Extinct plants of Israel

As a result of rapid land development in Israel during the past three decades, some 26 species of higher plants, about one percent of the local flora, have become extinct. In addition to listing such species, this paper deals with the ecological implications of this finding. Recommendations for the prevention of further damage to the local flora, and rare plants in particular, are given.     

Seasoned Sprat Products’ Acceptance in Estonia and in Thailand

The aim of the study was to describe and evaluate competitiveness of Estonian spice-cured sprat products in Estonia and Thailand. Sample A was saltiest, Sample B had lowest overall spiciness, and Sample C had highest pepper flavor and sour taste intensity. The main drivers of consumer acceptance for the spice-cured sprat products were different: flavor and appearance in Estonia and appearance and odor in Thailand. In Estonia, one cluster of consumers liked the traditional (Sample A) and lightly spiced (Sample B) sprat products, while the other cluster liked the traditional (Sample A) and the marinated (Sample C) sprat products. In Thailand, all samples scored low, but manual clustering indicated that marinated (Sample C) sprat products are most acceptable. The current study showed that spice-cured sprat products in general can be accepted by Thai consumers, especially as part of meals, if further flavor development is carried out with the products.     

Evaluation of foliar resistance in potato to Phytophthora infestans based on an international field trial network

During the period 2000–03, local potato cultivars in Estonia, Latvia, Lithuania, Poland and Denmark were tested for foliar resistance to Phytophthora infestans (late blight) in an international field trial network. Four standard cultivars were included in the trials: Sava, Oleva, Danva and Kuras. Primary disease-assessment data were entered into a common database, and parameters from the disease progress curves were calculated and made available on interactive web pages. A regression model, using relative area under disease progress curve (RAUDPC) values for cv. Oleva as a reference, was developed for the estimation of 1–9 scale values, where 1 = most susceptible. Standard deviations for the estimated 1–9 scale values and a nonparametric rank stability analysis of RAUDPC were used to evaluate the stability of resistance of the cultivars. Overall, the results showed stability of resistance for cvs Sava, Oleva and Danva, but not for Kuras. Use of the Internet-based Web-Blight service in this study facilitated comparison of results among countries for the level and stability of resistance. The estimated 1–9 scale values were similar to, or slightly lower than, those from official cultivar lists or from the European Cultivated Potato Database, especially for the more resistant cultivars. Possible reasons for discrepancies from different sources and locations are discussed. It is concluded that RAUPDC and the derived 1–9 scale values are useful for ranking cultivars for resistance to P. infestans , but this information is not detailed enough for use in a decision support system for late blight control.     

Microphytic crusts,shrub patches and water harvesting in the Negev Desert: the Shikim system

Human-made contour banks are a central component of theShikim water harvesting system in Israels Negev Desert.Efficient water capture depends on the presence of a stable microphytic crustwhich directs surplus surface runoff into the banks where it is stored. We usedsimulated rainfall to examine the impact of soil surface disturbance on runoffand sediment transport, and the effect of this on the efficiency of resourcecapture within the Shikim system. Two disturbance regimes:1) removal of the microphytic crust only, and 2) removal of the crust and shrubpatches by cultivation, were compared with an undisturbed control. In theundisturbed state, 32% of rainfall was redistributed as runoff. This runoffpenetrated approximately 27% deeper under the shrub patches compared with themicrophytic crust. When the microphytic crust was destroyed by simulatedtrampling, the runoff coefficient declined to 13%, and there was no significantdifference in water penetration between shrub and crust patches. Completedestruction of the shrub hummocks and crust by cultivation resulted in adeclinein the runoff coefficient to 6%. The result of sustained disturbance in thesepatchy Negev shrublands is a breakdown in spatial heterogeneity, a loss ofecosystem function, a reduction in ecosystem goods and services such as plantdiversity and production, and ultimately a reduction in pastoral productivity.These results reinforce the view that microphytic crusts are critical for theefficient operation of the Shikim water harvesting system.Given that practices such as cultivation and trampling which disturbmicrophyticcrusts result in enhanced infiltration, crusts should be left intact tomaximisethe water harvesting efficiency in these desert landscapes.This revised version was published online in May 2005 with corrections to the Cover Date.     

Isotopic evidence and quantification assessment of in situ RDX biodegradation in the deep unsaturated zone

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is an explosive compound whose extensive use has resulted in significant contamination of soils and groundwater worldwide. We studied its in situ biodegradation along the unsaturated zone beneath an explosives wastewater lagoon using compound-specific isotope analysis (CSIA) of RDX in the unsaturated zone, together with biodegradation slurry experiments under anaerobic conditions. We found the highest degradation potential of RDX and its nitroso derivatives in the upper part of the soil profile while in the lower parts, RDX-degradation potential was lower and the nitroso derivatives tended to persist. This was also observed in the field, as reflected by the isotopic composition of RDX along the profile. We also found a correlation between biodegradation potential and clay content: biodegradation was further enhanced in layers characterized by high-clay content or in those influenced by the high-clay layers. In addition, in the presence of high organic matter content, further enhancement of biodegradation was observed. We obtained different isotopic enrichment factors (?) for RDX biodegradation in different sections of the unsaturated profile and suggest that different degradation pathways exist simultaneously in situ, in variable proportions. Using the range of enrichment factors, we were able to assess the biodegradation extent of RDX at different sampling points along the profile, which ranged between 30 and 99.4%. The novel application of CSIA together with slurry experiments provides better insight into degradation processes that are otherwise difficult to detect and assess.     

