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Title: RE-EXAMINING CURRENT QUESTIONS OF WHEAT LEAF APPEARNACE AND TEMPERATURE

Author
item McMaster, Gregory
item HUNT, L. - UNIVERSITY OF GUELPH

Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 1/15/2001
Publication Date: 4/23/2001
Citation: MCMASTER, G.S., HUNT, L.A. RE-EXAMINING CURRENT QUESTIONS OF WHEAT LEAF APPEARNACE AND TEMPERATURE. MEETING ABSTRACT. 2001. GIS, Series 03-01.pages 18-22.

Interpretive Summary: The rate of leaf appearance, or the phyllochron, is critical in simulating canopy development, structure, and dynamics. Many factors can influence the phyllochron of wheat (Triticum aestivum L.), but the most important factor is temperature. This paper explores some current questions about the complicated relationship between wheat leaf appearance and temperature. Specifically, the questions of whether the phyllochron is linearly related to temperature and where the site of temperature perception is located are addressed. While the temperature response across the entire temperature range is clearly non-linear,the existence of a linear region has caused some confusion. Another confounding factor is that both during and across days, temperatures when leaves are produced are normally within the linear region, but often can flucuate beyond the linear phase. In addition, cultivars can vary slightly in their temperature response, and temperature can interact with other factors. While measuring the phyllochron response to temperature may be largely a physics problem, it is complicated by the question of where to measure the temperature since the meristematic region covers a significant distance and temperatures in other parts of the plant will affect secondary factors that influence the phyllochron.

Technical Abstract: The rate of leaf appearance, or the phyllochron, is critical in simulating canopy development, structure, and dynamics. Many factors can influence the phyllochron of wheat (Triticum aestivum L.), but the most important factor is temperature. This paper explores some current questions about the complicated relationship between wheat leaf appearance and temperature. Specifically, the questions of whether the phyllochron is linearly related to temperature and where the site of temperature perception is located are addressed. While the temperature response across the entire temperature range is clearly non-linear,the existence of a linear region has caused some confusion. Another confounding factor is that both during and across days, temperatures when leaves are produced are normally within the linear region, but often can flucuate beyond the linear phase. In addition, cultivars can vary slightly in their temperature response, and temperature can interact with other factors. While measuring the phyllochron response to temperature may be largely a physics problem, it is complicated by the question of where to measure the temperature since the meristematic region covers a significant distance and temperatures in other parts of the plant will affect secondary factors that influence the phyllochron.