Benefits of a symbiotic association with endophytic fungi are subject to water and nutrient availability in Achnatherum sibiricum
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Symbiotic relationships with microbes may influence how plants respond to environmental change. Here, we investigated how fungal endophyte infection affected the growth of a native grass under altered water and nutrient availability. In a two-month field experiment, we compared the performance of endophyte-infected (EI) and endophyte-free (EF) Achnatherum sibiricum subjected to four treatments comprised of a factorial combination of two levels of water availability and two levels of fertilization. The greatest benefits of endophyte infection occurred in the well-watered fertilized treatment. With reduced water and/or nutrient availability, the benefits declined. EI plants subjected to drought and fertilization had higher root:shoot ratios and allocated more nitrogen to photosynthetic machinery and thus had a higher net photosynthetic rate than EF counterparts. In the well-watered unfertilized treatment, EF plants allocated more nutrients to photosynthetic machinery, while EI plants allocated more resources to defense. Thus EI plants were superior to EF plants in terms of nutrient conservation. In the drought unfertilized treatment, no significant difference occurred between EI and EF plants. Our results support the idea that the endophyte-grass interactions are dependent on available resources. However, we did not find a clear cost of endophyte infection. For A. sibiricum, fertilizer addition resulted in greater benefits of the symbiosis for plant growth, but this advantage decreased under drought.
KeywordsEndophyte infection Achnatherum sibiricum Drought Nutrient Interaction
This research was funded by the National Key Basic Research Special Foundation (No. 2007CB106802), the National Natural Science Foundation (30970460), the Doctoral Program Foundation of Institutions of Higher Education of China (20090031110026), and the Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministry (2009–2011).
- Belesky DP, Devine OJ, Pallas JE Jr, Stringer WE (1987) Photosynthetic activity of tall fescue as influenced by a fungal endophyte. Photosynthetica 21:82–87Google Scholar
- Buck GW, Elbersen HW, West CP, Sleper DA (1994) Endophyte enhances drought survival of Moroccan fescues. Arkansas Farm Res 43:6–7Google Scholar
- Díaz S, Hodgson JG, Thompson K, Cabido M, Cornelissen JHC, Jalili A et al (2004) The plant traits that drive ecosystems: evidence from three continents. J Veg Sci 15:295–304Google Scholar
- Farquhar GD, Sharkey TD (1982) Stomatal conductance and photosynthesis. Annu Rev Plant Physiol 11:191–210Google Scholar
- Jin XM, Han GD (2010) Effects of grazing intensity on species diversity and structure of meadow steppe community. Pratacultural Sci (in Chinese) 27(4):7–10Google Scholar
- Laisk A (1977) Kinetics photosynthesis and photorespiration in C3 plants. Nauka, MoscowGoogle Scholar
- Latch GCM, Christensen MJ, Samuels GJ (1984) Five endophytes of Lolium and Festuca in New Zealand. Mycotaxon 20:535–550Google Scholar
- Li X, Han R, Ren AZ, Gao YB (2010) Using high-temperature treatment to construct endophyte-free Achnatherum sibiricum. Microbiol China 37:1395–1400Google Scholar
- Lin FP, Chen ZH, Chen ZP, Zhang DM (1999) Physiological and biochemical responses of the seedlings of four legume tree species to high CO2 concentration. Chin J Plant Ecol 23:220–22Google Scholar
- Morse LJ, Faeth SH, Day TA (2007) Neotyphodium interactions with a wild grass are driven mainly by endophyte haplotype. FunctEcol 21:813–822Google Scholar
- Wu ZL, Lu SL (1995) On geographical distribution of Achnatherum beauv. (Gramineae). Acta Phytotaxon Sin 34:152–161Google Scholar