<i>In Vitro</i>Germination and Early Vegetative Growth of Five Tomato (<i>Solanum lycopersicum</i>L.) Varieties under Salt Stress Conditions

In Senegal, tomato (Solanum lycopersicum L.) cultivation is affected by salinity in many agro-ecological zones. The selection of salt tolerant varieties would be an alternative solution to enhance the production. Thus, germination and growth are studied under axenic conditions for five varieties of tomato subjected to increasing concentrations of NaCl [0, 35, 70 and 105 mM], and supplemented in an MS/2 medium for 30 days. The results reveal that salt negatively affects the evaluated parameters. The Rodeo and Lady Nema varieties have the lowest final germination rates (50%) unlike the Mongal variety (55%). These last two varieties have a decrease of 71.78% and 81.28% in the height of the stem, respectively, in the presence of NaCl at [105 mM] while that of the Rodeo variety is 70%. The Xewel variety has the greatest average number of leaves in the presence of [NaCl 35 mM] (4.95 leaves) and [NaCl 70 mM] (4.77 leaves). The Lady Nema variety records the longest taproot length (2.99 cm) unlike the Rodeo variety (2.25 cm) at [NaCl 105 mM]. The Ganila variety reveals the highest number of secondary roots at the concentrations of [0, 35 and 105 mM] of NaCl with, respectively, 44.12, 29.25, and 4.25 roots. The Lady Nema variety records the highest fresh weight of aerial (0.055 g) and root parts (0.014 g) and the lowest root dry weights (0.0023 g). These results allow to conclude that the Lady Nema and Mongal varieties seem more tolerant, Ganila and Xewel are moderately tolerant and Rodeo is more sensitive to the presence of salt.

<i>In Vitro</i>Germination and Early Vegetative Growth of Five Tomato (<i>Solanum lycopersicum</i>L.) Varieties under Water Stress Conditions

Water is the main limiting factor in the cultivation of tomato (Solanum lycopersicum L.) in Senegal. Thus, the selection of varieties tolerant to water stress would be an alternative solution for their production. In vitro germination, growth, total chlorophyll and proline levels were studied in five varieties of tomato subjected to increasing osmotic pressures (0, 5, 10 and 15 kPa) thanks to the PEG-8000 incorporated in an MS/2 medium for 30 days. A strong sensitivity to water stress for in vitro seed germination in the Rodeo variety (41%) is recorded at 5 kPa and maintained at 15 kPa (20.83%) while it was only noticed at 15 kPa in the other tomato varieties. The Xewel and Lady Nema varieties obtained the smallest reductions in the number of leaves of vitroplants, with 30.79% and 27.97% at 15 kPa, respectively, and the Rodeo variety recorded a reduction of 35.97%. From 5 kPa, the varieties record reductions in the number of secondary roots of more than 15%. The effect of osmotic pressures on decreasing the taproot height and length is not significant. The Xewel variety had the highest average fresh (0.483 g) and dry (0.082 g) weights of the aerial part at 15 kPa and the Rodeo variety had the lowest ones (0.308 g and 0.0501 g). The Lady Nema variety had the highest average fresh (0.171 g) and dry (0.039 g) root weights and the Rodeo variety had the lowest ones (0.086 and 0.020 g). The vitroplants of Rodeo variety recorded the highest decreases in total chlorophyll contents at all osmotic pressures and the lowest increase in proline content (53.37%) at 15 kPa. A contrario, the Xewel variety recorded the greatest increase in proline content (116.26%). Ultimately, the vitroplants of Lady Nema and Xewel varieties were more tolerant to water stress, the Ganila and Mongal varieties were moderately tolerant and the Rodeo variety was the most sensitive.

Response to Inoculation with Arbuscular Mycorrhizal Fungi of Two Tomato (Solanum lycopersicum L.) Varieties Subjected to Salt Stress under Semi-Controlled Conditions

