scholarly journals Effects of Inoculations with Mycorrhizal Fungi of Soilless Potting Mixes During Transplant Production on Watermelon Growth and Early Fruit Yield

HortScience ◽  
2008 ◽  
Vol 43 (2) ◽  
pp. 354-360 ◽  
Author(s):  
Andreas Westphal ◽  
Nicole L. Snyder ◽  
Lijuan Xing ◽  
James J. Camberato

Watermelon, Citrullus lanatus (Thunb.) Matsum. & Nakai, crops are continuously exposed to soilborne diseases. In many areas of the United States, greenhouse-raised watermelon seedlings are transplanted to the field to allow for early crop establishment and early fruit production. This practice can result in weakened root systems, which potentially make the plant prone to premature senescence and reduce crop productivity. Mycorrhizal fungi have been reported to improve plant growth in many crops through enhanced root growth and function. We hypothesized that amending potting mixes with commercial inocula of mycorrhizal fungi during seeding of watermelon in a greenhouse would improve watermelon production when seedlings were transplanted to the field. Colonization of watermelon roots with mycorrhizal fungi from three commercial formulations was compared with the colonization of onion roots to confirm the efficacy of the mycorrhizae. Two inocula of mycorrhizal fungi that resulted in colonization of watermelon roots were tested in the field and glasshouse for their potential to improve watermelon production. MycoApply improved early plant growth in two tests, one under Meloidogyne incognita-infested conditions in loamy sand and another at two phosphorus fertilizer levels (0 or 22 kg·ha−1 P) in a loam soil. Mycor Vam Mini plug improved early fruit yield in soil infested with M. incognita. Application of Myconate (formononetin), a potential enhancer of colonization with mycorrhizae, increased early fruit yield in M. incognita-infested soil. Myconate had positive effects when potting mixes were not amended with inoculum of mycorrhizal fungi, but reduced watermelon growth when mycorrhizal fungi were supplied in the potting mix. In glasshouse tests, inoculation with mycorrhizal fungi did not suppress disease. Mycorrhizal fungi inoculations improved early plant establishment and increased the most valuable early fruit yield under some environmental stress conditions but did not increase total fruit yields.

2019 ◽  
Vol 20 (7) ◽  
pp. 1769 ◽  
Author(s):  
Manoj Kaushal

Drought conditions marked by water deficit impede plant growth thus causing recurrent decline in agricultural productivity. Presently, research efforts are focussed towards harnessing the potential of microbes to enhance crop production during drought. Microbial communities, such as arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) buddy up with plants to boost crop productivity during drought via microbial induced systemic tolerance (MIST). The present review summarizes MIST mechanisms during drought comprised of modulation in phytohormonal profiles, sturdy antioxidant defence, osmotic grapnel, bacterial exopolysaccharides (EPS) or AMF glomalin production, volatile organic compounds (VOCs), expression of fungal aquaporins and stress responsive genes, which alters various physiological processes such as hydraulic conductance, transpiration rate, stomatal conductivity and photosynthesis in host plants. Molecular studies have revealed microbial induced differential expression of various genes such as ERD15 (Early Response to Dehydration 15), RAB18 (ABA-responsive gene) in Arabidopsis, COX1 (regulates energy and carbohydrate metabolism), PKDP (protein kinase), AP2-EREBP (stress responsive pathway), Hsp20, bZIP1 and COC1 (chaperones in ABA signalling) in Pseudomonas fluorescens treated rice, LbKT1, LbSKOR (encoding potassium channels) in Lycium, PtYUC3 and PtYUC8 (IAA biosynthesis) in AMF inoculated Poncirus, ADC, AIH, CPA, SPDS, SPMS and SAMDC (polyamine biosynthesis) in PGPR inoculated Arabidopsis, 14-3-3 genes (TFT1-TFT12 genes in ABA signalling pathways) in AMF treated Solanum, ACO, ACS (ethylene biosynthesis), jasmonate MYC2 gene in chick pea, PR1 (SA regulated gene), pdf1.2 (JA marker genes) and VSP1 (ethylene-response gene) in Pseudomonas treated Arabidopsis plants. Moreover, the key role of miRNAs in MIST has also been recorded in Pseudomonas putida RA treated chick pea plants.


2018 ◽  
Vol 64 (No. 6) ◽  
pp. 283-289 ◽  
Author(s):  
Shao Ya-Dong ◽  
Zhang De-Jian ◽  
Hu Xian-Chun ◽  
Wu Qiang-Sheng ◽  
Jiang Chang-Jun ◽  
...  

