boron and indoleacetic-acid

Boron (B) alleviates aluminum (Al) toxicity in higher plants; however, the underlying mechanisms behind this phenomenon remain unknown. Here, we used bromocresol green pH indicator, noninvasive microtest, and microelectrode ion flux estimation techniques to demonstrate that B promotes root surface pH gradients in pea (

Topics: Aluminum; Arabidopsis; Arabidopsis Proteins; Biological Transport; Boron; Cell Membrane; Hydrogen-Ion Concentration; Indoleacetic Acids; Mutation; Phthalimides; Pisum sativum; Plant Proteins; Plant Roots; Proton-Translocating ATPases

Plant hormones (PH) adjust plant growth to environmental conditions such as nutrient availability. Although responses of individual PHs to growth-determining nutrient supplies have been reported, little is known about simultaneous dynamics in the metabolism of different PH species. Brassica napus seedlings were grown under increasing supply of B, and LC-MS/MS was used to characterize bioactive forms of different PH species together with several of their precursors, storage and inactivated forms. Increasing shoot B concentrations in response to B supply were accompanied by decreasing concentrations of abscisic acid (ABA) and indole-3-acetic acid (IAA), which appeared to be synthesized under B deficiency mainly via indole-3-acetonitrile (IAN). By contrast, shoot B concentrations correlated closely with cytokinins, and the B-dependent growth response appeared to be triggered primarily by de-novo synthesis of cytokinins and by re-routing less active towards highly active forms of cytokinin. Also gibberellin biosynthesis strongly increased with B supply, in particular gibberellin species from the non-13-hydroxylation pathway. The brassinosteroid castasterone appeared to support shoot growth primarily at suboptimal B nutrition. These results indicate that a variable B nutritional status causes coordinated changes in PH metabolism as prerequisite for an adjusted growth response.

Topics: Abscisic Acid; Boron; Brassica napus; Cholestanols; Cytokinins; Gibberellins; Indoleacetic Acids; Plant Growth Regulators; Plant Shoots; Seedlings; Tandem Mass Spectrometry

With intact Phaseolus aureus plant as test material, this paper studied the effects of boron deficiency on its axillary bud growth and polar auxin transportation. The results showed that boron deficiency induced axillary bud growth significantly, while applying indole-3-acetic acid (IAA) could suppress the axillary bud growth induced by the decapitation of boron sufficient plant. When the plant deficient in boron was decapitated, applying IAA could delay the axillary bud growth. Compared with boron sufficient plant, the plant deficient in boron had an inhibited auxin basipetal movement in terms of the shorter distance of 3H-IAA peak from apex, and less total radioactivity detected in stem. No radioactivity was found in the axillary buds in any of the treatments, suggesting that the basipetal IAA transportation in stem rather than the IAA accumulation in bud was required for the inhibition of bud growth. A 24 h boron supply to the boron deficient plant could restore its 3H-IAA transportation.

Topics: Biological Transport; Boron; Indoleacetic Acids; Phaseolus; Plant Stems

Niacin (Nicotinic acid, B3 vitamin) may be involved in reduction of toxic effects of boron by regulating growth metabolism. This study was designed to examine whether external niacin treatment would improve the boron mobility in carrot callus cells or not. The results showed that excess boron caused tracheary inversions in meristematic root tissue, and also a shortage was seen in tracheary lengths with boric acid treatment. Boron excess induced the plant tolerance to water stress inverting the tracheary cells. This shortage converted nearly to normal size with niacin and boron treatment together. The results showed that boron mobility induced by niacin could reduce significantly the fresh and dry weight of carrot root cells, protein and ABA content was reduced also, in contrary, external boron and boron with niacin treatment considerable increased the two factors after one month stress. Fresh weight reduction and ABA content reduction indicated that niacin treatment caused water stress on the root cells of carrot, but boron treatment and boron with niacin treatment increased drought tolerance in carrot cells by increasing the both factors. In addition, turning the conversion of the length of the trachearies to their normal size proved that niacin treatment ended the polarizing effects of boron on cell walls.

Topics: Abscisic Acid; Boron; Culture Media; Daucus carota; Indoleacetic Acids; Niacin; Plant Proteins; Plant Roots