Crop tolerance to saline sprinkling water

Summary Crops sprinkled with saline irrigation water are subject to foliar salt absorption and injury as well as to injury from soil salinity. Yield reductions caused by soil salinity alone are well documented, and data are presented here for 71 agricultural crops. Factors affecting these data and their applicability to sprinkler-irrigated crops are discussed. Although foliar injury has been observed with many sprinkled crops, particularly tree crops, essentially no information is available to predict yield losses as a function of the salt concentration of the irrigation water. Salinity thresholds for sprinkling-induced foliar injury are estimated for some crops; however, climatic conditions greatly affect the onset and degree of injury. Managment strategies that minimize sprinkling injury are mentioned.     

Determination of trimethoprim in low-volume human plasma by liquid chromatography.

Trimethoprim is an anti-infective agent used in the treatment of urinary and respiratory tract infections and mild to moderate pneumocystis carinii pneumonia. Trimethoprim is also a selective in vitro inhibitor of cytochrome P450 2C8 and may have utility as an in vivo inhibitor of this enzyme. A simplified high performance liquid chromatography (HPLC) method was developed to determine trimethoprim in human plasma. Samples are processed by protein precipitation with perchloric acid and chromatographic separation is achieved on a Synergi Polar-RP column (4 micron, 150 mm x 4.6 mm) using a mobile phase consisting of 50 mM ammonium formate-acetonitrile-methanol (pH=3.0; 90:6:4 (v/v/v)). Detection is monitored at 280 nm. Intra- and inter-day precision ranged from 1.1 to 1.9 and 0.9 to 4.1%, respectively. The assay is simple, economical, precise, and is directly applicable to human studies involving steady state trimethoprim pharmacokinetics.     

Chilling-induced ethylene production by beans and peas

The effects of chilling on ethylene production by leaf discs and whole plants of bean (chilling-sensitive) and pea (chilling-tolerant) were studied. When pea or bean leaf discs were excised and incubated at 25°C, transient increases in ethylene production and 1-aminocyclopropane-1-carboxylic acid (ACC) accumulation were observed. Both pea and bean discs kept at 5°C evolved little ethylene, but levels of ACC increased in pea discs and not in bean discs. When discs of either species were chilled at 5°C immediately after excision and then transferred to 25°C 9 h later, increases in their ACC levels and ethylene production rates were observed. Discs were also incubated at 25°C for 12 h to allow excision-induced ethylene production to subside and then chilled at 5°C. Nine hours later, these discs were transferred to 25°C, and an increase in ethylene production was observed. These data indicate that chilling suppresses excision-induced ethylene production and enhances the production of ethylene after transfer to 25°C. Chilling of whole plants resulted in increased production of ethylene and ACC in the chilling-sensitive bean but not in the chilling-tolerant pea. Treatment of bean plants with the ethylene antagonists silver thiosulfate, norbornadiene, or aminooxyacetic acid, or of pea plants with ethylene, did not affect the appearance of chilling injury symptoms, indicating that ethylene does not induce injury symptoms and may not have an adaptive role in chilling stress.     

The microflora of soak water during tempeh production from various beans

The microflora of soak water was studied during the soaking of horsebean, pea, chickpea and soybean for tempeh production. Lactic streptococci dominated the flora in both unacidified and acidified soak water. Coliforms and yeasts were found only in unacidified soak water. Growth of micro-organisms in acidified and unacidified soak water resulted in a decrease in pH value of the cooked beans. Microbial acidification during soaking is considered to be important in tempeh production.     

Dependence of lung injury on surface tension during low-volume ventilation in normal open-chest rabbits.

