Effects of Monochromatic Light on Growth and Quality of Pistacia vera L.

Light-emitting diodes (LEDs) are popular as a light source for in vitro plants because they save energy and allow the morphology of the plant to be altered. The purpose of this study was to show that switching from classical fluorescent light (FL) to LED light can have both beneficial and adverse effects. Pistacia vera plantlets were exposed to FL, monochromatic Blue LED light (B), monochromatic Red LED light (R), and a 1:1 mixture of both B and R (BR). R increased the total weight, shoot length, number of shoots ≥ 1 cm, and proliferation. It also reduced hyperhydricity (HH), but also dramatically increased shoot tip necrosis (STN) and leaf necrosis (LN). B cured plants of HH and STN, but hardly enabled proliferation. It did not solve the problem of LN, but the plants were high in total chlorophyll and carotenoids. BR reduced HH but enabled limited proliferation, high STN, and LN. All three LED treatments reduced HH compared to FL. B induced both high total phenolic and flavonoid content and high DPPH-scavenging activity. These results show that switching from FL to LED can have a significant positive or negative effect on proliferation and quality. This suggests that finding an optimal lighting regimen will take a lot of trial and error.

Incorporation of Organic Growth Additives to Enhance In Vitro Tissue Culture for Producing Genetically Stable Plants.

The growing demand for native planting material in ecological restoration and rehabilitation for agro-silvo-pastoral ecosystems has resulted in a major global industry in their sourcing, multiplication, and sale. Plant tissue culture is used for producing high-quality, disease-free, and true-to-type plants at a fast rate. Micropropagation can help to meet the increasing demand for planting material and afforestation programs. However, in vitro plant propagation is an expensive technique compared to conventional methods using suckers, seeds, and cuttings. Therefore, adopting measures to lower production costs without compromising plant quality is essential. This can be achieved by improving the culture media composition. Incorporating organic growth additives can stimulate tissue growth and increase the number of shoots, leaves, and roots in culture media. Organic growth supplementation speeds up the formation and development of cultures and yields vigorous plants. Plant regeneration from meristems (shoot tips and axillary buds) is a reliable way to produce true-to-type plants compared with callus and somatic embryogenesis regeneration, but in vitro culture environments can be mutagenic. Therefore, detecting somaclonal variations at an early stage of development is considered crucial in propagating plants. The genetic stability of in vitro regenerated plants needs to be ascertained by using DNA-based molecular markers. This review aims to provide up-to-date research progress on incorporating organic growth additives to enhance in vitro tissue culture protocols and to emphasize the importance of using PCR-based molecular markers such as RAPD, ISSR, SSR, and SCoT. The review was assessed based on the peer-reviewed works published in scientific databases including Science Direct, Scopus, Springer, JSTOR, onlinelibrary, and Google Scholar.

Topolin cytokinins enhanced shoot proliferation, reduced hyperhydricity and altered cytokinin metabolism in Pistacia vera L. seedling explants.

The effect of 10 µM meta-topolin (mT) and meta-topolin riboside (mTR) on in vitro proliferation and anomalies of Pistacia vera L. were evaluated and compared to that of 6-benzylaminopurine (BA). The highest proliferation rate (15.6) was recorded in the mT-medium, with a value 6 times higher than in BA-medium. Moreover, the lowest percentage of hyperhydric usable shoots (58,9%) and callus weight (46,9%) were found in mTR-treated shoots. Shoot tip as well as leaf necrosis were not influenced by cytokinin (CK) type. Image analysis was used to evaluate photosynthetic efficiency as well as anthocyanin index. Photosynthesis was more efficient with BA and mTR but the higher anthocyanin accumulation in BA-treated shoots suggests more stress. Endogenous CKs and their metabolites were determined in seedlings and, for the first time, the metabolism of exogenous BA, mT and mTR was studied in pistachio. The stimulating effect on cis-zeatin and its riboside and the appearance of BA and traces of ortho-topolin and para-topolin as natural CKs are discussed. The quantitative and qualitative CK metabolite analyses provides some initial clues as to why topolin would be superior to BA in terms of proliferation rate and avoiding hyperhydricity and allowed a better understanding of the effect of exogenous administration of CK.

Chemical characterisation and technical assessment of agri-food residues, marine matrices, and wild grasses in the South Mediterranean area: A considerable inflow for biorefineries.

