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Influence of Rhizophagus irregularis inoculation on salt tolerance in Cucurbita maxima Duch.

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Okon O. G. , Okon I. E.

World News of Natural Sciences

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2018

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tom 19

EN

The influence of mycorrhizal fungi (Rhizophagus irregularis) on salt tolerance of Cucurbita maxima grown in saline soil was investigated in a pot experiment. The experiment was laid out in a completely randomized design, with treatments replicated thrice. Accordingly, soil salinity significantly (p=0.05) reduced total photosynthetic pigments from 58.06 to 38.06 mg/kg. Mineral contents, biomass yield, AMF colonization were also significantly (p=0.05) reduced. In contrast, mycorrhizal dependency was significantly (p=0.05) increased in saline soil plants (from 26.91% to 66.45%). Furthermore, inoculation with R. irregularis significantly (p=0.05) increased total photosynthetic pigments from 58.06 to 62.06 mg/kg; N from 4.88 to 5.47%; P 860.40 to 896.22 mg/kg; K 4430.00 to 4630.00 mg/kg; Mg 558.99 to 592.10 mg/kg and Ca 2810.00 to 3151.00 mg/kg; biomass yield; leaf dry weight from 0.06 to 0.14g; vine dry weight 3.68 to 5.09g; roots dry weight 0.32 to 0.74 and total dry weight 4.06 to 5.97g, R. irregularis colonization (from 33.77 to 58.44%) and mycorrhizal dependency in C. maxima was evident in both saline and non-saline soil treatments. The results of this work shows that R. irregularis can enhance the ability of C. maxima to resist salt stress - possibly through some morphological/ physiological changes, as well as improved vigour, probably via the extensive network of the mycorrhizal roots. This last is considered to be one of several mechanisms that magnify the salt tolerance of host plants through increased nutrient acquisition (N, P, K, Mg and Ca) and water uptake. Inoculation with appropriate AMF can, therefore, be used to increase the productivity of C. maxima in saline soils.

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Effect of salinity stress on mycorrhizal association and growth response of Telfairia occidentalis Hook F. infected by Glomus geosporum

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Okon O. G. , Esenowo G. J.

World News of Natural Sciences

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2018

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tom 19

EN

The effect of arbuscular mycorrhizal fungi (Glomus geosporum) inoculation on Telfairia occidentalis grown in saline soil was investigated in a pot experiment. The experiment was laid out in a completely randomized design, with treatments replicated thrice. Standard recommended methods were used to determine photosynthetic pigments, minerals contents, biomass yield, AMF colonization and dependency. Our results show that saline soil treatment significantly (p=0.05) reduced total photosynthetic pigments contents - from 39.73 to 21.30 mg/kg, percentage AMF root colonization - from 53.97 to 22.41%, mineral contents; N - from 5.84 to 3.13%; P - 424.11 to 212.31 mg/kg; K - 3215.00 to 1220.00 mg/kg; Mg - 326.00 to 107.04 mg/kg; and Ca - 1640.00 to 813.00 mg/kg. Biomass yield of T. occidentalis was also significantly (p=0.05) reduced. In contrast, mycorrhizal dependency was significantly (p=0.05) increased in saline soil plants - from 15.13% to 100.00%. Herein, inoculation with G. geosporum significantly (p=0.05) increased total photosynthetic pigments - from 39.73 to 45.53 mg/kg; N - from 5.84 to 6.07%; P - 424.11 to 463.00 mg/kg; K - 3215.00 to 3470.12 mg/kg; Mg - 326.00 to 345.00 mg/kg and Ca -1640 to 1658.12 mg/kg; leaf dry weight - from 0.13 to 0.17g; vine dry weight - 5.21 to 5.81g; roots dry weight - 0.57 to 1.03 and total dry weight - 5.91 to 7.01g. Biomass yield was also significantly increased. R. irregularis colonization (from 22.41 to 53.97%) and mycorrhizal dependency in C. maxima was evident in both saline and non-saline soil treatments. The results of this work have shown that G. geosporum can enhance the ability of T. occidentalis to resist salt stress (possibly through several morphological/physiological changes and through improved vigour) via the extensive network of the mycorrhizal roots (which increases nutrient and water uptake). Inoculation with appropriate AMF can, therefore, be used to increase the productivity of T. occidentalis in saline soils.

