This paper presents thermal conductivity data for highly compacted Ca-smectite, Na-smectite, illite, and palygorskite as a function of density (i.e., compaction pressure), water content, and temperature. All the clays behaved similarly: thermal conductivity increased directly with density and water content. Specifically, the thermal conductivity increased from 0.63 to 1.32 W/m·K as the dry density increased from 1.2 to 1.8 g/cm3 (for a water content of 17%). An increase of water content from 6 to 17% resulted in an increase in thermal conductivity from 0.63 to 1.22 W/m·K (for a dry density of 1.6 g/cm3). Differences from one clay to the other were less important. The thermal conductivity (in W/m·K) for constant conditions of 12% of water and a dry density of 1.6 g/cm3 were: Ca-smectite 0.80, Na-smectite 0.74, palygorskite 0.71, and illite 0.69. Heating to 188°C produced only a 10% increase in the thermal conductivity.

Bentonite is considered as an ideal buffer/backfill material for preparing an engineering barrier for high-level radioactive waste (HLW) disposal. During initial sample preparation, the tendency of wet bentonite powder to gather into large agglomerates and the water to be spread unevenly in the traditional water content adjustment process decreases the homogeneity of compacted bentonite. The main purpose of this study was to solve this problem by applying a new wetting method, which mixes ice powder with bentonite powder (the ice-bentonite mixing method). This new method was used to adjust the water distribution in Gaomiaozi County, China (GMZ) bentonite powder and was compared to the traditional spray method. The screening method was used to separate macro-agglomerates (≥ 0.25 mm) from the water and bentonite mixture. The properties, the content of the various size agglomerates in loose mixtures, and the heterogeneity defects observed in compacted bentonite were compared. An index (P) was defined to quantitatively evaluate the water distribution in a loose bentonite/water mixture. Macro-agglomerates in loose mixtures produced heterogeneities in water content, density, and shrinkage. By using the ice-bentonite mixing method, fewer macro-agglomerates were formed and a homogeneous distribution of water was produced in the compacted bentonite. A homogeneous water distribution had the tendency to decrease the number of shrinkage cracks after the drying process and to maintain high mechanical strength in the compacted bentonite. Although the production of ice powder was laborious, the ice-bentonite mixing method has workability advantages: (i) a high mixing efficiency, (ii) a low mass loss rate, and (iii) a small deviation between measured water content and target water content. The low thawing efficiency of ice-bentonite mixtures can be solved by using a microwave-assisted thawing method. This research can improve the sample preparation method used to produce compacted buffer/backfill materials for HLW disposal.

Sub-surface clay samples are difficult to characterize using conventional methods so non-invasive Nuclear Magnetic Resonance (NMR) techniques were used to evaluate in a preserved state the pore structure, porosity, water mobility, and affinity of various clay systems. Within the CLAYWAT project launched by the NEA Clay Club, some of the most advanced NMR techniques were applied to samples from 11 clay-rich sedimentary formations (Boom Clay, Yper Clay (both Belgium); Callovo-Oxfordian shale, Upper Toarcian (both France); Opalinus Clay from two sites (Switzerland); Queenston Fm., Georgian Bay Fm., Blue Mountain Fm. (all Canada); Boda Clay (Hungary); and Wakkanai Fm. and Koetoi Fm. (Japan)). The degree of induration within this suite of samples varies substantially, resulting in a wide porosity range of 0.02–0.6. The key finding is the determination of pore-size distribution by NMR cryoporometry in the range of 2 nm–1 μm with the native fluid present in the pore space for most samples. The water volume in pore sizes of <2 nm could also be measured, thus providing a full description of the porosity system. A specific preparation by sample milling was applied to the preserved original cores minimizing disturbances to the samples in terms of water loss. The water content measured by NMR relaxation was comparable to values obtained by drying at 105°C. In general, the narrow T2 distributions indicate that water was diffusing throughout the pore network during the magnetization lifetime, implying that T2 distributions cannot be considered as proxies for the pore-size distributions. For the set of samples considered, the T1/T2 varied between 1.7 and 4.6, implying variable surface affinity. Finally, for most samples, a pore-shape factor of ~2.4, intermediate between a sheet (1) and a cylinder (4), was deduced.

