Proposed physiologic functions of boron in plants pertinent to animal and human metabolism.

Boron has been recognized since 1923 as an essential micronutrient element for higher plants. Over the years, many roles for boron in plants have been proposed, including functions in sugar transport, cell wall synthesis and lignification, cell wall structure, carbohydrate metabolism, RNA metabolism, respiration, indole acetic acid metabolism, phenol metabolism and membrane transport. However, the mechanism of boron involvement in each case remains unclear. Recent work has focused on two major plant-cell components: cell walls and membranes. In both, boron could play a structural role by bridging hydroxyl groups. In membranes, it could also be involved in ion transport and redox reactions by stimulating enzymes like nicotinamide adenine dinucleotide and reduced (NADH) oxidase. There is a very narrow window between the levels of boron required by and toxic to plants. The mechanisms of boron toxicity are also unknown. In nitrogen-fixing leguminous plants, foliarly applied boron causes up to a 1000% increase in the concentration of allantoic acid in leaves. In vitro studies show that boron inhibits the manganese-dependent allantoate amidohydrolase, and foliar application of manganese prior to application of boron eliminates allantoic acid accumulation in leaves. Interaction between borate and divalent cations like manganese may alter metabolic pathways, which could explain why higher concentrations of boron can be toxic to plants

Constituyentes del aceite esencial de Lavándula Lanata Boiss

We studied the essential oil of Lavandula Lanata Boiss, in which thirty four substances were identified, camphor, lavandulol and 3-octanone being the most abundant of them. The percentages of these compounds were found to vary considerably depending on the vegetative stage on which the plant was collected.Hemos estudiado la composición química del aceite esencial de Lavandula Lanata Boiss, habiendo identificado treinta y cuatro sustancias, de las cuales, lavandulol, 3-octanona y alcanfor son las más abundantes. Se ha encontrado que el porcentaje de estos componentes varía considerablemente en función de la época de recogida de la planta

Constituyentes del aceite esencial de Lavándula Lanata Boiss

Hemos estudiado la composición química del aceite esencial de Lavandula Lanata Boiss, habiendo ·identificado treinta y cuatro sustancias, de las cuales, lavandulol, 3-octanona y alcanfor son las más abundantes. Se ha encontrado que el porcentaje de estos componentes varía considerablemente en función de la época de recogida de la planta.We studied the essential oil of Lavandula Lanata Boiss, in which thirty four substances were identified, camphor, lavandulol and 3-octanone being the most abundant of them. The percentages of these compounds were found to vary considerably depending on the vegetative stage on which the plant was collected

Diversity of AMF associated with Ammophila arenaria ssp. arundinacea in Portuguese sand dunes

Abstract Dune vegetation is essential for the formation and preservation of sand dunes and the protection of the coast line. Coastal sand dunes are harsh environments where arbuscular mycorrhizal fungi (AMF) play an important role in promoting plant establishment and growth. We present a study of the diversity of AMF associated with A. arenaria ssp. arundinacea in two locations of the Portuguese coast under a Mediterranean climate. These two locations were selected to compare a well-preserved dune system from a protected area with a degraded dune system from a public beach. AMF diversity was assessed mainly by cloning and sequencing of a fragment of the ribosomal SSU using the primer NS31 and AM1. Most of the 89 AMF clones obtained from the rhizosphere and roots of A. arenaria belonged to the genus Glomus, the largest clade within the Glomeromycota. Higher AMF diversity was found in the least disturbed site, in which spores of Scutellospora persica, Glomus constrictum and Glomus globiferum were found in the rhizosphere of A. arenaria