Chilling-Dependent Release of Seed and Bud Dormancy in Peach Associates to Common Changes in Gene Expression

Reproductive meristems and embryos display dormancy mechanisms in specialized structures named respectively buds and seeds that arrest the growth of perennial plants until environmental conditions are optimal for survival. Dormancy shows common physiological features in buds and seeds. A genotype-specific period of chilling is usually required to release dormancy by molecular mechanisms that are still poorly understood. In order to find common transcriptional pathways associated to dormancy release, we analyzed the chilling-dependent expression in embryos of certain genes that were previously found related to dormancy in flower buds of peach. We propose the presence of short and long-term dormancy events affecting respectively the germination rate and seedling development by independent mechanisms. Short periods of chilling seem to improve germination in an abscisic acid-dependent manner, whereas the positive effect of longer cold treatments on physiological dwarfing coincides with the accumulation of phenylpropanoids in the seed

Determination of amino acids separated by micellar electrokinetic chromatography after pre-column derivatization with <i>o</i>-phthalaldehyde

1095-1098A simple, sensitive and rapid analytical method has been developed for the determination of amino acids separated by micellar electrokinetic chromatography after pre-column derivatization with o-phthalaldehyde. The separated amino acids have been detected using ultraviolet as well as electrochemical detection modes. The OPA derivatized amino acids have been separated on a 75μm (internal diameter) fused silica capillary. UV detection has been performed at 220 and 335 nm respectively,while electrochemical detection has been done at 500 mV against Ag/AgCl reference electrode. Optimum separation has been achieved using an applied voltage of 28 kV. Enhanced sensitivity is achieved with the electrochemical detection mode. The standard curve of amino acids is found to be linear in the range of 10-5 to 5×10-7 M. The % relative standard deviation for retention time is found to be less than 0.4 while for peak height and peak area it is within 1%

Determination of amino acids separated by micellar electrokinetic chromatography after pre-column derivatization with o-phthalaldehyde

1095-1098A simple, sensitive and rapid analytical method has been developed for the determination of amino acids separated by micellar electrokinetic chromatography after pre-column derivatization with o-phthalaldehyde. The separated amino acids have been detected using ultraviolet as well as electrochemical detection modes. The OPA derivatized amino acids have been separated on a 75μm (internal diameter) fused silica capillary. UV detection has been performed at 220 and 335 nm respectively,while electrochemical detection has been done at 500 mV against Ag/AgCl reference electrode. Optimum separation has been achieved using an applied voltage of 28 kV. Enhanced sensitivity is achieved with the electrochemical detection mode. The standard curve of amino acids is found to be linear in the range of 10-5 to 5×10-7 M. The % relative standard deviation for retention time is found to be less than 0.4 while for peak height and peak area it is within 1%