Mineral Uptake, Total Polyphenols and Total Flavonoids of Barley as Affected by Tillage Practices under Semi-Arid Conditions

Aims: Conservation agriculture has been recommended as an option to mitigate climate change impact when practicing conventional, to ensure sustainability and food security This study examined the effect of conventional tillage (CT) and no tillage (NT) on mineral elements uptake, total phenolic content (TPC) and total flavonoid content (TFC) of barley. Study Design: Split-plot design was applied for this study. Place and Duration of Study: The experiment was conducted in ESAK station (Boulifa, kef, North West Tunisia) during 2016/2017 cultivation year. Methodology: Mineral elements uptake, total phenolic content (TPC) and total flavonoid content (TFC) of barley were studied as affected by conventional tillage (CT) and no tillage (NT) for tillering and grain filling stages. Results: The results showed that tillage practices (T) had no significant effect on mineral uptake, total phenolic content and total flavonoids content under rainfed conditions. The stage (S) had showed significant effects on P, Ca and Na amounts for both tillage practices when it had no effect on K amount. The interaction T x S had no significant effect on mineral elements concentrations and TFC. However, this interaction had affected TPC significantly. Phosphorous (P) showed high significant positive correlations with Ca and Na. In addition, P presented high significant negative correlations with TPC and TFC. For partial correlation based on Tillage practices, similar correlations values were noted. Considering the partial correlation based on plant stages, no significant correlations had been noted. Conclusion: This work enlarges our knowledge on barley mineral elements uptake, TPC and TFC as influenced by tillage practices aiding decision makers in increasing no tillage adoption in Tunisia under rainfed conditions.

Growth, mineral uptake, chlorophyll content, biochemical constituents and non-enzymatic antioxidant compounds of white pepper (Piper nigrum L.) grown under saline conditions

Salinity stress is the main abiotic constraints limiting crop yield worldwide. We investigated the effect of salt stress on growth, dry weight partitioning, chlorophyll content, mineral uptake, biochemical constituents and non-enzymatic antioxidant compounds of white pepper (Piper nigrum L.). White pepper seeds were planted in polythene bags previously filled with sand and supplied with a nutrient solution in a greenhouse during six weeks as a completely randomized design. Plants were subjected to four different concentrations of NaCl (0, 50, 100 and 200 mM). Supplies of intake doses of NaCl in the culture medium significantly decreased the dry biomass, stem height, leaf area and chlorophyll contents respectively from 100 mM NaCl. Mineral elements (K, Ca and Mg) significantly (P < 0.001) decreased in plant organs. The different biochemical constituents (proline, total soluble carbohydrates, soluble proteins and total free amino acids), total phenolic and flavonoids contents significantly (P < 0.001) increased from 50 mM NaCl. The accumulation of biochemical constituents in the leaves increased the osmotic potential of white pepper and could be considered as biochemical indicators of early selection and osmotic adjustment ability for salt tolerant plants. The planting of white pepper in salt affected soils could be encouraged for better development.

Effect of fungal endophytes on plant growth and nutrient uptake in Trifolium subterraneum and Poa pratensis as affected by plant host specificity

The introduction of well-adapted species, such as Trifolium subterraneum (subclover) and Poa pratensis (Kentucky bluegrass), might enhance the forage yield and quality of dehesa pastures for feeding livestock. However, the climatic hardness and poor soils in these agrosystems may limit plant establishment and development. Since fungal endophytes have been found to alleviate the environmental stresses of their host, the aim of this study was to assess the effect of five isolates on forage yield, nutritive value, and plant mineral uptake after their inoculation in the two abovementioned plant species. Two experiments were established (under greenhouse and field conditions) using plants inoculated with two isolates in 2012/2013 (Epicoccum nigrum, Sporormiella intermedia) and three isolates in 2013/2014 (Mucor hiemalis, Fusarium equiseti, Byssochlamys spectabilis). Fusarium equiseti (E346) increased the herbage yield of T. subterraneum under greenhouse conditions, and B. spectabilis improved the forage quality of T. subterraneum by reducing fiber content and of P. pratensis by increasing crude protein. S. intermedia increased the mineral uptake of Ca, Cu, Mn, Pb, Tl, and Zn in subclover, and M. hiemalis increased the uptake of K and Sr in Kentucky bluegrass. These results evidence the potential of the studied fungal endophytes to enhance herbage yield and nutritional value of forage, although further studies should include all of the target forage species as certain host specificity in the effect was observed.

Halotolerant Microbial Consortia for Sustainable Mitigation of Salinity Stress, Growth Promotion, and Mineral Uptake in Tomato Plants and Soil Nutrient Enrichment

