Differential Inhibition of Shootvs.Root Growth at Low Temperature and its Relationship with Carbohydrate Accumulation in Different Wheat Cultivars

Abstract

Abstract Shoot and root growth rate, carbohydrate accumulation (including fructan), reducing sugar content and dry matter percentage were measured in six wheat cultivars, ranging from winter to spring types, grown at either 5 or 25 °C. At 5 °C (compared with 25 °C), the relative growth rate (RGR) of shoots was similarly reduced in all cultivars, but the RGR of shoots was more affected in winter wheats. This difference resulted in smaller root:shoot ratios than in spring wheats, which also developed more first-order lateral roots. A direct relationship between carbohydrate accumulation at low temperatures and reduction in root growth was established. These results suggest that differential shoot vs. root growth inhibition at low temperature may play a key role in carbohydrate accumulation at chilling temperatures. This differential response might lead to improvements in survival at temperatures below 0 °C, regrowth during spring, and water and nutrient absorption at low temperatures.