Showing papers by "Jitendra P. Khurana published in 1988"

Floral induction in a photoperiodically insensitive duckweed, Lemna paucicostata LP6

Abstract: The effects of 20 amino acids and two amides were studied on the flowering of a photoperiodically insensitive duckweed, Lemna paucicostata LP6. Alanine, asparagine, aspartate, cystine, glutamate, glutamine, glycine, lysine, methionine, proline, serine, and threonine induced flowering under a photoperiodic regime of 16 hours light and 8 hours darkness. Among these, glutamate and aspartate were found to be the most effective for flower induction. These acids could initiate flowering even at 5×10 -7 molar level, though maximal flowering (about 80%) was obtained at 10 -5 molar. Change in the photoperiodic schedule or the pH of the nutrient medium did not influence glutamate- or aspartate-induced flowering. The low concentrations at which glutamate and aspartate are effective suggests that they may have a regulatory role rather than simply acting as metabolites.

Role of Adenosine 3′5′-Cyclic Monophosphate in Flowering of a Short-Day Duckweed Lemna paucicostata 6746

Abstract: The well-known second messenger in animal systems, adenosine 3',5'-cyclic monophosphate (cAMP), stimulated flowering in the short-day plant, Lemna paucicostata 6746, under both inductive and non-inductive photoperiods, when grown on modified Bonner and Devirian medium. Flowering could be achieved even in continuous light in the presence of cAMP, although the intensity of the response was still daylength-dependent. Besides flower induction, cAMP also enhanced their development. 5'-AMP and 5'-ATP also induced some flowering under non-inductive long days, but the response was weak as compared to that of cAMP. 5'-ADP, in contrast, had no effect whatsoever on flowering under long days, whereas a small effect was observed under inductive short days. What could be the probable mechanism of action of cAMP and whether its effect on flowering is mediated through the cAMP-adenylcyclase system, has been discussed.

Floral Induction in a Photoperiodically Insensitive Duckweed, Lemna paucicostata LP6 : Role of Glutamate, Aspartate, and Other Amino Acids and Amides

Abstract: The effects of 20 amino acids and two amides were studied on the flowering of a photoperiodically insensitive duckweed, Lemna paucicostata LP6. Alanine, asparagine, aspartate, cystine, glutamate, glutamine, glycine, lysine, methionine, proline, serine, and threonine induced flowering under a photoperiodic regime of 16 hours light and 8 hours darkness. Among these, glutamate and aspartate were found to be the most effective for flower induction. These acids could initiate flowering even at 5 × 10−7 molar level, though maximal flowering (about 80%) was obtained at 10−5 molar. Change in the photoperiodic schedule or the pH of the nutrient medium did not influence glutamate- or aspartate-induced flowering. The low concentrations at which glutamate and aspartate are effective suggests that they may have a regulatory role rather than simply acting as metabolites.