The regulation of plasma membrane H+-ATPase was considered in imbibing Vicia faba seeds, a distinctive feature of which is germination by cell elongation, whereas the mitotic activity starts later. The enzyme activation is known to precede germination because it provides H+ ion efflux from the cytoplasm to cell walls which favours their modification and loosening, being the prerequisites of cell elongation commencement. The presence of an enzyme in imbibing embryo axes was confirmed immunochemically. H+ ion efflux was recorded with a pH-meter as acidification of ambient solution by the embryonic axes for 5 min. The activation of the enzyme and its subsequent activity are regulated in different ways. Enzyme activation is hydration-driven, it starts when water content increases up to the threshold level of 55% (fresh weight basis). This value was confirmed by imbibition in the presence of the osmoticum polyethylene glycol 6000, at various osmotic potentials. The activation does not depend on indolylacetic or abscisic acid treatment. Hydration-triggered activation of the enzyme favours rapid seed germination and its correspondence to the soil water potential. Enzyme activity after its activation is inhibited by 60–70% by 10−5–10−7 M abscisic acid, whereas indolylacetic acid exerted no effect. The regulation of plasma membrane H+-ATPase activity is presumably accomplished by the interaction of the enzyme with 14-3-3 proteins and endogenous fusicoccin, present in imbibing axes.

Low-pressure regional aureoles with steep metamorphic field gradients are critical to understanding progressive metamorphism in high-temperature metasedimentary rocks. Delicately layered pelitic and psammitic metasedimentary rocks at Mt Stafford, central Australia, record a greenschist- to granulite-facies Palaeoproterozoic regional aureole, associated with S-type granite plutons, reflecting metamorphism in the range 500–800 °C and at ∼3 kbar. The rocks experienced minimal deformation during metamorphism and partial melting. Partial melting textures evolve progressively along the steep metamorphic field gradient from the incipient stages of melting marked by cuspate grains with low dihedral angles, to melt proportions sufficient to form diatexite with schollen. Phase equilibria modelling in the NCKFMASHTO system for pelitic, semi-pelitic and high- and low-ferromagnesian psammitic samples quantitatively illustrates the dependence of partial melting on rock composition and water volume. Pelitic compositions are more fertile than psammitic compositions when the water content in the rocks is low, especially during the early stages of melting. The whole-rock ferromagnesian component additionally influences melt fertility, with ferromagnesian-rich psammite being more fertile than psammite with a lower ferromagnesian component. Subtle variations in free water content can result in obvious changes in melt volume but limited variation in melt composition. Distinct melting histories of pelitic and psammitic rocks inferred from field relationships may be partially attributed to potential differences in water volume retained to super-solidus conditions. Melt composition is more dependent on the rock composition than the variation in water content.

Data on the dehydration of pentahydroborite, CaB2O(OH)6·2H2O and nifontovite, Ca3B6O6(OH)12·2H2O from the Fuka mine, Japan are presented. Critical temperatures of the dehydration of the borates were determined by thermogravimetric analysis/differential thermal analysis measurements. The untreated mineral samples and their heating products were investigated by X-ray diffraction and Raman spectroscopy. Upon dehydration, both minerals decompose and undergo amorphization, and at greater temperatures crystallize as an orthorhombic calcium borate, CaB2O4 (Pnca). The dehydration paths of the two minerals are different, with nifontovite showing a greater resistance to decomposition and amorphization than pentahydroborite. Differences in the dehydration processes are related to the residuals of the water content and structural accommodation of the borate polyanion.

