Halophyte plants as potential sources of Anticancer agents: a comprehensive review

Salt-tolerant plants (halophytes) are widely distributed worldwide in several environments such as coastal salt marshes, sand dunes, and inland deserts. To cope with the harsh conditions that characterize those habitats, which include high salinity and radiation levels, such plants have developed morphological and physiological traits, the latter including the synthesis and accumulation of important secondary metabolites such as alkaloids and polyphenols. While essential in maintaining plant homeostasis, these compounds are highly valued in the medical field for the treatment of several human diseases, including cancer. Cancer is one of the most life-threatening disorders worldwide, which accentuates the need to improve current cancer therapies and minimize potential adverse secondary side-effects. In this context, the pharmacological evaluation of natural compounds has attracted growing interest since nature has already provided some important anti-cancer drugs. This review compiles, for the first time, research regarding the anticancer activity of halophytes from different families, including, whenever possible, the bioactive molecules involved in such therapeutical properties along with possible mechanisms of action. The introduction section provides some pertinent information regarding cancer and a summary of the most important characteristics of halophytes. The next section gives information regarding the in vitro and in vivo cytotoxic properties of several halophyte species, grouped by families, including contents in bioactive metabolites and proposed modes of action, if possible. Lastly, the conclusion presents the most relevant metabolites and/or promising species and extracts that could be further explored in anticancer drug research.info:eu-repo/semantics/publishedVersio

Editorial: Mineral nutrition and plant stress tolerance

In conclusion, the articles included in this Research Topic contribute to our understanding of the efficacy of various nutrients in alleviating diverse stresses and plant nutrient relations, while illustrating the need for more such research. A better understanding of different nutrient elements could lead to more rational fertilizing practices, avoiding interactions that could contribute to the unbalanced mineral nutrition of plants for maximizing crop yield. This knowledge is also necessary to obtain more efficient genotypes in the acquisition of different nutrients

Effect of Ozonated Fertigation in Pepper Cultivation under Greenhouse Conditions

Ozone has a high oxidizing power avoiding the presence of residues, so it is a good candidate for use in organic farming. However, its application in fertigation has been little studied. Two experiments were conducted simultaneously to check the aims of this work. The aim of the first experiment was to study pepper response under the nutrient solution supply and the application of O3 and its interactions, and the aim of the second experiment was to determine the optimal dosage of O3 to be supplied, from the point of view of plant development and nutritional and physiological status in both experiments. We conclude that O3 supply via fertigation increased pepper biomass production. According to the results obtained, we recommend that the optimal dosage of O3 in pepper plants be from 0.18 to 0.36 mg L−1 due to its higher associated biomass production. Under these dosages, pepper plants showed a higher leaf area and higher photosynthetic pigment concentration. Similarly, under these dosages, N, P, and K plant uptake were higher, allowing a higher synthesis of bioassimilates

Spatial Distribution and Mobility of Nutrients on Sand Mulching Soil for Fertigated Green Bean Crops under Greenhouse Conditions in Southern Spain: (I) Macronutrients

Information about the nutrients distribution in sand-mulched soils is rather scarce; therefore, the aim of this experiment was to determine the spatial distribution and mobility of macronutrients in the wet bulb zone in two sand-mulched soils (a technique where manure and sand are layered over existing soil) for fertigated green bean with a drip irrigation distribution system under greenhouse conditions. The experimental design was multifactorial (4): soil type (S1 (1.0% organic matter (OM)) and S2 (2.5% OM)), time of sampling (before planting and after crop harvest) and spatial distribution: distance (0.1, 0.2, and 0.3 m) from the emitter and soil depth (0.1–0.2, 0.2–0.3 and 0.3–0.4 m) with three blocks and one replication per block. The chemical parameters (pH, electrical conductivity (EC), and macronutrients concentration) were analyzed in each soil sample. The testing crop was green bean (Phaseolous vulgaris L. c.v. Mantra RZ), lasting 90 days. The results obtained showed the highest value of EC and NO3−-N, K, and Ca concentration in the sand layer in both soils. At all soil profile depths, nutrient concentrations of NH4+-N and soil EC were lower in the high OM soil. Comparing the soil profile at the beginning and at the end of the experiment, there was a significant decrease in NO3−-N, P and Ca concentration and a significant increase in EC value and Mg concentration at the end of the crop. In distance, EC and K showed the highest concentration at 0.30 m. In depth, there was a decline in EC value and NH4+-N, P, K, Ca and Mg concentration. The comparison between the sand layer and the soil profile in both soils reported a similar trend in pH, EC, NO3−-N, P and Mg concentration. Considering the mobility of macronutrients in a sandy mulched soil, it would be recommendable to develop a sustainable and dynamic fertigation management, adjusting nutrient inputs over time

