Maite Olaetxea

• Universidad de Navarra

Background Ascophyllum Nodosum (L.) Extracts (ANE), even at low concentrations, are reported to behave as plant growth promoters and inducers of resistance to diverse abiotic and biotic stresses. However, the mechanisms regulating ANE's actions on plant metabolism have not been fully described. This study has two main objectives: (1) to investigate...

Many studies have shown the capacity of soil humic substances (HS) to improve plant growth in natural ecosystems. This effect involves the activation of different processes within the plant at different coordinated molecular, biochemical, and physiological levels. However, the first event triggered by plant root-HS interaction remains unclear. Some...

Some studies have reported that the capacity of humic substances to improve plant growth is dependent on their ability to increase root hydraulic conductivity. It was proposed that this effect is directly related to the structural conformation in solution of these substances. To study this hypothesis, the effects on root hydraulic conductivity and...

Humic substances (HS, fulvic and humic acids) are widely used as fertilizers or plant growth stimulants, although their mechanism of action still remains partially unknown. Humic substances may be applied either directly to the soil or as foliar sprays. Despite both kind of application are commonly used in agricultural practices, most of the studie...

The role of soil humus in soil fertility and crop production has been well established by many studies and practical farming experience. This role is related to the presence of a family of organic substances, known as humic substances, with the capacity to increase the pool of plant-available nutrients in soil for root uptake. The improvement in pl...

Although the ability of humic (HA) and fulvic acids (FA) to improve plant growth has been demonstrated, knowledge about the mechanisms responsible for the direct effects of HA and FA on the promotion of plant growth is scarce and fragmentary. Our study investigated the causal role of both root PM H+‐ATPase activity and ABA in the SHA‐promoting acti...

Availability of fresh water for crop irrigation is becoming scarce and rather expensive. In this context, the research about the potential reutilization of non-conventional water sources becomes highly relevant, principally in arid and semi-arid areas. On many occasions these new water resources involve water with a moderate concentration of salt,...

The ability of rhizospheric humic substances to improve plant growth has been well established by many studies carried out using diverse plant species cultivated under many different conditions. These beneficial effects of humic substances on plant development are expressed in both root and shoot. However, the mechanisms responsible for this action...

Numerous studies have shown the ability of humic substances to improve plant development. This action is normally reflected in an enhancement of crop yields and quality. However, the mechanisms responsible for this action of humic substances remain rather unknown. Our studies have shown that the shoot promoting action of sedimentary humic acids is...

Effects of a sedimentary humic acid on plant growth: study of the general mechanisms of action upon root application in cucumber plants (Cucumis sativus L. cv Ashley).

The importance of soil humus in soil fertility has been well established many years ago. However, the knowledge about the whole mechanisms by which humic molecules in the rhizosphere improve plant growth remains partial and rather fragmentary. In this review we discuss the relationships between two main signaling pathway families that are affected...

The physiological and metabolic mechanisms behind the humic acid-mediated plant growth enhancement are highly discussed. Experiments using cucumber plants show that the shoot growth enhancement caused by a structurally well characterized humic acid with sedimentary origin is functionally associated with significant increases in ABA root concentrati...

A number of studies have demonstrated the key role of nitric oxide in the regulation of many fundamental physiological processes that includes plant responses to abiotic and biotic stresses. On the other hand, beneficial action of humic substances on plant growth has been well corroborated, particularly when plants are subjected to abiotic stresses...

The main aim of this communication is to discuss the current knowledge about the potential direct mechanisms that are involved in the beneficial action of humic substances on plant development. To this end, we present and discuss here recent results obtained in our laboratory, along with other findings published by other authors. Finally, we propos...

The main aim of this communication is to discuss the current knowledge about the potential direct mechanisms that are involved in the beneficial action of humic substances on plant development. To this end, we present and discuss here recent results obtained in our laboratory, along with other findings published by other authors. Finally, we propos...

A number of studies have shown the ability of natural organic matter (NOM) in general and humic substances (HS) in particular, to affect the development of plants and microorganisms in many different natural ecosystems and agro-ecosystems. Regarding plants, these NOM and HS effects were expressed in both root growth and architecture, and shoot grow...