Studies were conducted to determine the growth responses of rice to PRE application of oxadiazon and POST application of bispyribac-sodium. Oxadiazon at 1.0 and 1.5 kg ha−1 and bispyribac-sodium at 0.030 and 0.045 kg ha−1 were applied to four rice varieties (‘IR64’, ‘IR72’, ‘RC09’, and ‘RC18’), which were grown in saturated and aerobic (30% of saturation) soils. Control treatments, where no herbicides were applied, were also included in the study. Shoot and root biomass, and height of rice plants were measured 14 d after application. Phytotoxic effects for both herbicides, including reduced shoot and root biomass, were consistent in all varieties. Rice phytotoxicity symptoms were greater when herbicides were applied to saturated than to aerobic soils. Oxadiazon at 1.0 kg ha−1 reduced rice shoot biomass by 22 to 36% in aerobic condition, and 43 to 56% in saturated condition when compared with the control. Bispyribac-sodium reduced rice shoot biomass by 9 to 17% at 0.030 kg ha−1 in aerobic soil and 23 to 37% in saturated soil. The results of this study suggest that soil water content is an important factor influencing herbicide phytotoxicity in rice, and its influence warrants further research to improve understanding of physiology of phytotoxicity to minimize the effects of these herbicides on crop production.

Seed shelf-life or longevity is difficult to predict or to measure on a practical time scale. Predictive models suggest that water has the same effect on ageing rate for all seed lots within a species and that initial seed quality is the dominating factor explaining within-species variation. These assumptions are used in ‘accelerated ageing’ or ‘controlled deterioration’ (AA/CD) tests, which are commonly used to predict seed longevity in commercial and research applications. In this study, we describe within-species variation of longevity for seeds of Secale cereale and S. strictum (cultivated rye and its wild progenitor) under typical dry storage conditions of a genebank, and show that initial seed quality is an important, but not sole, factor explaining measured longevity. We also test the correlation of seed longevity, measured under humid and dry conditions, using 50 cultivars of rye, wheat (Triticum aestivum) and the intergeneric cross triticale, to assess how well AA/CD tests predict seed shelf-life during dry storage. Known differences in longevity between wheat and rye were confirmed at all water contents, and triticale seeds demonstrated intermediate behaviour. Longevity measured for humid and dry conditions were weakly correlated when comparisons included all grain types and were not correlated in within-grain-type comparisons. Response to moisture varied among cultivars. These findings do not support assumptions made in seed ageing models that use AA/CD tests. Our results suggest that more traits are involved in the expression of seed longevity than those typically measured in studies of initial seed vigour.

The size–weight relationships, percentage water, ash-free dry weight and biochemical (protein, lipid and carbohydrate) contents of the coronate jellyfish species Periphylla periphylla have been analysed. A total of 48 medusae ranging in size from 13 to 80 mm bell diameter were collected from mesopelagic depths in the eastern Gulf of Mexico. The dry mass of whole medusae ranged from 1.12 to 10.53% of wet weight (mean 5.49%), while ash-free dry weight, a proxy for organic content, varied between 25.19 and 34.89% of dry weight (mean 30.14%). Preservation in 2% glutaraldehyde resulted in shrinkage in >75% of the medusae, with preserved bell diameters 2.9% to 28.6% smaller than the original fresh bell diameters. Preservation also produced a significant adjustment to the bell diameter to wet weight relationship. With regard to biochemical content, the typical gelatinous zooplankton trend of low carbohydrate (mean 8.99 mg gDW−1), intermediate lipid (mean 20.57 mg gDW−1) and high protein (mean 63.71 mg gDW−1) was observed. Although there was a high degree of variability in biochemistry, there was no apparent trend with size.

When seeds deteriorate, they lose vigour and become more sensitive to stresses upon germination. Eventually seeds lose the ability to germinate. The factors which determine the rate of this ‘aging’ are the temperature and moisture content at which seeds are stored and an ill-defined parameter, seed quality. While it has been known for many years that manipulation of these factors influences the longevity of seeds, the precise interactions among them are so poorly understood as to preclude the prediction of longevity for a particular seed lot. Concepts from studies of materials and food stability can be applied to seed aging research, and this may help us take a more integrative approach to understanding the kinetics of seed deterioration. These concepts describe the physical environment of the seed matrix in response to changing water contents and temperature. Water activity models describe the state of water in the seed, while the glass models describe the state of the aqueous solution. Both models presume that changes of state affect the nature and kinetics of chemical reactions. Thus, the physical and chemical environment within the seed are inextricably linked.

