Photomixotrophic growth response of sugarcane "in vitro" plantlets using different light intensities and culture vessel types

Sugarcane is a very important crop in tropical areas around the world. Optimizing the light intensity and culture vessel for sugarcane in vitro propagation can improve protocols for large-scale in vitro mass clonal propagation. The objective of this study was to evaluate biométrie and anatomical characteristics of in vitro propagated sugarcane plantlets using different light intensities and culture vessel types. The study also aimed to stimulate desired photoautotrophic and/or photomixotrophic traits and to study correlations between survival and ex vitro vigor with in vitro data. Fluorescent lights at 70 µmol m⁻²s⁻¹ and light-emitting diodes (LEDs) at 120 and 200 m⁻²s⁻¹ were used combined with different culture vessel types, including microboxes without a filter, microboxes with a filter, and baby food jars. Propagation and rooting growth were observed in all in vitro culture conditions. However, an increase in light intensity and change of culture vessel type provided improved results. When sugarcane plantlets were cultivated within microboxes with a filter under 120 and 200 m⁻²s⁻¹, they showed improved growth, increased chlorophyll content, the lowest leaf yellowing percentage, an increase in bulliform cells and, consequently, increased leaf thickness under in vitro culture. After 60 d in greenhouse conditions, in vuro-derived plantlets under LEDs and microbox culture vessels showed the highest biométrie values and high ex vitro survival.