Domestication of plants for sustainable agriculture in drylands: Experience from the Negev Desert

With globalization in the last century, introduction of exotic plant species for commercial use has become more accessible. Such attempts may involve extreme land changes. We stress that domestication of native species should be preferred to the introduction of exotic species. We took the initial steps in domesticating several species by examining commercial uses and studying aspects of plant physiology. The following desert plants were considered: Bassia indica, for salt phytoremediation and for livestock feed; Commiphora gileadensis, as an agent against cancer cells; Artemisia sieberi and A. judaica, as plants with allopathic traits; Ficus palmate, as a stand for fig plantation; Balanites aegyptiaca, as a medicinal plant and for other uses; Portulaca oleracea and Scorzonera judaica, as food crops with added values; and Pistacia atlantica, as rootstock for P. vera.     

Molecular self-assembly of two-terminal, voltammetric microsensors with internal references

Self-assembly of a ferrocenyl thiol and a quinone thiol onto Au microelectrodes forms the basis for a new microsensor concept: a two-terminal, voltammetric microsensor with reference and sensor functions on the same electrode. The detection is based on measurement of the potential difference of current peaks for oxidation and reduction of the reference (ferrocene) and indicator (quinone) in aqueous electrolyte in a two-terminal, linear sweep voltammogram in which a counterelectrode of relatively large surface area is used. The quinone has a half-wave potential, E((1/2)), that is pH-sensitive and can be used as a pH indicator; the ferrocene center has an E(1/2) that is a pH-insensitive reference. The key advantages are that such sensors require no separate reference electrode and function as long as current peaks can be located for reference and indicator molecules.     

Early pottery at 20,000 years ago in Xianrendong Cave, China

The invention of pottery introduced fundamental shifts in human subsistence practices and sociosymbolic behaviors. Here, we describe the dating of the early pottery from Xianrendong Cave, Jiangxi Province, China, and the micromorphology of the stratigraphic contexts of the pottery sherds and radiocarbon samples. The radiocarbon ages of the archaeological contexts of the earliest sherds are 20,000 to 19,000 calendar years before the present, 2000 to 3000 years older than other pottery found in East Asia and elsewhere. The occupations in the cave demonstrate that pottery was produced by mobile foragers who hunted and gathered during the Late Glacial Maximum. These vessels may have served as cooking devices. The early date shows that pottery was first made and used 10 millennia or more before the emergence of agriculture.     

Oscillations and sparsening of odor representations in the mushroom body

In the insect olfactory system, oscillatory synchronization is functionally relevant and reflects the coherent activation of dynamic neural assemblies. We examined the role of such oscillatory synchronization in information transfer between networks in this system. The antennal lobe is the obligatory relay for olfactory afferent signals and generates oscillatory output. The mushroom body is responsible for formation and retrieval of olfactory and other memories. The format of odor representations differs significantly across these structures. Whereas representations are dense, dynamic, and seemingly redundant in the antennal lobe, they are sparse and carried by more selective neurons in the mushroom body. This transformation relies on a combination of oscillatory dynamics and intrinsic and circuit properties that act together to selectively filter and synthesize the output from the antennal lobe. These results provide direct support for the functional relevance of correlation codes and shed some light on the role of oscillatory synchronization in sensory networks.     

Spatial and temporal patterns of vegetation recovery following sequences of forest fires in a Mediterranean landscape,Mt. Carmel Israel

The Mediterranean ecosystem of Mt. Carmel is subjected to increasing number of forest fires at various extents and severities due to increasing human activities. Accordingly, we tested whether in areas exposed to different fire histories vegetation regeneration is different in north versus south facing slopes, and the potential impact on erosion processes. Using remote sensing techniques we evaluated the Enhanced Vegetation Index (EVI) to monitor vegetation recovery following a single fire and three successive fires, using a series of Landsat images taken between 1985–2002. Following a single fire, vegetation cover reached pre-disturbance values within less than 5 years. Repeated fires caused further reduction of EVI values, especially at south facing slopes (SFS). The effects of three successive fires within 10 years, followed by a three year recovery period, however, are negligible when considering vegetation cover values. This was deduced as north facing slope EVI values returned to pre-disturbance conditions at the end of the 3 years and SFS EVI values to 80% of the pre-disturbance conditions. Our results indicate that Mediterranean eco-geomorphic systems are quite resilient, showing quick response, at least in terms of return to pre-disturbance states of vegetation cover, and hence of soil erosion rates. This is true not only in response to a disturbance caused by a single fire, but also for repetitive fire incidents.     

