Cleistogamy and phylogenetic position ofViola uliginosa(Violaceae) re-examined

Abstract

Viola uliginosa is an endangered species throughout its range in Central Europe. Based on an unusual combination of morphological characters, including a reported lack of cleistogamous (CL) flowers, it was previously placed in the monotypic subsection Repentes, section Viola. Available individual phylogenetic analyses identify V. uliginosa as a lineage deeply embedded in section Viola, but hitherto its exact position was unknown. Here we confirm the occurrence of cleistogamy in V. uliginosa. Unlike other species of section Viola, V. uliginosa produced both chasmogamous and CL flowers at the same time, not at different times of the year (seasonal cleistogamy). The two flower types differed conspicuously in morphology and microstructure, especially in size and shape of the pistil and stamens as confirmed by scanning electron microscopy. Secondly, we resolved the phylogenetic position of V. uliginosa as a lineage deeply embedded in subsection Rostratae by means of a multigene multispecies coalescent analysis using *BEAST. In this analysis, V. mirabilis and V. uliginosa were successive sisters to the rest of subsection Rostratae and, because allopolyploids exist between V. mirabilis and the last one, subsection Rostratae needs to comprise all these taxa to be monophyletic. The evolution of key morphological traits is briefly discussed.

Using genomic information for management planning of an endangered perennial, Viola uliginosa

“…Viola uliginosa reproduces primarily by clonal propagation using subterranean stems (Cieślak, Paul, & Ronikier, ; Paul et al, ), but it also forms seeds that are able to exist in a seed bank and can be viable for years (Ranta & Siitonen, ). Individual plants can develop both chasmogamous (CH, open flowers, enabling cross‐pollination) and cleistogamous (CL, closed flowers, resulting in obligatory self‐pollination) flowers, as well as intermediate forms (semi‐CL) (Małobęcki et al, ). Pollination in this species has not been studied in detail, but cross‐pollination occurs by several species of bees, hoverflies, and flies, as in other Viola species, in addition to self‐pollination (Beattie, ).…”

Low Genetic Diversity of Declining Viola uliginosa (Violaceae) at its Southern Range Limits in Poland

“…In each of the studied populations, significant influence of clonality on genetic diversity has also been detected. Although non-seasonal cleistogamy based on simultaneous presence of chasmogamous (CH) open, self-and cross-pollinated flowers and CL, closed, obligatorily self-pollinated flowers, has recently been detected in the NDB population (Małobęcki et al, 2016), so far it has not been observed in other V. uliginosa populations. It has been demonstrated that cleistogamy might influence the genetic structure of violets' populations.…”

“…It has chasmogamous (CH) flowers and its lack of cleistogamous (CL) flowers had been assumed before (Becker, 1925;Zabłocki, 1947;Valentine, 1968;Kuta, 1978;Marcussen and Karlsson, 2010). However, the presence of cleistogamy has recently been recorded for the first time in one of the Polish populations (Nowa Dęba, NDB; Małobęcki et al, 2016). Genetic studies on the locus classicus population (Cieślak et al, 2006) revealed its very low genetic diversity, thus the question arose, whether it is characteristic of the species over a wider range or only of that very limited declining population.…”

“…Recent studies by means of a multigene multispecies coalescent analysis (Marcussen et al, 2015;Małobęcki et al, 2016) have indicated V. uliginosa as a strongly supported lineage within subsect. Rostratae Kupffer of section Viola which was also supported by the presence cleistogamy (common in Rostratae) recorded recently (Małobęcki et al, 2016). Close relationship of V. uliginosa with the subsect.…”

紫花地丁两型花相互转变过程中花部形态结构的变化式样研究

“…A long photoperiod could inhibit the development of partial stamens and petals, and a short photoperiod could prevent the suppression of long-day light and promote the development of stamens and petals. (Stebbins, 1957;Beattie, 1976;Solbrig, 1976), 降低自交衰退及由生境改变 而 引 起 的 灭 绝 风 险 (Schemske, 1978;Schoen & Lloyd, 1984); 而闭锁花绝对的自交能在远交不利的 情 况 下 为 植 物 提 供 繁 殖 保 障 (Schemske, 1978;Campbell, 1982), 保存有利的基因型 (Stebbins, 1957;Beattie, 1976;Solbrig, 1976), 防止有害基因渗入 (Waller, 1984), 减少因吸引传粉者所需的能量投入 (Solbrig, 1976;Schemske, 1978;Waller, 1979), 并在 不利的环境下保护花的生殖器官 (Campbell, 1982;Campbell et al, 1983)。 堇菜属(Viola)广泛分布在北温带及热带地区的 山地森林中 (Wahlert et al, 2014), 全球有525-600种, 其中, 80多种具有开放花与闭锁花的混合繁育系统 (Culley & Klooster, 2007), 且在一些物种中有形态 介于开放花与完全闭锁花之间的过渡闭锁花类型 (Lord, 1981;Culley & Klooster, 2007;Li et al, 2016;Malobecki et al, 2016) Hardenack et al, 1994;Ainsworth et al, 1995;Kater et al, 2001;Li et al, 2012)。在紫花地丁中, 两型花 的形态差异也出现在花芽发育的中后期, 部分花器…”