Inoculation of forest seedlings with mycorrhizal fungi and rhizobacteria can improve the morphological and physiological qualities of plants, especially those used for regeneration of arid areas. In this paper, under standard nursery conditions, Aleppo pine seedlings were inoculated with Pseudomonas fluorescens CECT 5281 rhizobacteria. Some of these seedlings were also inoculated with the ectomycorrhizal fungus Pisolithus tinctorius. Five months after the inoculations, we examined the growth, water parameters (osmotic potential at full turgor [Ψπfull], osmotic potential at zero turgor [Ψπ0], and the tissue modulus of elasticity near full turgor [E max]), mycorrhizal colonisation, and concentration of macronutrients (N, P, K, Ca and Mg) in the seedlings. Subsequently, a trial was conducted to assess the root growth potential. P. fluorescens CECT 5281 decreased the cellular osmotic potential of P. halepensis seedlings but increased its elasticity. P. tinctorius + P. fluorescens caused osmotic adjustment at zero turgor and increased tissue elasticity, which improved tolerance to water stress. All inoculations improved the growth and nutrition of the seedlings but caused non-significant effects on root growth potential. The co-inoculation Pisolithus tinctorius + Pseudomonas fluorescens at the nursery may be a suitable technique for producing improved seedling material for restoration purposes.
References
[1]
Marulanda, A.; Barea, J.M.; Azcon, R. An indigenous drought-tolerant strain of Glomus intraradices associated with a native bacterium improves water transport and root development in Retama sphaerocarpa. Microb. Ecol. 2006, 52, 670–678, doi:10.1007/s00248-006-9078-0.
[2]
Martínez-Ferri, E.; Balaguer, L.; Valladares, F.; Chico, J.M.; Manrique, E. Energy dissipation in drought-avoiding and drought-tolerant tree species at midday during the Mediterranean summer. Tree Physiol. 2000, 20, 131–138, doi:10.1093/treephys/20.2.131.
[3]
Maestre, F.T.; Cortina, J. Are Pinus halepensis plantations useful as a restoration tool in semiarid Mediterranean areas? For. Ecol. Manag. 2004, 198, 303–317, doi:10.1016/j.foreco.2004.05.040.
[4]
Caravaca, F.; Alguacil, M.M.; Azcón, R.; Parladé, J.; Torres, P.; Roldán, A. Establishment of two ectomycorrhizal shrub species in a semiarid site after in situ amendment with sugar beet, rock phosphate, and Aspergillus níger. Microb. Ecol. 2005, 49, 73–82, doi:10.1007/s00248-003-0131-y.
[5]
Chanway, C.P. Inoculation of tree roots with plant growth promoting soil bacteria: An emerging technology for reforestation. For. Sci. 1997, 43, 99–112.
[6]
Rousseau, J.V.D.; Reid, C.P.P.; English, R.J. Relationship between biomass of the mycorrhizal fungus Pisolithus tinctorius and phosphorus uptake in loblolly pine seedlings. Soil Biol. Biochem. 1992, 24, 183–184, doi:10.1016/0038-0717(92)90276-4.
[7]
Eltrop, L.; Marschner, H. Growth and mineral nutrition of non-mycorrhizal and mycorrhizal Norway spruce (Picea abies) seedlings grown in semi-hydroponic sand culture. I. Growth and mineral nutrient uptake in plants supplied with different forms of nitrogen. New Phytol. 1996, 133, 469–478.
[8]
Finlay, R.D.; Odham, G.; S？derstr？m, B. Mycelial uptake, translocation and assimilation of nitrogen from 15N-labelled ammonium by Pinus sylvestris plants infected with four different ectomycorrhizal fungi. New Phytol. 1988, 110, 59–66, doi:10.1111/j.1469-8137.1988.tb00237.x.
[9]
Caravaca, F.; García, C.; Hernández, M.T.; Roldán, A. Aggregate stability changes after organic amendment and mycorrhizal inoculation in the afforestation of a semiarid site with Pinus halepensis. Appl. Soil Ecol. 2002, 19, 199–208, doi:10.1016/S0929-1393(01)00189-5.
