No abstract

Glucosinolates, a class of secondary metabolites, mainly found in Brassicaceae, are affected by the changing environment. This review is focusing on the physiological significance of glucosinolates and their hydrolysis products in the plant response to different abiotic stresses. Special attention is paid to the crosstalk between some of the physiological processes involved in stress response and glucosinolate metabolism, with the resulting connection between both pathways in which signaling mechanisms glucosinolate may act as signals themselves. The function of glucosinolates, further than in defense switching, is discussed in terms of alleviating pathogen attack under abiotic stress. The fact that the exogenous addition of glucosinolate hydrolysis products may alleviate certain stress conditions through its effect on specific proteins is described in light of the recent reports, but the molecular mechanisms involved in this response merit further research. Finally, the transient allocation and re-distribution of glucosinolates as a response to environmental changes is summarized.

The ability of AM plants to switch between water transport pathways could allow a higher flexibility in the response of these plants to water shortage according to the demand from the shoot.

Many by-products of the agrifood industry may be useful as sources of nutrients and potentially functional ingredients, giving the opportunity to obtain added-value products. Previous studies have been focused on edible florets, but in this case we are interested in adding value to broccoli by-products that represent a real problem in the production sites because no intended use for this material has been envisaged. Therefore, the aim of this study was to add value to the broccoli-derived by-products, since recycling all this agrowaste to obtain bioactive ingredients for industry can boost profits and reduce costs and environmental problems.

No abstract

-Interest in nutrient absorption and accumulation is derived from the need to increase crop productivity by better nutrition and also to improve the nutritional quality of plants as foods and feeds. This review focuses on contrasting data on the importance for human health of food mineral nutrients (Ca, Mg, K, Na and P) and also the trace elements considered essential or beneficial for human health (Cr, Co, Cu, Fe, Mn, Mo, Ni, Se and Zn). In addition, environmental stresses such as salinity, drought, extreme temperatures and light conditions that affect mineral content were revised in the light that the effect of these factors depends on the species or cultivar, and the specific plant organ, as well as the intensity and duration of the stress. Differences between inorganic and organic fertilisation practices on the mineral levels were also analysed to evaluate the influence of external factors on the quality of plant-based foods.

To evaluate the variations in the nutritional components of a broccoli cultivar under saline stress, two different NaCl concentrations (40 and 80 mM) were assayed. Glucosinolates, phenolic compounds, and ascorbic and dehydroascorbic acids (vitamin C) were analyzed by HPLC, and mineral composition was determined by ICP spectrophotometry. Qualitative differences were observed for several bioactive compounds depending on the plant organ and the intensity of the salt stress. Glucosinolate content showed the most significant increase in the florets; phenolic compounds also increased in the florets, whereas no variation in the vitamin C content was observed as a result of the saline treatments. The mineral composition of the edible parts of the inflorescences remained within the range of the recommended values for human consumption. Overall, the nutritional quality of the edible florets of broccoli was improved under moderate saline stress.

Silicon (Si) is an abundant and differentially distributed element in soils that is believed to have important biological functions. However, the benefits of Si and its essentiality in plants are controversial due to differences among species in their ability to take up this element. Despite this, there is a consensus that the application of Si improves the water status of plants under abiotic stress conditions. Hence, plants treated with Si are able to maintain a high stomatal conductance and transpiration rate under salt stress, suggesting that a reduction in Na+ uptake occurs due to deposition of Si in the root. In addition, root hydraulic conductivity increases when Si is applied. As a result, a Si-mediated upregulation of aquaporin (PIP) gene expression is observed in relation to increased root hydraulic conductivity and water uptake. Aquaporins of the subclass nodulin 26-like intrinsic proteins are further involved in allowing Si entry into the cell. Therefore, on the basis of available published results and recent developments, we propose a model to explain how Si absorption alleviates stress in plants grown under saline conditions through the conjugated action of different aquaporins.