Does root-sourced ABA play a role for regulation of stomata under drought in quinoa (Chenopodium quinoa Willd.)

The Andean seed crop quinoa (Chenopodium quinoa Willd.) is traditionally grown under drought and other adverse conditions that constrain crop production in the Andes, and it is regarded as having considerable tolerance to soil drying. The objective of this research was to study how chemical and hydraulic signalling from the root system controlled gas exchange in a drying soil in quinoa. It was observed that during soil drying, relative g_s and photosynthesis A_max (drought stressed/fully watered plants) equalled 1, until the fraction of transpirable soil water (FTSW) decreased to 0.82 ± 0.152 and 0.33 ± 0.061, respectively, at bud formation, indicating that photosynthesis was maintained after stomata closure. The relationship between relative g_s and relative A_max at bud formation was represented by a logarithmic function (r² = 0.79), which resulted in a photosynthetic water use efficiency WUE_Amax_/gs$\text{WU}{\text{E}}_{A_{\text{max}}/g_{\text{s}}}$ of 1 when FTSW > 0.8, and increased by 50% with soil drying to FTSW 0.7–0.4. Mild soil drying slightly increased ABA in the xylem. It is concluded that during soil drying, quinoa plants have a sensitive stomatal closure, by which the plants are able to maintain leaf water potential (ψ_l) and A_max, resulting in an increase of WUE. Root originated ABA plays a role in stomata performance during soil drying. ABA regulation seems to be one of the mechanisms utilised by quinoa when facing drought inducing decrease of turgor of stomata guard cells.     

Deficit irrigation based on drought tolerance and root signalling in potatoes and tomatoes

Agriculture is a big consumer of fresh water in competition with other sectors of the society. Within the EU-project SAFIR new water-saving irrigation strategies were developed based on pot, semi-field and field experiments with potatoes (Solanum tuberosum L.), fresh tomatoes (Lycopersicon esculentum Mill.) and processing tomatoes as model plants. From the pot and semi-field experiments an ABA production model was developed for potatoes to optimize the ABA signalling; this was obtained by modelling the optimal level of soil drying for ABA production before re-irrigation in a crop growth model. The field irrigation guidelines were developed under temperate (Denmark), Mediterranean (Greece, Italy) and continental (Serbia, China) climatic conditions during summer. The field investigations on processing tomatoes were undertaken only in the Po valley (North Italy) on fine, textured soil. The investigations from several studies showed that gradual soil drying imposed by deficit irrigation (DI) or partial root zone drying irrigation (PRD) induced hydraulic and chemical signals from the root system resulting in partial stomatal closure, an increase in photosynthetic water use efficiency, and a slight reduction in top vegetative growth. Further PRD increased N-mineralization significantly beyond that from DI, causing a stay-green effect late in the growing season. In field potato and tomato experiments the water-saving irrigation strategies DI and PRD were able to save about 20-30% of the water used in fully irrigated plants. PRD increased marketable yield in potatoes significantly by 15% due to improved tuber size distribution. PRD increased antioxidant content significantly by approximately 10% in both potatoes and fresh tomatoes. Under a high temperature regime, full irrigation (FI) should be undertaken, as was clear from field observations in tomatoes. For tomatoes full irrigation should be undertaken for cooling effects when the night/day average temperature >26.5 °C or when air temperature >40 °C to avoid flower-dropping. The temperature threshold for potatoes is not clear. From three-year field drip irrigation experiments we found that under the establishment phase, both potatoes and tomatoes should be fully irrigated; however, during the later phases deficit irrigation might be applied as outlined below without causing significant yield reduction:

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Potatoes

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After the end of tuber initiation, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.

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Fresh tomatoes

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From the moment the 1st truce is developed, DI is applied at 85-80% of FI for two weeks. In the middle period, DI or PRD is applied at 70% of FI. During the last 14 days of the growth period, DI or PRD is applied at 50% of FI.

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Processing tomatoes

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From transplanting to fruit setting at 4th-5th cluster, the PRD and DI threshold for re-irrigation is when the plant-available soil water content (ASWC) equals 0.7 (soil water potential, Ψ_soil = −90 kPa). During the late fruit development/ripening stage, 10% of red fruits, the threshold for re-irrigation for DI is when ASWC = 0.5 (Ψ_soil = −185 kPa) and for PRD when ASWC (dry side) = 0.4 (Ψ_{soil, dry side} = −270 kPa).

The findings during the SAFIR project might be used as a framework for implementing water-saving deficit irrigation under different local soil and climatic conditions.     

Reactivity of workshop monoclonal antibodies on paraformaldehyde-fixed porcine blood mononuclear cells

One hundred sixty-four monoclonal antibodies (mAbs) of the second international swine CD workshop were tested for their reactivity with porcine blood mononuclear cells before and after fixing the cells with varying concentrations of paraformaldehyde (PFA) (1, 5 and 10 g l⁻¹). A total of 38 (out of 134) positive reacting mAbs were significantly affected in their binding behavior on fixed cells. Modulation was seen as reduction in binding (staining intensity and/or % positive cells, n=18) or in elevated values (n=20). Modified mAb binding occurred after fixing cells with 5 to 10 g l⁻¹ PFA.     