Germination characters in wild and cultivated Anemone coronaria L.

Summary Achenes of wild forms of Anemone coronaria growing in Israel differ in their germination requirements from achenes of the cultivated de Caen type. The optimum temperature for dark germination was between 10–15°C in the former and between 15–20°C in the latter. Maximum daily rates of germination were higher, reaching 16% per day, and the minimum lag period between sowing and seedling emergence was shorter in achenes of the cultivated than in those of the wild anemone when the two types were incubated under identical conditions. Wild achenes showed a marked post-harvest maturation requirement, and attained full germination, a minimum pre-emergence lag period after sowing, and a maximum daily germination rate only when dry-stored for several months subsequent to harvesting. In the cultivated plant this requirement was far less pronounced or absent. Most embryos in freshly harvested achenes of both the wild and the cultivated anemone were torpedo-shaped but in the cultivated form embryos were larger. In both types embryos remained unchanged in shape and size during dry storage.     

The competitive advantage of a dual-transporter system

Cells use transporters of different affinities to regulate nutrient influx. When nutrients are depleted, low-affinity transporters are replaced by high-affinity ones. High-affinity transporters are helpful when concentrations of nutrients are low, but the advantage of reducing their abundance when nutrients are abundant is less clear. When we eliminated such reduced production of the Saccharomyces cerevisiae high-affinity transporters for phosphate and zinc, the elapsed time from the initiation of the starvation program until the lack of nutrients limited growth was shortened, and recovery from starvation was delayed. The latter phenotype was rescued by constitutive activation of the starvation program. Dual-transporter systems appear to prolong preparation for starvation and to facilitate subsequent recovery, which may optimize sensing of nutrient depletion by integrating internal and external information about nutrient availability.     

An artificial capillary barrier to improve root zone conditions for horticultural crops: physical effects on water content

Capillary barriers (CBs) occur at the interface of two soil layers having distinct differences in textural and hydraulic characteristics. The objective of this study was to introduce an artificial CB, created by a layer of gravel below the root zone substrate, in order to optimize conditions for the cultivation of horticultural crops. Potential root zone formats were analyzed with and without the gravel CBs for variables including the following: depth of CB; barrier separating the root zone from the surrounding soil; and root zone soil texture. Field and simulated results revealed that artificial CBs increased root zone water content and changed water flow dynamics. Volumetric soil water content was increased by 20–70%, depending on the soil texture and depth of the barrier. Sandy soil texture and shallower placement resulted in relatively higher water content. For sandy soil without plants, a shallow (0.2 m depth) CB increased water content of the overlaying soil by 50% compared to the control. The introduction of a gravel CB below the root zone of pepper plants (Capsicum Annum L.) lead to 34% higher matric head, 50% lower diurnal fluctuations in matric head and 40% increase in pepper fruit yield. Increasing water content by way of artificial CBs appeared to improve the water use efficiency of pepper plants. Such an improvement could lead to reduced water and fertilizer application rates and subsequent reduction in contamination below the root zone. This is especially relevant for substrates of low water-holding capacity typically used in horticulture crop production.     

Regulation of milk intake in young ruminants

We studied the influence of the three main nutritive components of milk - saccharides, fat and amino acids - on milk intake in suckling lambs and on the role of insulin as a key metabolic hormone for the regulation of milk intake. The intake was slowed down after p.o. administration of milk fat (p less than 0.05), after i. v. administration of methionine (p less than 0.001) and after p. o. administration of glucose, lactose (p less than 0.01, p less than 0.001) and sorbitol (p less than 0.001). After i. v. administration of glycerol, lysine, threonine, arginine, glucose, and i. v. and p. o. administration of galactose the intake of milk did not change significantly (p greater than 0.05). The findings indicate that the short-time regulation of milk intake in suckling ruminant animals is not subjected to the specific effect of some of the milk components. Regarding the metabolic effects, the problem concerns the speed of resorption of easily metabolizable sources of energy from the digestive system to the liver and to the whole body. Neutral Zn-insulin administered intraperitoneally at a dose of 4 U X kg-1 increased the milk intake (p less than 0.01, p less than 0.001), in 8 to 22 hours after the administration only when the animals were on the low-fat milk diet (5.9%-11% fat in dry matter). We assume that the long-range hyperphagy can be related mainly with the fast metabolizing of energy-rich substances (glucose) into the body stores (glycogen, fat) accompanied by subsequent hormonal changes.(ABSTRACT TRUNCATED AT 250 WORDS)     

Food intake in suckling rats after glycerol administration

The influence of administered glycerol on the food intake was followed in suckling rats in five age periods (on the 5th, 9th, 13th, 17th and 23rd day of life). Glycerol significantly reduced the food intake (P less than 0.01) in the last three age categories. This finding indicates that from the 13th day of life glycerol becomes one of the limiting factors of food intake for suckling rats in connection with a gradual functional maturing of their control mechanism, regulating the food intake.