The integration of easily available and under-exploited biomasses is considered a sustainable strategy in biorefining approaches. Mediterranean countries, especially Algeria, Morocco, and Tunisia, offer such under-exploited waste of different origins. This study revealed the chemical composition and phytochemical characteristics of various agri-food side-products, marine residues, and wild grasses collected in the Maghreb region. Results showed that these wastes contained variable proportions of polysaccharides, lignin, constitute molecules (proteins, lipids, and inorganic molecules) and, various secondary metabolites, mainly flavonoids and condensed tannins. Based on this, the Mediterranean waste was divided into three categories. The first category included waste with high lignin content (40 wt%). The second category contained waste with lignin content below 10 wt% and structural carbohydrate content below 50 wt%. Additionally, the waste in this category comprised noticeable amounts of flavonoids and condensed tannins, particularly from thistle, speedwell, and spurge. Finally, the third category included waste with lignin content above 15 wt% and carbohydrate content in the range of 45-55 wt%. The results also showed that the waste in the third category has a chemical composition similar to that of raw materials envisioned for use in European or North American commercial biorefineries. The findings of this study indicate that the biomass waste employed in this study can be used to develop marketable bioproducts and may be a potential raw material for a biorefinery facility.

Hydrothermal Dehydration of Monosaccharides Promoted by Seawater: Fundamentals on the Catalytic Role of Inorganic Salts.

In biorefining, the conversion of carbohydrates under subcritical water conditions is a field of extensive studies. In particular, the hydrothermal decomposition of benchmark C6- and C5-monosaccharides, i.e., D-glucose and D-xylose, into furanics and/or organic acids is fully considered. Herein, we propose to establish the fundamentals of the decomposition of D-glucose and D-xylose under subcritical water conditions in the presence of specific salts (i.e., NaCl and KI) and in seawater. Our results demonstrated that the introduction of inorganic salts was found to modify sugars dehydration yields. Different NaCl concentrations from 0.21 to 1.63 mol L-1 promoted the conversion of D-xylose to 2-furfural (2-F) from 28 to 44% (molar yield). NaCl also improved 5-hydroxymethylfurfural (5-HMF) generation from D-glucose as well as rehydration of 5-HMF to levulinic and formic acid. KI favored other pathways toward formic acid production from D-glucose, reaching 20% in the upper concentration. Compared to a solution of equivalent NaCl concentration, seawater enhanced selectivity toward lactic acid which was raised by 10% for both monosaccharides, and sugars conversion, especially for D-glucose whose conversion was increased by 20%. 5-HMF molar yield around 30% were achieved from D-glucose in seawater at 211°C and 20 bars after 15 min.

Physiological response and mineral elements accumulation pattern in Sesuvium portulacastrum L. subjected in vitro to nickel.

Sesuvium portulacastrum, a halophyte with high tolerance to heavy metals like Cd, Pb and Ni is considered for phytoremediation of metal contaminated saline soils. The tolerance to a selected metal ion could, by hypothesis, be stimulated through in vitro adaptation and regeneration of the plant. Seedlings obtained by in vitro micro-propagation, were exposed to 0, 25 and 50 µM Ni, as NiCl2, in agar-based medium for 30 days. Growth parameters, plant water content, the concentration of photosynthetic pigments, proline and malondialdehyde (MDA) concentrations were determined. Nickel and nutrients distribution in leaves was studied by micro-Proton-Induced-X-ray-Emission (µ-PIXE). The results showed that Ni was mainly accumulated in vascular bundles, next in water storage tissues and chlorenchyma. Ni concentrations in chlorenchyma increased with increasing Ni in culturing medium, in direct relation to decrease of photosynthetic pigments and increase of oxidative stress. As compared to control plants, Ni induced substantial increase in MDA and proline accumulation. Plants exposed to 50 µM Ni accumulated up to 650 µg g-1 of Ni in the shoots, exhibiting chlorosis and necrosis and a drastically reduced plant growth. Perturbations in uptake and distribution of nutrients were observed, inducing mineral deficiency, probably through membrane leakage. The mineral nutrient disturbances induced by Ni could be highly implicated in the restriction of S. portulacastrum development under the acute 50 µM Ni level.

Steviol glycosides targeted analysis in leaves of Stevia rebaudiana (Bertoni) from plants cultivated under chilling stress conditions.

Stevia rebaudiana is an important agricultural crop for the production of a high-potency natural sweetener, sensitive to low temperature during the developmental stage. Stimulation of chilling stress with a pre-treatment with endogenous signalling components and in particular with salicylic acid (SA), hydrogen peroxide (H2O2), 6-benzylaminopurine (BAP) and calcium chloride (CaCl2) could induce tolerance to chilling and could constitute a suitable way to maintain quality and quantity of steviol glycosides under controlled artificial environment. In the present work the effects of different putative signalling molecules on the morpho-physiological parameters were evaluated, and a specific method for the quali-quantitative analysis of steviol glycosides in S. rebaudiana plants cultivated under controlled conditions was developed, by using LC-ESI-FT (Orbitrap) MS, LC-ESI-QqQ-MS/MS and multivariate data analysis. This approach underlined that the pre-treatment has influence on the production of secondary metabolites. In particular Stevia plants characterised by higher contents of rebaudioside A and stevioside, were identified.

