Behavior of lateral roots in winter wheat as affected by temperature

Abstract The experiment was conducted to evaluate the effects of temperature on growth of laterals on the seminal roots of wheat ( Triticum aestivum L.). Wheat seedling root growth was measured on alternate days for 28 days beginning at 4 days after planting. The length, number, time of emergence, and the distance apart of primary lateral roots and the length of the unbranched axis were determined on the plants under air temperatures of 10, 20, 25 and 30°C. The primary lateral roots (i) emerged earlier with increased temperature, and developed closer to the tip of the seminal axis at 20 and 30°C than at 10 and 25°C, (ii) were more closely spaced along the seminal axis at the higher temperatures, (iii)_increased in density along a segment of root within a period of time after planting that varied with temperature, indicating that lateral root emergence did not follow an acropetal sequence, (iv) had a distribution in length that was unaffected by temperature, (v) were fewest in number and least in length at 10°C, greatest in number and length at 25°C, and were intermediate in length and number at 20 and 30°C, and (vi) had lengths that accounted for about 46, 83, 85 and 72% of the total seminal root length at 10, 20, 25 and 30°C, respectively.