Phytochemical content, antioxidant potential, and fatty acid composition of dried Tunisian fig (Ficus carica L.) cultivars

This study reports the main phenolic compounds, as well as phenolic profiles and antioxidant activity in nine sun-dried fig cultivars with different skin color, originating from South-Eastern and Middle-Eastern Tunisia. For all evaluated parameters, a considerable variability with high significant differences was observed among the cultivars studied. Dark fruits exhibited a higher total polyphenol contents (201.77 mg GAE/100g DM in cultivar Saoudi Douiret) compared to green fruits (73.74 mg GAE/100g DM in cultivar Bayoudhi Douiret). Fatty acid methyl esters, identified by GC-MS, distinguished the presence of (C16: 0), (C18: 1), ((C18: 2) 9, 12), ((C18: 3) 9, 12, 15) and (C20: 0). Strong correlations between the amounts of total phenolics, phenolic acids, flavonoids, fatty acids and antioxidant capacity were found. A principal component analysis showed three groups of cultivars regarding their similarity level

Biochemical and physiological characterizations of Rhizobium-Pea (Pisum sativum L.) symbiotic association under abiotic constraints

Pea (Pisum sativum L.) is an important leguminous for the agricultural sector. It is a source of biological nitrogen that efficiently contributes to the soil fertility. In Tunisia, low pea production is due to bad nitrogen management, lack of phosphorus availability and to the abiotic constraints. Thus, in order  to improve the pea production ,a new farming technique involving the rhizobia inoculation was applied. The symbiotic, biochemical, physiological characterization and inoculation trials were performed in both the laboratory, greenhouse and open field. Pea Lincoln variety was used as legume species and fifteen Rhizobium strains isolated from the roots of the nodulated pea were collected from different Tunisian areas. Several physiological and biochemical parameters, i.e. pH, temperature, calcium carbonate and salinity were assessed to characterize the strains nodulating pea. All the rhizobia tests were evaluated on Yeast Extract Mannitol Agar medium (YEMA). Pea nodulation and Gallery API test were carried out under controlled conditions. Significant differences (p<0.01) between the nodules number induced by the different bacterial strains and between strains for the dry matter quantities of aerial and root parts were registered. The pH medium test results showed that among 15 strains only 8 strains having a halo diameter greater than 1 cm at basic pH. The most of isolates are able to grow at both low and high temperatures. The limestone test results qualify these rhizobia as calcifuges. Gallery API test results showed a great diversity of rhizobia assimilation of carbohydrates implying genetic diversity. Our results us to select the most efficient solubilizer Rhizobium strains nodulating pea. In order to confirm the previously cited notions on the diversity of  Rhizobium strains isolated from Pisum sativum roots in Tunisia, inoculation trial with both selected strains in controlled and open field conditions confirmed the capacity of selected strains to fix atmospheric nitrogen and promote plant growth

Influence of Water Stress on Growth, Chlorophyll Contents and Solute Accumulation in Three Accessions of <em>Vicia faba</em> L. from Tunisian Arid Region

In this study, we aim to investigate the physiological and biochemical adaptations of Vicia faba plants to moderate irrigation regime (T1) and describe the effects of water stress on their growth performance and chlorophyll contents. For this reason, three Tunisia accessions (ElHamma, Mareth and Medenine) were studied. An experiment was conducted for one month. Faba bean plants were first grown in a greenhouse and then, exposed to water stress, whereby they were irrigated up to the field capacity (FC) of 0% (control, T0) and 50% of the control (moderate stress, T1). The effect of water stress on physiological parameters showed differences in relation to the accessions studied and the water regime. Relative water content (RWC) of ElHamma accession does not seem to be affected by stress as compared with the control regime. Total chlorophyll content decreases, whereas soluble sugar contents increases for all accessions studied. ElHamma has the highest content. About morphological parameters, bean growth varies according to the ascension and treatment. Hydric stress impedes the growth of the root part and caused a significant reduction in the shoot and root Dry Weight (DW) of the T1-stressed beans, compared to the optimal irrigation (T0)