To evaluate the role of pulmonary surfactant in the prevention of lung injury caused by mechanical ventilation (MV) at low end-expiratory volumes, lung mechanics and morphometry were assessed in three groups of eight normal, open-chest rabbits ventilated for 3-4 h at zero end-expiratory pressure (ZEEP) with physiological tidal volumes (Vt = 10 ml/kg). One group was left untreated (group A); the other two received surfactant intratracheally (group B) or aerosolized dioctylsodiumsulfosuccinate (group C) before MV on ZEEP. Relative to initial MV on positive end-expiratory pressure (PEEP; 2.3 cmH(2)O), quasi-static elastance (Est) and airway (Rint) and viscoelastic resistance (Rvisc) increased on ZEEP in all groups. After restoration of PEEP, only Rint (124%) remained elevated in group A, only Est (36%) was significantly increased in group B, whereas in group C, Est, Rint, and Rvisc were all markedly augmented (274, 253, and 343%). In contrast, prolonged MV on PEEP had no effect on lung mechanics of eight open-chest rabbits (group D). Lung edema developed in group C (wet-to-dry ratio = 7.1), but not in the other groups. Relative to group D, both groups A and C, but not B, showed histological indexes of bronchiolar injury, whereas all groups exhibited an increased number of polymorphonuclear leukocytes in alveolar septa, which was significantly greater in group C. In conclusion, administration of exogenous surfactant largely prevents the histological and functional damage of prolonged MV at low lung volumes, whereas surfactant dysfunction worsens the functional alterations, also because of edema formation and, possibly, increased inflammatory response.     

The microflora of soak water during tempeh production from various beans

The microflora of soak water was studied during the soaking of horsebean, pea, chickpea and soybean for tempeh production. Lactic streptococci dominated the flora in both unacidified and acidified soak water. Coliforms and yeast were found only in unacidified soak water. Growth of micro-organisms in acidified and unacidified soak water resulted in a decrease in pH value of the cooked beans. Microbial acidification during soaking is considered to be important in tempeh production.     

Lactic acid bacteria dynamics during spontaneous fermentation of cocoa beans verified by culture-independent denaturing gradient gel electrophoresis

Cocoa is naturally fermented in the field before the cocoa seeds are removed for processing. We assessed the dynamics of lactic acid bacteria during cocoa fermentation in Bahia, Brazil. During five days of fermentation, temperature and pH were measured and beans were collected for genomic DNA extraction every 12 h. The DNA was used as a template for amplification with Lac1-Lac2 and Lac3-Lac2 for denaturing gradient gel electrophoresis analyses. pH values ranged from 3.34 to 4.98, while the temperature varied from 23° to 50°C. Lac1-Lac2 primers permitted detection of 11 operational taxonomic units. Twenty-eight operational taxonomic units were obtained with the primer pair Lac3-Lac2. It was observed that there were variations between the numbers of operational taxonomic units throughout the process, probably because of changes in pH and temperature. The greatest similarity in amplified samples was obtained with the primers Lac3-Lac2.     

Dependence of lung injury on inflation rate during low-volume ventilation in normal open-chest rabbits.

Lung mechanics and morphometry were assessed in two groups of nine normal open-chest rabbits mechanically ventilated (MV) for 3-4 h at zero end-expiratory pressure (ZEEP) with physiological tidal volumes (Vt; 11 ml/kg) and high (group A) or low (group B) inflation flow (44 and 6.1 ml x kg(-1) x s(-1), respectively). Relative to initial MV on positive end-expiratory pressure (PEEP; 2.3 cmH(2)O), MV on ZEEP increased quasi-static elastance and airway and viscoelastic resistance more in group A (+251, +393, and +225%, respectively) than in group B (+180, +247, and +183%, respectively), with no change in viscoelastic time constant. After restoration of PEEP, quasi-static elastance and viscoelastic resistance returned to control, whereas airway resistance, still relative to initial values, remained elevated more in group A (+86%) than in group B (+33%). In contrast, prolonged high-flow MV on PEEP had no effect on lung mechanics of seven open-chest rabbits (group C). Gas exchange on PEEP was equally preserved in all groups, and the lung wet-to-dry ratios were normal. Relative to group C, both groups A and B had an increased percentage of abnormal alveolar-bronchiolar attachments and number of polymorphonuclear leukocytes in alveolar septa, the latter being significantly larger in group A than in group B. Thus prolonged MV on ZEEP with cyclic opening-closing of peripheral airways causes alveolar-bronchiolar uncoupling and parenchymal inflammation with concurrent, persistent increase in airway resistance, which are worsened by high-inflation flow.     

