Light spectra on in vitro seed germination of the Brazilian cactus Cereus jamacaru DC. subsp. jamacaru

In Brazil, the cactus species Cereus jamacaru DC. subsp. jamacaru, commonly referred to as mandacaru, thrives in arid and semiarid areas across the North and Northwest regions. The cultivation of Cactaceae has expanded because of their excellent adaptability for foraging and their ornamental features. This study aims to investigate the light spectra on in vitro seed germination of the Brazilian cactus Cereus jamacaru DC. subsp. jamacaru. Mandacaru seeds were cultivated in vitro under four light treatments: (1) 70% red + 30% blue light, (2) 100% white light (control), (3) 100% red light (645–675 nm), and (4) 100% blue light (450–465 nm). Plant growth was evaluated at 35, 64 and 125 days after introduction. The morphological characteristics of seedlings evaluated were number of roots, root and shoot length, and seedling thickness. In contrast, the variables primary root protrusion, horn appearance, and germination were assessed daily during the initial 35 days after introduction. Exposure to red light accelerated germination and promoted higher shoot length in mandacaru seedlings (p < 0.05). This is the first report on measuring the effects of light spectra on in vitro seed germination of the Brazilian cactus mandacaru.