Assessment of the physio-biochemical performance of Tunisian barley landraces under deficit saline-irrigation during grain filling stage

Salinity is one of the main and important abiotic stresses that adversely affects crop growth, development and production. In this study, two barley (Hordeum vulgare L.) landraces were subjected to three treatments of deficit saline-irrigation (12 dS/cm) (T0 = 100%ETc, T1 = 75%ETc, and T2 = 50%ETc) during grain filling stage. Carbon isotope discrimination (Δ13C) was associated with some physio-biochemical parameters to evaluate barley response to saline conditions. Results of this study showed that deficit saline-irrigation significantly (p < 0.05) decreases Δ13C in both barley landraces. Moreover, photosynthetic rate (A), transpiration (E), stomatal conductance (gs), and instantaneous water use efficiency (iWUE) were significantly affected by treatments. Relative water content (RWC), chlorophyll a, and chlorophyll (SPAD) value were significantly (p < 0.01 and p < 0.001) were affected by deficit saline-irrigation. In addition, phenolic compounds were affected by treatments and landraces (except syringic and p-coumaric acids), and their interactions (except syringic acid). Moreover, high correlations were noticed between Δ13C and physio-biochemical parameters. Results suggested that both barley landraces make a higher iWUE, and a weak variation in phenolic compounds. Moreover, Δ13C associated with physio-biochemical traits can also be good criteria for screening of salt-tolerance of barley during grain filling stage. Taken together, our study suggests that the response to deficit saline-irrigation in barley landraces involves an interplay between various physiological and biochemical mechanisms mainly related to Δ13C

Biochemical and physiological characterizations of Rhizobium-Pea (Pisum sativum L.) symbiotic association under abiotic constraints

Pea (Pisum sativum L.) is an important leguminous for the agricultural sector. It is a source of biological nitrogen that efficiently contributes to the soil fertility. In Tunisia, low pea production is due to bad nitrogen management, lack of phosphorus availability and to the abiotic constraints. Thus, in order  to improve the pea production ,a new farming technique involving the rhizobia inoculation was applied. The symbiotic, biochemical, physiological characterization and inoculation trials were performed in both the laboratory, greenhouse and open field. Pea Lincoln variety was used as legume species and fifteen Rhizobium strains isolated from the roots of the nodulated pea were collected from different Tunisian areas. Several physiological and biochemical parameters, i.e. pH, temperature, calcium carbonate and salinity were assessed to characterize the strains nodulating pea. All the rhizobia tests were evaluated on Yeast Extract Mannitol Agar medium (YEMA). Pea nodulation and Gallery API test were carried out under controlled conditions. Significant differences (p<0.01) between the nodules number induced by the different bacterial strains and between strains for the dry matter quantities of aerial and root parts were registered. The pH medium test results showed that among 15 strains only 8 strains having a halo diameter greater than 1 cm at basic pH. The most of isolates are able to grow at both low and high temperatures. The limestone test results qualify these rhizobia as calcifuges. Gallery API test results showed a great diversity of rhizobia assimilation of carbohydrates implying genetic diversity. Our results us to select the most efficient solubilizer Rhizobium strains nodulating pea. In order to confirm the previously cited notions on the diversity of  Rhizobium strains isolated from Pisum sativum roots in Tunisia, inoculation trial with both selected strains in controlled and open field conditions confirmed the capacity of selected strains to fix atmospheric nitrogen and promote plant growth

Bioactive compounds, antioxidant and antimicrobial activities of extracts from different plant parts of two Ziziphus Mill. species.