Physiological and nutritional responses to ozone application in tomato seedling plants

Research on environmentally friendly techniques for the agroindustry is growing constantly. In this sense, the supply of ozone (O3) has been taken into consideration, especially for disinfection because of its high oxidizing power. However, there is not enough information about the application of dissolved O3 via fertigation in crops. For that reason, in this study, two trials were carried out simultaneously to determine the consequences of O3 application on plant growth and quality of tomato plants. The first trial aimed to assess the effects on tomato fertigated with the nutrient solution and the application of O3. The second trial was performed to establish the ideal O3 supply rate for tomato plants. In both experiments, we measured the biometric, physiological, and nutritional parameters of the tomato plant. The results obtained showed that the application of O3 treatment resulted in the highest overall dry weight gain, whereas O3 application decreased leaf proline and total soluble sugars concentrations. There was no clear effect on chlorophyll and total soluble sugars in tomato plants under O3 application. Regarding nutritional parameters, the application of O3 led to a higher content of P and K in tomato plants. These findings indicate that the use of dissolved O3 via fertigation may present several advantages for tomato plants’ growth and quality

Secretory structures in plants: lessons from the Plumbaginaceae on their origin, evolution and roles in stress tolerance

Special IssueThe Plumbaginaceae (non-core Caryophyllales) is a family well known for species adapted to a wide range of arid and saline habitats. Of its salt-tolerant species, at least 45 are in the genus Limonium; two in each of Aegialitis, Limoniastrum and Myriolimon, and one each in Psylliostachys, Armeria, Ceratostigma, Goniolimon and Plumbago. All the halophytic members of the family have salt glands, which are also common in the closely related Tamaricaceae and Frankeniaceae. The halophytic species of the three families can secrete a range of ions (Na+, K+, Ca2+, Mg2+, Cl−, HCO3 −, SO4 2-) and other elements (As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn). Salt glands are, however, absent in salt-tolerant members of the sister family Polygonaceae. We describe the structure of the salt glands in the three families and consider whether glands might have arisen as a means to avoid the toxicity of Na+ and/or Cl− or to regulate Ca2+ concentrations within the leaves. We conclude that the establishment of lineages with salt glands took place after the split between the Polygonaceae and its sister group the Plumbaginaceaeinfo:eu-repo/semantics/publishedVersio

Correlations between R, G, and B Values, Pigment Concentration, and Nitrogen Status in Three Ornamental Potted Plants

Image technologies have been used for real-time estimation of nitrogen (N) and leaf chlorophyll (Chl) concentrations as well as for photosynthetic properties. The aim of this work was to establish correlations between RGB values and chlorophyll and nitrogen concentrations in three ornamental potted plants. We evaluated the RGB values, nitrogen status, and chlorophyll concentrations in the leaves of Peperomia obtusifolia, Maytenus senegalensis, and Rosmarinus officinalis. The correlation between the RGB values and the chlorophyll and nitrogen concentrations in the leaves was different for each species, since baby rubber correlated with the R and G values, the confetti tree correlated with the G and B values, and rosemary correlated with the R, G, and B values. The correlation between the normalized RGB (rgb) values and the color parameters and the chlorophyll and nitrogen concentrations showed R2 values lower than 0.70 in all species. Moreover, the estimation of vegetation indices was not effective due to the lack of correlations between these indices and the chlorophyll and nitrogen concentrations in the leaves of each species. According to the findings, rosemary exhibited the best association between the RGB values and chlorophyll and nitrogen concentrations in the leaves

Chloroplast-associated molecular patterns as concept for fine-tuned operational retrograde signalling.

