The roots of Chrysopogon zizanioides (L.) Roberty, belonging to the Poaceae family, are the main source of volatile that has substantial value in perfume, cosmetics, pharmaceutical and food industries. The study of C. zizanioides volatiles, obtained from plant roots cultivated in Tunisia, using GC and GC/MS revealed that more than 50 compounds were detected of which 14 constituents were identified representing 33.87% of the total. Oleic acid (17.09%) and (E) -3-Eicosene (7.77%) were the major components at the species level. However, 10,13 methyl ester octadecadienoic acid (0.01%), (Z) - 9,17-octadecadienal (0.01%), (Dimethylethyl-1,1) Bis-2,6 Methyl- 4 Phenol (0.04%), methyl pentadecanoic acid, 13-methyl-, methyl ester (0.05%), (Z) -13-octadecenal (0.06%) and linoleic acid ethyl ester (0 , 06%) are the constituents which have the lowest contents.

Aloe vera L. is used largely in the pharmaceutical, cosmetic, and agro-food industries. The in vitro technique was proposed as an alternative method for large-scale propagation and/or conservation breeding programmes in response to the increasing demand for Aloe vera. Unfortunately, a major problem in the application of plant tissue culture is the browning of cultured tissues and microbial contamination. This work investigates for the first time the efficacy of using Essential Oils (EOs) to control enzymatic browning and contamination of cultures from Aloe vera. Murashige and Skoog (MS) (1962) medium supplemented with 1 mg/L b-indole butyric acid (IBA) was used as a basic medium for A. vera for in vitro culture. The effect of the addition of charcoal (at 0.5 g/L), thyme (Thymus vulgaris L.) and rosemary (Rosmarinus officinalis L.) essential oils (at concentrations of 0.1 and 0.2%) to the basic medium was assessed. While thyme Essential Oil (EO) inhibited explant growth, rosemary EO induced the highest explant survival percentage, the lowest browning diffusion and contamination percentage. Moreover, a second experiment was conducted to determine the optimal rosemary EO concentration (0.025, 0.05, 0.075, and 0.1%). Explant survival percentage was 100% after four weeks of culture with rosemary EO concentrations of 0.05, 0.075, and 0.1% with no signs of browning. The lowest infection percentage (10%) was observed for media containing 0.075 and 0.1% of rosemary EO. The highest average number of leaves per explant was 3.71 with 0.1% rosemary EO and the greatest leaf length was 3.18 cm with 0.05%. The analytical techniques used to detect rosemary EO compounds were GCFID (gas chromatography - flame ionization detection) and GC-MS (gas chromatography-mass spectrometry). The main constituents found were 1,8-cineole (53.92%), a-pinene (15.86%), b-pinene (10.79%), and camphor (7.99%). Additionally, the antioxidant activity of the rosemary EO was determined by the DPPH (Free radical-scavenging activity) (24.66 mg mL-1) and FRAP (Ferric reducing antioxidant power) (35.16 mmol Fe2+L - 1) tests. The chemical composition together with the antioxidant effect and the most widely recognized anti-infectious properties of the used rosemary EO could explain its role in the inhibition of both enzymatic browning and microbial growth in culture media. These results could be a scope for further screening of EOs to be used for the improvement of in vitro culture of A. vera and other industrial crops. (c) 2021 SAAB. Published by Elsevier B.V. All rights reserved.

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.

