Wow thanks man this is very interesting. I've been reading alot about rhododendrons in this area all very interrelated
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Dasiphora fruticosa comprises male, female and hermaphrodite plants, which are distributed sympatrically in some populations on the Qinghai-Tibet Plateau. To explore what governs the coexistence of these three sexual phenotypes, we investigated the DNA contents, pollen and ovule production, pollen deposition, and performed hand-pollination in both hermaphroditic and dioecious individuals of D. fruticosa. Flow cytometry confirmed that the DNA content of males and females were almost twice as much as that of the hermaphrodites. Male and female flowers produced more pollen grains and ovules than hermaphroditic flowers. Hand-pollinated treatments showed that unisexual flowers were sterile in one sexual function and bisexual flowers were fertile for both functions, but no sterile seeds were produced between unisexual and bisexual flowers. Our findings imply that polyploidy is related to gender dimorphism, and both are likely to play a strong role in the coexistence of two cryptic biological species of D. fruticosa (low ploidy hermaphroditic species and high ploidy dioecious species) in the Qinghai-Tibet Plateau.
1. Introduction
Most flowering plants are hermaphroditic, and unisexual individuals (dioecious) have evolved from hermaphroditic ancestors many times (Renner, 2014). Trioecy is an uncommon sexual system in which hermaphrodites, females, and males coexist in some species. Trioecy occurs during the evolutionary transition from hermaphroditism to dioecy (Charlesworth and Charlesworth, 1978, Ross, 1982, Spigler and Ashman, 2012). Trioecy is a stable evolutionary stage under pollen limitation of female seed production because pollen limitation reduces the fitness of females but not self-fertile hermaphrodites, counteracting the seed fertility advantage of females (Maurice and Fleming, 1995). However, previous research has shown that this sexual system is not stable because when the conditions that enable invasion by females into androdioecious populations are the same as those that result in the displacement of hermaphrodites by females, the sexual system will become dioecy (Perry et al., 2012, Wolf and Takebayashi, 2004). Thus, the stable coexistence of hermaphroditic and dioecious plants remains poorly understood.
Ploidy level (diploid and polyploid) and gender polymorphism (dioecy, gynodioecy, subdioecy, and trioecy) are associated in several flowering plant genera (Miller et al., 2016, Miller and Venable, 2000, Pannell et al., 2004, Ramsey and Ramsey, 2014, Spigler and Ashman, 2012). For example, in Lycium, polyploidy is a trigger for the evolution of gender dimorphism in self-incompatible groups (Miller and Venable, 2000, Miller and Venable, 2002). In Leptinella, gender dimorphism has evolved from monoecy; and, dioecy has been found in two tetraploid species (Himmelreich et al., 2012)……
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