerful technique that could improve understanding of CFE and enable more accurate forecasts of terrestrial carbon uptake.

Severe drought can cause lagged effects on tree physiology that negatively impact forest functioning for years. These "drought legacy effects" have been widely documented in tree-ring records and could have important implications for our understanding of broader scale forest carbon cycling. However, legacy effects in tree-ring increments may be decoupled from ecosystem fluxes due to (a) postdrought alterations in carbon allocation patterns; (b) temporal asynchrony between radial growth and carbon uptake; and (c) dendrochronological sampling biases. In order to link legacy effects from tree rings to whole forests, we leveraged a rich dataset from a Midwestern US forest that was severely impacted by a drought in 2012. At this site, we compiled tree-ring records, leaf-level gas exchange, eddy flux measurements, dendrometer band data, and satellite remote sensing estimates of greenness and leaf area before, during, and after the 2012 drought. After accounting for the relative abundance of tree species in the stand, we estimate that legacy effects led to ~10% reductions in tree-ring width increments in the year following the severe drought. Despite this stand-scale reduction in radial growth, we found that leaf-level photosynthesis, gross primary productivity (GPP), and vegetation greenness were not suppressed in the year following the 2012 drought. Neither temporal asynchrony between radial growth and carbon uptake nor sampling biases could explain our observations of legacy effects in tree rings but not in GPP. Instead, elevated leaf-level photosynthesis co-occurred with reduced leaf area in early 2013, indicating that resources may have been allocated away from radial growth in conjunction with postdrought upregulation of photosynthesis and repair of canopy damage. Collectively, our results indicate that tree-ring legacy effects were not observed in other canopy processes, and that postdrought canopy allocation could be an important mechanism that decouples tree-ring signals from GPP.

Ecosystem models show divergent responses of the terrestrial carbon cycle to global change over the next century. Individual model evaluation and multi-model comparisons with data have largely focused on individual processes at sub-annual to decadal scales. Thus far, data-based evaluations of emergent ecosystem responses to climate and CO2 at multi-decadal and centennial time scales have been rare. We compared the sensitivity of net primary productivity (NPP) to temperature, precipitation, and CO2 in ten ecosystem models with the sensitivities found in tree-ring reconstructions of NPP and raw ring-width series at six temperate forest sites. These model-data comparisons were evaluated at three temporal extents to determine whether the rapid, directional changes in temperature and CO2 in the recent past skew our observed responses to multiple drivers of change. All models tested here were more sensitive to low growing season precipitation than tree-ring NPP and ring widths in the past 30 years, although some model precipitation responses were more consistent with tree rings when evaluated over a full century. Similarly, all models had negative or no response to warm growing season temperatures while tree-ring data showed consistently positive effects of temperature. Although precipitation responses were least consistent among models, differences among models to CO2 drive divergence and ensemble uncertainty in relative change in NPP over the past century. Changes in forest composition within models had no effect on climate or CO2 sensitivity. Fire in model simulations reduced model sensitivity to climate and CO2, but only over the course of multiple centuries. Formal evaluation of emergent model behavior at multi-decadal and multi-centennial time scales is essential to reconciling model projections with observed ecosystem responses to past climate change. Future evaluation should focus on improved representation of disturbance and biomass change as well as the feedbacks with moisture balance and CO2 in individual models.

Plant isoprene emissions have been linked to several reaction pathways involved in atmospheric photochemistry. Evidence exists from a limited set of past observations that isoprene emission rate (I(sub s)) decreases as a function of increasing atmospheric CO2 concentration, and that increased temperature suppresses the CO2 effect. We studied interactions between intercellular CO2 concentration (C(sub I)) and temperature as they affect I(sub s) in field-grown hybrid poplar trees in one of the warmest climates on earth - the Sonoran Desert of the southwestern United States. We observed an unexpected midsummer down regulation of I(sub s) despite the persistence of relatively high temperatures. High temperature suppression of the I(sub s):C(sub I) relation occurred at all times during the growing season, but sensitivity of I(sub s) to increased C(sub I) was greatest during the midsummer period when I(subs) was lowest. We interpret the seasonal down regulation of I(sub s) and increased sensitivity of I(sub s) to C(sub I) as being caused by weather changes associated with the onset of a regional monsoon system. Our observations on the temperature suppression of the I(sub s):C(sub I) relation are best explained by the existence of a small pool of chloroplastic inorganic phosphate, balanced by several large, connected metabolic fluxes, which together, determine the C(sub I) and temperature dependencies of phosphoenolpyruvate import into the chloroplast.

