Comparative Analysis of Reproductive and Vegetative Resource Allocation Strategies between Licorice Species (Glycyrrhiza uralensis and G. korshinskyi) under Varying Temperatures

This study aimed to investigate the long-term effects of temperature variations on the reproductive and underground characteristics of two licorice species-Glycyrrhiza uralensis and G. korshinskyi (Wongam)-under a controlled-temperature gradient tunnel (TGT) system over a five-year cultivation period.The experiment analyzed aboveground growth, flowering, fruiting, and underground biomass accumulation in response to temperature shifts across T1 to T4 zones (with up to a 5.9C difference).Results indicated that G. uralensis exhibited significantly reduced flowering and fruiting under higher-temperature zones, with an average of only 2.2 flowers and 0.2 fruits per plant in the second year, compared to 56.2 and 24.6 respectively for Wongam.In contrast, Wongam maintained stable reproductive output under elevated temperatures, though its reproductive yield plateaued after the third year.A correlation analysis showed a strong positive association between shoot length and flowering number (r = 0.809-0.972)and a strong negative association between high temperatures and fruit numbers, particularly in July (r = -0.742--0.978).An underground biomass analysis in the fifth year revealed that Wongam allocated approximately 91% of its underground mass to rhizomes, compared to 63% in G. uralensis, indicating a shift toward vegetative propagation.These findings suggest divergent reproductive strategies between the two species: G. uralensis gradually increases sexual reproduction with age, while Wongam exhibits early flowering followed by a shift to clonal propagation via rhizomes.This research provides foundational physiological insights for optimizing seed production and cultivar management of licorice in warming climates.