Tea plants grown in acidic soils are strongly dependent on arbuscular mycorrhizas, whereas it is not clear whether soil arbuscular mycorrhizal fungi (AMF) improve plant growth, root development, and nutrient absorption in tea plants. A potted study was conducted to determine the effects of Claroideoglomus etunicatum, Diversispora spurca, D. versiformis and a mixture of the three AMF species on plant growth, root morphology, root-hair growth, and leaf nutrient status in Camellia sinensis cv. Fuding Dabaicha in Jingzhou, China. After 12 weeks of AMF inoculation, root mycorrhizal colonization ranged from 15.12% to 40.23%. AMF inoculation heavily increased plant height, shoot and root biomass, and total leaf area, whilst the increased effect was ranked as C. etunicatum > D. spurca > mixed-AMF > D. versiformis in the decreasing order. Mycorrhizal inoculation also considerably increased total root length and volume, whereas obviously inhibited root-hair length and number, in company with an increment in root-hair diameter. Leaf N, P, K, Ca, Mg, Zn, and Mn contents were significantly higher in AMF-inoculated plants than in non-AMF-inoculated plants, regardless of AMF species. It concludes that AMF inoculation had positive effects on plant growth performance, root morphology, and leaf nutrient levels in cv. Fuding Dabaicha seedlings, whilst C. etunicatum performed the best effects.


Plants ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1596
Author(s):  
Karivaradharajan Swarnalakshmi ◽  
Vandana Yadav ◽  
Deepti Tyagi ◽  
Dolly Wattal Dhar ◽  
Annapurna Kannepalli ◽  
...  

Grain legumes are an important component of sustainable agri-food systems. They establish symbiotic association with rhizobia and arbuscular mycorrhizal fungi, thus reducing the use of chemical fertilizers. Several other free-living microbial communities (PGPR—plant growth promoting rhizobacteria) residing in the soil-root interface are also known to influence biogeochemical cycles and improve legume productivity. The growth and function of these microorganisms are affected by root exudate molecules secreted in the rhizosphere region. PGPRs produce the chemicals which stimulate growth and functions of leguminous crops at different growth stages. They promote plant growth by nitrogen fixation, solubilization as well as mineralization of phosphorus, and production of phytohormone(s). The co-inoculation of PGPRs along with rhizobia has shown to enhance nodulation and symbiotic interaction. The recent molecular tools are helpful to understand and predict the establishment and function of PGPRs and plant response. In this review, we provide an overview of various growth promoting mechanisms of PGPR inoculations in the production of leguminous crops.


2018 ◽  
Vol 46 (2) ◽  
pp. 365-370 ◽  
Author(s):  
Li TIAN ◽  
Yan LI ◽  
Qiang-Sheng WU

Arbuscular mycorrhizas (AMs) need the carbohydrates from host plants for its growth, whereas it is not clear whether exogenous carbon affects mycorrhizal roles. A two-chambered rootbox was divided into root + hyphae chamber and hyphae chamber (free of roots) by 37-μm nylon mesh, in which trifoliate orange (Poncirus trifoliata) seedlings and Funneliformis mosseae were applied into root + hyphae chamber, and exogenous 40 mmol/L fructose, glucose and sucrose was applied to hyphae chamber. Application of exogenous sugars dramatically elevated root mycorrhizal colonization. Sole arbuscular mycorrhizal fungi (AMF) inoculation significantly promoted plant growth and root morphology than non-AMF treatment. Mycorrhiza-improved plant growth and root modification could be enlarged by exogenous carbon, especially fructose. Exogenous carbon markedly increased root fructose, glucose and sucrose accumulation in mycorrhizal plants, especially sucrose. Exogenous fructose significantly reduced leaf and root sucrose synthase (SS) activity in synthesis direction and increased them in cleavage direction in AMF seedlings. Exogenous glucose and sucrose heavily elevated root SS activity of mycorrhizal seedlings in synthesis and cleavage direction and reduced leaf SS activity in synthesis direction. Leaf acid invertase (AI) and neutral invertase (NI) activities of mycorrhizal seedlings were decreased by exogenous carbon, except sucrose in NI. Exogenous fructose significantly increased root AI and NI activity in mycorrhizal plants. These results implied that mycorrhizal inoculation represented positive effects on plant growth, root morphology, and sucrose metabolism of trifoliate orange, which could be magnified further by exogenous carbon, especially fructose.


