Sexual lability during an individual’s life: the case of the sedge Carex secalina

7 May 2019

Lembicz, Marlena; Bogdanowicz, Agnieszka; Żukowski, Waldemar

Various environmental and physiological factors that affect sex expression in plants have been identified. We made a presumption that in perennials, age may be a key factor that significantly diversifies sex expression over consecutive years of an individual’s life. To verify this hypothesis, we chose the sedge Carex secalina, a plant that reproduces only sexually and exhibits different sex expression patterns. These patterns had been previously observed in natural populations. In a four-year experiment, the sex of spikes formed on reproductive tillers of 100 individuals originating from three populations was monitored. A significant association between individuals’ age and number of female/male spikes was found for each population. In addition, significant differences between the populations in the ratio of shoots with bisexual spikes to shoots with unisexual spikes were revealed. We also showed that the proportion of shoots with bisexual spikes in the individual populations changed significantly with the age of an individual and that in the successive years of the individual’s life, the production level of female and male structures changed. Moreover, an age-dependent decrease in both the number and length of female and male spikes was observed.