Ambient CO2 concentration (together with CO2 exchange and microclimate) was recorded every 30 min for 15 months for Lecanora muralis growing in the Botanical Garden Würzburg (Germany, northern Bavaria), a habitat on the outskirts of the city. Annual mean CO2 was around 17 ppm higher than the global average reported for the time of measurement (361 ppm; 1995/96), and daily values ranged from 317 to 490 ppm. Diel courses of CO2 could be classified into three different types. Type A, when CO2 levels rose overnight and then fell strongly to below global levels during the day, which predominated in the summer (about 75 of days); Type B, irregular diel courses occurred during all seasons with often very rapid changes apparently due to advective CO2 transport; Type C, CO2 concentration was typically almost stable at generally between c. 330 and 430 ppm which predominated in the winter (63 of days).

Under controlled conditions, CO2 saturation of net photosynthesis (NP) of L. muralis at optimal hydration and light occurred at around 1000 ppm. NP was also affected by low CO2 at limiting light and thallus water contents. Based upon these data, we estimated the improvement of NP of L. muralis due to transient increase of ambient CO2 (as compared with the global average) for one selected combination of environmental factors (nocturnal dew or frost). This combination is an important source of water for the lichen, resulting in 40 of its annual production and, especially in these situations, photosynthesis was increased by high ambient CO2 in the early morning under prevailing Type A conditions. After dew activation, light compensation point of NP occurred at an average concentration of 413 ppm and diel maxima of NP at 402 ppm. This allows a rough estimate that the transiently elevated CO2 increased the photosynthetic gain of the lichen after dew of 7, or an improvement to its annual carbon balance of about 3. Conditions, especially interrelationships between lichen hydration, light and CO2 are so complex that we are not yet able to extend our estimates to other environmental situations of photosynthetic activity of L. muralis.

The relationships among water content, relative humidity and temperature were documented in both seeds and excised embryos of Coffea spp. using water sorption isotherms. Isotherms were constructed at 5, 15 and 25°C and calculated for lower temperatures. There were no apparent differences in sorption characteristics among whole seeds of several cultivars of C. arabica and among different species of Coffea. Excised embryos of genetically diverse Coffea germplasm also exhibited similar sorption characteristics, though there were substantial differences observed between embryos and whole seeds. The shape of isotherms of coffee seed tissues was intermediate to the reverse sigmoidal shape observed for orthodox seeds and the monotonic shape observed for desiccation intolerant plant tissues. The heats of sorption calculated for RH ≤ 25% for whole seeds of Coffea spp. were similar to orthodox seeds. In contrast, the heats of sorption calculated in the same RH range for excised embryos were intermediate between those of orthodox and recalcitrant embryos. Our observations are consistent with earlier observations that desiccation sensitivity or poor longevity is linked with low levels of water sorption at relative humidities less than 25%. An explanation for this remains elusive.

