Effect of soil moisture and transpiration on mineral content in leaves and berries of cabernet sauvignon grapevine

Leaf and berry transpiration ratio in grapevine (Vitis vinifera L.) was found to be affected by soil moisture. With the condition of diminished soil moisture, berry transpiration is higher prior to vèraison compared to conditions when the water content in the substrate is higher and berry transpiration decreases with an increase of leaf transpiration. Studies were conducted in 1993 and 1994 to investigate the link between soil moisture, traspiration, and accumulation of certain mineral elements in leaves and berries on plants of the Cabernet sauvignon cultivar grafted on Kober 5 BB rootstock. Leaf and berry transpiration and mineral accumulation were evaluated by gaseous exchange measurements, soil sampling and moisture analysis, and leaf and berry sampling and analysis of mineral content. Observations were repeated at about 15‐day intervals between full bloom and berry ripening. Transpiration per unit of surface area (mmol H₂O m^‐2 s^‐1) was always higher in leaves than in berries. Leaf transpiration varied from 5.62 mmol H₂O m^‐2 s^‐1 to 2.92 mmol H₂O m^‐2 s^‐1 in 1993 in the period between the 8th and 86th day after full bloom (DAFB), and from 6.49 mmol H₂O m^‐2 s^‐1 to 4.37 mmol H₂O m^‐2 s^‐1 in 1994 between the 12th and 94th DAFB. Berry transpiration ranged between 3.86 mmol H₂O m^‐2 s^‐1 and 1.04 mmol H₂O m^‐2 s^‐1 in 1993 and between 4.34 mmol H₂O m^‐2 s^‐1 and 0.5 mmol H₂O m^‐2 s^‐1 in 1994. Leaf transpiration was not correlated with the mineral element content in the leaves, whereas berry transpiration was directly correlated with the nitrogen (N), calcium (Ca), potassium (K), and phosphorus (P) content in berries. Leaf mineral composition was affected only for iron (Fe) content by the variation on soil moisture, whereas the berry N, P, K, and Ca contents were positively correlated with soil water content. The leaf and berry Ca content appeared to be greater with high soil moisture, i.e., in conditions which favor intense metabolism of the whole plant.     

The importance of biochar quality and pyrolysis yield for soil carbon sequestration in practice

Biochar is a carbon (C)-rich material produced from biomass by anoxic or oxygen-limited thermal treatment known as pyrolysis. Despite substantial gaseous losses of C during pyrolysis, incorporating biochar in soil has been suggested as an effective long-term option to sequester CO₂ for climate change mitigation, due to the intrinsic stability of biochar C. However, no universally applicable approach that combines biochar quality and pyrolysis yield into an overall metric of C sequestration efficiency has been suggested yet. To ensure safe environmental use of biochar in agricultural soils, the International Biochar Initiative and the European Biochar Certificate have developed guidelines on biochar quality. In both guidelines, the hydrogen-to-organic C (H/C_org) ratio is an important quality criterion widely used as a proxy of biochar stability, which has been recognized also in the new EU regulation 2021/2088. Here, we evaluate the biochar C sequestration efficiency from published data that comply with the biochar quality criteria in the above guidelines, which may regulate future large-scale field application in practice. The sequestration efficiency is calculated from the fraction of biochar C remaining in soil after 100 years (F_perm) and the C-yield of various feedstocks pyrolyzed at different temperatures. Both parameters are expressed as a function of H/C_org. Combining these two metrics is relevant for assessing the mitigation potential of the biochar economy. We find that the C sequestration efficiency for stable biochar is in the range of 25%–50% of feedstock C. It depends on the type of feedstock and is in general a non-linear function of H/C_org. We suggest that for plant-based feedstock, biochar production that achieves H/C_org of 0.38–0.44, corresponding to pyrolysis temperatures of 500–550°C, is the most efficient in terms of soil carbon sequestration. Such biochars reveal an average sequestration efficiency of 41.4% (±4.5%) over 100 years.     

