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 b...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<sup>+</sup> and Cl<sup>-</sup>) 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<sup>+</sup>, Na<sup>+</sup>) 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<sup>+ </sup>(Leaves: 7.5 mg⋅g<sup>-1</sup>;Roots: 4.4 mg⋅g<sup>-1</sup> of dry matter), P (Leaves: 15.15 mg⋅g-1</sup> of dry matter) and proline (975 nmoles⋅g-1</sup> of fresh matter) were also recorded by this pair, with the lowest Na<sup>+</sup> contents (Leaves: 1.93 mg⋅g-1</sup>;Roots: 0.96 mg⋅g-1</sup> 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<sup>+</sup> (Leaves: 6.1 mg⋅g-1</sup>;Roots: 3.09 mg⋅g-1 </sup>of dry matter), P (Leaves: 12.49 mg⋅g-1</sup> of dry matter) and proline (942 nmoles⋅g-1</sup> of fresh matter) the most important and those in Na<sup>+</sup> the lowest (Leaves: 2.03 mg⋅g-1</sup>;Roots: 1.53 mg⋅g-1</sup> 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.展开更多
<p align="justify"> <span style="font-family:Verdana;">Soil salinization is one of the major causes of land degradation. In Senegal, this phenomenon continues to grow, making soils unsu...<p align="justify"> <span style="font-family:Verdana;">Soil salinization is one of the major causes of land degradation. In Senegal, this phenomenon continues to grow, making soils unsuitable for agriculture. To rehabilitate salty lands, one of the recommended strategies is the use of salt-tolerant plants. Among them, plants of </span><i><i><span style="font-family:Verdana;">Casuarinaceae</span></i></i><span style="font-family:Verdana;"> family form a relationship with symbiotic microorganisms such as arbuscular mycorrhizal fungi and nitrogen fixing bacteria. It has been shown that symbiotic microorganisms play an important role in the establishment of tolerant plants in saline conditions (Djighaly </span><i><i><span style="font-family:Verdana;">et al</span></i></i><span style="font-family:Verdana;">., 2018). They improve plant performance and reduce transplant shock under salt stress conditions (Diagne </span><i><i><span style="font-family:Verdana;">et al</span></i></i><span style="font-family:Verdana;">., 2014). These microorganisms can be used as biofertilizers. However, inocula containing symbiotic microorganisms are either too expensive or unavailable in many developing countries. The aim of this study is to test alternatively affordable and low-tech solutions to promote symbiotic interactions such as Casuarina crushed nodule, Casuarina rhizosphere soil and Casuarina leaves compost that may contain symbiotic microorganisms and also nutrients such as N and phosphorus. Two species of Casuarina (</span><i><i><span style="font-family:Verdana;">Casuarina equisetifolia</span></i></i><span style="font-family:Verdana;"> L. and </span><i><i><span style="font-family:Verdana;">Casuarina obesa</span></i></i><span style="font-family:Verdana;"> Miq.) were grown in the greenhouse on sterile soil to which an amendment was added (Casuarina crushed nodules, Casuarina Rhizospheric soil or Casuarina leaves compost). Plants were subjected to saline stress. After four months of cultivation, they were harvested and morphological and physiological parameters were determined. Results showed that inoculation with Casuarina crushed nodules, Casuarina rhizospheric soil and Casuarina leaves compost improved growth, total dry biomass, total chlorophyll and proline contents of </span><i><i><span style="font-family:Verdana;">C. equisetifolia</span></i></i><span style="font-family:Verdana;"> and </span><i><i><span style="font-family:Verdana;">C. obesa</span></i></i><span style="font-family:Verdana;"> plants in salt stress condition. These positive effects were more important in </span><i><i><span style="font-family:Verdana;">C. obesa</span></i></i><span style="font-family:Verdana;"> plants amended with Casuarina leaves compost. This study shows that Casuarina leaves compost can play an important role in the rehabilitation of saline soils by improving Casuarina trees performance in saline conditions.</span> </p>展开更多
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 establi...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<sup>−1</sup> of fresh material), followed by those of the Xewel variety inoculated with R. fasciculatus (580.36, 763.65, and 1112.11 nmoles•g<sup>−1</sup> 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.展开更多
文摘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<sup>+</sup> and Cl<sup>-</sup>) 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<sup>+</sup>, Na<sup>+</sup>) 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<sup>+ </sup>(Leaves: 7.5 mg⋅g<sup>-1</sup>;Roots: 4.4 mg⋅g<sup>-1</sup> of dry matter), P (Leaves: 15.15 mg⋅g-1</sup> of dry matter) and proline (975 nmoles⋅g-1</sup> of fresh matter) were also recorded by this pair, with the lowest Na<sup>+</sup> contents (Leaves: 1.93 mg⋅g-1</sup>;Roots: 0.96 mg⋅g-1</sup> 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<sup>+</sup> (Leaves: 6.1 mg⋅g-1</sup>;Roots: 3.09 mg⋅g-1 </sup>of dry matter), P (Leaves: 12.49 mg⋅g-1</sup> of dry matter) and proline (942 nmoles⋅g-1</sup> of fresh matter) the most important and those in Na<sup>+</sup> the lowest (Leaves: 2.03 mg⋅g-1</sup>;Roots: 1.53 mg⋅g-1</sup> 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.
