Production of N‐Acetyl‐Phosphinothricin: A Substance used for Inducing Male Sterility in Transgenic Plants

The non‐toxic compound N‐acetyl‐L‐phosphinothricin (N‐Ac‐L‐PPT) is used in a so‐called deacetylation system to induce male sterility in transgenic plants by tapetum specific deacetylation to the herbicide L‐phosphinothricin (L‐PPT). A procedure was developed to produce pure racemic and L‐isomeric N‐Ac‐PPT containing less than 30 ppm residual PPT. Experiments applied to wild type tobacco and PPT‐resistant tobacco showed that the maximal tolerated N‐Ac‐PPT concentration would be less than 45 mM of the L‐isomer. Otherwise unspecific deacetylation by several acylases, as well as by environmental conditions like higher temperatures or pHs beyond neutrality, increased the residual L‐PPT content to toxic concentrations. In contrast, N‐acetyl‐L‐phosphinothricyl‐alanyl‐alanine (N‐Ac‐L‐PPTT), a substance also occurring during the biosynthesis of phosphinothricyl‐alanyl‐alanine (PPTT) by some Streptomyces species, was tolerated up to 274 mM by wild type tobacco plants. However, the ArgE deacatylase from Escherichia coli originally used in the deacetylation system, as well as some other acylases, showed no activity towards N‐Ac‐L‐PPTT.     

Medicinal plants of the Argentine Yungas plants of the Las Yungas biosphere reserve, Northwest of Argentina, used in health care

We have compared the species richness of medicinal plants and the differential patterns of use amongst settlements in the Andean communities of Northwest Argentina which have differing levels of isolation. About 259 ethnoespecies, belonging to 74 plant families, were included, representing between 70 and 80% of the total estimate. The results indicate that Coronopus didymus is the most relevant and important species. The method of use of medicinal plants and the ailments treated by rural doctors compared to those of the layperson is different. Native and exotic plants are used differently according to the body system treated. There are some relationships between internal and external use and body systems and recipes. The greater medicinal species richness found in the less isolated locations is due to external enriching cultural influences.     

A method to study zhizosphere processes in thin soil layers of different proximity to roots

Frankia is the diverse bacterial genus that fixes nitrogen within root nodules of actinorhizal trees and shrubs. Systematic and ecological studies of Frankia have been hindered by the lack of morphological, biochemical, or other markers to readily distinguish strains. Recently, nucleotide sequence of 16 S RNA from the small ribosomal subunit has been used to classify and identify a variety of microorganisms. We report nucleotide sequences from portions of the 16 S ribosomal RNA from Frankia strains AcnI1 isolated from Alnus viridis ssp. crispa (Ait.) Turrill and PtI1 isolated from Purshia tridentata (Pursh) DC. The number of nucleotide base substitutions and gaps we find more than doubles the previously reported sequence diversity for the same variable regions within other strains of Frankia.     

Relationship between the concentration of sugars in the roots and VA mycorrhizal infection

Summary The VA-infected wheat varieties showed an increase of total (Lozano var.) and reducing (Lozano and Pane vars.) sugars in their root extracts. However, no clear relationship between sugar concentration in the root and VA mycorrhizal infection level could be established.In addition, the VA mycorrhizal hosts sorghum, alfalfa, sunflower and maize, and non-host radish and cabbage plants were tested for sugar content in their root extracts after fifteen days of growth. Sugars present in the root extracts of these plants did not seem to be a decisive factor in plant susceptibility to VA infection.     

Ethnobotanical review of wild edible plants in Spain

This paper compiles and evaluates the ethnobotanical data currently available on wild plants traditionally used for human consumption in Spain. Forty-six ethnobotanical and ethnographical sources from Spain were reviewed, together with some original unpublished field data from several Spanish provinces. A total of 419 plant species belonging to 67 families was recorded. A list of species, plant parts used, localization and method of consumption, and harvesting time is presented. Of the seven different food categories considered, green vegetables were the largest group, followed by plants used to prepare beverages, wild fruits, and plants used for seasoning, sweets, preservatives, and other uses. Important species according to the number of reports include: Foeniculum vulgare , Rorippa nasturtium-aquaticum , Origanum vulgare , Rubus ulmifolius , Silene vulgaris , Asparagus acutifolius , and Scolymus hispanicus . We studied data on the botanical families to which the plants in the different categories belonged, overlapping between groups and distribution of uses of the different species. Many wild food plants have also been used for medicinal purposes and some are considered to be poisonous. This review highlights the rich traditional knowledge on edible plants that has remained in rural Spain. Until recently, many wild plants were used as dietary supplements. However, most of this knowledge survives only in the memory of the elderly, and will probably disappear in a few decades.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 152 , 27–71.     