Bark beetle outbreaks are widespread in western North American forests, reducing primary productivity and transpiration, leading to forest mortality across large areas and altering ecosystem carbon cycling. Here the carbon isotope composition (δ(13) C) of soil respiration (δJ ) was monitored in the decade after disturbance for forests affected naturally by mountain pine beetle infestation and artificially by stem girdling. The seasonal mean δJ changed along both chronosequences. We found (a) enrichment of δJ relative to controls (

Rapid changes to the biosphere are altering ecological processes worldwide. Developing informed policies for mitigating the impacts of environmental change requires an exponential increase in the quantity, diversity, and resolution of field-collected data, which, in turn, necessitates greater reliance on innovative technologies to monitor ecological processes across local to global scales. Automated digital time-lapse cameras – “phenocams” – can monitor vegetation status and environmental changes over long periods of time. Phenocams are ideal for documenting changes in phenology, snow cover, fire frequency, and other disturbance events. However, effective monitoring of global environmental change with phenocams requires adoption of data standards. New continental-scale ecological research networks, such as the US National Ecological Observatory Network (NEON) and the European Union's Integrated Carbon Observation System (ICOS), can serve as templates for developing rigorous data standards and extending the utility of phenocam data through standardized ground-truthing. Open-source tools for analysis, visualization, and collaboration will make phenocam data more widely usable.

In the southwest United States, the current prolonged warm drought is similar to the predicted future climate change scenarios for the region. This study aimed to determine patterns in vegetation response to the early 21st century drought across multiple biomes. We hypothesized that different biomes (forests, shrublands, and grasslands) would have different relative sensitivities to both climate drivers (precipitation and temperature) and legacy effects (previous‐year's productivity). We tested this hypothesis at eight Ameriflux sites in various Southwest biomes using NASA Moderate‐resolution Imaging Spectroradiometer Enhanced Vegetation Index (EVI) from 2001 to 2013. All sites experienced prolonged dry conditions during the study period. The impact of combined precipitation and temperature on Southwest ecosystems at both annual and sub‐annual timescales was tested using Standardized Precipitation Evapotranspiration Index (SPEI). All biomes studied had critical sub‐annual climate periods during which precipitation and temperature influenced production. In forests, annual peak greenness (EVImax) was best predicted by 9‐month SPEI calculated in July (i.e., January–July). In shrublands and grasslands, EVImax was best predicted by SPEI in July through September, with little effect of the previous year's EVImax. Daily gross ecosystem production (GEP) derived from flux tower data yielded further insights into the complex interplay between precipitation and temperature. In forests, GEP was driven by cool‐season precipitation and constrained by warm‐season maximum temperature. GEP in both shrublands and grasslands was driven by summer precipitation and constrained by high daily summer maximum temperatures. In grasslands, there was a negative relationship between temperature and GEP in July, but no relationship in August and September. Consideration of sub‐annual climate conditions and the inclusion of the effect of temperature on the water balance allowed us to generalize the functional responses of vegetation to predicted future climate conditions. We conclude that across biomes, drought conditions during critical sub‐annual climate periods could have a strong negative impact on vegetation production in the southwestern United States.

Forest insects and pathogens are major disturbance agents that have affected millions of hectares in North America in recent decades, implying significant impacts to the carbon (C) cycle. Here, we review and synthesize published studies of the effects of biotic disturbances on forest C cycling in the United States and Canada. Primary productivity in stands was reduced, sometimes considerably, immediately following insect or pathogen attack. After repeated growth reductions caused by some insects or pathogens or a single infestation by some bark beetle species, tree mortality occurred, altering productivity and decomposition. In the years following disturbance, primary productivity in some cases increased rapidly as a result of enhanced growth by surviving vegetation, and in other cases increased slowly because of lower forest regrowth. In the decades following tree mortality, decomposition increased as a result of the large amount of dead organic matter. Net ecosystem productivity decreased immediately following attack, with some studies reporting a switch to a C source to the atmosphere, and increased afterward as the forest regrew and dead organic matter decomposed. Large variability in C cycle responses arose from several factors, including type of insect or pathogen, time since disturbance, number of trees affected, and capacity of remaining vegetation to increase growth rates following outbreak. We identified significant knowledge gaps, including limited understanding of carbon cycle impacts among different biotic disturbance types (particularly pathogens), their impacts at landscape and regional scales, and limited capacity to predict disturbance events and their consequences for carbon cycling. We conclude that biotic disturbances can have major impacts on forest C stocks and fluxes and can be large enough to affect regional C cycling. However, additional research is needed to reduce the uncertainties associated with quantifying biotic disturbance effects on the North American C budget.

