Asterarcys Quadricellulare Triggers Bioactive Amines Promoting Sugarcane Sprout and Growth

Abstract

The production of pre-sprouted seedlings using mini-setts brings advantages over the conventional method of planting, which uses larger sections of stalk. Sugarcane planting using propagules from different stalk sections can impair the sprouting rate and initial development of plants, which restricts yield. Thus, biofertilizers, by stimulating sprouting and regulating plant growth, can reduce losses from unsprouted propagules and boost their development. The hypothesis that the bioactivity of Asterarcys quadricellulare is related to its composition in polyamines and L-amino acids was investigated in the early development of sugarcane (RB036152). Sugarcane propagules were immersed in A. quadricellulare biomass solution to assess its effect on sprouting and growth promotion in propagules from different sections of the stalk, analyzing biometric and biochemical changes. The immersion of the propagules in a 2.5 g L-1 solution of the microalga biomass increased the sprouting rate and boosted plant growth, especially in apical and medial propagules. Metabolic changes were also promoted by the microalga biomass. The accumulation of total sugars in the propagules was higher in the sections treated with microalga, the same occurred on leaves from apical and basal propagules. The application of microalga also increased the levels of bioactive amines, such as spermidine in the propagules and spermine in the culms. The biofertilizer also increased the levels of tryptophan in the propagules and serotonin in the leaves, when compared to the control. This work demonstrated the bioactivity of A. quadricellulare biomass and its interaction with different physiologic ages of mini-setts of sugarcane.