Amounts Of GA3 Research Articles

Electrochemical Luminescence of Gallium-Ion-Doped MgIn2O4 Electrodes

Electrochemical luminescence (ECL) under anodic polarization involves an excitation process that is analogous to the excitation process of inorganic electroluminescence (EL) devices, i.e., the so-called impact excitation process. ECL is suitable for facilitating the exploration of new materials to be used for fabricating EL devices, because the luminescent property associated with ECL can be examined by simple electrochemical measurements without fabricating an emitting device. In the present study, MgIn2O4 (MgGaxIn2−xO4) doped with various amounts of Ga3+ were synthesized and their ECL property was investigated to develop a new white-emitting EL material. The ECL spectra of the MgGaxIn2−xO4 largely depended on the doped Ga3+ content. The main peak in the emission spectra of a sample with x = 0.1 was a broad one (400–600 nm). With an increase in the Ga3+ content, the MgGaxIn2−xO4 samples with x = 0.2 and 0.3 showed two sharp emissions (in the form of lines) in the green region and these two sharp lines became main luminescence in the sample with x = 0.3. The surface of an electrode showed white-plane emission in the sample with x = 0.3. This change in the luminescent property upon changing the Ga3+ content appears to be caused by the change in the distribution of the Ga3+ ions in the MgGaxIn2−xO4 structure.

Biological activity, identification and quantification of gibberellins in seedlings of Norway spruce (Picea abies) grown under different photoperiods

Short photoperiod induces growth cessation in seedlings of Norway spruce (Picea abies (L.] Karst.). Application of different gibberellins (GAS) to seedlings growing under a short photoperiod show that GA9 and GA20 can not induce growth. In contrast application of GA, and GA4 induced shoot elongation. The results indicate that 3β‐hydroxylation of GA9 to GA4 and of GA20 to GA1 is under photoperiodic control. To confirm that conclusion, both qualitative and quantitative analyses of endogenous GAs were performed. GA1, GA3, GA4, GA7, GA9, GA12, GA15, GA15, GA20, GA29, GA34 and GA51 were identified by combined gas chromatography‐mass spectrometry in shoots of Norway spruce seedlings. The effect of photoperiod on GA levels was determined by using deuterated and 14C‐labelled GAs as intermal standards. In short days, the amounts of GA9, GA4 and GA1 are less than in plants grown in continuous light. There is no significant difference in the amounts of GA3, GA12, and GA20 between the different photoperiods. The lack of accumulation of GA9 and GA20 under short days is discussed.

THERMODYNAMIC STUDY OF M3+/H+EXCHANGE SYSTEMS ON TITANIUM ANTIMONATE CATION EXCHANGER

ABSTRACT Selectivity coefficients KH M for trivalent metal ions / hydrogen ions (M3+/H+) exchanges on titanium antimonate cation exchanger (TiSbA) have been determined for group 13 metals (Al3+, Ga3+, and In3+) and rare earth metals (La3+, Nd3+, Eu3+, Yb3+, and Y3+) ions by batch equilibration at 30, 45, and 60 °c in nitric acid media. Kielland plots (logKH M vs. the fractional exchange X¯M) for these exchange systems have been analyzed and found to show a break point at X¯M=0.005-0.01. This behavior can be interpreted assuming a two-site model. A site available at infinitesimal X¯M value has a large steric effect. The selectivity in this site increased in the order: Al3+ < Ga3+ < In3+ for group 13 metal ions and Y3+ < Yb3+ < Eu3+ < Nd3+ < La3+ for rare earth metal ions in the X¯M<0.02 region at 30°C. The amounts of Ga3+ exchanged by TiSbA increased with a rise in temperature. The selectivity of group 13 metal ions changed to: AI3+ < In3+ < Ga3+ at 60°C. On the other hand, the selectivity order for rare e...

Quantitation of gibberellins A1, A3, A4, A9 and an A9-conjugate in good- and poor-flowering clones of Sitka spruce (Picea sitchensis) during the period of flower-bud differentiation

The levels of endogenous gibberellin A1 (GA1), GA3, GA4, GA9 and a cellulase-hydrolysable GA9-conjugate in needles and shoot stems of Sitka spruce [Picea sitchensis (Bong.) Carr.] grafts with different coning or flowering histories were estimated by combined gas chromatography-mass spectrometry selected ion monitoring using deuterated GA3, GA4 and GA9 as internal standards. The samples were taken at the approximate time of the start of flower-bud differentiation, i.e. when the shoots had elongated approx. 95% of the final length. The needles of the good-flowering clones contained 11-12 ng per g fresh weight (FW) and 15-28 ng· (g FW) (-1) of GA9-conjugate and GA9, respectively. The shoot stems of the same material contained no detectable amounts of GA9-conjugate and 11-15 ng-(g FW)(-1) of GA9. The amounts of GA9-conjugate and GA9 were apparently lower in the poor-flowering clones, the needles containing 4-9 ng-(g FW)(-1) and 7-17 ng·(g FW)(-1), respectively. Also in this material the shoot stems contained no detectable amounts of GA9-conjugate. The amounts of GA4 were very small in both materials, ranging from 1-1.6 ng-(g FW)(-1). The good-flowering clones contained no detectable amounts of the more polar gibberellins, GA1 and GA3. The poor-flowering clones, on the other hand, contained high levels of GA15 17-19ng·(gFW)(-1) in the needles and 10-13 ng·(g FW) (-1) in the shoot stems, and also smaller amounts of GA3, 2-3 ng·(g FW)(-1) in the needles and approx. 1 ng·(g FW)(-1) in the shoot stems. The results demonstrate differences in GA-metabolism between the poor- and the good-flowering clones. The higher amounts of GA9-conjugate and GA9 might indicate a higher capacity for synthesizing GA4 in the good-flowering material. This synthesis does not, however, result in a build-up of the GA4-pool, maybe because of a high rate of turnover. Gibberellin A4 was apparently neither hydroxylated to GA1 nor converted to GA3 in the goodflowering material, as was the case in the poor-flowering material. This might indicate that gibberellin metabolism in the poor-flowering material is directed towards GA1 and GA3, GAs preferentially used in vegetative growth.

Essai de remplacement de la réfrigération vernalisante par des applications d’acide gibbérellique chez la jusquiame noire bisannuelle (hyoscyamus niger L.)

Applications of various amounts of GA3 onto the shoot apex of biennial rosette-plantHyoscyamus niger L., exposed to long days and non vernalized, caused internodes formation and stem elongation. The stem length was proportional to the amount of GA3 applied. Number and length of developed internodes and the whole length of the shoot were maximal in plants treated with a greater amount of GA3. In the end, stem elongation stopped and plants formed perchedrosettes without flowering. Hence, gibberellic acid participates in mechanisms of flowering only by indirect effect on stem elongation and not directly on flower formation itself.