Coriander (Coriandrum sativum L.) and its bioactive constituents.

Coriander (Coriandrum sativum L.), a member of the Apiaceae family, is among most widely used medicinal plant, possessing nutritional as well as medicinal properties. Thus, the aim of this updated review is to highlight the importance of coriander as a potential source of bioactive constituents and to summarize their biological activities as well as their different applications from data obtained in recent literature, with critical analysis on the gaps and potential for future investigations. A literature review was carried out by searching on the electronic databases including PubMed, Scopus, ScienceDirect, and Google Scholar for studies focusing on the biological and pharmacological activities of coriander seed and herb bioactive constituents. All recent English-language articles published between 2000 and 2014 were searched using the terms 'C. sativum', 'medicinal plant', 'bioactive constituents', and 'biological activities'. Subsequently, coriander seed and herb essential oils have been actively investigated for their chemical composition and biological activities including antimicrobial, antioxidant, hypoglycemic, hypolipidemic, anxiolytic, analgesic, anti-inflammatory, anti-convulsant and anti-cancer activities, among others. Although coriander has been reported to possess a wide range of traditional medicinal uses, no report is available in its effectiveness use in reactive airway diseases such as asthma and bronchiolitis. In brief, the information presented herein will be helpful to create more interest towards this medicinal species by defining novel pharmacological and clinical applications and hence, may be useful in developing new drug formulations in the future or by employing coriander bioactive constituents in combination with conventional drugs to enhance the treatment of diseases such as Alzheimer and cancer.

Effects of arbuscular mycorrhizal inoculation and fertilization on mycorrhizal Statute of Jacaranda mimosifolia D.Don cultivated in nurseries.

The effects of fertilization and the nature of the inoculum as well as the variation of the dose intake of the latter on the level of Jacaranda mimosifolia D.Don mycorhization were tested. Young plants were treated with two inoculums presenting different origins, compositions and modes of application: one is a commercial product containing Glomus irregulare, and the other is a composite indigenous inoculum resulting from trapping five species of genus Glomus and also from multiplication on mycotrophic plants: leek (Allium porrum L.) and vetch (Vicia sativa L.). For each inoculum, two doses were tested and for each dose of inoculum, four levels of fertilization based on a complete commercial fertilizer (Osmocote) were tested: 0 g/plant, 2 g/plant, 4 g/plant, and 6g/plant. Three repetitions were performed for each combination treatment of inoculum/fertilizer. One-year-old young Jacaranda plants, being about 40 cm high, were cultured under greenhouse in 10/12 cm caliber pots. After six months, all the inoculated plants were mycorrhized. According to endomycorrhizal structures found on their roots, plants receiving doses of composite indigenous inoculum reached a more advanced stage of mycorrhization than those treated with the commercial inoculum. The existence of an interaction effect between the inoculum dose and the level of fertilization on Jacaranda mycorhization rate was excluded. These two parameters of variation were studied as simple effects. The increase in commercial inoculum dose had a significant positive influence on the level of Jacaranda plants mycorrhization (P=0.05). The rate of mycorrhization jumped from 12.69% to 21.92%. Nonetheless, for plants receiving increasing doses of composite indigenous inoculum, the level of mycorrhization has varied randomly. In both instances of inoculum treatments, increasing the dose of fertilizer significantly inhibited endomycorrhizal colonization of Jacaranda roots (P=0.01). Thus, the rate of root colonization decreased from 47.43% to 2.41% for plants receiving the composite indigenous inoculums. It decreased from 32.35% to 3.95% for those treated with the commercial inoculum. Mycorrhization had a positive effect on root dry biomass of Jacaranda, as in the case of unfertilize ave the highest rates of colonization.

Potential of kenaf (Hibiscus cannabinus L.) and corn (Zea mays L.) for phytoremediation of dredging sludge contaminated by trace metals.

The potential of kenaf (Hibiscus cannabinus L.) and corn (Zea mays L.) for accumulation of cadmium and zinc was investigated. Plants have been grown in lysimetres containing dredging sludge, a substratum naturally rich in trace metals. Biomass production was determined. Sludge and water percolating from lysimeters were analyzed by atomic absorption spectrometry. No visible symptoms of toxicity were observed during the three- month culture. Kenaf and corn tolerate trace metals content in sludge. Results showed that Zn and Cd were found in corn and kenaf shoots at different levels, 2.49 mg/kg of Cd and 82.5 mg/kg of Zn in kenaf shoots and 2.1 mg/kg of Cd and 10.19 mg/kg in corn shoots. Quantities of extracted trace metals showed that decontamination of Zn and Cd polluted substrates is possible by corn and kenaf crops. Tolerance and bioaccumulation factors indicated that both species could be used in phytoremediation.