Background <p>Bryophytes are the earliest known plant lineage that switched to invade land from their aquatic predecessors. Therefore, they might have evolved with cytoskeleton modifications to cope with adverse environmental stress. Microtubule dynamics/modifications have often been shown to be correlated with stress. Here, using <i>Physcomitrium patens</i> as a model, we tried to evaluate (i) the occurrence of tubulin post-translational modifications (PTMs) in the earliest known land plant lineage and (ii) the impact of different light, phytohormones, temperature and exogenous calcium (Ca²⁺).</p> Result <p>Here, we (i) use in silico analysis to show that the key enzymes responsible for tubulin PTMs are conserved in various mosses, (ii) perform microscopy to detect the modified protein, and (iii) assess the abundance of tyrosinated, acetylated and polyglutamylated α-tubulin under different environmental stresses. We also visualise the calcium dynamics in moss using a GCaMP6f <i>P. patens</i> line. Notably, we demonstrate for the first time that red and far-red light increase the levels of polyglutamylated tubulin in protonemal cells. Additionally, the exogenous application of auxin and cytokinin significantly affects the abundance of tyrosinated and polyglutamylated tubulin, respectively. Furthermore, we demonstrate the trends in the abundance of modified tubulin under different temperatures and Ca²⁺-treatment. We also show that the flux of intracellular Ca²⁺ is influenced by auxin and cytokinin, temperature, and exogenously applied Ca²⁺.</p> Conclusion <p>The current work demonstrates unequivocally the PTMs of tubulin during land plant evolution and its possible role in stress adaptation. The dynamic accumulation of modified tubulin in <i>P. patens</i> is differentially regulated in response to abiotic factors. This study is relevant in the context of global warming, temperature-induced cell damage as observed in different crops, and the development of improved modern agricultural practices.</p>