The Responsiveness to Temperature of the Extension Rates of Leaves of Wheat Growing in the Field under Different Levels of Nitrogen Fertilizer

Abstract

The response of the rates of extension (LER) of wheat leaves (Triticum aestivum cv. Gamenya) to temperatures maintained for a short period was measured by changing the temperature of the extension zone and recording the changes in leaf length. The range of temperatures used was from 4-38 °C. The LER of all leaves responded to increases in temperature as field temperatures were suboptimal. The data obtained from several series of measurements over different ranges of temperature were combined to produce a general response curve. The minimum temperature for LER was considered to be approximately 0 °C, the optimum was 28.4 °C, while the maximum was in excess of 38 °C. The responsiveness of LER to temperature, measured by the Q₁₀, declined exponentially from >6 at 5 °C to 2 at 20 °C. The Q₁₀ at 15 °C was not affected by nitrogen supply.