The earth’s future climate state is highly dependent upon changes in terrestrial C storage in response to rising concentrations of atmospheric CO2. Here we show that consistently enhanced rates of net primary production (NPP) are sustained by a C-cascade through the root-microbe-soil system; increases in the flux of C belowground under elevated CO2 stimulated microbial activity, accelerated the rate of soil organic matter decomposition and stimulated tree uptake of N bound to this SOM. This process set into motion a positive feedback maintaining greater C gain under elevated CO2 as a result of increases in canopy N content and higher photosynthetic N-use efficiency. The ecosystem-level consequence of the enhanced requirement for N and the exchange of plant C for N belowground is the dominance of C storage in tree biomass but the preclusion of a large C sink in the soil.

As global temperatures increase, the potential for longer growing seasons to enhance the terrestrial carbon sink has been proposed as a mechanism to reduce the rate of further warming. At the Niwot Ridge AmeriFlux site, a subalpine forest in the Colorado Rocky Mountains, we used a 9-year record (1999-2007) of continuous eddy flux observations to show that longer growing season length (GSL) actually resulted in less annual CO 2 uptake. Years with a longer GSL were correlated with a shallower snow pack, as measured using snow water equivalent (SWE). Furthermore, years with a lower SWE correlated with an earlier start of spring. For three years, 2005, 2006, and 2007, we used observations of stable hydrogen isotopes (δD) of snow vs. rain, and extracted xylem water from the three dominant tree species, lodgepole pine, Engelmann spruce, and subalpine fir, to show that the trees relied heavily on snow melt water even late into the growing season. By mid-August, 57% to 68% of xylem water reflected the isotopic signature of snow melt. By coupling the isotopic water measurements with an ecosystem model, SIPNET, we found that annual forest carbon uptake was highly dependent on snow water, which decreases in abundance during years with longer growing seasons. Once again, for the 3 years 2005, 2006, and 2007, annual gross primary productivity, which was derived as an optimized parameter from the SIPNET model was estimated to be 67% 77%, and 71% dependent on snow melt water, respectively. Past studies have shown that the mean winter snow pack in mountain ecosystems of the Western US has been declining for decades and is correlated with positive winter temperature anomalies. Since climate change models predict continuation of winter warming and reduced snow in mountains of the Western US, the strength of the forest carbon sink is likely to decline further.

*Understanding controls over plant-atmosphere CO(2) exchange is important for quantifying carbon budgets across a range of spatial and temporal scales. In this study, we used a simple approach to estimate whole-tree CO(2) assimilation rate (A(Tree)) in a subalpine forest ecosystem. *We analysed the carbon isotope ratio (delta(13)C) of extracted needle sugars and combined it with the daytime leaf-to-air vapor pressure deficit to estimate tree water-use efficiency (WUE). The estimated WUE was then combined with observations of tree transpiration rate (E) using sap flow techniques to estimate A(Tree). Estimates of A(Tree) for the three dominant tree species in the forest were combined with species distribution and tree size to estimate and gross primary productivity (GPP) using an ecosystem process model. *A sensitivity analysis showed that estimates of A(Tree) were more sensitive to dynamics in E than delta(13)C. At the ecosystem scale, the abundance of lodgepole pine trees influenced seasonal dynamics in GPP considerably more than Engelmann spruce and subalpine fir because of its greater sensitivity of E to seasonal climate variation. *The results provide the framework for a nondestructive method for estimating whole-tree carbon assimilation rate and ecosystem GPP over daily-to weekly time scales.

