Effects of endophytic fungi on some drought tolerance mechanisms of tall fescue in a hydroponics culture |
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Authors: | F Bayat A Mirlohi M Khodambashi |
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Institution: | (1) Department of Agronomy, Faculty of Agriculture, Shahrekord University, Shahrekord, Iran;(2) Department of Agronomy and Plant Breeding, College of Agriculture, Isfahan University of Technology, Isfahan, 84154, Iran;(3) Present address: Timiryazev Institute of Plant Physiology, Botanicheskaya ul. 35, Moscow, 127576, Russia |
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Abstract: | Neotyphodium, a seed-transmissible nonpathogenic fungal endophyte (symbiont) is considered beneficial because endophyte-infected grasses
are more drought-tolerant, produce more dry matter, utilize soil nitrogen more efficiently, and deter insects. In this study,
the effects of endophytes on physiological mechanisms of drought tolerance in tall fescue (Festuca arundinacea Schreb.) were studied in a greenhouse. Two clonally propagated genotypes of tall fescue (F. arundinacea Schreb.), naturally containing endophyte (EI), and their endophyte-free ramets (EF) were tested at three water stress treatments
exerted by PEG 6000 in a hydroponics system. Relative water content (RWC), cell membrane stability (CMS), proline and chlorophyll
contents in plant leaves were measured during water stress treatments. After harvest, K+, Ca2+, and Mg2+ contents were measured in plant roots and shoots. After 20 days under stress conditions, plants were transferred to basal
hydroponics medium, and their survival after stress relief was evaluated. The results showed that endophyte considerably contributes
to host grass water stress tolerance. Both genotypes of EI and EF plants did not differ in RWC, but, regardless of the infection
status, genotype 75 had the higher RWC than genotype 83. EI clones of both genotypes maintained slightly higher chlorophyll
content and membrane stability than EF clones, although these differences were not significant. The EI plants of genotype
83 concentrated significantly more proline than EF plants, but in the genotype 75, differences between EI and EF clones were
not significant. Plant mineral absorption was also influenced by the endophyte presence. EI clones had the higher concentrations
of K+ in the shoots of both genotypes. The Mg2+ and Ca2+ contents in EF plants of both genotypes were higher than EI plants in the roots, but in the shoots there were no differences
between EI and EF clones. EI clones survived longer after stress removal. These results strongly suggest that Neotyphodium endophytes exert their effects on tall fescue drought tolerance through alteration of various physiological mechanisms involved.
Published in Russian in Fiziologiya Rastenii, 2009, Vol. 56, No. 4, pp. 563–570.
This test was submitted by the authors in English. |
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Keywords: | Festuca arundinacea Neotyphodium coenophialum water stress tolerance hydroponics |
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