Microbes growing on flowers have adverse effects on their fruit yields. This is why plants are quick to shed their flowers, reveals a new study involving both field experiments and plant microbiome analyses.
Microbes growing on flowers have adverse effects on their yields. This is why plants are quick to shed their flowers, reveals a new study involving both field experiments and plant microbiome analysis.
Scientifically speaking, flowers are a reproductive structure of a plant. Unlike mammals, though, perennial plants develop those de novo every season and only retain them for as long as needed.
While a few earlier studies have already looked into the variation in flower lifespan among species, they were mainly concerned with the tradeoff between plants spending energy on producing and maintaining their flowers, and the benefit they would achieve from retaining their reproductive organs.
Prior to the present study, however, the team found another perspective to look at the phenomenon: why did plants invest their energy – even if the ‘cost’ was minimal – to produce fragile flowers that would wither in a matter of days, rather than investing a bit more of it to produce a lot more durable ones, thereby increasing their reproductive success?
Flowers provide various habitats for microbes. They attract pollinators by secreting nectar, which is rich in sugars, and often contains other nutrients, such as amino acids and lipids. The stigma is a germination bed for pollen grains connected to a growth chamber for pollen tubes. It maintains humidity and nutrients necessary for pollen tube growth. Not surprisingly, abundance of the microbes increases over time on individual flowers after it opens.
Before jumping to their conclusions, the scientists set out to conduct field experiments to see what microbial communities would appear on flowers if their longevity was prolonged.
To do this, they took microbes from old flowers of wild ginger (Alpinia japonica) – a species found in Japan and blooming in the early summer when the hot and humid weather in the country is ideal for microbial growth. Then, they transferred the microbes to other wild ginger plants, whose flowers had just opened.
In line with their initial hypothesis, the research team noted that the plant produced significantly fewer fruits, yet there were no visible symptoms on the flowers or fruits to suggest a disease. However, an analysis of the plants’ microbiomes revealed the presence of several groups of bacteria that were increasing with time. As these bacteria can also be found on the flower buds of flowers that have not been treated, the bacteria is categorised as “resident” for the plant.
“So far, flower characteristics have mostly been studied in the context of their interactions with pollinators. Recent studies have raised the question whether we have overlooked the roles of microbes in the studies of floral characteristics.
For example, flower volatiles – which are often regarded as a primary pollinator attractant – can also function to suppress antagonistic microbes. The impacts of microbes on plant reproductive ecology may be more deeply embedded in the evolution of angiosperms than we have considered,”
Jiménez Elvira N, Ushio M, Sakai S (2022) Are microbes growing on flowers evil? Effects of old flower microbes on fruit set in a wild ginger with one-day flowers, Alpinia japonica (Zingiberaceae). Metabarcoding and Metagenomics 6: e84331. https://doi.org/10.3897/mbmg.6.84331
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Scientific names get chosen for lots of reasons: they can honor an important person, or hint at what an organism looks like or where it’s from. For a tropical wildflower first described by scientists in 2000, the scientific name “extinctus” was a warning. The orange wildflower had been found 15 years earlier in an Ecuadorian forest that had since been largely destroyed; the scientists who named it suspected that by the time they named it, it had already become extinct. But in a new paper in PhytoKeys, researchers report the first confirmed sightings of Gasteranthus extinctus in 40 years.
“Extinctus was given its striking name in light of the extensive deforestation in western Ecuador,” says Dawson White, a postdoctoral researcher at Chicago’s Field Museum and co-lead author of the paper. “But if you claim something’s gone, then no one is really going to go out and look for it anymore. There are still a lot of important species that are still out there, even though overall, we’re in this age of extinction.”
The rediscovered plant is a small forest floor-dweller with flamboyant neon-orange flowers.
“The genus name, Gasteranthus, is Greek for ‘belly flower.’ Their flowers have a big pouch on the underside with a little opening top where pollinators can enter and exit,” says White.
G. extinctus is found in the foothills of the Andes mountains, where the land flattens to a plane that was once covered in cloud forest. The region, called the Centinela Ridge, is notorious among biologists for being home to a unique set of plants that vanished when its forests were almost completely destroyed in the 1980s. The late biologist E. O. Wilson even named the phenomenon of organisms instantly going extinct when their small habitat is destroyed “Centinelan extinction.”
The story of Centinela was also an alarm to draw attention to the fact that over 97% of the forests in the western half of Ecuador have been felled and converted to farmland. What remains is a fine mosaic of tiny islands of forest within a sea of bananas and a handful of other crops.