Summary 1. Species differences in susceptibility to pathogens acting at early life history stages may strongly influence the abundance and distribution of tropical trees. Here, we test the susceptibility of 10 congeners of the pioneer genus Cecropia to fungal seed and seedling pathogens and compare interspecific differences in intrinsic seed defences with survival. 2. Pathogens were experimentally removed through fungicide addition and ⁄ or autoclave sterilization of forest soil to determine the relative importance of fungal versus other microbial pathogens. Treatments were applied during a 4-month seed incubation (pre-emergence) phase or during an 8-week germination phase to distinguish between seed and seedling mortality. 3. Overall, seedling emergence after incubation in fungicide-treated, autoclaved soil was twice that in live soil, with significant positive effects of fungicide for six of 10 species. Pathogen infection occurred while seeds were quiescent in soil; fungicide addition during germination had no effect on emergence. Seedling emergence after burial ranged from 6 to 58%, indicating large interspecific variation in the capacity for Cecropia seeds to persist in the seed bank. Neither interspecific variation in survivorship, nor the relative strength of fungicide effects on survivorship was correlated with seed defence traits. 4. For four species, measurements of fungicide effects on emergence were coupled with direct measurements of the fungal and bacterial infection of seeds and seedlings. For two species, fungicide addition resulted in lower fungal infection rates and higher emergence success. However, Cecropia peltata, the species with the highest overall emergence success, also had the highest fungal infection rate. This suggests that either C. peltata was infected by a different suite of fungi than other congeners, or that fungi had low pathogenicity when colonizing this host species. 5. Synthesis. Our study shows strong interspecific variation in seed survival and susceptibility to fungal infection among congeneric tree species with similar life history. These differences are likely to influence recruitment success from the soil seed bank and may play a role in species coexistence.

Rising CO2 is predicted to increase forest productivity, although the duration of the response and how it might be altered by variation in rainfall, temperature and other environmental variables are not well understood. We measured the basal area of rapidly growing Pinus taeda trees exposed to free-air CO2 enrichment for 8 years and used these measurements to estimate monthly and annual growth. We used these measurements in a statistical model to estimate the start and end of growth in each year. Elevated CO2 increased the basal area increment (BAI) of trees by 13–27%. In most years, exposure to elevated CO2 increased the growth rate but not the duration of the active growth period. With the exception of 1 year following an extreme drought and a severe ice storm, BAI was positively correlated with the amount of rainfall during the active growth period. The interannual variation in the relative enhancement of BAI caused by elevated CO2 was strongly related to temperature and rainfall, and was greatest in years with high vapor pressure deficit. There was no evidence of a systematic reduction in the stimulation of growth during the first 8 years of this experiment, suggesting that the hypothesized limitation of the CO2 response caused by nitrogen availability has yet to occur.

The effects of elevated [CO2] on 25 variables describing soyabean physiology, growth and yield are reviewed using meta-analytical techniques. This is the first meta-analysis to our knowledge performed on a single crop species and summarizes the effects of 111 studies. These primary studies include numerous soyabean growth forms, various stress and experimental treatments, and a range of elevated [CO2] levels (from 450 to 1250 ppm), with a mean of 689 ppm across all studies. Stimulation of soyabean leaf a CO2 assimilation rate with growth at elevated [CO2] was 39%, despite a 40% decrease in stomatal conductance and a 11% decrease in Rubisco [ribulose-bisphosphate carboxylase] activity. Increased leaf CO2 uptake combined with an 18% stimulation in leaf area to provide a 59% increase in canopy photosynthetic rate. The increase in total dry weight was lower at 37%, and seed yield still lower at 24%. This shows that even in an agronomic species selected for maximum investment in seed, several plant level feedbacks prevent additional investment in reproduction, such that yield fails to reflect fully the increase in whole plant carbon uptake. Large soil containers (>9 litres) have been considered adequate for assessing plant responses to elevated [CO2]. However, in open-top chamber experiments, soyabeans grown in large pots showed a significant threefold smaller stimulation in yield than soyabeans grown in the ground. This suggests that conclusions about plant yield based on pot studies, even when using very large containers, are a poor reflection of performance in the absence of any physical restriction on root growth. This review supports a number of current paradigms of plant responses to elevated [CO2]. Namely, stimulation of photosynthesis is greater in plants that fix N and have additional carbohydrate sinks in nodules. This supports the notion that photosynthetic capacity decreases when plants are N-limited, but not when plants have adequate N and sink strength. The root:shoot ratio did not change with growth at elevated [CO2], sustaining the charge that biomass allocation is unaffected by growth at elevated [CO2] when plant size and ontogeny are considered.