Growth of broad beans infected by Uromyces viciae-fabae

The effect of artificially regulating the level of a rust infection with Uromyces viciae-fabae (Pers.) Schroet. on the growth and yield of two cultivars of Viciafaba L. (broad beans) was examined in 1973/74. Disease decreased leaf area ratio without increasing net assimilation rate particularly during the stage of ‘pod filling’. Consequently, assimilate supply to developing beans was diminished and the weight of beans per pod and yield of beans per plant decreased. This is unlike the effect of Botrytis fabae Sard, on broad beans which reduces yield by decreasing the number of pods per plant. This suggests that the two leaf spotting pathogens decrease yield in different ways and so may require different approaches to minimise yield losses.     

Water uptake by dry beans observed by micro-magnetic resonance imaging

BACKGROUND AND AIMS: Water uptake by dry kidney beans (Phaseolus vulgaris 'Rajma') and adzuki beans (Vigna angularis) was traced using micro-magnetic resonance imaging in order to elucidate the channel of water entry, the manner of water delivery and the timing of swelling of the seeds. METHODS: Magnetic resonance images of beans absorbing water were continuously measured with the single-point imaging method for 16 h or 20 h at 15-min intervals. With this technique, it was possible to detect and visualize the location of water in the beans, at a low water content, in the initial stages of water entry. KEY RESULTS: Water was taken up through a specified tissue, the lens, near the hilum, and distributed primarily to the testa. When water reached the radicle, it began to be incorporated into cotyledons with considerable swelling of the seeds. Water uptake took place within a short time for kidney beans. The initial process of water entry was associated with mechanical vibration of the seed. Rapid hydration of the testa and the swelling of the cotyledons were then observed. Water was supplied to cotyledons through the adaxial epidermis. In contrast, it took a long time, approx. 7 h, to activate the water channel of the lens for adzuki beans which have a tightly fitting testa. Steeping of the testa was not uniform, which induced temporary slanting before enlargement of the seed. CONCLUSIONS: The activation of the lens as the sole water channel, the delivery of water to the radicle within the testa, the swelling of the cotyledons, and the further increment of water are physiologically different processes during imbibition, and were separated by locating water in various tissues and by analysing the time course of water uptake using magnetic resonance imaging with the single-point imaging method.     

On-line low-volume transesterification-based assay for immobilized lipases

A method has been developed for fast evaluation of transesterification activity of immobilized lipases using microlitre and submicrolitre volumes of substrate solutions. The model reaction (acylation of isopropanol with vinyl acetate) is catalyzed by microbial lipases immobilized on ceramic particles, diatoms or acrylic resin, packed into a Teflon tube connected to fused-silica capillary tubing. The substrate solution is pumped through the microreactor and the product of transesterification, acetaldehyde, quantified on capillary by UV absorbance at 280 nm. Using this system in the continuous-flow mode, comparisons were made of transesterification catalysed by PS-C II lipase in two different solvent mixtures. Acetonitrile was found to be a compatible solvent that can be used as a solubilizer without suppressing enzymatic activity. The method has been used to compare conversions at a fixed flow rate using a single pass of substrate through packed beds containing approximately 0.2 mg of supported enzyme. Spatial distributions of the product have been visualized using a complementary metal oxide semiconductor (CMOS) imaging detector in conjunction with the microreactor system operated in the stopped-flow mode.     

Determination of propofol in low-volume samples by high-performance liquid chromatography with fluorescence detection

In order to determine propofol in rat whole-blood samples of 50 μl, we developed a rapid, simple and reliable method which is characterized by precipitation of blood elements with acetonitrile and submission of the supernatant to HPLC analysis with fluorescence detection. The method described is linear from 0.4 to 40 mg/l and the relative standard deviations in this concentration range are less than 10%. The limit of quantification proved to be 0.4 mg/l. Blood constituents do not interfere with the assay.     