Salinity is a major problem that seriously impacts agricultural production, particularly that of tomato (Solanum lycopersicum L.). However, the plant has the ability to associate with Arbuscular Mycorrhizal Fungi to better tolerate salt stress. Thus, thanks to the extension of the AMF hyphae, the hydromineral nutrition and the tolerance to excess toxic ions (Na+ and Cl-) of the plant are optimized. In this context, the contribution of AMF to the salt stress tolerance of two tomato varieties under semi-controlled conditions was studied. To do this, the frequency and intensity of mycorrhization, the relative mycorrhizal dependency, the survival rates, the aerial and root dry weights, the mineral (P, K+, Na+) and proline contents of the plants subjected to four levels of salinity [0, 70, 140 and 210 mM of NaCl] were evaluated. All the parameters assessed appeared to be dependent on the variety, the fungal strain and the NaCl concentration. With the Lady Nema variety, inoculation with the Claroideoglomus etunicatum strain at [NaCl 140 mM] resulted in the highest frequencies (54%), intensities (40.47%), and relative mycorrhizal dependencies (19.65%). This same symbiotic couple recorded high survival rates (55%) and aerial (2.03 g) and root (0.50 g) dry weights. Significant contents of K+ (Leaves: 7.5 mg⋅g-1;Roots: 4.4 mg⋅g-1 of dry matter), P (Leaves: 15.15 mg⋅g-1 of dry matter) and proline (975 nmoles⋅g-1 of fresh matter) were also recorded by this pair, with the lowest Na+ contents (Leaves: 1.93 mg⋅g-1;Roots: 0.96 mg⋅g-1 of dry matter). For the Mongal variety, at [NaCl 140 mM], the highest frequencies (50.36%), intensities (35.14%) and relative mycorrhizal dependencies (43.95%) were obtained thanks to inoculation with Rhizophagus fasciculatus. The highest survival rates (59%) and aerial (2.58 g) and root (0.79 g) dry weights were also obtained with this symbiotic couple. The contents of K+ (Leaves: 6.1 mg⋅g-1;Roots: 3.09 mg⋅g-1 of dry matter), P (Leaves: 12.49 mg⋅g-1 of dry matter) and proline (942 nmoles⋅g-1 of fresh matter) the most important and those in Na+ the lowest (Leaves: 2.03 mg⋅g-1;Roots: 1.53 mg⋅g-1 of dry matter) were also recorded for this same pair. Thus, the best fungal partner for the Lady Nema variety is C. etunicatum, followed by F. mosseae and R. fasciculatus, while for the Mongal variety it is R. fasciculatus, followed by C. etunicatum and F. mosseae.

RETRACTED:Effect of Long-Term Inorganic Fertilization on Diversity and Abundance of Bacterial and Archaeal Communities at Tillage in Irrigated Rice Field

Short Retraction Notice The paper does not meet the standards of "Advances in Bioscience and Biotechnology". This article has been retracted to straighten the academic record. In making this decision the Editorial Board follows COPE's Retraction Guidelines. The aim is to promote the circulation of scientific research by offering an ideal research publication platform with due consideration of internationally accepted standards on publication ethics. The Editorial Board would like to extend its sincere apologies for any inconvenience this retraction may have caused. Editor guiding this retraction: Prof. Abass Alavi (EiC of ABB). Please see the article page for more details. The full retraction notice in PDF is preceding the original paper which is marked "RETRACTED".

Response to Inoculation with Arbuscular Mycorrhizal Fungi of Two Tomato (Solanum lycopersicum L.) Varieties Subjected to Water Stress under Semi-Controlled Conditions

In arid and semi-arid regions, the growth and development of cultivated plants, especially tomato (Solanum lycopersicum L.), are severely limited by water deficit. Thus, to cope with this constraint, the plant establishes symbiotic relationships with arbuscular mycorrhizal fungi (AMF) in the soil whose extension of the hyphae allows a better and deeper exploration;this notably improves the hydromineral nutrition of the plant. Therefore, the choice of fungal partner becomes crucial for the establishment of a crop in water-deficient soil. In this context, the contribution of AMF to the water stress tolerance of two varieties of tomato plants was assessed under semi-controlled conditions. Parameters, such as the mycorrhizal frequency, intensity of mycorrhization, relative mycorrhizal dependency, growth, and biochemical parameters (carbon, nitrogen, phosphorus, and proline contents) of plants subjected to three levels of water stress (T100, T70, and T30), were evaluated. The highest frequencies and intensities of mycorrhization and relative mycorrhizal dependencies were obtained with plants of the Xewel variety inoculated with Rhizophagus fasciculatus (F: 95.24%, 88.35%, and 13.64%;M: 40.52%, 37.52%, and 11.22%;D: 23.7%, 54.4%, and 78.82%) and in those of the Lady Nema variety inoculated with Claroideoglomus etunicatum (F: 95.12%, 87.01%, and 15.25%;M: 40.66%, 37.99%, and 11.42%;D: 19.27%, 57.01%, and 70.98%), respectively at water regimes of T100, T70 and T30. These same symbiotic couples recorded, at T30, the best survival rates (+ 40%) and the higher aerial (77% and 74%) and root dry weights (80% and 59%). Plants of the Xewel variety inoculated with R. fasciculatus recorded the highest contents of carbon (T70: 30.59% and T30: 21.55%) and phosphorus (T70: 0.18% and T30: 0.17%). Plants of the Lady Nema variety recorded the highest nitrogen contents with 3.51% and 3.20%, respectively at T70 and T30. Plants of the Lady Nema variety, inoculated with C. etunicatum, also recorded the highest proline contents (572.25, 739.44, and 1165 nmoles•g−1 of fresh material), followed by those of the Xewel variety inoculated with R. fasciculatus (580.36, 763.65, and 1112.11 nmoles•g−1 of fresh matter), respectively at T100, T70, and T30. For the Lady Nema variety, the best fungal partner is C. etunicatum, followed by R. fasciculatus and, finally, Funneliformis mosseae. However, for the plants of the Xewel variety, R. fasciculatus is the most efficient, followed by F. mosseae and C. etunicatum. This suggests that, in tomatoes, the efficiency of mycorrhizal symbiosis under water stress conditions is not only dependent on the host plant but on both associated symbiotic partners. Hence, it is a need for screening to identify the best symbiotic couples in a stressful environment.

