Natures wonders: no photsynthesis, no pollination (Introduction)

by David Turell , Saturday, October 15, 2016, 18:40 (2959 days ago) @ David Turell

The plant lives off a fungus food supply and develops closed flowers that self-fertilize internally:

https://www.sciencedaily.com/releases/2016/10/161014092115.htm

A new species of plant has been discovered on the subtropical Japanese island of Kuroshima (located off the southern coast of Kyushu in Kagoshima prefecture) and named it Gastrodia kuroshimensis.... However, G. kuroshimensis was a particularly special discovery because it is both completely mycoheterophic, deriving its nutrition not from photosynthesis but from host fungi, and completely cleistogamous, producing flowers that never bloom.

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G. kuroshimensis was a particularly special discovery because it is both completely mycoheterophic, deriving its nutrition not from photosynthesis but from host fungi, and completely cleistogamous, producing flowers that never bloom.

Cleistogamy, literally meaning 'a closed marriage', refers to plants that produce flowers in which self-fertilization occurs within closed buds. This mechanism of reproduction has intrigued botanists since the time of Darwin, and is now recognized as an important mechanism of self-pollination that is found in a diverse range of plant taxa. However, most cleistogamous species also produce chasmogamous (cross-pollinating) flowers. Cleistogamous flowers are considered a bet-hedging strategy, since they require less resources than chasmogamous flowers, and because they can provide reproductive assurance by setting seeds in the absence of pollinators and under disadvantageous environmental conditions. In addition, cleistogamous flowers can also promote adaptation to local habitats, as both maternal sets of genes can be passed onto the progeny, purging deleterious alleles (gene variants which are generally harmful). However, this is a somewhat risky strategy as the progeny are also less able to adapt to changes in spatially and temporally heterogeneous habitats.

The evolution of complete cleistogamy is therefore somewhat of a mystery. Chasmogamous flowers are an important factor in the success of most plants as even a small degree of outcrossing can result in a relatively rapid decline in linkage disequilibrium across the genome, and is sufficient to overcome the negative effects associated with an absence of effective recombination, such as the accumulation of deleterious mutations and a slowdown in the rate of adaptation. The discovery of G. kuroshimensis, therefore, provides a useful opportunity to further investigate the ecological significance, evolutionary history, and genetic mechanisms underlying the evolution of complete cleistogamy.

Comment: The symbiosis with a fungus is not unusual, but the reproductive method is like the hermaphroditic reproduction seen in animals. An odd twist to the usual evolutionary developments. It indicates that evolutionary progress is open to many, many roads that lead to survival.