How do elevated CO2 and O3 affect the interception and utilization of radiation by a soybean canopy?

Net productivity of vegetation is determined by the product of the efficiencies with which it intercepts light (?_i) and converts that intercepted energy into biomass (?_c). Elevated carbon dioxide (CO₂) increases photosynthesis and leaf area index (LAI) of soybeans and thus may increase ?_i and ?_c; elevated O₃ may have the opposite effect. Knowing if elevated CO₂ and O₃ differentially affect physiological more than structural components of the ecosystem may reveal how these elements of global change will ultimately alter productivity. The effects of elevated CO₂ and O₃ on an intact soybean ecosystem were examined with Soybean Free Air Concentration Enrichment (SoyFACE) technology where large field plots (20‐m diameter) were exposed to elevated CO₂ (～550 μmol mol^?1) and elevated O₃ (1.2 × ambient) in a factorial design. Aboveground biomass, LAI and light interception were measured during the growing seasons of 2002, 2003 and 2004 to calculate ?_i and ?_c. A 15% increase in yield (averaged over 3 years) under elevated CO₂ was caused primarily by a 12% stimulation in ?_c , as ?_i increased by only 3%. Though accelerated canopy senescence under elevated O₃ caused a 3% decrease in ?_i, the primary effect of O₃ on biomass was through an 11% reduction in ?_c. When CO₂ and O₃ were elevated in combination, CO₂ partially reduced the negative effects of elevated O₃. Knowing that changes in productivity in elevated CO₂ and O₃ were influenced strongly by the efficiency of conversion of light energy into energy in plant biomass will aid in optimizing soybean yields in the future. Future modeling efforts that rely on ?_c for calculating regional and global plant productivity will need to accommodate the effects of global change on this important ecosystem attribute.     

Identification of significant regions of transcription factor DP-1 (TFDP-1) involved in stability/instability of the protein

We previously reported the identification of DP-1 isoforms (α and β), which are structurally C-terminus-deleted ones, and revealed the low-level expression of these isoforms. It is known that wild-type DP-1 is degraded by the ubiquitin-proteasome system, but few details are known about the domains concerned with the protein stability/instability for the proteolysis of these DP-1 isoforms. Here we identified the domains responsible for the stability/instability of DP-1. Especially, the DP-1 “Stabilon” domain was a C-terminal acidic motif and was quite important for DP-1 stability. Moreover, we propose that this DP-1 Stabilon may be useful for the stability of other nuclear proteins when fused to them.     

Hatchery selection promotes boldness in newly hatched brown trout (Salmo trutta): implications for dominance

By using newly hatched (approximately 2 weeks old) brown trout(Salmo trutta) from six families of wild and six families ofsea-ranched origin (seventh generation), we tested the hypothesesthat (1) the hatchery environment selects for increased boldness,and (2) boldness predicts dominance status. Sea-ranched troutspend their first 2 years in the hatchery before being releasedinto the wild at the onset of seaward migration. Trout werepresented with a novel object (tack) and with food (brine shrimp),and their responses were measured and scored in terms of boldness.Siblings with increasing difference in boldness were then pairedin dyadic contests. Fish of sea-ranged origin were on averagebolder than were fish of wild origin, and bolder individualswere more likely to become dominant regardless of origin. Boldnesswas not related to RNA levels, indicating that bold behaviorwas not a consequence of higher metabolism or growth rate. Neitherwas size a predictor of bold behavior or the outcome of dyadiccontests. These results are consistent with studies on olderlife stages showing increased boldness toward predators in hatchery-selectedfish, which suggests that behavioral consequences of hatcheryselection are manifested very early in life. The concordancebetween boldness and dominance may suggest that these behaviorsare linked in a risk prone-aggressive phenotype, which may bepromoted by hatchery selection. However, we also found significantvariation in behavioral and growth-related traits among families,suggesting that heritable variation has not been exhausted bysea-ranching procedures.     

