Light Conditions and Auxin Influence the In Vitro Efficiency of Rooting and Acclimatization of Pennisetum ‘Vertigo®’

This paper reports an efficient in vitro rooting and acclimatization method for Pennisetum ‘Vertigo®’. For that purpose, the influence of the IAA (indole-3-acetic acid) in MS (Murashige and Skoog) media, and different types of LED light (100% blue, 100% red, a combination of red and blue (70% + 30%), a combination of red, blue with yellow, green, or far-red (35% + 15% + 50%), and white LED) were investigated. A fluorescent lamp and a medium without auxin were used as controls. Subsequently, the plants were transferred ex vitro in trays to the greenhouse and later transplanted into pots. In all tested combinations, the shoots rooted at a high rate of 70–100% (except under blue light). The best results were obtained under white LED or the fluorescent lamp, where the highest number of roots was formed; however, IAA did not increase the rooting rate, the number, or the weight of roots. Shoots rooted under LEDs and on media containing IAA generally exhibited higher soluble sugar content compared to those rooted on auxin-free media. Consistent with the rooting results, the best acclimatization was observed in plants rooted under white LED or fluorescent light on auxin-free media.