Cloned Eucalyptus spp. plantations are based in greenhouse production of plants generated by vegetative propagation. Diverse studies have demonstrated that rhizospheric bacteria can stimulate plant growth, and more recently that they can increase rooting in vegetative material. Considering this potential, the objective of this study was to verify the effect of bacterial strains on rooting Eucalyptus globulus. A total of 132 bacterial strains isolated from the rhizosphere of E. globulus and Eucalyptus nitens were studied. The bacterial inoculums in a concentration of 4 9 10 8 cfu/ml were applied to the rooting substrate at the cutting installation and 45 days after by irrigation. Rooting was evaluated on days 60 and 75 after cutting installation, considering the number of roots as well as their fibrosity and roots biomass. Of the 132 strains evaluated, 26 significantly increased cutting rooting in a range of 191.4-69.4% with respect to the control. Additionally, some strains stimulated the development of fine roots and incremented the roots biomass. The strains identificated that produced a rooting effect were: Bacillus firmus, Bacillus mycoides, Bacillus stearothermophilus, Bacillus subtilis, B. subtilis/amyloliquefaciens, Bacillus circulans, Brevibacillus brevis, Paenibacillus lautus and Stenotrophomona maltophilia. These first trials suggest the potential of these bacteria to be used in clonal production programs for E. globulus.
The characteristics of supersonic ion beams from the alternative low power hybrid ion engine (ALPHIE) are discussed. This simple concept of a DC powered plasma accelerator that only needs one electron source for both neutral gas ionization and ion beam neutralization is also examined. The plasma production and space charge neutralization processes are thus coupled in this plasma thruster that has a total DC power consumption of below 450 W, and uses xenon or argon gas as a propellant. The operation parameters of the plasma engine are studied in the laboratory in connection with the ion energy distribution function obtained with a retarding-field energy analyzer. The ALPHIE plasma beam expansion produces a mesothermal plasma flow with two-peaked ion energy distribution functions composed of low and high speed ion groups. The characteristic drift velocities of the fast ion groups, in the range 36.6–43.5 Km/s, are controlled by the acceleration voltage. These supersonic speeds are higher than the typical ion sound velocities of the low energy ion group produced by the expansion of the plasma jet. The temperatures of the slow ion population lead to ion Debye lengths longer than the electron Debye lengths. Furthermore, the electron impact ionization can coexist with collisional ionization by fast ions downstream the grids. Finally, the performance characteristics and comparisons with other plasma accelerator schemes are also discussed.
The influence of different levels of water deficit on physiological and morphological alterations in Myrtus communis plants was investigated to evaluate their adaptability to such conditions. M. communis plants growing under greenhouse conditions were subjected to three irrigation treatments between February and August 2007: a control, and two water deficit treatments. Plants submitted to severe water deficit showed reduced shoot and root dry weights, leaf numbers, leaf areas and plant heights, while moderate water deficit reduced only plant height. Leaf colour was not affected by either water deficit treatment. Root hydraulic resistance increased proportionally to the level of drought and lower values of leaf water potential at pre-dawn were observed in both deficit treatments. The absence of osmotic adjustment could explain the reduction of leaf turgor potential at midday. Photosynthesis decreased in both water deficit treatments and was related to stomatal factors, since no significant changes in the values of chlorophyll fluorescence, chlorophyll content or ion leakage were observed. The highest leaf water potential values (Ψl) were found in the early morning and the lowest at midday, in all treatments; the latter coincided with the minimum values of stomatal conductance. Significant differences in Ψl values during the day were noted between treatments, but were always highest in the control. Cell wall rigidity, measured as increased bulk modulus of elasticity increased under severe water stress resulting in a loss of turgor at lower leaf water potential values.
The latest edition of the Standards for Educational and Psychological Testing ( APA, 1999 ) promotes the analysis of respondents’ response processes in order to obtain evidence about the fit between the intended construct and the response process produced. The aim of this paper was twofold. First, we assess whether cognitive interviewing can be used to gather such validity evidence, and secondly, to analyze the usefulness of the evidence provided for interpreting the results from traditional psychometric analysis. The usefulness of the Cognitive Interviewing Reporting Framework ( Boeije & Willis, 2013 ) for reporting the cognitive interviewing findings was also evaluated. As an empirical example, we tested the (Spanish language) APGAR family function scale. A total of 21 pretest cognitive interviews were conducted, and psychometric analyzes were conducted of data from 28,371 respondents who were administered the APGAR scale. Results and utility of CIRF as a reporting framework are discussed.
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