Effects of sucrose on the formation of root border-like cells and aluminum tolerance in Stylosanthes guianensis

Objective Root border cells (BCs) play important roles in plant resistance to biotic and abiotic stresses. However, the physiological mechanisms of BCs formation remains further exploration. This study was aimed to investigate the effects of sucrose on root border-like cells (BLCs) formation and aluminum (Al) tolerance function of stylo (Stylosanthes guianensis).

Method Genotype ‘Reyan No.2’ was used as plant material, exogenous carbohydrate sources were applied in the growth medium for treatments, and the morphology of stylo BLCs and the stylo Al tolerance were investigated.

Result Both sucrose and glucose obviously promoted stylo BLCs formation. Compared with sugar-free, sucrose increased the fresh weight, length and width of stylo BLCs by 50%, 14% and 62% respectively, and the number of cell layers was also higher as indicated by 3−4 layers more. The stylo retaining BLCs had strong aluminum resistance. Moreover, compared with sugar-free control, BLCs induced by sucrose showed stronger Al absorption ability, this subsequently enhanced the stylo Al resistance as indicated by the lower root tip Al accumulation and higher root relative growth rate, which increased by 45%.

Conclusion Sucrose can promote BLCs formation in stylo, and subsequently enhance the stylo Al resistance. These results expand the knowledge on the development of BLCs and their function in stylo Al resistance.