Unal D, Garcia-Caparros P, Kumar V, Dietz K-J. Chloroplast-associated molecular patterns as concept for fine-tuned operational retrograde signalling. Philosophical transactions of the Royal Society of London. Series B, Biological sciences. 2020;375(1801): 20190443.Chloroplasts compose about one-quarter of the mesophyll cell volume and contain about 60% of the cell protein. Photosynthetic carbon assimilation is the dominating metabolism in illuminated leaves. To optimize the resource expenditure in these costly organelles and to control and adjust chloroplast metabolism, an intensive transfer of information between nucleus-cytoplasm and chloroplasts occurs in both directions as anterograde and retrograde signalling. Recent research identified multiple retrograde pathways that use metabolite transfer and include reaction products of lipids and carotenoids with reactive oxygen species (ROS). Other pathways use metabolites of carbon, sulfur and nitrogen metabolism, low molecular weight antioxidants and hormone precursors to carry information between the cell compartments. This review focuses on redox- and ROS-related retrograde signalling pathways. In analogy to the microbe-associated molecular pattern, we propose the term 'chloroplast-associated molecular pattern' which connects chloroplast performance to extrachloroplast processes such as nuclear gene transcription, posttranscriptional processing, including translation, and RNA and protein fate. This article is part of the theme issue 'Retrograde signalling from endosymbiotic organelles'

Tolerance mechanisms of three potted ornamental plants grown under moderate salinity

The scarcity of water in the Mediterranean area has frequently led to the use of saline water in order to irrigate ornamental plants in many nurseries. However, before the large-scale use of such waters, the ways in which the plants deal with the salinity need to be evaluated. Plants of Aloe vera L. Burm, Kalanchoe blossfeldiana Poelln and Gazania splendens Lem sp. were grown in pots with a mixture of sphagnum peat moss and Perlite. In order to evaluate the effects of different levels of salinity, three treatments using different NaCl concentrations (Electrical conductivity = 2.0 (control), 4.5 and 7.5 dS m(-1)) were applied over a period of 60 days. At the end of the experiment, the growth, physiological parameters and mineral content of the roots and leaves were assessed for each salinity treatment. After 60 days of exposure to salinity, the total biomass of all species decreased similarly. The mineral composition of roots and leaves was clearly affected. Osmolytes, such as praline, played an important role in the osmotic adjustment in all species increasing in the roots and leaves at the higher ECi. Different mechanisms of the salt tolerance were triggered in each species. A vera plants showed Na+ accumulation at the root level and a decrease in succulence index of leaves. K. blossfeldiana plants shed leaves to release Na+ and G. splendens plants accumulated Cl- and Na+ at the root level, secreted salt from leaves, lost salt by shedding of old leaves and increased the succulence index of remaining leaves. We concluded that the use of saline waters is feasible for growing these ornamental plants, and G. splendens seems to be particularly well adapted to salinity, a consideration that is particularly relevant in arid saline areas. (C) 2016 Elsevier B.V. All rights reserved

Effect of Ozonated Fertigation in Pepper Cultivation under Greenhouse Conditions

Ozone has a high oxidizing power avoiding the presence of residues, so it is a good candidate for use in organic farming. However, its application in fertigation has been little studied. Two experiments were conducted simultaneously to check the aims of this work. The aim of the first experiment was to study pepper response under the nutrient solution supply and the application of O3 and its interactions, and the aim of the second experiment was to determine the optimal dosage of O3 to be supplied, from the point of view of plant development and nutritional and physiological status in both experiments. We conclude that O3 supply via fertigation increased pepper biomass production. According to the results obtained, we recommend that the optimal dosage of O3 in pepper plants be from 0.18 to 0.36 mg L−1 due to its higher associated biomass production. Under these dosages, pepper plants showed a higher leaf area and higher photosynthetic pigment concentration. Similarly, under these dosages, N, P, and K plant uptake were higher, allowing a higher synthesis of bioassimilates