Maximizing growth rate at low temperatures: RNA:DNA allocation strategies and life history traits of Arctic and temperate DaphniaReport as inadecuate




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Polar Biology

, Volume 33, Issue 9, pp 1255–1262

First Online: 23 May 2010Received: 22 August 2009Revised: 30 March 2010Accepted: 30 April 2010

Abstract

Many short-lived or univoltine organisms at high latitudes and altitudes face the challenge to complete their life-cycle within a brief growing season. This means that they need to maintain a high growth rate at low temperatures, and one way of doing this is to allocate limiting resources like phosphorus to RNA in order to maximize protein synthesis. We here explore the allocations of phosphorus to RNA relative to DNA, and the potential bearings on growth rate and life history traits of polyploid high-Arctic and diploid temperate Daphnia pulex. The polyploid clone matured earlier at low temperature 8°C but later than the diploid clone at high temperature 18°C. Juveniles of Arctic Daphnia had both higher specific levels of RNA and higher growth rates at low temperature compared with the temperate clone of Daphnia. We hypothesize that Arctic Daphnia may overcome growth constraints posed by low temperature and polyploidy by increasing their allocation of resources to RNA. The prevalence of polyploidy in Arctic populations strongly suggests that the potential drawbacks of polyploidy are counteracted by an increased allocation of resources to RNA to keep a high rate of protein synthesis even under low temperatures.

KeywordsStoichiometry Polyploidy Cold acclimatization  Download fulltext PDF



Author: G. J. Van Geest - R. Sachse - M. Brehm - E. Van Donk - D. O. Hessen

Source: https://link.springer.com/



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