Article

Mycorrhiza

, Volume 15, Issue 3, pp 159-165

First online:

Mycorrhizal C costs and nutritional benefits in developing grapevines

  • P. E. MortimerAffiliated withBotany Department, University of Stellenbosch
  • , E. ArcherAffiliated withDepartment of Viticulture and Oenology, University of Stellenbosch
  • , A. J. ValentineAffiliated withDepartment of Environmental Sciences, Applied Sciences Faculty, Cape Peninsula University of Technology Email author 

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Abstract

Arbuscular mycorrhizal (AM) C-costs in grapevines were investigated. Dormant vines rely on stored C for initial growth. Therefore AM colonisation costs would compete with plant growth for available C reserves. One-year-old grapevines, colonised with Glomus etunicatum (Becker and Gerdemann), were cultivated under glasshouse conditions. The C-economy and P utilisation of the symbiosis were sequentially analysed. AM colonisation, during the 0–67 day growth period, used more stem C relative to root C, which resulted in lower shoot growth. The decline in AM colonisation during the period of 67–119 days coincided with stem C replenishment and higher shoot growth. Construction costs of AM plants and root C allocation increased with root P uptake. The efficiency of P utilisation was lower in AM roots. The reliance of AM colonisation on stem C declined with a decrease in colonisation, providing more C for the refilling of stem carbohydrate reserves and shoot growth. Once established, the AM symbiosis increased P uptake at the expense of refilling of root C reserves. Although higher root C allocation increased plant construction costs, AM roots were more efficient at P utilisation.

Keywords

C-economy Arbuscular mycorrhiza P utilisation efficiency Grapevine