2018 ◽  
Vol 39 (4) ◽  
pp. 1437
Author(s):  
Mario Gámiz Infante ◽  
Manuel Avilés Guerrero ◽  
Celia Borrero Vega ◽  
Wilian Carlo Demetrio ◽  
Jair Alves Dionísio

Earthworms are soil invertebrates that play an important environmental role and are often referred to as “ecosystem engineers”. These invertebrates can influence several organisms, from microscopic life forms to plants. Although many works had reported positive effects of earthworms on plant growth, studies combining these invertebrates and soil pathogens showed numerous positive interactions. Fusarium wilt is a global disease that can cause severe damage to strawberry fields. The aim of this study was to evaluate the effects of inoculation of earthworms (Lumbricus terrestris) and Fusarium wilt (Fusarium oxysporum f. sp. fragariae) in strawberry plants. This greenhouse experiment was carried out in the University of Seville School of Agricultural Engineering, Utrera City, Spain. Strawberries (Rooted cuttings) were planted in plastic pots and administered the following treatments: Control (absence of F. oxysporum f. sp. fragariae and earthworms), T1 (absence of F. oxysporum f. sp. fragariae, two L. terrestris per pot), T2 (inoculum of F. oxysporum f. sp. fragariae, absence of L. terrestris), and T3 (inoculum of F. oxysporum f. sp. fragariae and two L. terrestris). Weekly fruit production was measured for seven months. After this period the shoot fresh weight and the leaf nutrient content was measured. The results obtained showed no interaction between L. terrestris and F. oxysporum f. sp. fragariae on strawberry production. T1 treatment resulted in fruit production superior to other treatments, including the control. An absence of differences in dry shoot matter was observed with earthworm treatment, and small differences were found in the leaf nutrient content. The earthworm inoculation was unable to suppress the negative effects of Fusarium wilt in strawberry production. However, positive effects such as a reduction in the disease severity were found in the earthworm treated plants. In treatments without F. oxysporum f. sp. fragariae inoculation, the presence of earthworms increased plant productivity by 44.21 g per pot, compared with the control.


2021 ◽  
Vol 9 (6) ◽  
pp. 1274
Author(s):  
Leardwiriyakool Chaiya ◽  
Jaturong Kumla ◽  
Nakarin Suwannarach ◽  
Tanongkiat Kiatsiriroat ◽  
Saisamorn Lumyong

Nowadays, microorganisms that display plant growth promoting properties are significantly interesting for their potential role in reducing the use of chemical fertilizers. This research study proposed the isolation of the actinobacteria associated with arbuscular mycorrhizal fungi (AMF) spores and the investigation of their plant growth promoting properties in the in vitro assay. Three actinobacterial strains were obtained and identified to the genus Streptomyces (GETU-1 and GIG-1) and Amycolatopsis (GLM-2). The results indicated that all actinobacterial strains produced indole-3-acetic acid (IAA) and were positive in terms of siderophore, endoglucanase, and ammonia productions. In the in vitro assay, all strains were grown in the presence of water activity within a range of 0.897 to 0.998, pH values within a range of 5–11, and in the presence of 2.5% NaCl for the investigation of drought, pH, and salt tolerances, respectively. Additionally, all strains were able to tolerate commercial insecticides (propargite and methomyl) and fungicides (captan) at the recommended dosages for field applications. Only, Amycolatopsis sp. GLM-2 showed tolerance to benomyl at the recommended dose. All the obtained actinobacteria were characterized as plant growth promoting strains by improving the growth of chili plants (Capsicum flutescens L.). Moreover, the co-inoculation treatment of the obtained actinobacteria and AMF (Claroideoglomus etunicatum) spores could significantly increase plant growth, contribute to the chlorophyll index, and enhance fruit production in chili plants. Additionally, the highest value of AMF spore production and the greatest percentage of root colonization were observed in the treatment that had been co-inoculated with Streptomyces sp. GETU-1.


