Morphological and reproductive differences among three charophyte species in response to variation in water depth

Abstract

Some charophyte species reproduce sexually by oospores and vegetatively by bulbils, and the proportion of branch whorls that contain reproductive organs can be used as quantitative measures of the degree of sexual reproduction. We examined inter-specific differences in the proportion of bulbils (PB) by total weight and the proportion of branch whorls containing gametangia (PG) or oospores (PO), as well as morphological and physiological differences among 3 charophyte species (Chara vulgaris Linnaeus, Chara braunii Gmelin, and Nitella gracilens Morioka) responding to variation in water depth (0.5, 1, 1.5, 2, and 3 m) in an outdoor experiment. A 2-way ANOVA contrasting species and water depth revealed that shoot elongation and the chlorophyll a to carotenoid (chl a/caro) ratio were primarily affected by water depth. However, variation among species contributed more than water depth to the differences in weight, sexual reproduction (PG and PO), and the chl a/chl b ratio. Additionally, variation among species contributed almost equally to the differences in PB that occurred among different water depths. Both Chara species extended their shoots and increased their PB in response to increasing water depth (from 0.5 to 1.5 m). However, deeper water (2 and 3 m) led to elongated shoots as well as decreased PB, PG, and PO. For N. gracilens, elongated shoots with increased water depth (from 0.5 to 3 m) occurred at the expense of both vegetative (decreased PB) and sexual reproduction (reduced PG and PO).

Persistence of submerged macrophytes in a drying world: Unravelling the timing and the environmental drivers to produce drought‐resistant propagules

“…Several life-history traits of the species, such as the breeding system (monoecy versus dioecy), are related to the different allocation of resources and can explain these distinct phenologies (Casanova & Brock, 1999). Species-specific phenological patterns in charophytes were already identified from a preliminary analysis of data from these ponds (Calero et al, 2015), and from previous studies (Auderset Bonis et al, 1993;Casanova & Brock, 1999;Wang, Liu, & Yu, 2015).…”

Ecology of charophytes – permanent pioneers and ecosystem engineers

“…Charophytes have three options to establish stands: A) vegetative growth from omnipotent nodal cells (Skurzyński and Bociąg 2011), B) vegetative growth from bulbils (Asaeda et al 2007;Wang et al 2015) or, C) germination of sexually produced oospores. Charophytes exhibit apical dominance, so lower nodal cells are activated "automatically" when the apical cell is removed or damaged (Schubert et al 2016;Kuczewski 1906;Pringsheim 1863).…”

“…Conversely some charophyte species in shallow waters need protection from high light intensity and UV-B radiation. These species can produce high concentrations of carotenoids, which protect the plants (in particular antheridia) from excessive light intensity (Wang et al 2015).…”

Hydrologic and anthropogenic influences on aquatic macrophyte development in a large, shallow lake in China

“…and a decline in Nymphaeaceae trichosclereids, but with continued presence of N. minor . Charophytes, which are overwintering species that thrive under stable, clear, and low to medium nutrient conditions, can change their reproductive behaviour to adjust to changes in water levels (Wang, Liu, & Yu, ); for instance, sexual reproduction and maturation of oospores are stimulated by decreasing water levels (Casanova, ; Casanova & Brock, ) and increasing light intensity (Wang & Yu, ). The abundance of Nymphaeaceae remained low during this phase, suggesting that water lilies retreated to the lake fringe.…”