Measurement of indolebutyric Acid in plant tissues by isotope dilution gas chromatography-mass spectrometry analysis.

An internal standard, [(13)C][indole-2]-indole-3-butyric acid, was synthesized from indole-2[(13)C] and was shown to be effective for the quantitative determination of indole-3-butyric acid from plant tissue. When this standard was used along with [(13)C(6)]indole-3-acetic acid, both indolic auxins could be quantified from the same tobacco (Nicotiana tabacam) leaf sample by isotope dilution analysis using selected ion monitoring gas chromatography-mass spectrometry for detection.

Factor structure of the WISC-R and ITPA for learning-disabled, emotionally disturbed, and control children.

There has been considerable interest in determining possible learning differences in specific populations of children. Stewart (1977) factor analyzed the WISC and ITPA for learning-disabled and mentally retarded samples and compared the results to a control group. He concluded that while the factors were quite similar, evidence suggested different learning processes in the groups studied. The present study (N = 301) enlarged and modified Stewart's study; it replaced the WISC with the WISC-R and the mentally retarded group with an emotionally disturbed sample. Three factors that emerged for all groups (linguistic, memory, and visual-motor) were similar to Stewart's findings. Additional factors highlighted motor skills and a separation in auditory and visual tasks for the learning-disabled group, an expressive factor for the emotionally disturbed, and a conceptual factor for the emotionally disturbed and control groups that was not found for the learning-disabled sample. Results suggested the need for individualized instruction.

Relationship between Indole-3-Acetic Acid Levels in Apple (Malus pumila Mill) Rootstocks Cultured in Vitro and Adventitious Root Formation in the Presence of Indole-3-Butyric Acid.

In vitro rooting response and indole-3-acetic acid (IAA) levels were examined in two genetically related dwarfing apple (Malus pumila Mill) rootstocks. M.26 and M.9 were cultured in vitro using Linsmaier-Skoog medium supplemented with benzyladenine (BA), indole-3-butyric acid (IBA), and 1,3,5-trihydroxybenzoic acid (PG). Rooting response was tested in Lepoivre medium supplemented with IBA and PG. IBA concentrations of 12.0 and 4.0 micromolar induced the maximum rooting percentages for M.9 and M.26, respectively. At these concentrations rooting response was 100% for M.26 and 80% for M.9. Free and conjugated IAA levels were determined in M.26 and M.9 shoots prior to root inducing treatment by high performance liquid chromatography with fluorescence detection and validated by gas chromatography-mass spectrometry using (13)[C(6)]IAA as internal standard. Basal sections of M.26 shoots contained 2.8 times more free IAA than similar tissue in M.9 (477.1 +/- 6.5 versus 166.6 +/- 6.7 nanograms per gram fresh weight), while free IAA levels in apical sections of M.26 and M.9 shoots were comparable (298.0 +/- 4.4 versus 263.7 +/- 9.3 nanograms per gram fresh weight). Conjugated IAA levels were significantly higher in M.9 than in M.26 indicating that a greater proportion of total IAA was present as a conjugate in M.9. These data suggest that differences between M.26 and M.9 rooting responses may be related to differences in free IAA levels in the shoot base.