Alpine vascular plant species richness: the importance of daily maximum temperature and pH

Species richness in the alpine zone varies dramatically when communities are compared. We explored (i) which stress and disturbance factors were highly correlated with species richness, (ii) whether the intermediate stress hypothesis (ISH) and the intermediate disturbance hypothesis (IDH) can be applied to alpine ecosystems, and (iii) whether standing crop can be used as an easily measurable surrogate for causal factors determining species richness in the alpine zone. Species numbers and standing crop were determined in 14 alpine plant communities in the Swiss Alps. To quantify the stress and disturbance factors in each community, air temperature, relative air humidity, wind speed, global radiation, UV-B radiation, length of the growing season, soil suction, pH, main soil nutrients, waterlogging, soil movement, number of avalanches, level of denudation, winter dieback, herbivory, wind damage, and days with frost were measured or observed. The present study revealed that 82% of the variance in␣vascular species richness among sites could be explained by just two abiotic factors, daily maximum temperature and soil pH. Daily maximum temperature and pH affect species richness both directly and via their effects on other environmental variables. Some stress and disturbance factors were related to species richness in a monotonic way, others in an unimodal way. Monotonic relationships suggest that the harsher the environment is, the fewer species can survive in such habitats. In cases of unimodal relationships (ISH and IDH) species richness decreases at both ends of the gradients due to the harsh environment and/or the interaction of other environmental factors. Competition and disturbance seemed only to play a secondary role in the form of fine-tuning species richness in specific communities. Thus, we concluded that neither the ISH nor the IDH can be considered useful conceptual models for the alpine zone. Furthermore, we found that standing crop can be used as an easily measurable surrogate for causal factors determining species richness in the alpine zone, even though there is no direct causality.     

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.     

The 24-h time budget of a takh harem stallion (Equus ferus przewalskii) pre- and post-reintroduction

Focal animal sampling was used to determine the 24-h time budget of a takh harem stallion (Equus ferus przewalskii) during the 2 weeks prior to, and the two weeks following, reintroduction into the Hustain Nuruu Steppe Reserve, Mongolia. Both before and after release, the stallion spent approximately 47% of his time grazing, 6% standing, and 5% in recumbent rest. The biggest changes to the time budget after release were a 4-fold increase in the amount of time spent moving, and a 50% decrease in the amount of time spent resting in a standing position. During the middle of the day when the temperatures were hottest, the stallion exhibited less grazing and more standing resting behaviour than in the morning or evening hours. Recumbent rest invariably occurred in the hours before dawn.     

Are the carbon costs of seed production related to the quantitative and qualitative performance? An appraisal for legumes and other crops

In the past great efforts have been made to gain a thorough understanding of the processes involved in carbon fixation but the fate of the acquired carbon has been somewhat neglected, although this aspect is crucial for improving yield performance without diminishing the quality of the harvested organs. To contribute to the crucial debate on that topic the aim of the present study was to propose some unbiased components concerning in particular grain legumes: ‘Is there any antagonism between high yield and increased nutritional quality, with a focus on protein content?’ An original approach has been used to study the impact of the modification of seed composition on the crop production, which combines theoretical calculations of energetic cost and field yield data. When applied to a wide range of species with varying seed composition, a plurispecific negative relationship between the theoretical carbon costs of seed production and the observed yields was demonstrated. The high-throughput of genetic markers could result in large-scale screening of seed quality parameters and such studies, while evaluating the impact of seed composition on crop yield, could also be used to provide data to forecast the economic impact of a new line with an original composition compared with its economically enhanced value.     

A comparative study of ammonium toxicity at different constatn pH of the nutrient solution

Seedlings of 14 species were grown for 14–28 days on nutrient solution with 6 mmol.l⁻¹ NH₄ as the sole nitrogen source. Solutions acidity was were kept constant at pH 4.0, 5.0, 6.0 and 7.0 by continuous titration with diluted KOH. The following species were used: barley, maize, oats sorghum, yellow and white lupin, pea, soybean, carrot, flax, castor-oil, spinach, sugarbeet and sunflower. Most plant species grew optimally at pH 6.0 with slight reductions at pH 5.0. Growth of many species was severely inhibited at pH 4.0, but this inhibition was not observed with the legume and cereal species. Yield depressions at pH 4.0 relative to pH 6.0 were well correlated with the respective relative decreases of the K concentration in their roots (P<0.002). In the roots of two species (sunflower and flax) total N concentrations were also strongly reduced at pH 4.0. apparently, the interactions between uptake of K, NH₄ and H ions become the prevalent problem at suboptimal pH. At pH 7.0, yields were also considerably decreased, with the exception of the lupines. At this pH, the roots of the growth inhibited plants were characterized by increased levels of total N and free NH₄. It is thought that the binding capacity of the roots for NH₄ is an important factor in preventing NH₄/NH₃ toxicity at supraoptimal pH.