Minimal assay detects population-level senescence in the aquatic plant <i>Lemna minor</i>

Abstract

At the population level, senescence occurs when older individuals have increased risk of death and reduced reproduction compared to younger individuals. We investigated senescence in the aquatic plant <i>Lemna minor</i> (common duckweed), an important species for plant senescence research. Our objectives were to (1) confirm or refute the presence of population-level senescence in this model species; (2) develop a minimal assay of senescence requiring only once-weekly data collection; and (3) test whether there were appreciable differences in senescence in plants grown in glass compared to polystyrene petri dishes, with an aim to reducing single-use plastic waste and long-term research materials costs. We found that weekly survival arced downward with age when viewed on a semi-log plot, and weekly production of descendants decreased with age, with both findings indicating population-level senescence that matched previous work using more frequent data-collection (per Objectives 1 and 2). Additionally, we found no noteworthy differences in senescence between plants grown in glass versus polystyrene petri dishes (per Objective 3). The use of weekly data collection could liberate personnel resources for other research-group functions, and could make the <i>Lemna</i> system suitable for senescence- or demography-education exercises. The use of glass dishes could reduce lab waste and expense.