“Centinela is a mythical place for tropical botanists,” says Pitman. “But because it was described by the top people in the field, no one really double-checked the science. No one went back to confirm that the forest was gone and those things were extinct.”
But around the time that Gasteranthus extinctus was first described in 2000, scientists were already showing that some victims of Centinelan extinction weren’t really extinct. Since 2009, a few scientists have mounted expeditions looking for G. extinctus was still around, but they weren’t successful. When White and Pitman received funding from the Field Museum’s Women’s Board to visit the Centinela Ridge, the team had a chance to check for themselves.
Starting in the summer of 2021, they began combing through satellite images trying to identify primary rainforest that was still intact (which was difficult, White recalls, because most of the images of the region were obscured by clouds). They found a few contenders and assembled a team of ten botanists from six different institutions in Ecuador, the US, and France, including Juan Guevara, Thomas Couvreur, Nicolás Zapata, Xavier Cornejo, and Gonzalo Rivas. In November of 2021, they arrived at Centinela.
“It was my first time planning an expedition where we weren’t sure we’d even enter a forest,” says Pitman. “But as soon as we got on the ground we found remnants of intact cloud forest, and we spotted G. extinctus on the first day, within the first couple hours of searching. We didn’t have a photo to compare it to, we only had images of dried herbarium specimens, a line drawing, and a written description, but we were pretty sure that we’d found it based on its poky little hairs and showy “pot-bellied” flowers.”
Pitman recalls mixed emotions upon the team finding the flower. “We were really excited, but really tentative in our excitement — we thought, ‘Was it really that easy?’” he says. “We knew we needed to check with a specialist.”
The researchers took photos and collected some fallen flowers, not wanting to harm the plants if they were the only ones remaining on Earth. They sent the photos to taxonomic expert John Clark, who confirmed that, yes, the flowers were the not-so-extinct G. extinctus. Thankfully, the team found many more individuals as they visited other forest fragments, and they collected museum specimens to voucher the discovery and leaves for DNA analysis. The team was also able to validate some unidentified photos posted on the community science app iNaturalist as G. extinctus.
The plant will keep its name, says Pitman, because biology’s code of nomenclature has very specific rules around renaming an organism, and G. extinctus’s resurrection doesn’t make the cut.
While the flower remains highly endangered, the expedition found plenty of reasons for hope, the researchers say.
“We walked into Centinela thinking it was going to break our heart, and instead we ended up falling in love,” says Pitman. “Finding G. extinctus was great, but what we’re even more excited about is finding some spectacular forest in a place where scientists had feared everything was gone.”
The team is now working with Ecuadorian conservationists to protect some of the remaining fragments where G. extinctus and the rest of the spectacular Centinelan flora lives on.
“Rediscovering this flower shows that it’s not too late to turn around even the worst-case biodiversity scenarios, and it shows that there’s value in conserving even the smallest, most degraded areas,” says White.
“It’s an important piece of evidence that it’s not too late to be exploring and inventorying plants and animals in the heavily degraded forests of western Ecuador. New species are still being found, and we can still save many things that are on the brink of extinction.”
Pitman NCA, White DM, Guevara Andino JE, Couvreur TLP, Fortier RP, Zapata JN, Cornejo X, Clark JL, Feeley KJ, Johnston MK, Lozinguez A, Rivas-Torres G (2022) Rediscovery of Gasteranthus extinctus L.E.Skog & L.P.Kvist (Gesneriaceae) at multiple sites in western Ecuador. PhytoKeys 194: 33–46. https://doi.org/10.3897/phytokeys.194.79638
Three new endemic orchid species were discovered in Ecuador and described in the open-access, peer-reviewed journal PhytoKeys. Lepanthes microprosartima, L. caranqui and L. oro-lojaensis are proof that Ecuador – one of the world’s megadiverse countries – hides much more biodiversity waiting to be explored.
For its size, Ecuador has an impressive biological diversity that harbours a unique set of species and ecosystems, many of them endemic or threatened. Because of this great biodiversity, most studies still focus on recording species richness and very little is known about how these species actually interact. This is why in 2017 Dr Catherine H. Graham from the Swiss Federal Institute for Forest, Snow and Landscape Research WSL, with support from the European Research Council and local NGO Aves y Conservation, initiated an ambitious project in the northwestern Andes of Ecuador to study the ecology of plant-hummingbird interactions along an altitudinal and land-use gradient.