Ziziphus lotus L. (Lam.) and Z. mauritiana Lam., as a widespread species in Tunisia, are well known for their medicinal and food uses. The aim of the present study was to screen the content of total polyphenols, flavonoids, and condensed tannins together with the radical scavenging capacity and the antimicrobial activity of leaves, fruits and seeds extracts of Z. lotus and Z. mauritiana from different localities. Results showed that leaves extracts presented the highest phenolic compounds content for both species. Furthermore, LC-ESI-MS analysis allowed the identification of 28 bioactive compounds regardless of species and organs, with the predominance of quinic acid and rutin. Leaves extract of Z. mauritiana possessed the highest total antioxidant capacity. The antimicrobial tests showed that leaves extracts of Z. mauritiana and Z. lotus from Oued Esseder exhibited the highest activity against four bacterial strains (Staphylococcus aureus, Listeria monocytogenes, Salmonella typhimurium and Escherichia coli). The main results showed that the studied species of Ziziphus genus are an excellent source of natural bioactive molecules that could be an interesting material for industrial and food purposes

Mitigating Salinity Stress in Barley (<i>Hordeum vulgare</i> L.) through Biochar and NPK Fertilizers: Impacts on Physio-Biochemical Behavior and Grain Yield

Increased soil salinity significantly inhibits crop production around the world. Over the last decade, biochar has been used in agriculture to improve plant productivity, soil quality, and as an alternative to plant amendment. This study was aimed to study the effect of biochar, NPK, and their combination on the growth, physio-biochemical traits, mineral contents, and grain yield of barley (Hordeum vulgare L.). Thus, a pot factorial experiment based on a completely randomized design with three replications was performed. Experimental treatments included four levels of biochar (0, 2, 5 and 10% of total pot mass), four different NaCl levels (0, 75, 125, and 200 mmol L−1), and with or without NPK fertilizer. The results showed that a negative effect on gas exchange parameters, photosynthetic pigments, SPAD value, minerals contents, and grain yield of barley under salinity treatments. In addition, our funding showed the negative effect on biochemical traits such as proline, soluble sugars, individual sugar, and phenolic compounds. The use of biochar, combined with NPK fertilizers, considerably increases these parameters and especially improves barley grains yield under severe salinity conditions (200 mM) with a dose of 2% and 5% (394.1 and 280.61 g m−2, respectively) of total pot mass. It is concluded that biochar amendment could be a promising practice to enhance barley growth under severe saline irrigation and NPK fertilization regimes

Assessment of the physio-biochemical performance of Tunisian barley landraces under deficit saline-irrigation during grain filling stage

Salinity is one of the main and important abiotic stresses that adversely affects crop growth, development and production. In this study, two barley (Hordeum vulgare L.) landraces were subjected to three treatments of deficit saline-irrigation (12 dS/cm) (T0 = 100%ETc, T1 = 75%ETc, and T2 = 50%ETc) during grain filling stage. Carbon isotope discrimination (Δ13C) was associated with some physio-biochemical parameters to evaluate barley response to saline conditions. Results of this study showed that deficit saline-irrigation significantly (p < 0.05) decreases Δ13C in both barley landraces. Moreover, photosynthetic rate (A), transpiration (E), stomatal conductance (gs), and instantaneous water use efficiency (iWUE) were significantly affected by treatments. Relative water content (RWC), chlorophyll a, and chlorophyll (SPAD) value were significantly (p < 0.01 and p < 0.001) were affected by deficit saline-irrigation. In addition, phenolic compounds were affected by treatments and landraces (except syringic and p-coumaric acids), and their interactions (except syringic acid). Moreover, high correlations were noticed between Δ13C and physio-biochemical parameters. Results suggested that both barley landraces make a higher iWUE, and a weak variation in phenolic compounds. Moreover, Δ13C associated with physio-biochemical traits can also be good criteria for screening of salt-tolerance of barley during grain filling stage. Taken together, our study suggests that the response to deficit saline-irrigation in barley landraces involves an interplay between various physiological and biochemical mechanisms mainly related to Δ13C