Embryonic axes of tea (desiccation sensitive) and pea (desiccation tolerant) were dried at different rates or stored at different water contents to distinguish between damage associated with the immediate effects of water loss and the longer-term effects of a partially hydrated state. No loss of viability was observed if pea axes were dried sufficiently rapidly (from 1.8 to 0.1 g H2O g-1dry mass (g/g) within 5 d). However, viability was lost in tea axes dried below 0.5 g/g (approximately -15 MPa) even if axes were dried within 1 h. Death in tea axes dried to moisture contents less than 0.5 g/g probably resulted from the removal of water necessary for cellular structural integrity (i.e. desiccation damage sensu stricto). When axes of both species were dried at slower rates, viability losses were observed at water potentials between about -3 and -15 MPa. The timing for this type of damage was species dependent, occurring within 2 d for tea and after 5 d for pea, and may be explained by higher oxidative activity in tea compared to pea. Embryos of both species with water potentials below -3 MPa were lethally damaged if oxygen consumption exceeded 1000–5000 μmol O2 g-1dry mass. Recalcitrant seeds are different than orthodox seeds because the former do not survive drying below a critical water content, regardless of the drying rate. Rapid drying is required for accurate assessment of the critical water content. Slow drying leads to metabolic imbalance and artefactual assessment of the critical water content for desiccation damage. Both tea and pea seeds were susceptible to damage from metabolic imbalances, suggesting that the predominant stress from slow drying is ageing.

Xanthoria mawsonii C. W. Dodge was found to perform well physiologically in a variety of habitats at high latitudes in continental Antarctica. The net photosynthetic rate of 7·5 μ mol CO2 kg−1 s−1 is exceptionally high for Antarctic lichens. Field and laboratory measurements proved the photosynthetic apparatus to be highly adapted to strong irradiance. The cold resistance of the photosystem II reaction centres is higher than the photosynthetic CO2 fixation process. Optimum temperature for net photosynthesis was c. 10°C. The lichen grows along water channels where it is frequently inundated and hydrated to maximum water content, although net photosynthesis is strongly depressed by super saturation. In these habitats the lichen is photosynthetically active for long periods of time. Xanthoria mawsonii also grows at sites where it depends entirely on the early spring snow melt and occasional snow fall for moisture. It has an exceptionally short reactivation phase and is able to utilize snow immediately. Recovery of activity by absorbing water vapour from air, though practically possible, seems to be of ecological importance only under snow at subzero temperatures.

Diel (24-h) time courses of microclimate, water relations, and CO2 exchange were measured under quasi-natural conditions at a forest edge in a lower montane, tropical rainforest in Panama for six Lobariaceae (Lobaria crenulata, L. dissecta, Pseudocyphellaria aurata, P. intricata, Sticta sublimbata, S. weigelii). Responses to experimentally controlled water content (WC), photosynthetic photon fluence rate (PPFR), and temperature were studied in most detail with P. aurata.

Photosynthesis was well adapted to high temperatures, and all species exhibited ‘shade plant’ characteristics with low light compensation points and low light saturation. Lobaria and Pseudocyphellaria species suffered from a strong depression of net photosynthesis (NP) at suprasaturating WC; suprasaturation depression was less in cyphellate Sticta species.

Photosynthetic capacity correlated with thallus nitrogen concentration, and maximal NP rates of the cyanobacterial Sticta species was 4 to 5 times higher than that of the green algal Lobaria species. However, high rates of NP were uncommon and brief events under natural conditions; the different environmental factors were rarely optimal simultaneously. Similar to earlier observations with other rainforest lichens, NP ceased during the period of highest irradiation on most days due to desiccation. During moist periods low light often limited carbon fixation, and high thallus hydration was often detrimental to NP. In spite of these limitations the maximal daily integrated net photosynthetic carbon income (ΣNP) was quite high especially for the Sticta species [17·3 and 24·1 mgC (gC)−1 day−1 for S. sublimbata and S. weigelii, respectively]. High nocturnal carbon loss, due to high night temperatures and continuous hydration, resulted in frequent negative diel carbon balances (ΣC) in all species. The average nocturnal carbon loss amounted to 83 and 70% ΣNP for P. aurata and P. intricata, respectively and to 64 and 59% of ΣNP for S. sublimbata and S. weigelii, respectively. Their average diel ΣC was as high as 3·7 and 5·3 mgC (gC)−1 day−1. In contrast, ΣC was much lower for the other species, it amounted to only 0·18 mgC (gC)−1 day−1 for L. crenulata. Thus, the Sticta species stood out amongst the species studied for their most successful adaptation of photosynthetic productivity to the habitat conditions in the lower montane rainforest.