Inoculation with arbuscular mycorrhizal fungi improves seedlings growth of two sahelian date palm cultivars (<i>Phoenix dactylifera</i>L., cv. Nakhla hamra and cv. Tijib) under salinity stresses

This study presents an analysis of the impact of mycorrhizal inoculation on growth under salt stress of date palms cultivars Nakhla hamra (NHH) and Tijib known in the Sahel for their earliness in flowering and fruiting. The seedlings were grown in a greenhouse on a sandy substrate watered to field capacity every two days and were subjected to increasing levels of NaCl (0, 1, 2, 4, 6, 8 and 16 g·L-1) and then inoculated with 5 strains of Glomus (G. aggregatum, G. intraradices, G. verriculosum, G. mosseae, G. fasciculatum). The experimental design was a randomized complete block with three factors (cultivars: Tijib and Nakhla Hamra x seven levels of NaCl concentrations x six levels of inoculum). The results showed that in the absence of NaCl, G. verriculosum significantly enhanced shoot growth: 33.5 cm against 30.3 cm in the control and roots growth: 81.5 cm against 78 cm in NHH, while in Tijib, the growth is stimulated by Glomus fasciculatum: 33.8 cm against 32.7 cm for stems and 90 cm against 86 cm for the roots of inoculated plants and controls. In contrast, in the presence of NaCl 8 g·L-1, NHH has a better growth in the presence of G. intraradices: 37.3 cm against 30.6 cm for stems and 77 cm against 73 for roots, while Tijib grows better in the presence of G. fasciculatum with respectively 31.9 cm against 31.7 cm and 51.27 cm against 51.6 cm for stems and roots of inoculated plants and controls. Biochemical analysis revealed that changes in levels of proline depend on the cultivar, the mycorrhizal strain used and concentrations of NaCl applied. These results open the prospect of using mycorrhizal fungi to improve the productivity of palm trees in the Sahel.

Effect of Arbuscular Mycorrhizal Fungal Inoculation on Sorghum bicolor Growth at Different Phosphate Levels: A Greenhouse Study

In sub-Saharan Africa, Sorghum (Sorghum bicolor) is an important cereal for both human being and animals. Unfortunately, its production is confronted to soils with deficiency of phosphorus. Traditional use of mineral phosphate on this culture fertilization is expensive and may cause contamination. It is thus necessary to seek more efficient and economic reasonable techniques to improve sorghum growth. Arbuscular mycorrhizal fungi (AMF) constitute a reference for phosphorus improvement and plant nutrition. This study aimed to investigate the effects of AMF strains (Rhizophagus irregulare, Glomus aggregatum, G. mosseae) on growth of sorghum cultivated in greenhouse on Sangalkam soil (Senegal) sterilized with or without Tilemsi natural phosphate (PNT). The phosphorus can represent until 0.2% of the dry weight of the plant. Two fertilizers were used separately and together to doses of 20 g by strain, 100 mg and 200 mg of PNT. The experiment lasted for 120 d. Results showed that mycorrhizal colonization intensity varied between 40% and 80% for all treatments. AMF inoculation increased sorghum plant height and biomass, regardless of PNT amendment. The inoculation permits to bring strain of AMF that intervene efficiently in the transportation and the availability of phosphorus for the plant.