To this end, researchers established 18 transects in areas of well-preserved cloud forest and sites at different altitude and with different levels of disturbance, and visited them monthly to count the flowers that attract hummingbirds and to place time-lapse cameras in flowering plants.
Several new species to science were discovered during the intensive botanical work of identifying the nearly 400 plant species recorded by the surveys and cameras. One of them is a new orchid species called Lepanthes microprosartima.
Found on the western slopes of Pichincha volcano in northern Ecuador, L. microprosartima is endemic to the Yanacocha and Verdecocha reserves, where it grows at 3200 to 3800 m above sea level in evergreen montane forest – remarkably, this species can thrive even under deep shade in the forest.
Over three years of monitoring, only 40 individuals of L. microprosartima were found, which suggests it is a rare species. Because of this, and because it is only found in a small area, researchers preliminarily assessed it as Critically Endangered according to IUCN criteria.
Within the same hummingbird monitoring project, another new orchid – Lepanthes caranqui – was discovered in eastern Pichincha. Around the same time, a different research group from the Pontifical Catholic University of Ecuador found the same species in Imbabura. While in Imbabura it was found growing in páramo, with small groups on roadside embankments, in Pichincha it grew in evergreen montane forest, on top of tree trunks or lower branches, in the company of other orchid species. Its name, Lepanthes caranqui, honors the Caranqui culture that historically occupied the areas where this plant grows.
But the wonders of Ecuadorean biodiversity don’t stop there – a research project of Ecuador’s National Institute of Biodiversity found another new species, as small as 3 cm, in the southwest of El Oro. Lepanthes oro-lojaensis was actually discovered on the border between El Oro and Loja provinces, hence its name. It was only found from one locality, where its populations are threatened by cattle ranching, fires, plantations of exotic species, and the collection of shrubs as firewood. This is why researchers believe it should be listed as Critically Endangered according to IUCN criteria.
These additions to the Ecuadorean flora are all described in the open-access, peer-reviewed journalPhytoKeys. They are proof that Ecuador – one of the world’s megadiverse countries – hides much more biodiversity waiting to be explored.
Suarez FT, López MF, Gavilanes MJ, Monteros MF, García TS, Graham CH (2021) Three new endemic species of Lepanthes (Orchidaceae, Pleurothallidinae) from the highlands of Ecuador. PhytoKeys 180: 111-132. https://doi.org/10.3897/phytokeys.180.62671
Orchids of the Boreal zone are rare species. Most of the 28,000 species of the Orchid family actually live in the tropics. In the Boreal zone, ground orchids can hardly tolerate competition from other plants — mainly forbs or grasses. So they are often pushed into ecotones — border areas between meadows and forests, or between forests and swamps.
Furthermore, there has been a decline in wild orchids all over North America and Eurasia, caused in part by human-induced destruction of their habitats, the transformation of ecosystems, and the harvesting of flowers from the wild.
In the Novosibirsk region, 30 orchid species have been found, and about 40 in the entire Siberia.
It is no coincidence that many orchids are included in regional and national Red Book lists, with dedicated protected areas created to preserve them. When specialists find high concentrations of orchid species in a small area, it is always a significant discovery, in terms of both science and ecology. A recent publication in the open-access, peer-reviewed scientific journal Acta Biologica Sibirica describes one such area.
About 15 years ago, local biology teacher Yuri Panov found a place with mass growth of 13 orchid species in the Novosibirsk region. Together with his students, he studied the territory and took care of it, hanging birdhouses. The place was informally called School Orchid Zapovednik.
In 2014, a wildfire from nearby farm fields broke out in the area. Fortunately, the orchid populations did not suffer much – in fact, this disturbance partially contributed to their growth in some areas, reducing competition from grasses and shrubs. However, the danger of frequent fires prompted Panov to invite specialists for a thorough botanical survey of the territory.
Researchers Alexander Dubynin, Inessa Selyutina and Alexandra Egorova of the Central Siberian Botanical Garden in Novosibirsk, and Mikhail Blinnikov of Kazan Federal University have been working in the area since 2017, registering the occurrences of orchids and photographing plants for the iNaturalist platform. There and in adjacent territories, they discovered a total of 14 orchid species, some of which were new to this territory and had never been registered before.
The area in Novosibirsk region is truly unique. Here, researchers found one of the largest populations of large-flowered lady’s-slipper (Cypripedium macranthos) in Northern Eurasia, with up to 5,000 individual plants. The Cypripedium calceolus Lady’s-slipper orchid and the rare and beautiful bloated lady’s slipper (Cypripedium ventricosum) were also plentiful. Some of the discovered orchids require further study, such as the hybrids between Dactylorhiza and Gymnadenia and some unusual forms of Platanthera.