文摘<p align="justify"> <span style="font-family:Verdana;">Soil salinization is one of the major causes of land degradation. In Senegal, this phenomenon continues to grow, making soils unsuitable for agriculture. To rehabilitate salty lands, one of the recommended strategies is the use of salt-tolerant plants. Among them, plants of </span><i><i><span style="font-family:Verdana;">Casuarinaceae</span></i></i><span style="font-family:Verdana;"> family form a relationship with symbiotic microorganisms such as arbuscular mycorrhizal fungi and nitrogen fixing bacteria. It has been shown that symbiotic microorganisms play an important role in the establishment of tolerant plants in saline conditions (Djighaly </span><i><i><span style="font-family:Verdana;">et al</span></i></i><span style="font-family:Verdana;">., 2018). They improve plant performance and reduce transplant shock under salt stress conditions (Diagne </span><i><i><span style="font-family:Verdana;">et al</span></i></i><span style="font-family:Verdana;">., 2014). These microorganisms can be used as biofertilizers. However, inocula containing symbiotic microorganisms are either too expensive or unavailable in many developing countries. The aim of this study is to test alternatively affordable and low-tech solutions to promote symbiotic interactions such as Casuarina crushed nodule, Casuarina rhizosphere soil and Casuarina leaves compost that may contain symbiotic microorganisms and also nutrients such as N and phosphorus. Two species of Casuarina (</span><i><i><span style="font-family:Verdana;">Casuarina equisetifolia</span></i></i><span style="font-family:Verdana;"> L. and </span><i><i><span style="font-family:Verdana;">Casuarina obesa</span></i></i><span style="font-family:Verdana;"> Miq.) were grown in the greenhouse on sterile soil to which an amendment was added (Casuarina crushed nodules, Casuarina Rhizospheric soil or Casuarina leaves compost). Plants were subjected to saline stress. After four months of cultivation, they were harvested and morphological and physiological parameters were determined. Results showed that inoculation with Casuarina crushed nodules, Casuarina rhizospheric soil and Casuarina leaves compost improved growth, total dry biomass, total chlorophyll and proline contents of </span><i><i><span style="font-family:Verdana;">C. equisetifolia</span></i></i><span style="font-family:Verdana;"> and </span><i><i><span style="font-family:Verdana;">C. obesa</span></i></i><span style="font-family:Verdana;"> plants in salt stress condition. These positive effects were more important in </span><i><i><span style="font-family:Verdana;">C. obesa</span></i></i><span style="font-family:Verdana;"> plants amended with Casuarina leaves compost. This study shows that Casuarina leaves compost can play an important role in the rehabilitation of saline soils by improving Casuarina trees performance in saline conditions.</span> </p>
文摘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<sup>−1</sup> of fresh material), followed by those of the Xewel variety inoculated with R. fasciculatus (580.36, 763.65, and 1112.11 nmoles•g<sup>−1</sup> 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.