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Enhancement of salt tolerance via glomus geosporum inoculation in Telfairia occidentalis Hook. F. seedlings

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Okon O. G. , Eneh G. D. O. , Uboh G. D. , Uyon P. P.

International Letters of Natural Sciences

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2019

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tom 76

EN

The leafy vegetable Telfairia occidentalis is a tropical vine grown in West Africa; it is indigenous to Southern Nigeria and is usually subjected to extreme salt stress in Southern Nigeria as well as in the world that results in significant loss of T. occidentalis production. Therefore, the present investigation was aimed at evaluating the response of T. occidentalis seedlings inoculated with arbuscular mycorrhizal fungi (Glomus geosporum) in saline soil and further to determine the threshold of T. occidentalis salinity tolerance in association with G. geosporum. The total photosynthetic pigments contents in saline soil treatment were significantly (p=0.05) reduced as well as percentage arbuscular mycorrhizal fungi colonization (53.97 to 22.41%). Mycorrhizal dependency was significantly (p=0.05) higher in saline soil treatments compared to control (100.00% to 15.13%). Mineral analysis of T. occidentalis leaves revealed increased uptake and accumulation of Na⁺ (500.00 mg/kg in control to 2920.13 mg/kg in saline soil treatment). Saline soil treatments significantly (p=0.05) reduced the K, Mg, N, P and Ca. AM Fungi significantly (p=0.05) increased the photosynthetic pigments and minerals both in saline and non-saline soil treatments. Using different mechanisms T. occidentalis by association with G. geosporum showed better salt tolerance thank the uninoculated plants. G. geosporum was able to impose some physiological and root morphological changes such as an extensive network of the mycorrhizal-plant roots to improve water and mineral nutrient uptake. Physiologically G. geosporum inoculation enriched T. occidentalis vigour, attuned the rate of K⁺/Na⁺ which restored nutrient and water balance in the plant and directly resulting in the enhancement of salt tolerance in T. occidentalis seedlings, thus improving growth and yield.

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Phytochemicals, nutraceuticals and antinutritional factors assessment of young leaves of Colocasia esculenta (L) Schott

70%

Eneh G. D. O. , Okon O. G. , Imabong F. E. , Mfoniso E. J. , Olajumoke I. O.

World News of Natural Sciences

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2018

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tom 20

EN

Phytochemicals, proximate, minerals and anti-nutrient compositions of young cocoyam (Colocasia esculenta) leaves were determined using standard methods. Qualitative and quantitative analyses for phytochemicals confirmed the presence of bioactive constituents such as alkaloids, flavonoids and saponins in appreciable amounts, while terpenes, cardiac glycocides and tannins were only present in trace concentrations. Mineral analysis revealed that K recorded the highest content - with 214.00 ± 2.11 mg/100g, followed by Ca - 157.10 ± 1.47 mg/100g, Mg - 63.00 ± 0.58 mg/100g, P - 32.00 ± 0.61 mg/100g, while Fe had the lowest value - 0.10 ± 0.14 mg/100g. Proximate composition analysis of C. esculenta leaves indicated that CHO, protein and crude fibre were present in high quantities (35.22, 17.10 and 16.41 % respectively), while fat was at the lowest content (8.82%). Antinutritional factor analysis of young leaves of C. esculenta indicated that phytates was present in huge quantity - 11.03 ± 0.12mg/g, followed by oxalates - 7.62 ± 0.14 mg/g, while tannins recorded the lowest anti-nutritional contents - 0.12 ± 0.06 mg/g. This study has also revealed that the young leaves of C. esculenta contain appreciable levels of bioactive components (phytochemicals such as as alkaloids, flavonoids and saponins; minerals K, Ca, Mg, P and Fe) and appreciable amounts of CHO, protein and crude fibre. The results of anti-nutrients analysis showed high contents of phytate and oxalate. The last is probably responsible for the itching effect and also interferes with the utilization of essential nutrients. Thus, young leaves of C. esculenta provide appreciable quantities of nutrients and thus can rival other conventional vegetables normally consumed in Nigeria.