[10]
Parke, J.L.; Linderman, R.G.; Black, C.H. The role of ectomycorrhizas in drought tolerance of Douglas fir seedlings. New Phytol. 1983, 95, 83–95, doi:10.1111/j.1469-8137.1983.tb03471.x.
[11]
García, C.; Hernández, T.; Roldán, A.; Albadalejo, J.; Castillo, V. Organic amendment and mycorrhizal inoculation as a practice in afforestation of soils with Pinus halepensis Miller: Effect on their microbial activity. Soil Biol. Biochem. 2000, 32, 1173–1181, doi:10.1016/S0038-0717(00)00033-X.
[12]
Bolton, H.J.; Fredickson, J.K.; Elliott, L.F. Microbial Ecology of the Rhizosphere. In Soil Microbial Ecology; Metting, F.B.J., Ed.; Marcel Dekker: New York, NY, USA, 1993; pp. 27–63.
[13]
Marschner, P.; Timonen, S. Bacterial Community Composition and Activity in Rhizosphere of Roots Colonized by AMF. In Microbial Activity in the Rhizosphere; Mukerji, K.G., Manoharachary, C., Singh, J., Eds.; Springer-verlag Berlin Heidelberg: Heidelberg, Germany, 2006; pp. 140–154.
[14]
Matthijs, S.; Tehrani, K.A.; Laus, G.; Jackson, R.W.; Cooper, R.M.; Cornelis, P. Thioquinolobactin, a Pseudomonas siderophore with antifungal and anti-Pythium activity. Environ. Microbiology 2007, 9, 425–434.
[15]
Arshad, M.; Shaharoona, B.; Mahmood, T. Inoculation with Pseudomonas spp. containing ACC-Deaminase partially eliminates the effects of drought stress on growth, yield, and ripening of pea (Pisum sativum L.). Pedosphere 2008, 18, 611–620, doi:10.1016/S1002-0160(08)60055-7.
[16]
Deveau, A.; Palin, B.; Delaruelle, C.; Peter, M.; Kohler, A.; Pierrat, J.C.; Sarniguet, A.; Garbaye, J.; Martin, F.; Frey-Klett, P. The mycorrhiza helper Pseudomonas fluorescens BBc6R8 has a specific effect on the growth, morphology and gene expression of the ectomycorrhizal fungus Laccaria bicolour S238N. New Phytol. 2007, 175, 743–755, doi:10.1111/j.1469-8137.2007.02148.x.
[17]
Frey-Klett, P.; Garbaye, J.; Tarkka, M. The Mycorrhiza helper bacteria revisited. New Phytol. 2007, 176, 22–36, doi:10.1111/j.1469-8137.2007.02191.x.
[18]
Heinonsalo, J.; Frey-Klett, P.; Pierrat, J.C.; Churin, J.L.; Vairelles, J.; Garbaye, J. Fate, tree growth effect and potential impact on soil microbial communities of mycorrhizal and bacterial inoculation in a forest plantation. Soil Biol. Biochem. 2004, 36, 211–216, doi:10.1016/j.soilbio.2003.09.007.
[19]
Roldán, A.; Querejeta, I.; Albaladejo, J.; Castell, V. Survival and growth of Pinus halepensis Miller seedlings in a semi-arid environment after forest soil transfer, terracing and organic amendments. Ann. For. Sci. 1996, 53, 1099–1112, doi:10.1051/forest:19960605.
[20]
Probanza, A.; Mateos, J.L.; Lucas, G.J.A.; Ramos, B.; de Felipe, M.R.; Gutierrez, M.F.J. Effects of inoculation with PGPR Bacillus and Pisolithus tinctorius on Pinus pinea L. growth, bacterial rhizosphere colonization, and mycorrhizal infection. Microb. Ecol. 2001, 41, 140–148.