Withdrawn food rate for larvae of Siberian moth on conifers of Siberia

Experimental evaluation of the mass of food withdrawn by larvae of the Siberian moth during their development on larch, cedar pine, fir, spruce, and common pine was carried out. The obtained dependences between the masses of larvae and food withdrawn by them can be directly used to determine the withdrawn food rate of Siberian moth on each of the Siberian conifer species.     

Factors influencing seasonal and monthly changes in the group size of chital or axis deer in southern India

Chital or axis deer (Axis axis) form fluid groups that change in size temporally and in relation to habitat. Predictions of hypotheses relating animal density, rainfall, habitat structure, and breeding seasonality, to changes in chital group size were assessed simultaneously using multiple regression models of monthly data collected over a 2 yr period in Guindy National Park, in southern India. Over 2,700 detections of chital groups were made during four seasons in three habitats (forest, scrubland and grassland). In scrubland and grassland, chital group size was positively related to animal density, which increased with rainfall. This suggests that in these habitats, chital density increases in relation to food availability, and group sizes increase due to higher encounter rate and fusion of groups. The density of chital in forest was inversely related to rainfall, but positively to the number of fruiting tree species and availability of fallen litter, their forage in this habitat. There was little change in mean group size in the forest, although chital density more than doubled during the dry season and summer. Dispersion of food items or the closed nature of the forest may preclude formation of larger groups. At low densities, group sizes in all three habitats were similar. Group sizes increased with chital density in scrubland and grassland, but more rapidly in the latter—leading to a positive relationship between openness and mean group size at higher densities. It is not clear, however, that this relationship is solely because of the influence of habitat structure. The rutting index (monthly percentage of adult males in hard antler) was positively related to mean group size in forest and scrubland, probably reflecting the increase in group size due to solitary males joining with females during the rut. The fission-fusion system of group formation in chital is thus interactively influenced by several factors. Aspects that need further study, such as interannual variability, are highlighted.     

Floristic turnover in Iceland from 15 to 6 Ma – extracting biogeographical signals from fossil floral assemblages

Aim This study aims to document the floristic changes that occurred in Iceland between 15 and 6 Ma and to establish the dispersal mechanisms for the plant taxa encountered. Using changing patterns of dispersal, two factors controlling floristic changes are tested. Possible factors are (1) climate change, and (2) the changing biogeography of Iceland over the time interval studied; that is, the presence or absence of a Miocene North Atlantic Land Bridge. Location The North Atlantic. Methods Species lists of fossil plants from Iceland in the time period 15 to 6 Ma were compiled using published data and new data. Closest living analogues were used to establish dispersal properties for the fossil taxa. Dispersal mechanisms of fossil plants were then used to reconstruct how Iceland was colonized during various periods. Results Miocene floras of Iceland (15–6 Ma) show relatively high floristic turnover from the oldest floras towards the youngest; and few taxa from the oldest floras persist in the younger floras. The frequencies of the various dispersal mechanisms seen in the 15‐Ma floras are quite different from those recorded in the 6‐Ma floras, and there is a gradual change in the prevailing mode of dispersal from short‐distance anemochory and dyschory to long‐distance anemochory. Two mechanisms can be used to explain changing floral composition: (1) climate change, and (2) the interaction between the dispersal mechanisms of plants and the increasing isolation of proto‐Iceland during the Miocene. Main conclusions Dispersal mechanisms can be used to extract palaeogeographic signals from fossil floras. The composition of floras and dispersal mechanisms indicate that Iceland was connected both to Greenland and to Europe in the early Middle Miocene, allowing transcontinental migration. The change in prevalence of dispersal modes from 15 to 6 Ma appears to reflect the break‐up of a land bridge and the increasing isolation of Iceland after 12 Ma. Concurrent gradual cooling and isolation caused changes in species composition. Specifically, the widening of the North Atlantic Ocean prevented taxa with limited dispersal capability from colonizing Iceland, while climate cooling led to the extinction of thermophilous taxa.