The Protective Role of 28-Homobrassinolide and Glomus versiforme in Cucumber to Withstand Saline Stress

The strategic role of phytohormones and arbuscular mycorrhizal fungi (AMF) to overcome various stress conditions is gaining popularity in sustainable agricultural practices. This current study aims to investigate and identify the protective roles of 28-homobrassinolide (HBL) and Glomus versiforme on two cucumber cultivars (salt sensitive Jinyou 1# and tolerant Chanchun mici (CCMC)) grown under saline conditions (100 mM NaCl). HBL and AMF were applied as individual and combined treatments on two cucumber cultivars and their effects were observed on the morphological growth and physiology under control and saline conditions. Findings revealed that the treated plants showed better performance under saline conditions through improved photosynthesis, leaf relative water content, and decreased electrolyte leakage in tolerant cultivar (CCMC) and to a lesser extent in sensitive (Jinyou 1#) cultivar. Comparable differences were noticed in the antioxidant enzymes activity such as superoxide dismutase, catalase, and peroxidase after every 10 days in both cultivars. Treating the plants with HBL and AMF also improved the mineral uptake regulation and lowered sodium concentration in roots compared to that in the non-treated plants. Current findings suggest that the protective role of HBL and AMF involves the regulation of antioxidants and lowers the risk of ion toxicity in the cucumber and hence enhance tolerance to salinity. These results are promising, but further studies are needed to verify the crop tolerance to stress and help in sustainable agricultural production, particularly vegetables that are prone to salinity.

Effect of N fertilizer on formation of Vam Fungi, growth and mineral concentration of Onion

The effects on N fertilization on growth and root colonization of preinoculated onion (Allium cepa) were studied. Onion transplants, inoculated with either Glomus intraradices, Glomus versiforme or nothing at sowing, were grown under three levels of N in soils which had either been irradiated, Irradiated and amended with non-mycorrhizal microflora, or not irradiated. Interactions between inoculation and soil treatment had a significant effect on dry biomass and final bulb diameter. Control plants cultivated in non-irradiated natural soil grew normally because of the presence of indigenous arbuscular mycorrhizae, but control plants in irradiated soils were stunted. There was no such difference among inoculated plants. In non-irradiated natural soil, bulbs of onions inoculated with G. intraradices or G. versiforme were significantly firmer than bulb of control plants. Bulb firmness decreased as N fertilization level increased. In non-irradiated natural soil, tissue P concentration of onion plants preinoculated with either fungus was significantly higher than that of control plants. In all soil types,- N, P, and Zn concentrations were higher in onion plants colonized by G. versiforme than in those colonized by G. intraradices. The opposite was true of Mn tissue concentration

MYCORRHIZAL GROWTH RESPONSE AND GLOMALIN PRODUCTION EFFECTED BY ARBUSCULAR MYCORRHIZAL FUNGI (AMF) AND NITROGEN OF ORGANIC MATERIALS ON CORN

Symbiotic relationships between arbuscular mycorrhizal fungi (AMF) and plants can increase the capacity of plants to absorb nutrients and water from the soil by exploring micropores not accessible to plant roots. The arbuscular mycorrhizal symbiosis between plants and soil fungi improves phosphorus and nitrogen acquisition under limiting conditions. Recent discoveries indicate that AMF hyphae containing glomalin as glycoproteins and function unitinge the soil particles to form stable soil aggregates. Glomalin acts as an adhesive (glue) produced by AMF symbiosis with the host plant. The AMF is capable of taking nitrogen and other nutrients from a source of organic materials to produce glomalin which is transferred to the host plant. The study was conducted using nitrogen from forage materials of Tithonia (Tithonia difersifolia) which the AMF needs to produce glomalin. This study assess the need for organic N by AMF to the mycorrhizal growth effect and its effects on glomalin. The study use sterile medium sand and zeolite mixture (w/w 1:1) in pot culture experiments with the corn as the host. For treatments using N derived from Tithonia are five doses, namely 0, 10, 20, 30, and 40 mg of N Tithonia each pot. At the time of planting, the corn roots inoculated with AMF spores of the two species, namely Glomus luteum and Glomus versiforme. We show that a positive mycorrhizal growth response (MGR) was observed only in the dose of range 20 to 30 mg N. This response did not appear to be affected by high nitrogen supply. Our results also show that in Glomus luteum at the dose of 20 mg N produce glomalin highest, namely 2.60 mg.g-1 in the planting medium. Glomus versiforme has produced glomalin is 2.38 mg.g-1 at the dose of 30 mg N. The AMF species did not significantly affect the results of glomalin, while the use of N from forage materials of Tithonia significantly influenced the production of glomalin.

Potential Selection of Arbuscular Mycorrhizal Fungi (AMF) Indigenous Ultisols through the Production of Glomalin

The arbuscular mycorrhizal fungi ( AMF ) with plants able to increase the capacity of plants to absorb nutrients and water from the soil. Recently, research was indicated that AMF hyphae containing glomalin as a glycoprotein that serves to unify the dispersed soil particles. The content of glomalin in soil is positively correlated with soil aggregate stability. The research potential of AMF species indigenous of Ultisol Darmasraya District of West Sumatra and glomalin production in experimental pots of sterile sand medium has been carried out. The purpose of this study was to determine the diversity of AMF species on Ultisol and to seeking indigenous AMF isolates that had the best glomalin production capability. AMF spores were isolated and identified from the rhizosphere soil of corn in Ultisol. AMF species that had been identified experimentally were tested in culture medium pot of sand and zeolite (w / w 1:1) using corn crops. The results found nine of the AMF species indigenous of Ultisol Darmasraya, namely Acaulospora scrobiculata, Glomus etunicatum, Glomus luteum, Glomus mosseae, Glomus verruculosum, Glomus versiforme, Scutellospora gregaria, Scutellospora heterogama and Gigaspora sp. AMF species that showed better colonization ability in corn was G. luteum, G. verruculosum and G. versiforme. All three species produced glomalin significantly higher than the other species, i.e. 1.29 mg g-1; 1.17 mg g-1; 1.15 mg g-1, respectively. [How to Cite: Eddiwal, A Saidi, I Lenin, EF Husin and A Rasyidin. 2014. Potential Selection of Arbuscular Mycorrhizal Fungi (AMF) Indigenous Ultisols through the Production of Glomalin. J Trop Soils 19: 181-189. Doi: 10.5400/jts.2014.19.3.181]