Evaporation ponds are becoming widely used by industry and agriculture for the disposal of brines as a result of increasingly strict regulations pertaining to off-site disposal methods. Migratory waterfowl and other wildlife can become reliant on such ponds, which can present biological hazards depending on the chemicals they receive. This study examined the algae, invertebrates, and chemistry of two large, hypersaline, industrial wastewater ponds near Phoenix, Arizona, at which waterfowl die-offs (primarily eared grebes, Podiceps nigricollis) were reported. The objectives were to determine what attracted birds to the ponds and whether the ponds were directly responsible for bird deaths. High levels of total salts and nitrate were detected in both ponds, but selenium (16 to 41 μg/L) was the only potentially toxic element that reached levels of concern in the water column. Dominant algae were diatoms, Chaeroceros sp. and Nitzschia frustrulum (Kurtz.) Grun. (up to 6.5 × 10 5 cells/mL), and cyanobacteria, Synechococcus Nageli 1849 (up to 8.8 × 10 6 cells/mL). These are normal components of hypersaline ponds and natural salt lakes. However, Chaetoceros levels were negatively correlated with salinity levels in the ponds and a species turnover is expected as ponds age. Primary aquatic fauna were Artemia franciscana (brine shrimp), a filter feeder that consumes algae, and Trichocorixa sp. (waterboatman), a carnivorous insect that presumably feeds on brine shrimp. Bnne shrimp were the primary attractant of birds; they were harvested by numerous resident and migratory waterfowl. Selenium levels in brine shrimp (2 to 10 mg/kg) were above recommended levels for food chain organisms in aquatic ecosystems but were well below levels that can cause acute toxicity. Brine shnmp fed to zebra danios fish (Brachydanio refio) in a bioassay were nontoxic. As at other locations where grebe mortality events have been reported in recent years, the cause of death of birds visiting these evaporation ponds is unknown. Therefore, it is concluded that these ponds may not be directly toxic to visiting wildlife, but that evaporation ponds such as these are attractants for wildlife and may pose a long-term hazard through the accumulation of selenium in the food chain. Zero-discharge evaporation ponds may be useful as an interim solution to the brine disposal problem but do not represent a safe, permanent solution.

Amid a worldwide increase in tree mortality, mountain pine beetles (Dendroctonus ponderosae Hopkins) have led to the death of billions of trees from Mexico to Alaska since 2000. This is predicted to have important carbon, water and energy balance feedbacks on the Earth system. Counter to current projections, we show that on a decadal scale, tree mortality causes no increase in ecosystem respiration from scales of several square metres up to an 84 km(2) valley. Rather, we found comparable declines in both gross primary productivity and respiration suggesting little change in net flux, with a transitory recovery of respiration 6-7 years after mortality associated with increased incorporation of leaf litter C into soil organic matter, followed by further decline in years 8-10. The mechanism of the impact of tree mortality caused by these biotic disturbances is consistent with reduced input rather than increased output of carbon.