Adaptation of quinoa (Chenopodium quinoa) to Northern European agriculture: studies on developmental pattern

The inheritance of resistance to clubroot, caused by Plasmodiophora brassicae in Brassica oleracea was studied in the F₁, F₂and backcross progenies of three crosses between resistant and susceptible doubled haploid lines. Fresh weights of affected (CW) and healthy (HRW) parts of the root system were measured and R = ln((HRW+0.5)/(CW+0.5)) was used as a measure of resistance. R was shown to have a normally distributed error term with a constant standard deviation over the entire scale. Analysis of means indicated the presence of two complementary resistance genes in one of the crosses. In the other two crosses analysis of means also indicated two-locus interactions, in these cases reducing the cumulative effects of loci homozygous for resistance or for susceptibility alleles. The numbers of segregating resistance genes in these two crosses could not be determined. The presence of epistatic interactions precluded analysis of variance; therefore in this case the measurements were not more informative than the symptom grades analyzed in a previous study.R showed a high rank correlation (-0.85) with symptom grades assigned to the same plants. The results of genetic analyses of R were generally in agreement with those obtained earlier using symptom grades. Symptom grades can therefore be regarded as a reliable measure of symptom development, despite their more subjective nature.     

Computerized apparatus for measuring dynamic flavor release from liquid food matrices

A fully computer-controlled apparatus was designed. It combines a glass reactor with a temperature-controlled hood, in which headspace volatiles are captured. Flavored liquids can be introduced into the reactor and exposed to conditions of temperature, air flow, shear rate, and saliva flow as they occur in the mouth. As the reactor is completely filled before measurements are started, creation of headspace just before sampling start prevents untimely flavor release resulting in real time data. In the first 30 s of flavor release the concentrations of the volatiles can be measured up to four times by on-line sampling of the dynamic headspace, followed by off-line trapping of the samples on corresponding Tenax traps and analysis using GC-TDS-FID. Flavor compounds from different chemical classes were dissolved in water to achieve concentrations typically present in food (micrograms to milligrams per liter). Most of the compounds showed constant release rates, and the summed quantities of each volatile of three 10 s time intervals correlated linearly with time. The entire method of measurement including sample preparation, release, sampling, trapping, thermodesorption, and GC analysis showed good sensitivity [nanograms (10 s)(-1)] and reproducibility (mean coefficient of variation = 7.2%).     

Intellectual deficit associated with transplacentally induced microcephaly in the rat

Fischer rats injected with methylazoxymethanol late in pregnancy produce young with considerably reduced cerebral hemispheres. They appear normal otherwise. As adults these animals make many more errors in the Hebb-Williams maze than do control animals.     

Commensurability and mobility in two-dimensional molecular patterns on graphite

Two-dimensional molecular patterns were obtained by the adsorption of long-chain alkanes, alcohols, fatty acids, and a dialkylbenzene from organic solutions onto the basal plane of graphite. In situ scanning tunneling microscopy (STM) studies revealed that these molecules organize in lamellae with the extended alkyl chains oriented parallel to a lattice axis within the basal plane of graphite. The planes of the carbon skeletons, however, can be oriented either predominantly perpendicular to or predominantly parallel with the substrate surface, causing the lamellar lattice to be either in or near registry with the substrate (alkanes and alcohols) or not in registry (fatty acids and dialkylbenzenes). In the case of the alcohols and the dialkylbenzene the molecular axes are tilted by +30 degrees or -30 degrees with respect to an axis normal to the lamella boundaries, giving rise to molecularly well-defined domain boundaries. Fast STM image recording allowed the spontaneous switch between the two tilt angles to be observed in the alcohol monolayers on a time scale of a few milliseconds.     

Epitaxial BiFeO3 multiferroic thin film heterostructures

Enhancement of polarization and related properties in heteroepitaxially constrained thin films of the ferroelectromagnet, BiFeO3, is reported. Structure analysis indicates that the crystal structure of film is monoclinic in contrast to bulk, which is rhombohedral. The films display a room-temperature spontaneous polarization (50 to 60 microcoulombs per square centimeter) almost an order of magnitude higher than that of the bulk (6.1 microcoulombs per square centimeter). The observed enhancement is corroborated by first-principles calculations and found to originate from a high sensitivity of the polarization to small changes in lattice parameters. The films also exhibit enhanced thickness-dependent magnetism compared with the bulk. These enhanced and combined functional responses in thin film form present an opportunity to create and implement thin film devices that actively couple the magnetic and ferroelectric order parameters.     

Influence of amperozide on disease occurrence in a pig fattening unit

The social and physical environments of animals and man have long been implicated in the etiology of infectious diseases. However, controlled experiments on adverse social and environmental stimuli and animal health are meagre (Kelley 1980). Recently the term psychoimmunology was coined to reflect the growing interest in the relationship between stress, reduced immune function and illness. For more than a decade it has been known that prolonged secretion of stress hormones, particularly corticosteroids, contributes to regression of the lymphoid tissues (Selye 1974, Freeman 1975). Now it has been shown more specifically, that the level of secretory immunoglobulin A is reduced in periods of high stress and that the activity of lymphocytes and natural killer cells are significantly reduced after intense stress periods (Wood 1985). Although the relationship between stress and immunity thus seems to be clear, studies linking those to disease are still a rarity.