[21]
Founoune, H.; Duponnois, R.; Meyer, J.M.; Ba, A.M.; Chotte, J.L.; Neyra, M. Interactions between ectomycorrhizal symbiosis and Pseudomonas fluorescens on Acacia holosericea: Isolation of mycorrhization helper bacteria (MHB) from a soudano-sahelian soil. FEMS Microbiol. Ecol. 2002, 41, 37–46, doi:10.1111/j.1574-6941.2002.tb00964.x.
[22]
Ouahmane, L.; Revel, J.C.; Hafidi, M.; Thioulouse, J.; Prin, Y.; Galiana, A.; Dreyfus, B.; Duponnois, R. Responses of Pinus halepensis growth, soil microbial catabolic functions and phosphate-solubilizing bacteria after rock phosphate amendment and ectomycorrhizal inoculation. Plant Soil 2009, 320, 169–179, doi:10.1007/s11104-008-9882-z.
[23]
Deka Boruah, H.P.; Dileep Kumar, B.S. Biological activity of secondary metabolites produced by a strain of Pseudomonas fluorescens. Folia Microbiol. 2002, 47, 359–363, doi:10.1007/BF02818690.
Sardans, J.; Rodá, F.; Pe？uelas, J. Effects of a nutrient pulse supply on nutrient status of the Mediterranean trees Quercus ilex subsp. ballota and Pinus halepensis on different soils and under different competitive pressure. Trees 2006, 20, 619–632.
[26]
Rincón, A.; Valladares, F.; Gimeno, T.E.; Pueyo, J.J. Water stress responses of two Mediterranean tree species influenced by native soil microorganisms and inoculation with a plant growth promoting rhizobacterium. Tree Physiol. 2008, 28, 1693–1701, doi:10.1093/treephys/28.11.1693.
[27]
Rincón, A.; Ruiz-Díez, B.; García-Fraile, S.; Lucas-García, J.A.; Fernández-Pascual, M.; Pueyo, J.J.; de Felipe, M.R. Colonization of Pinus halepensis roots by Pseudomonas fluorescens and interaction with the ectomycorrhizal fungus Suillus granulatus. FEMS Microbiol. Ecol. 2005, 51, 303–311, doi:10.1016/j.femsec.2004.09.006.
[28]
Tarka, M.T.; Frey-Klett, P. Mycorrhiza helper bacteria. In Mycorrhiza; Varma, A., Ed.; Springer-Verlag Berlin Heidelberg: Heidelberg, Germany, 2008; pp. 113–132.
[29]
Barea, J.M. Mycorrhiza/Bacteria Interactions on Plant Growth Promotion. In Plant Growth Promoting Rhizobacteria, Present Status and Future Prospects; Ogoshi, A., Kobayashi, L., Homma, Y., Kodama, F., Kondon, N., Akino, S., Eds.; OCDE: Paris, France, 1997; pp. 150–158.
[30]
Villar-Salvador, P.; Ca？a, L.; Pe？uelas, J.; Carrasco, I.; Domínguez, S.; Renilla, I. Relaciones hídricas y potencial de formación de raíces en plántulas de Pinus halepensis Mill. sometidas a diferentes niveles de endurecimientos por estrés hídrico. Monographs Spanish Soc. For. Sci. 1997, 4, 81–92.
[31]
Abrams, M.D.; Kubiscke, M.E. Synchronous changes in tissue water parameters of mature foliage from well-watered and periodically droughted tree seedlings. J. Exp. Bot. 1994, 45, 171–177, doi:10.1093/jxb/45.2.171.
[32]
Stewart, J.D.; Lieffers, V.J. Preconditioning effects of nitrogen relative addition rate and drought stress on container-grown lodgepole pine seedlings. Can. J. For. Res. 1993, 23, 1663–1671, doi:10.1139/x93-207.
