Using LED lighting in somatic embryogenesis and micropropagation of an elite sugarcane variety and its effect on redox metabolism during acclimatization

Abstract

This study investigated the ability of a light emitting diode (LED) to induce somatic embryogenesis (SE), shoot multiplication, and rooting of sugarcane (RB98710). We also accessed the effects on acclimatization. MS medium was used for all stages and was supplemented with different concentrations of growth regulators according to the culture stage. The material was maintained in a growth room under fluorescent (FL) or LED (82 % red, 18 % blue) lighting after rooting plants were acclimatized. We conducted both biometric and biochemical analyses before and after acclimatization. The LED conditions favored the formation of callus; however, the FL was more efficient at plant regeneration. A histological analysis showed the formation of somatic embryos occurred through direct and indirect pathways. The plants obtained through SE and grown under LED had a higher multiplication rate over six subcultures. Shoots rooted in both light sources, but the number of shoots and the weight gain of the roots were higher under LED. The malondialdehyde (MDA) level did not differ among treatments. Our results indicate the SE induction phase should be conducted under FL and the remaining micropropagation process should be performed using LED. After acclimatization the plants grown under LED did not change the SOD and CAT activities during the first 5 days, which suggests there was no acclimatization impact. The H2O2 and MDA values observed do not suggest damage to membranes. There was better development, lower water loss, and higher survival rate in plants from in vitro culture under LED conditions when compared to FL.