Effect of sprinkling on feedlot microclimate and cattle behavior

Experiments were conducted to evaluate strategies designed to reduce heat stress of cattle. In the first experiment, cattle were sprinkled for 20 min every 1.5 h between 1000 hours and 1750 hours (WET) versus not sprinkled (DRY). In a second experiment, treatments consisted of: (1) control, no water application; (2) water applied to the pen surfaces between 1000 hours and 1200 hours (AM); and (3) water applied to pen surfaces between 1400 hours and 1600 hours (PM). In both experiments, sprinkling lowered (P < 0.05) mid-afternoon temperatures. In the first experiment, relative humidity (RH) of WET versus DRY pens differed (P < 0.05) and averaged 72.4 and 68.9%, respectively. The average temperature–humidity index (THI) in WET pens was 0.5 units lower (P < 0.05), than the THI in DRY pens. In the second experiment, RH in sprinkled pens was also greater (P < 0.05) than RH in control (CON) pens However, THI differed (P < 0.05) among treatments, being 81.5, 80.9, and 80.3, respectively for CON, AM, and PM. Pens with sprinklers had a larger percentage of steers in areas where sprinkling took place, even on days when sprinkling had not occurred. Based on differences in percentage of cattle panting in sprinkled and non-sprinkled treatments, sprinkling was found to have a positive effect on cattle feeding area microclimate and to reduce the susceptibility of cattle to hyperthermia. However, cattle acclimatization to being sprinkled can result in slight hyperthermia even during cooler days when sprinkling would normally not be utilized.     

Evapotranspiration under advective conditions

Arid and semi-arid regions are heterogeneous landscapes in which irrigated fields are surrounded by arid areas. The advection of sensible heat flux from dry surfaces is a significant source of energy that has to be taken into consideration when evaluating the evaporation from crops growing in these areas. The basic requirement of most of the common methods for estimating evapotranspiration [Bowen ratio, aerodynamic and Penman–Monteith (PM) equation] is that the horizontal fluxes of sensible and latent heat are negligible when compared to the corresponding vertical fluxes. We carried out measurements above an irrigated tomato field in a desert area. Latent and sensible heat fluxes were measured using a four-level Bowen machine with aspirated psychrometers. Our results indicate that under advective conditions only measurements carried out in the lowest layer are satisfactory for the estimation of latent heat fluxes and that the use of the PM equation with an appropriately parameterized canopy resistance may be preferable.This work was carried out by the author during her sojourn at the Wyler Department for Drayland Agriculture, Jacob Blaustein Institute for Desert Research, Ben Gurion University of the Negev, Israel.Manufacturers names are provided for the benefit of the reader and do not imply endorsement by the authors.     

Intratumoral low-volume jet-injection for efficient nonviral gene transfer

Jet-injection has become an applicable technology among other established nonviral delivery systems, such as particle bombardment or in vivo electroporation. The low-volume jet injector employed in this study uses compressed air to inject solutions of 1.5–10 μL containing naked DNA into the desired tissue. The novel design of this prototype makes multiple jet-injections possible. Therefore, repeated jet-injections into one target tissue can be performed easily. This jet-injector hand-held system was used for the direct in vivo gene transfer of plasmid DNA into tumors to achieve efficient expression of reporter genes (β-galactosidase, green fluorescent protein [GFP]) and of therapeutic genes (TNF-α) in different tumor models. The study presented here revealed the key parameters of efficient in vivo jet-injection (jet-injection volume, pressure, jet penetration, DNA stability) to define the optimal conditions for a jet-injection-aided nonviral gene therapy.     

Heliotropic leaf movements in common beans controlled by air temperature

Heliotropic leaf movements were examined in common beans (Phaseolus vulgaris cv Blue Lake Bush) under outdoor and laboratory conditions. Heliotropic leaf movements in well-watered plants were partly controlled by temperature, and appeared to be independent of atmospheric humidity and CO₂ concentration. When environmental conditions were held constant in the laboratory, increased air temperature caused bean leaves to orient more obliquely to a light source. Ambient CO₂, intercellular CO₂, and net photosynthesis were not correlated with the temperature-induced changes in heliotropic movements, nor did they significantly affect these movements directly. The effect of air temperature on leaf movements need not be mediated through a change in leaf water potential, transpiration, or leaf conductance. Air temperature modified laminar orientation in light through its effect on tissue temperature in the pulvinal region, not that of the lamina or petiole. However, under darkness the temperature effects on leaf movements were not expressed. Active heliotropic movements in response to air temperature allowed lamina temperature to remain close to the thermal optimum of photosynthesis. This temperature effect underlies a commonly observed pattern of leaf movements under well-watered conditions: a tendency for leaves to face the sun more obliquely on hot days than cool days.