Tools and Techniques to Quantify PGR Content in Plants

Plant growth regulators play a pivotal role in finely tuning plant growth, development, and responses to environmental cues. Advancing our understanding requires insights into hormone structure, distribution at various levels, and the genes governing the hormone process. Qualitative analysis of plant hormones in minute quantities poses challenges, leading to the development of sensitive techniques. Modern mass spectrometry (MS)-based methodologies have replaced early bioassays and immunoassays. While MS presents challenges like matrix interference, triple-quadrupole mass spectrometers (QQQ) excel in targeted quantitative analysis, allowing multiple reaction monitoring (MRM) or selected reaction monitoring (SRM). Gas chromatography (GC) and liquid chromatography (LC) coupled with MS, such as GC-MS and LC-MS/MS, quantify PGRs. HPLC-MS/MS is preferred for its high sensitivity and specificity. Challenges like matrix interference are addressed by QQQ, making it suitable for complex samples. Gas chromatography is limited to volatile and thermostable PGRs. This chapter delves into techniques like HPLC-MS, GC, LC, QQQ, and the tobacco syringe agroinfiltration assay for PGR quantification. Updated protocols for detecting and quantifying PGRs in plant tissues are also highlighted, providing comprehensive insights into PGR analysis.