Summary An interpretation of carpophore morphogenesis is presented which is derived both from the literature and from original observations. Cultured material of Coprinus cinereus (also called C. macrorhizus and C. lagopus) has been studied using biochemical assays together with light-, scanning- and transmission electron microscopy to provide details of histology and the levels and distribution of protein, glycogen and NADP-linked glutamate dehydrogenase during the course of development of stipe and cap. Initially, aggregates of hyphae form primordia which subsequently develop into mature carpophores. During stipe development glycogen deposition is at first restricted to cells forming a cup-shaped mass in the stipe base, but very early in primordium development this deposit is depleted and glycogen accumulates in the gills, particularly the subhymenium, where it probably serves as a reserve material for the later stages of cap development. The distribution of cytochemically detectable protein differs from that of glycogen in that the former initially accumulates in the upper regions of the primordial stipe and in the gill hymenium. The stipe showed no conspicuous change in its content of protein during development although in the cap the fraction of the dry wt represented by protein increased substantially. Primordial stipes are composed of overlapping cells of hyphal dimensions with dense cytoplasm and small vacuoles. Stipe development depends on cell enlargement, this seeming to be biphasic; an initial increase in volume being attributable to an increase in cell diameter to give an undifferentiated dikaryotic central region and a differentiated multi-nucleate cortex. Stipe growth depends on reallocation of cellular components, no one reserve material being identifiable as of prime importance although a few simple sugars do appear to be correlated with the osmoregulatory activity connected with the large scale uptake of water involved in stipe elongation. In the primordium cap the subhymenium is an open tissue of interwoven hyphae, the cells containing large accumulations of glycogen. The hymenium is formed from dikaryotic branches of the subhymenial hyphae to become an organised layer of hyphal tips. Subsequently, although the subhymenial hyphae remain as such, the hymenial cells become inflated. The paraphyses come to form a pavement of appressed and interlocked cells each containing a large central vacuole. Basidia are only slightly enlarged and contain dense cytoplasm with few vacuoles; they contrast with the much extended and inflated cystidia. Despite their inflation, all three cell types still show continuity with the subhymenial hyphae. During cap expansion the major inflationary force is paraphyseal enlargement but as the gill lamellae are removed by autodigestion further cell inflation in the pileal flesh enables it to assume a supportive role. In the earlier stages there is some correlation between declining glycogen content of the cap and increasing activity of NADP-linked glutamate dehydrogenase. It is suggested that cap expansion is driven osmotically and that at least some of the osmotically active materials are synthesised through the urea cycle. At first this activity could be supported by glycogenolysis and amination but later on substrates may be provided by autodigestion of spent gill tissues. It is concluded that cap development is regulated by a metabolism quite distinct from those of either the parental mycelium or the stipe, and that the fundamental metabolic changes occurring throughout carpophore development are orchestrated by light. As carbohydrate nutrients in the medium approach exhaustion suppression of mycelial morphogenesis into hyphal aggregates is lifted, but the subsequent switch from the vegetative pathway of sclerotium development to carpophore formation is normally dependent on illumination with low intensity blue light. Growth then becomes polarized to form a presumptive pileus and glycogen is mobilized from the surrounding mycelium to accumulate at the base of the stipe. Receipt of a second illumination inhibits further growth of the stipe base and causes glycogen reserves to be translocated to the cap. Glycogen is utilized in the cap to produce glycolytic intermediates, allowing regulation of many aspects of metabolism by catabolite concentration and contributiong to the diverse syntheses required for spore formation and dissemination.

SUMMARY Acrylamide gel electrophoresis was used to resolve buffer-soluble proteins and enzymes extracted from tissues of Coprimis cinereus. The electrophoretograms of proteins of two related but compatible monokaryons differed from one another, and both differed from the electrophoretogram of the dikarvon made by crossing the monokaryons together. The electrophoretogram of the youngest carpophore primordia was markedly different from that of the dikaryon on which they were produced, and the protein spectrum of both cap and stipe altered as the tissues matured. The protein electrophoretic pattern observed in the cap was always different from that of the stipe on which the cap was borne. However, when carpophores of quite different dikaryons were compared it was found that differences between the strains were so considerable that it was not possible to identify features common to a particular tissue or structure. Variation was also found in respect of isozyme patterns even though only two quite closely related monokaryons were compared. In the case of two enzyme activities (malate dehydrogenase and NADPH-dehydrogenase) the monokaryons exhibited different numbers of isozymes, and in a further three (alcohol dehydrogenase, NADH-dehydrogenase and esterase) there were clear differences in the way in which the isozyme pattern in each monokaryon related to the period of growth. The dikaryon was not associated with any predictable change in the isozyme pattern, but in all cases the dikaryon was in some way different from the parental monokaryons. Further differences were observed in carpophore tissues: in all cases the carpophore differed from its parental dikaryon. In most cases this difference was expressed as a distinctive developmental pattern of isozymes which were also detectable in mycelium; and in this the cap was often quite different from the stipe. However, for alcohol dehydrogenase and esterase, extracts of carpophore tissues possessed isozymes not detectable in extracts of mycelia.

Summary The NAD- and NADP-linked glutamate dehydrogenases were detected in frozen sections of carpophore tissues by means of tetrazolium salt. Material at all stages of development was examined. From the earliest stages NAD-glutamate dehydrogenase was uniformly distributed in the basidial cells of the hymenium, and as the carpophore developed an increasing proportion of cells of the subhymenium came to express enzyme activity. The NADP-glutamate dehydrogenase (NADP-GDH) was initially limited to basidial cells in isolated patches of the hymenium. As development proceeded the proportion of basidia exhibiting NADP-GDH activity increased, as did the proportion of subhymenial cells showing this enzyme activity. No NADP-GDH activity was detectable in sections of stipe tissue.