NAA-BAP Effects on Callus Induction and Morphology in Gypsophila arrostii

Plant tissue culture is a key tool for propagation, biotechnological production, and ex situ conservation because dedifferentiation can be directed under controlled conditions. Here, we quantitatively assessed the effects of 1-naphthaleneacetic acid (NAA) and 6-benzylaminopurine (BAP) combinations on callus induction and morphological outputs (color and size) in Gypsophila arrostii leaf explants. Callus formation was obtained in 208 out of 273 explants, with induction rates ranging from 65.57% to 93.33% across media. The highest induction occurred on 2.0 mg/L NAA + 1.0 mg/L BAP (93.33%) and 2.0 mg/L NAA + 0.5 mg/L BAP (90.38%). Callus color composition varied among treatments: a pronounced yellow-dominant profile emerged under 1.5 mg/L NAA + 0.5 mg/L BAP, whereas the remaining treatments generally showed white-dominant or near white–yellow distributions. Most calli fell within the 0.3-0.6 cm size class, and size-class distributions did not differ significantly among hormone combinations. Overall, our findings indicate that auxin-cytokinin balance is likely a major determinant of callus induction performance in G. arrostii, providing a data-driven baseline for protocol optimization and subsequent regeneration-oriented studies.