2003 ◽  
Vol 128 (5) ◽  
pp. 767-775 ◽  
Author(s):  
Victoria Estaún ◽  
Amelia Camprubí ◽  
Cinta Calvet ◽  
Jorge Pinochet

This paper reports the effects of inoculation with arbuscular mycorrhizal fungi on early plant development, field establishment, and crop yield of the olive (Olea europaea L.) cultivar Arbequina. The response of olive plants to the fungi Glomus intraradices (Schenck and Smith) and G. mosseae (Nicol.& Gerd.) Gerdemann & Trappe in different potting mixes was studied in two different nursery experiments. Pre-inoculation with selected arbuscular mycorrhizal fungi prior to transplanting in the field improved plant growth and crop yield up to three years after inoculation. G. intraradices was more efficient at promoting plant growth than both G. mosseae and the native endophytes present in the orchard soil. Inoculation at the time of transplanting enhanced early plant growth in all the field situations studied. Diminishing mycorrhizal effects over time resulted from natural colonization of noninoculated seedlings and related to the native arbuscular mycorrhizal (AM) fungal population of the field soil. Early inoculation of olive seedlings enhances early plant development and crop productivity of olive trees.


2021 ◽  
Vol 7 (7) ◽  
pp. 531
Author(s):  
Modhi O. Alotaibi ◽  
Ahmed M. Saleh ◽  
Renato L. Sobrinho ◽  
Mohamed S. Sheteiwy ◽  
Ahmed M. El-Sawah ◽  
...  

Arbuscular mycorrhizal fungi (AMF) can promote plant growth and induce stress tolerance. Proline is reported to accumulate in mycorrhizal plants under stressful conditions, such as aluminum (Al) stress. However, the detailed changes induced in proline metabolism under AMF–plant symbiosis has not been studied. Accordingly, this work aimed to study how Al-stressed grass (barley) and legume (lotus) species respond to AMF inoculation at growth and biochemical levels. The associated changes in Al uptake and accumulation, the rate of photosynthesis, and the key enzymes and metabolites involved in proline biosynthesis and degradation pathways were studied. Soil contamination with Al induced Al accumulation in tissues of both species and, consequently, reduced plant growth and the rate of photosynthesis, while more tolerance was noticed in lotus. Inoculation with AMF significantly reduced Al accumulation and mitigated the negative impacts of Al on growth and photosynthesis in both species; however, these positive effects were more pronounced in barley plants. The mitigating action of AMF was associated with upregulation of proline biosynthesis through glutamate and ornithine pathways, more in lotus than in barley, and repression of its catabolism. The increased proline level in lotus was consistent with improved N metabolism (N level and nitrate reductase). Overall, this study suggests the role of AMF in mitigating Al stress, where regulation of proline metabolism is a worthy mechanism underlying this mitigating action.


2019 ◽  
Author(s):  
Alicia Franco ◽  
Jesús Pérez-Moreno ◽  
Gabriela Sánchez ◽  
Carlos R. Cerdán ◽  
Juan J. Almaraz ◽  
...  

AbstractTraditionally, it is thought that arbuscular mycorrhizae establish a mutualist symbiosis only with the roots of angiosperm plants. In this mutualism, fungi receive carbon from the plants, and angiosperms receive nutrients through the external mycelium of the arbuscular mycorrhizal fungi (AMF). However, the enhanced contents of macro- and micronutrients in gymnosperm plants, and therefore the mutualistic relationship, with AMF has not been reported so far. The present work evaluated whether arbuscular mycorrhizae were able to establish and enhance 9 nutrient contents in the neotropical Pinaceae species Pinus greggii. The tree seedlings were inoculated with three consortia of AMF isolated from an agricultural site, a forest of Cupressus lusitanica and a forest of Pinus hartwegii. The effect of AMF inoculation on plant growth and nutrient enhancement, in addition to colonization, was evaluated. There was evidence of enhancement of plant growth and 9 macro- and micronutrients in plants inoculated with the three evaluated consortia. After 7 months, the translocation was greater for Mg, Mn and Zn in plants inoculated with the consortium of AMF from pine forest. The presence of hyphae, vesicles and arbuscules was detected in the roots of the Pinus greggii plants inoculated with the AMF consortia. In addition to these positive effects, colonization of 10 to 15% and 20 to 38% was observed depending on the AMF consortia after 2 and 7 months, respectively. The presence of arbuscules which is the translocation structure among involved symbionts was also recorded; and photographed for the first time. In the present work, we report for the first time that arbuscular mycorrhiza affects the mobilization of N, P, K, Ca, Mg, Fe, Mn, Zn, Cu and B in gymnosperms, indicating that this mycorrhizal symbiosis is more complex than previously believed.


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