Characterization of Organic Matter in Compost Produced with Municipal Solid Wastes: An Italian Approach

Stabilization of the organic matter of a static pile of compost from municipal solid wastes (MSW) under a forced-pressure ventilation composting system was followed for 55 days during winter season. The materials were analyzed according to the official methodologies required by Italian regulations regarding the quality of composts from MSW. The stabilization process of the organic matter was monitored using both the degree of humification (DH), i.e. the ratio between the humified fractions (HA + FA) and the total extractable carbon (TEC), and the electrofocusing technique (EF). The DH increased steadily in compost during stabilization process and converged asymptotically at the end of the period of composting. The EF analyses of the organic extracts of compost from MSW showed a definite trend in the humification process and confirmed the actual evolution of the organic matter composted.     

Shape and intraporosity of topsoil aggregates under maquis and pasture in the Mediteranean region

The clearing of Mediterranean maquis along with the creation of new pasture land has been an important factor of soil and land degradation in the Mediterranean region. The present research compared soil aggregates and their intraporosity in paired pasture/maquis plots in central E Sardinia (Italy), to study the impact of land use change on soil structure. Undisturbed surface horizons were sampled for thin‐section analysis. Aggregate shape was compared and intraporosity was studied for representative aggregates at different depths. Furthermore, the interaction of root activity and grazing under pasture and maquis cover was discussed. The outcomes revealed a complex interplay of trampling and root activity effects. A decrease (–44%) in total voids (regular pores), along with higher aggregate regularity, was observed under pasture in the 0–2 cm layer, and an increase (+261%) in 50–100 μm planar (elongated) pores was determined in the 2–4 cm layer, suggesting a possible surface compaction due to trampling and an increased subsurface fine root activity by the grassland vegetation.     

The effects of sediment deposits from Namibian diamond mines on intertidal and subtidal reefs and rock lobster populations

• 1. Extensive diamond mining occurs on land and in the sea on the west coasts of South Africa and Namibia, raising fears that diamond‐mining activities may impact commercial rock‐lobster fisheries and benthic communities. To explore this possibility, the effects of the diamond‐mining fines‐discharge on intertidal and subtidal rocky‐shore communities and on the population structure of the rock lobster Jasus lalandii were assessed at Elizabeth Bay.
• 2. Sampling over six years at sites covering a range of wave exposures compared impacted sites with comparable reference sites never exposed to the fines. Percentage cover and densities of benthic organisms were recorded on both intertidal and subtidal reefs. Rock‐lobster abundance was estimated from counts and catch‐per‐unit‐effort, and their length frequencies and sex ratios compared in impacted and reference areas.
• 3. The deposition of fines had no effect at wave‐exposed sites, but did impact intertidal and subtidal communities at sheltered localities where fines accumulated because wave action was insufficient to disperse them. Reductions of grazers, proliferation of algae and increased dominance by filter‐feeders were recorded at the impacted sites and persisted throughout the monitoring programme. Differences in community structure associated with different levels of wave exposure were, however, greater than those produced by depositing fines. The detected effects of fines‐deposits on the benthos were local and likely to be reversible after cessation of mining.
• 4. The fines‐deposit had no detectable effects on the sex‐ratio, size or abundance of rock lobsters, indicating that there is no conflict between the deposition of fines and the fishery for rock lobsters, although substantial inter‐site variability makes it difficult to regard the results as definitive.

Copyright © 2002 John Wiley & Sons, Ltd.     