As in vitro culture environments can be mutagenic, it's challenging to produce true-to-true type plants from meristems. Therefore, the present study aimed to devlop an efficient protocol for micropropagation from shoot tip explants of medicinally important Aloe vera using different concentrations of A. vera leaf gel (AvG) as organic supplement to the culture media. Assessment of the genetic stability of A. vera in vitro multiplied plants compared to the donor plant is one of the most important pre-requisites especially before its use for commercial and medicinal purposes. For shoot multiplication, the highest number of axillary shoots recorded was 13.27 +/- 5.11 with an average length of 2.21 +/- 0.84 cm on M3 medium (MS + 0.2 mg L-1 of b-indole butyric acid (IBA) + 3 mg L-1 benzylamino-purine (BA) + 5% AvG). All three strength of MS medium (1, 1/2, 1/ 4) with different concentrations of AvG resulted in 100% root induction after 4 weeks of culture. All the rooted microshoots (100%) were successfully acclimatized. To provide a reliable conclusion on its nutritive supply to MS medium, the total phenolic (TPC), condensed tannins (TTC), flavonoid (TFC), and flavonol (TFlC) content as well as the antioxydant activity of AvG were investigated. TPC and TTC values were found to be 31.02 +/- 0.46 mg gallic acid equivalent mg-1 of extract and 4.00 +/- 0.96 mg catechin equivalent mg(-1) of extract, respectively while TFC and TFlC were 13.58 +/- 0.84 and 9.75 +/- 0.58 mg rutin equivalent mg(-1) of extract, respectively. The results of antioxydant activity of AvG following DPPH, FRAP and ABTS assays were equal to 12.50 +/- 0.89; 49.59 +/- 2.07 and 64.93 +/- 3.23 mmol Trolox equivalent mg-1 of extract, respectively which may explain the positive role of AvG as supplement. The genetic stability of in vitro propagated A. vera plants was evaluated using 10 inter simple sequence repeat (ISSR), 10 start codon targeted (SCoT) and 10 simple sequence repeat (SSR) markers. Out of these, 5 ISSR, 3 SCoT and 6 SSR primers produced resolvable, reproducible and scorable bands. ISSR primers generated 32 amplification products ranging from 200 to 1040 bp in size with a mean number of 6.4 bands while SCoT primers generated 33 amplicons with an average of 11 bands in the range of 160-2410 bp. In the SSR products, 6 bands were observed, each primer produced one band ranging from 410 to 720 bp. All banding profiles were monomorphic proving that the stability of the micropropagated A. vera plants was maintained. This study proved the suitability of supplementing in vitro culture media with AvG to enhance direct regeneration through shoot tip explants of A. vera for large scale micropropagation applications.(C) 2021 SAAB. Published by Elsevier B.V. All rights reserved.

Climate change and degradation of natural resources pose daunting challenges in arid and semi-arid rangelands of southern Mediterranean region. Overcoming these challenges requires considerable management actions efforts. In this context, the current two-year (2017/2018 and 2018/2019) study investigated the effects of soil surface scarification and reseeding of rangelands with sulla (Hedysarum coronarium L.) on botanical composition, biomass production, water productivity and pastoral value in the Sbaihia community, Tunisia. The experimental design consisted of a randomised complete block design with six replications. The treatments were: (i) soil surface superficial scarification; (ii) reseeding sulla following soil scarification; and, (iii) control. Despite the relatively important interannual variation, the highest aboveground net primary production (2 307 and 5 330 kg dry matter ha-1), water productivity (9.5 and 11.8 kg DM mm-1), and pastoral value (2 099 and 4 853 forage units ha-1) values were recorded in the rangelands reseeded with sulla in both growing seasons. Sulla contribution in the species composition of reseeded rangelands increased from 1.7% in 2018 to 2% in 2019. Although soil surface scarification increased the vegetation cover, its effect on biomass production was not significant. Therefore, combined soil scarification and reseeding well-adapted native forage species has a great potential to improve productivity of semi-arid rangelands.

Direct seeding techniques often result in unsatisfactory outcomes in rangeland rehabilitation, primarily because of low seedling emergence and poor establishment. Seed processing techniques aimed at improving seedling emergence have gained interest by pasture managers. The purpose of this study was to investigate the combined effects of bracteole removal and seeding rate on seedling emergence in seven halophytic species: Atriplex halimus, A. canescens, A. leucoclada, A. nummularia, A. lentiformis, Salsola vermiculata and Haloxylon aphyllum under semi-arid conditions in Tel Hadya (Syria). Each of these species was evaluated for seedling emergence under two seed treatments (bracteoles removed and non-removed bracteoles) with three seeding rates (10, 30 and 60 seeds per pot), in a completely randomised block design. The results showed a positive effect of seed treatment on seedling emergence for all studied species. The native A. halimus had the highest emergence percentages whereas the introduced A. mummularia, had the lowest. However, there were no significant effects of seeding rates on seedling emergence. These results showed that bracteole removal could improve germination and seedling emergence, and potentially increase the rate of establishment of the species studied. Therefore, when implementing rangeland rehabilitation projects, bracteole removal needs to be considered. The native S. vermiculata should be recommended for direct seeding in the West Asia and North Africa region given its high seedling emergence, known high palatability, nutritive value, and high auto-regeneration performance.

The objective of this study was to investigate farmers' adoption of sulla (Hedysarum coronarium L.) cultivation in northern Tunisia. Sulla adoption at farmer level and farmers' perception about the role of sulla were investigated through a survey of 216 farming households in 2017. The cultivation of sulla by farmers in the region reflected its adoption, with most farmers introducing it to their crop rotation cultivating system. The results obtained confirm the general acceptability of sulla in contributing towards farmers' livelihoods, and also that sulla is well adapted to grow in northern Tunisia.