University of Tehran International Journal of Horticultural Science and Technology 2322-1461 12 1 2025 01 01 Comprehensive Analysis of Pollen Viability, in vitro Germination, and Self-incompatibility in Hamelia patens Jacq. Pollen 145 156 100058 10.22059/ijhst.2024.372736.782 EN ANUKRISHNA KANNERI SREE NEELAKANTA GOVERNMENT SANSKRIT COLLEGE, PATTAMBI RESMI MOHANKUMAR SARALADEVI SREE NEELAKANTA GOVERNMENT SANSKRIT COLLEGE, PATTAMBI RAMSEENA VADAKKETHIL RASACK SREE NEELAKANTA GOVERNMENT SANSKRIT COLLEGE, PATTAMBI VIVEK PADMANABHAN JAYANTHIKUMARI SREE NEELAKANTA GOVERNMENT SANSKRIT COLLEGE, PATTAMBI Journal Article 2024 02 20 Pollen or male gametophyte ensures genetic exchange, establishment, as well as survival of higher plants. Experiments were conducted to explore pollen viability, in vitro pollen germination, and in vivo pollen tube growth in Hamelia patens Jacq., a promising plant from the Rubiaceae family. Among the various staining techniques applied, the modified Alexander staining method emerged as the most effective for assessing pollen viability in this species. This method’s viability results (81.80%) closely matched the highest pollen germination rate observed in in vitro experiments (81.33%). In vitro analyses revealed that incorporating an optimal sucrose concentration (10%) along with lower boron (0.01%) and calcium (0.01%) concentrations in the artificial medium significantly enhanced both pollen germination percentage and pollen tube growth rate. Isolated application of these factors was not as effective in increasing germination rates. In contrast, their combined use substantially improved pollen germination and tube elongation. Moreover, in vivo pollen germination studies utilizing aniline blue fluorescence microscopy reinforce previous reports of a self-incompatibility system in this species, confirming that it does not involve a late-acting self-incompatibility (LSI) system or ovarian sterility (OS). https://ijhst.ut.ac.ir/article_100058_d43cacbb247b917d6286494f6e2bb509.pdf