Leaf shape × sowing density interaction affects chickpea grain yield

Modifying plant architecture is considered a promising breeding option to enhance crop productivity. Modern chickpea (Cicer arietinum L.) cultivars with either compound (wild‐type) or simple leaf shapes are commercially grown but the relationships between leaf shape and yield are not well understood. In this study, a random sample of ‘Kabuli’ type progeny lines of both leaf types, derived from two crosses between modern American simple leaf cultivars and early‐flowering wild‐type breeding lines, were planted at different sowing densities. Leaf area development and final grain yield in genotypes of the two leaf types responded differently to changes in sowing densities. Compound leaf lines attained higher leaf area indices and higher grain yields at both low and high sowing densities. Yield responses of the simple leaf lines to increasing sowing density were significantly higher compared to compound leaf genotypes in two of three field experiments. The prospects for utilizing the simple leaf trait as a breeding target for short‐season growing areas are discussed.     

A description of the postlarva of Cygnodraco mawsoni Waite, 1916 (Pisces,Bathydraconidae), from the Southern Ocean

Eight postlarvae of Cygnodraco mawsoni Waite, 1916, were collected off the Australian Antarctic Mawson Station in the South Indian Ocean, during the South African SIBEX II expedition. These postlarvae are distinctive by having a long and slender body, projecting lower jaw and bicoloured caudal fin. Their morphology and pigmentation are unlike any known bathydraconid early life history stages.     

Introduced <Emphasis Type="Italic">Tuber aestivum</Emphasis> replacing introduced <Emphasis Type="Italic">Tuber melanosporum</Emphasis>: a case study

A Tuber melanosporum plantation established in 1994/1995 on Kibbutz Bar’am (in the Upper Galilee, Israel) gradually lost its T. melanosporum mycorrhiza. In 1999, T. aestivum inoculated seedlings were inadvertently introduced into the plantation to fill the gaps between trees. A single T. melanosporum fruit body was found in 1999. Although no truffles were found after 1999 and until 2009, in that year and in 2010, truffles were collected. Morphological and molecular analyses proved these to be T. aestivum. Thus, the intentionally introduced T. melanosporum mycorrhiza was replaced by that of another introduced mycorrhizal fungus, T. aestivum. Local oak species produced higher yields compared to introduced host species known to be good T. melanosporum plant symbionts. The yield was comparable to that reported for young commercial orchards, but the fruiting season was earlier than in Europe.     

The role of hydropedologic vegetation zones in greenhouse gas emissions for agricultural wetland landscapes

Net greenhouse gas (GHG) source strength for agricultural wetland ecosystems in the Prairie Pothole Region (PPR) is currently unknown. In particular, information is lacking to constrain spatial variability associated with GHG emissions (CH₄, CO₂, and N₂O). GHG fluxes typically vary with edaphic, hydrologic, biologic, and climatic factors. In the PPR, characteristic wetland plant communities integrate hydropedologic factors and may explain some variability associated with trace gas fluxes at ecosystem and landscape scales. We addressed this question for replicate wetland basins located in central North Dakota stratified by hydropedologic vegetation zone on Jul 12 and Aug 3, 2003. Data were collected at the soil-atmosphere interface for six plant zones: deep marsh, shallow marsh, wet meadow, low prairie, pasture, and cropland. Controlling for soil moisture and temperature, CH₄ fluxes varied significantly with zone (p < 0.05). Highest CH₄ emissions were found near the water in the deep marsh (277,800 μg m^− 2 d^− 1 CH₄), which declined with distance from water to − 730 μg m^− 2 d^− 1 CH₄ in the pasture. Carbon dioxide fluxes also varied significantly with zone. Nitrous oxide variability was greater within zones than between zones, with no significant effects of zone, moisture, or temperature. Data were extrapolated for a 205.6 km² landscape using a previously developed synoptic classification for PPR plant communities. For this landscape, we found croplands contributed the greatest proportion to the net GHG source strength on Jul 12 (45,700 kg d^− 1 GHG-C equivalents) while deep marsh zones contributed the greatest proportion on Aug 3 (26,145 kg d^− 1 GHG-C equivalents). This was driven by a 30-fold reduction in cropland N₂O–N emissions between dates. The overall landscape average for each date, weighted by zone, was 462.4 kg km^− 2 d^− 1 GHG-C equivalents on Jul 12 and 314.3 kg km^− 2 d^− 1 GHG-C equivalents on Aug 3. Results suggest GHG fluxes vary with hydropedologic soil zone, particularly for CH₄, and provide initial estimates of net GHG emissions for heterogeneous agricultural wetland landscapes.