Does endophyte influence resource acquisition and allocation in defoliated tall fescue as a function of microsite conditions?

• Published in: Environmental and experimental botany 2008-05, Vol.63 (1), p.368-377
• Main Authors: Belesky, David P., Burner, David M., Ruckle, Joyce M.
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biochemistry and biology; Biological and medical sciences; Chemical, physicochemical, biochemical and biological properties; defoliation; dry matter accumulation; Dry matter production; endophytes; Festuca arundinacea; Festuca arundinacea subsp. arundinacea; forage crops; forage grasses; Fundamental and applied biological sciences. Psychology; Growth allometry; height; Lolium; Microbiology; microhabitats; Neotyphodium coenophialum; nutrient transport; nutrient uptake; photosynthates; Physics, chemistry, biochemistry and biology of agricultural and forest soils; plant persistence; roots; seed germination; seedlings; Shade; shoots; silvopastoral systems; site factors; Soil science; Tiller production
• ISSN: 0098-8472; 1873-7307
• DOI: 10.1016/j.envexpbot.2007.12.013

Tall fescue [ Lolium arundinaceum (Schreb.) Darbysh.] often benefits in terms of productivity and persistence when infected with Neotyphodium coenophialum ([Morgan-Jones and Gams], Glenn, Bacon, and Hanlin) endophyte, but the influence of novel non-ergogenic endophytes is unclear. We conducted a field experiment using container-grown tall fescue plants to determine how plants allocated resources when clipped repeatedly in microsites differing in the amount of available light associated with open (full sun), and partially shaded (about 20 or 40% of full sun) conditions. Plants of the same tall fescue cultivar (Jesup) were host to either a native or novel non-ergogenic fungal endophyte (MaxQ™), or were devoid of endophyte. Seedlings of plants infected with the novel endophyte had slower germination, germinated later, and allocated more photosynthate to shoots than roots, when compared to J− or J+ plants. Herbage production of undisturbed canopies was not influenced by host–endophyte association within a microsite, with more herbage produced at the open than at the heavily shaded site. Clipping plants to a 5- or a 10-cm residue height tended to accentuate differences, with diminished productivity and greater variability occurring when plants were maintained at 5 cm. This trend was supported by allometric resource allocation patterns, and in terms of vegetative propagule mass relative to the number of propagules. Tall fescue, irrespective of host–endophyte association, grown as forage in silvopastoral situations should be managed to maintain no less than a 10-cm residual plant height. Trends in photosynthate allocation and plant size might influence persistence and should be investigated for more than two growing seasons.