Diel (24-h) time courses of CO2 exchange, water relations, and microclimate of the foliose lichen, Sticta tomentosa (Swartz) Ach., and responses to experimentally manipulated conditions were measured at a forest edge in a lower montane rainforest in Panama.

Similar to earlier observations on two other rain forest lichens, daily desiccation suppressed net photosynthesis (NP) during the period when irradiation was highest. Not surprisingly, the light response curves of NP showed saturation at rather low light levels. Rehydration was associated with an initial resaturation burst of short duration, which could be demonstrated both under natural conditions and experimentally. This additional loss of CO2 seems too low to be ecologically relevant. Moreover, high thallus hydration was also detrimental to NP: at maximum water content net CO2 uptake was depressed by >50%. Although NP was well adapted to the prevailing high temperatures, the latter also stimulated dark respiration. On average, almost 60% of the diurnal carbon gain was lost during the night.

In spite of these limitations, the integrated 24-h C gain was quite high, on average 0·5% of the thallus C content. Whilst these figures were determined for horizontally exposed samples, we also assessed the role of different exposures on photosynthetic performance. Diel C gain was highest under conditions of semi-shade (westerly exposure), which allowed long periods of activity, whilst much higher irradiance at other exposures could not be utilized for photosynthetic production: easterly exposed thalli dried out even faster than horizontally exposed samples.

The seasonal changes in water content and fat content of olive psylla, Euphyllura olivina in the field were investigated in two successive years. The overwintering adults of olive psylla had more fat than spring and summer generation adults. There was a steady increase in % fat contents of females from mid-October to early January. The % fat of both sexes decreased sharply in May, June and July. There was a gradual reduction in % water content from mid-June to early October and then decreased steadily until early November. The % water in the overwintering adults ranged from 57.5 to 45% and became constant around 52.5% of live body weight in February and March. Seasonal changes in % water was positively related to population changes of olive psylla. The % water in olive psylla was negatively related to the fat content.

This paper summarizes data from previous and current studies on two adjacent farms, one organically managed and the other conventionally managed, in the Palouse region of eastern Washington. The 320-hectare organic farm has been managed without the use of commercial fertilizers and only limited use of pesticides since the farm was first plowed in 1909. The 525-hectare conventional farm, first cultivated in 1908, began receiving recommended rates of commercial fertilizers and pesticides in 1948 and the early 1950's, respectively. The organically-farmed Naff silt loam soil had significantly higher organic matter, cation exchange capacity, total nitrogen, extractable potassium, water content, pH, polysaccharide content, enzyme levels, and microbial biomass than did the conventionally-farmed Naff soil. Also, the organically-farmed soil had significantly lower modulus of rupture, more granular structure, less hard and more friable consistence, and 16 centimeters more topsoil. This topsail difference between farms was attributed to significantly greater erosion on the conventionally-farmed soil between 1948 and 1985. The difference in erosion rates between farms was most probably due to their different crop rotation systems; Le., only the organic farm included a green manure crop in its rotation, and it had different tillage practices. These studies indicate that, in the long-term, the organic farming system was more effective than the conventional farming system in maintaining the tilth and productivity of the Naff soil and in reducing its loss to erosion.

Groups of Rhipicephalus appendiculatus adults were prepared at three levels of hydration (100, 85 and 65%) and placed in small field enclosures. Some of the ticks were broadcast over the vegetation, while others were confined in nylon gauze bags and placed at soil level. Weight changes in the bagged ticks were monitored for 3 consecutive days by twice-daily weighing. Observations were made in the hot dry season, rainy season and the cool dry season. During the hot dry season there was a progressive loss in weight over the observation period, as during the night the ticks could not fully replace the water lost by day. In the rainy season there was an initial rapid uptake of water at night by the dehydrated groups and any weight losses during the day were easily replaced at night. In the cool dry season water losses were slight, and though ticks regained water at night, neither of the dehydrated groups became 100% hydrated during the period of observation.