Nav: Home

Closed marriage: An orchid that never blooms

January 11, 2018

Video: https://www.youtube.com/watch?v=Y0SBE_J7bxo

Lecanorchis nigricansin Kami City, Kochi Prefecture. Timelapse footage created from shots taken every 30 minutes between July 27 and August 27, 2017. The plant does not bloom for the whole month, but despite this it still bears fruit.

A flower identified as Lecanorchis nigricans has been revealed to be a different identity, Lecanorchis nigricans var. patipetala. Both species are self-pollinating, but the flowers of the true L. nigricans never open.

The findings were made by Associate Professor SUETSUGU Kenji (Kobe University), FUKUNAGA Hirokazu (independent botanical researcher), SHIMAOKA Chie and Professor SAWA Shinichiro (both Kumamoto University). The research was published in the online edition of Phytokeys on January 7.

Some plants have evolved to be parasites, feeding off host fungi. These plants are known as mycoheterotrophs. They don't photosynthesize, so they only show themselves above ground for brief periods when fruiting or in flower. This makes them hard to find and classify, and the true identities of many species remain a mystery. Professor Suetsugu works with other researchers to document mycoheterotrophic plants in Japan.

Professor Suetsugu's research team noticed that L. nigricans (found in Japan's Miyagi prefecture and Kochi prefecture) bears fruit without blooming at all. The flower has spatula-shaped purple-tipped petals that don't branch. From these characteristics the team were able to identify it as L. nigricans or a close relative. However, the species known as L. nigricans is documented as having flowers that fully open. This open-flower (chasmogamous) L. nigricans is found in many parts of Japan.

L. nigricans was first discovered in 1931 by HONDA Masatsugu in Japan's Wakayama prefecture. In the plant description, he wrote "The flowers are not open, and the petals are connected to form a cylindrical tube". From this description, it seems that the original L. nigricans did not bloom (cleistogamous). Professor Suetsugu's team went to the place where L. nigricans was first discovered and verified that the species of L. nigricans in this region never opens its flowers (fig. 1). In other words, the original L. nigricans is the variety that does not bloom. After further examination, the team found that this variety has other features that distinguish it from the open-flower L. nigricans: the closed-flower variety has smaller flowers, the colored area of the petals is larger, and the hairs at the end of the petals are branched.

So what should we call the more common open-flower variety, if it is not L. nigricans? In 1981, SAWA Yutaka presented the open-flowering variety found in Kochi prefecture as L. nigricans var. patipetala. However, his description of the plant was very brief, and it was hard to go against the general assumption that L. nigricans is an open-flowering plant.

L. nigricans var. patipetala is generally the more common variety in Japan (in Kochi prefecture the closed-flower L. nigricans is more common). This may have led to the widely-held misconception that the L. nigricans var. patipetala is L. nigricans. It is now clear that the species discovered by SAWA Yutaka is the same as the open-flower L. nigricans in other locations (see fig. 2).

As well as abandoning photosynthesis, the L. nigricans also self-pollinates - its flowers remain buds until they fall. Non-photosynthesizing plants such as L. nigricans often grow on the dark forest floor, an environment that bees and butterflies rarely visit. Because of this, L. nigricans and L. nigricans var. patipetala are both self-pollinating species. L. nigricans may have stopped opening its flowers because this used up too many resources. Similar evolutionary patterns are occurring in other mycoheterotrophic plants.

"When plants give up photosynthesis, this changes their relationship with other organisms, such as the insects who may pollinate them", comments Professor Suetsugu. "Through taxonomic and ecological research on mycoheterotrophs, I will continue to study the changes that take place when plants make the extreme decision to abandon photosynthesis".
-end-


Kobe University

Related Photosynthesis Articles:

Strange bacteria hint at ancient origin of photosynthesis
Structures inside rare bacteria are similar to those that power photosynthesis in plants today, suggesting the process is older than assumed.
Just how much does enhancing photosynthesis improve crop yield?
In the next two decades, crop yields need to increase dramatically to feed the growing global population.
Algal library lends insights into genes for photosynthesis
To identify genes involved in photosynthesis, researchers built a library containing thousands of single-celled algae, each with a different gene mutation.
New molecular blueprint advances our understanding of photosynthesis
Researchers at Lawrence Berkeley National Laboratory have used one of the most advanced microscopes in the world to reveal the structure of a large protein complex crucial to photosynthesis, the process by which plants convert sunlight into cellular energy.
How bacteria build hyper-efficient photosynthesis machines
Researchers facing a future with a larger population and more uncertain climate are looking for ways to improve crop yields, and they're looking to photosynthetic bacteria for engineering solutions.
More Photosynthesis News and Photosynthesis Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Erasing The Stigma
Many of us either cope with mental illness or know someone who does. But we still have a hard time talking about it. This hour, TED speakers explore ways to push past — and even erase — the stigma. Guests include musician and comedian Jordan Raskopoulos, neuroscientist and psychiatrist Thomas Insel, psychiatrist Dixon Chibanda, anxiety and depression researcher Olivia Remes, and entrepreneur Sangu Delle.
Now Playing: Science for the People

#537 Science Journalism, Hold the Hype
Everyone's seen a piece of science getting over-exaggerated in the media. Most people would be quick to blame journalists and big media for getting in wrong. In many cases, you'd be right. But there's other sources of hype in science journalism. and one of them can be found in the humble, and little-known press release. We're talking with Chris Chambers about doing science about science journalism, and where the hype creeps in. Related links: The association between exaggeration in health related science news and academic press releases: retrospective observational study Claims of causality in health news: a randomised trial This...