[33]
Lamhamedi, M.S.; Bernier, P.Y.; Fortín, J.A. Growth, nutrition and response to water stress of Pinus pinaster inoculated with ten dikaryotic strains of Pisolithus sp. Tree Physiol. 1992, 10, 153–167, doi:10.1093/treephys/10.2.153.
[34]
Boiero, L.; Perrig, D.; Masciarelli, O.; Pena, C.; Cassán, F.; Luna, V. Phytohormone production by strains of Bradyrhizobium japonicum and possible physiological and technological implications. Appl. Microbiol. Biotechnol. 2007, 74, 874–880, doi:10.1007/s00253-006-0731-9.
[35]
Alberdi, M.; Alvarez, M.; Valenzuela, E.; Godoy, R.; Olivares, E.; Barrientos, M. Response to water deficit of Nothofagus dombeyi plants inoculated with a specific (Descolea antarctica Sing) and non-specific (Pisolithus tinctorius (Pers.) Coker & Couch) ectomycorrhizal fungi. Rev. Chil. Hist. Nat. 2007, 80, 479–491.
[36]
Benlloch-González, M.; Arquero, O.; Fournier, J.M.; Barranco, D.; Benlloch, M. K+ starvation inhibits water-stress-induced stomatal closure. J. Plant Physiol. 2008, 165, 623–630, doi:10.1016/j.jplph.2007.05.010.
[37]
Patakas, A.; Nikolaou, N.; Zioziou, K.; Radoglou, K.; Noitsakis, B. The role of organic solute and ion accumulation in osmotic adjustment in drought-stressed grapevines. Plant Sci. 2002, 163, 361–367, doi:10.1016/S0168-9452(02)00140-1.
[38]
Miles, A.A.; Misra, S.S. The estimation of the bactericidal power of the blood. J. Hyg. 1938, 38, 732–749, doi:10.1017/S002217240001158X.
[39]
Tyree, M.; Hammel, H.T. The measurement of the turgor pressure and the water relations of plants by the pressure technique. J. Exp. Bot. 1972, 23, 267–282, doi:10.1093/jxb/23.1.267.
[40]
Robichaux, R.H. Variation in the tissue water relations of two sympatric Hawaiian Dubautia species and their natural hybrid. Oecologia Berlin 1984, 65, 75–81, doi:10.1007/BF00384465.
[41]
Scholander, P.F.; Hammel, H.T.; Bradstreet, E.D.; Hemmingsen, E.A. Sap pressure in vascular plants. Science 1965, 148, 339–346.
[42]
Cheung, Y.N.S.; Tyree, M.T.; Dainty, J. Water relations parameters on single leaves obtained in a pressure bomb and some ecological interpretations. Can. J. Botany 1975, 53, 1342–1346, doi:10.1139/b75-162.
[43]
Jones, M.M.; Turner, N.C. Osmotic adjustment in expanding and fully expanded leves of sunlower in response to water deficits. Aust. J. Plant Physiol. 1980, 7, 181–192, doi:10.1071/PP9800181.
[44]
Tyree, M.; Jarvis, P.G. Water in tissues and cells. In Encyclopedia of Plant Physiology, New Series, Physiological Plant Ecology II; Lange, O.L., Nobel, P.S., Osmond, C.B., Ziegler, H., Eds.; Springer-verlag Berlin Heidelberg: Heidelberg, Germany, 1982; Volume 12B, pp. 36–77.
[45]
Bowman, W.D.; Roberts, S.W. Seasonal changes in tissue elasticity in chaparral shrubs. Physiol. Plant. 1985, 65, 233–236, doi:10.1111/j.1399-3054.1985.tb02388.x.
[46]
Colour Atlas of Ectomycorrhizae, 1st–11th ed.; Agerer, R., Ed.; Einhorn: Schw？bisch Gmünd, Germany, 1987–1998.
[47]
Burdett, A.N. Understanding root growth capacity: Theoretical considerations in assessing planting stock quality by means of root growth tests. Can. J. For. Res. 1987, 17, 768–775, doi:10.1139/x87-123.