Benthic foraminifera as proxies of marine influence in the Orosei marine caves,Sardinia, Italy

1. As a result of their location at the boundary between marine and continental domains, marine caves are affected by wide spatial and seasonal environmental changes. Only recently have benthic foraminifera been recognized as reliable indicators for the ecological zonation of these environments.
2. The present study is focused on two marine caves of the Orosei Gulf, Sardinia, Italy: Bue Marino and Bel Torrente. It investigates the spatial and seasonal variability of benthic foraminiferal assemblages relative to sediment grain size and water parameters (temperature, salinity, pH, and dissolved oxygen) collected during two campaigns in August 2014 and April 2015. The results from 2014 have been partially published.
3. Based on a comparison of the results of the two campaigns, the considerable reduction of foraminiferal abundance in Bel Torrente was deduced to occur because of the strong freshwater flows occurring during the rainy season; in Bue Marino, the less severe water flow allowed the identification of both living and dead foraminifera, although strongly reduced in number. These identifications allowed benthic foraminifera to be used to define the ecological zonation.
4. Entrance, confluence, and transitional ecozones were identified in Bue Marino cave on the basis of species abundance. The second ecozone, not recognized in 2014, was correlated with plant debris at the confluence of the two cave branches. The other two ecozones, which are characterized by the faunal shift from hyaline‐ to agglutinated‐prevalent assemblages, were attributed to the gradient of abiotic parameters detected from the outer to the inner portions of the cave. In both campaigns the same ecozones were recognized in terms of species composition, with exceptions being found to different extents as a result of seasonal variability.
5. As the distribution of foraminiferal ecozones is conditioned by a decreasing gradient of marine influence, long‐term monitoring may be regarded as a promising tool for future studies on sea‐level change.

     

Hydrophobic collapse in multidomain protein folding

We performed molecular dynamics simulations of the collapse of a two-domain protein, the BphC enzyme, into a globular structure to examine how water molecules mediate hydrophobic collapse of proteins. In the interdomain region, liquid water persists with a density 10 to 15% lower than in the bulk, even at small domain separations. Water depletion and hydrophobic collapse occur on a nanosecond time scale, which is two orders of magnitude slower than that found in the collapse of idealized paraffin-like plates. When the electrostatic protein-water forces are turned off, a dewetting transition occurs in the interdomain region and the collapse speeds up by more than an order of magnitude. When attractive van der Waals forces are turned off as well, the dewetting in the interdomain region is more profound, and the collapse is even faster.     

Feeding of yeast (Candida spp.) improves in vitro ruminal fermentation of ifbrous substrates

In vitro gas production technique (IVGPT) was used with the objective of determining the inclusion effect of live cel s of two strains of Candida yeast on in vitro ruminal fermentation of two ifbrous s...     

Evaluation of on-farm irrigation scheduling methods for potatoes

The neutron probe, infrared thermometry and crop water stress index (CWSI), and a computer-assisted irrigation scheduling method were evaluated in terms of their effect on tuber yield, tuber quality, and water use. The experiment was conducted during 1990 and 1991 near Othello, central Washington, using Russet Burbank potatoes grown in a silt loam soil. Irrigation treatments did not commence until after tuber initiation. In general, no differences in total number of tubers and total tuber yield resulted from the different scheduling methods. However, the canopy temperature method showed reduction in the yield of number one tubers in 1990. The least total irrigation water was applied during the growing season with the neutron probe method. Using CWSI values above 0.5 to 1.0 (scale 0 to 10) for two consecutive days as a threshold to schedule irrigations appeared to be adequate for potatoes grown in silt loam soils. However, shortcomings of infrared thermometry suggested that this method may not be practical for scheduling irrigation of potatoes.     

Oxygenated Polyketides from Plakinastrella mamillaris as a New Chemotype of PXR Agonists

Further purification of the apolar extracts of the sponge Plakinastrella mamillaris, afforded a new oxygenated polyketide named gracilioether K, together with the previously isolated gracilioethers E–G and gracilioethers I and J. The structure of the new compound has been elucidated by extensive NMR (¹H and ¹³C, COSY, HSQC, HMBC, and ROESY) and ESI-MS analysis. With the exception of gracilioether F, all compounds are endowed with potent pregnane-X-receptor (PXR) agonistic activity and therefore represent a new chemotype of potential anti-inflammatory leads. Docking calculations suggested theoretical binding modes of the identified compounds, compatible with an agonistic activity on hPXR, and clarified the molecular basis of their biological activities.