Salinity significantly impacts the growth, development, and reproductive biology of various crops such as vegetables. The cultivable area is reduced due to the accumulation of salts and chemicals currently in use and is not amenable to a large extent to avoid such abiotic stress factors. The addition of microbes enriches the soil without any adverse effects. The effects of microbial consortia comprising Bacillus sp., Delftia sp., Enterobacter sp., Achromobacter sp., was evaluated on the growth and mineral uptake in tomatoes (Solanum Lycopersicum L.) under salt stress and normal soil conditions. Salinity treatments comprising Ec 0, 2, 5, and 8 dS/m were established by mixing soil with seawater until the desired Ec was achieved. The seedlings were transplanted in the pots of the respective pH and were inoculated with microbial consortia. After sufficient growth, these seedlings were transplanted in soil seedling trays. The measurement of soil minerals such as Na, K, Ca, Mg, Cu, Mn, and pH and the Ec were evaluated and compared with the control 0 days, 15 days, and 35 days after inoculation. The results were found to be non-significant for the soil parameters. In the uninoculated seedlings’ (control) seedling trays, salt treatment significantly affected leaf, shoot, root dry weight, shoot height, number of secondary roots, chlorophyll, and mineral contents. While bacterized seedlings sown under saline soil significantly increased leaf (105.17%), shoot (105.62%), root (109.06%) dry weight, leaf number (75.68%), shoot length (92.95%), root length (146.14%), secondary roots (91.23%), and chlorophyll content (−61.49%) as compared to the control (without consortia). The Na and K intake were higher even in the presence of the microbes, but the beneficial effect of the microbe helps plants sustain in the saline environment. The inoculation of microbial consortia produced more secondary roots, which accumulate more minerals and transport substances to the different parts of the plant; thus, it produced higher biomass and growth. Results of the present study revealed that the treatment with microbial consortia could alleviate the deleterious effects of salinity stress and improve the growth of tomato plants under salinity stress. Microbial consortia appear to be the best alternative and cost-effective and sustainable approach for managing soil salinity and improving plant growth under salt stress conditions.

Effect of Fungal Endophytes on Plant Growth and Nutrient Uptake in Trifolium Subterraneum and Poa Pratensis as Affected by Plant Host Specificity

The introduction of well-adapted species, such as Trifolium subterraneum and Poa pratensis, might enhance the forage yield and quality of dehesas pastures for feeding livestock. However, the climatic hardness and poor soils in these agrosystems may limit plant establishment and development. Since fungal endophytes have been found to alleviate the environmental stresses of their host, the aim of this study was to assess the effect of five isolates on forage yield, nutritive value and plant mineral uptake after their inoculation in the two above-mentioned plant species. Two experiments were established (under greenhouse and field conditions) using plants inoculated with two isolates in 2012/2013 (Epicoccum nigrum, Sporormiella intermedia) and three isolates in 2013/2014 (Mucor hiemalis, Fusarium equiseti, Byssochlamys spectabilis). Thus, F. equiseti (E346) increased the herbage yield of T. subterraneum under greenhouse conditions, B. spectabilis was found to improve the forage quality of T. subterraneum by reducing fibre content and of P. pratensis by increasing crude protein. Also, S. intermedia increased the mineral uptake of Ca, Cu, Mn, Pb, Tl and Zn in subclover and M. hiemalis, the uptake of K and Sr in Kentucky bluegrass. These results evidenced the potential of the studied fungal endophytes to enhance herbage yield and the forage nutritional value, although further studies should include all of the intended forage species as certain host specificity in the effect was observed.

Effect of Fungal Endophytes on Plant Growth and Nutrient Uptake in Trifolium Subterraneum and Poa Pratensis as Affected by Plant Host Specificity

The introduction of well-adapted species, such as Trifolium subterraneum and Poa pratensis, might enhance the forage yield and quality of dehesas pastures for feeding livestock. However, the climatic hardness and poor soils in these agrosystems may limit plant establishment and development. Since fungal endophytes have been found to alleviate the environmental stresses of their host, the aim of this study was to assess the effect of five isolates on forage yield, nutritive value and plant mineral uptake after their inoculation in the two above-mentioned plant species. Two experiments were established (under greenhouse and field conditions) using plants inoculated with two isolates in 2012/2013 (Epicoccum nigrum, Sporormiella intermedia) and three isolates in 2013/2014 (Mucor hiemalis, Fusarium equiseti, Byssochlamys spectabilis). Thus, F. equiseti (E346) increased the herbage yield of T. subterraneum under greenhouse conditions, B. spectabilis was found to improve the forage quality of T. subterraneum by reducing fibre content and of P. pratensis by increasing crude protein. Also, S. intermedia increased the mineral uptake of Ca, Cu, Mn, Pb, Tl and Zn in subclover and M. hiemalis, the uptake of K and Sr in Kentucky bluegrass. These results evidenced the potential of the studied fungal endophytes to enhance herbage yield and the forage nutritional value, although further studies should include all of the intended forage species as certain host specificity in the effect was observed.

Exogenous application of melatonin alleviates salt stress-induced decline in growth and photosynthesis in Glycine max (L.) seedlings by improving mineral uptake, antioxidant and glyoxalase system

Soybean plants grown under NaCl were foliar sprayed twice with melatonin (MLT). Results revealed that salt stress reduced growth, biomass accumulation, photosynthesis, mineral uptake, the content of δ-aminolevulinic acid, chlorophylls, carotenoids and PSII efficiency. However, MLT application enhanced pigment synthesis and PSII activity. MLT up-regulated the antioxidant system and glyoxalase function resulting in reduced accumulation of reactive oxygen species (ROS). Reduced ROS in MLT-treated plants protected membrane functioning by reducing lipid peroxidation, electrolyte leakage and lipoxygenase activity. Nevertheless, MLT application reduced methylglyoxal accumulation while increased the content of reduced glutathione and ascorbic acid. It could be concluded that exogenous MLT mitigated the salt stress damage in soybean plants by improving photosynthesis, antioxidant systems, controlling ion homeostasis and minimising excessive ROS accumulation.