LAZing around: The intricate dance of amyloplast sedimentation and gravity sensing in plants

Gravitropism, the remarkable ability of plants to adjust their growth in response to gravity, is fundamental to their existence on Earth. Pioneering research on gravitropism can date back to the work in the 1880s, notably by Charles and Francis Darwin, who documented root positive gravitropism and stem negative gravitropism ( Baldwin et al., 2013 Baldwin K.L. Strohm A.K. Masson P.H. Gravity Sensing and Signal Transduction in Vascular Plant Primary Roots. Am. J. Bot. 2013; 100: 126-142 Crossref PubMed Scopus (100) Google Scholar ). The starch–statolith hypothesis, proposed in 1900, has played a key role in understanding how plants perceive and respond to gravity ( Baldwin et al., 2013 Baldwin K.L. Strohm A.K. Masson P.H. Gravity Sensing and Signal Transduction in Vascular Plant Primary Roots. Am. J. Bot. 2013; 100: 126-142 Crossref PubMed Scopus (100) Google Scholar ). It was hypothesized that amyloplasts filled with starch in gravity-sensing cells act as statoliths, descending within cells to indicate the direction of gravity.