After an expert description of the territory, a new Important Plant Area was nominated for South Siberia. “Based on the analysis of plant species composition of protected areas in Novosibirsk Region,” Alexander Dubynin resumes, “we conclude that in situ preservation of orchids in the region is overall insufficient. It is therefore necessary to organize a new protected area ‘Orchid Zapovednik’ in the category of ‘botanical Zakaznik’ on 335 hectares with an explicit floral diversity conservation mandate and long-term orchid population monitoring.”
Over the past three years, the territory has increasingly attracted the attention of researchers and educators, becoming a kind of a ‘field laboratory’ for the study of orchid communities in South Siberia.
Dubynin A, Selyutina I, Egorova A, Blinnikov M (2021) An orchid (Orchidaceae)-rich area recommended for preservation in Novosibirsk Region, Russia. Acta Biologica Sibirica 7: 1–18. https://doi.org/10.3897/abs.7.e63131
One of the biggest scientific expeditions ever undertaken in Indonesia, Lengguru 2014, made it possible to study and collect dozens of unknown plant and animal species, including four new orchids. Curiously, the research team, led by Dr. Lina Juswara, Cibinong Science Centre, Indonesia, collected three of these novelties over the span of a single day at the top of a small and unexplored mountain at 1000-metre elevation. The findings, which confirm previous suggestions that many species still await discovery there, are described and published in the open-access journal Phytokeys.
Thanks to the 2014 Lengguru scientific expedition some of the mysteries of Lengguru, an almost impenetrable mountainous area in an isolated and difficult-to-reach part of the Indonesian half of the New Guinea island, have been revealed. About a hundred participants, including 25 European and 45 Indonesian scientists, took part in it with the shared goal to collect essential data on the biodiversity of West Papua.
Lengguru remains one of the last unexplored territories on the planet. Covering an area, comparable in size to Sardinia, it consists of limestone formations, known as ‘karst’, forming a mosaic of natural ecosystems. The Lengguru 2014 expedition attempted to investigate Lengguru’s biodiversity in order to generate scientific data for molecular, ecological, taxonomical and biogeographical studies.
During the 6-week expedition, 72 fertile/flowering orchid specimens have been collected from the field by the internal team of Indonesian, French and Belgian botanists. So far, four new species have been identified among them.
“After the expedition, we examined and compared the Lengguru orchids with reference material housed in scientific collections,” explains Dr. Lina Juswara. Together with Dr. Vincent Droissart from the Research Institute for Development, France, they were the experts in charge to gather data on the large and glamorous Orchid family during the expedition. The identifications, descriptions and drawings of the new species were realized in close collaboration with Dr. Andre Schuiteman, Royal Botanical Garden Kew, United Kingdom, an internationally recognized expert on the orchid flora of Asia.
New Guinea is known to harbor one of the richest orchid floras in the world, surpassed only by Colombia, Ecuador, and Peru. All four new orchid species discovered in Lengguru have been collected in high altitude forest, at over 1000 meters above sea level. These particular habitats, usually shrouded in clouds, are home to an exceptional plant diversity with a high degree of endemism, meaning the species cannot be found anywhere else in the world. The specific environmental conditions and the very small surface occupied by these ‘isolated islands’ of mountain forests make them particularly vulnerable to global climate change.
“Large parts of New Guinea have been overlooked in terms of collection initiatives and it is likely that many species still await discovery there”, says Dr. Lina Juswara. “More field studies are also required to find additional populations of the new species we found in Lengguru, in order to better characterize their habitat, ecology and conservation status. Of the four new orchid species collected during the expedition, three were collected on a single day, confirming that the flora of Lengguru is still far from completely described.”
Juswara L, Schuiteman A, Droissart V (2016) Four new orchid species from the Lengguru fold belt, West Papua, Indonesia. PhytoKeys 61: 47-59. doi: 10.3897/phytokeys.61.7590
Fieldwork, laboratory activities and herbarium visits were supported by the Project Lengguru 2014 (http://www.lengguru.org), conducted by the French Institut de Recherche pour le Développement (IRD), the Indonesian Institute of Sciences (LIPI), the University of Papua (UNIPA), the University of Cendrawasih (UNCEN), the University of Musamus (UNMUS) and the Sorong Fisheries Academy (APSOR) with corporate sponsorship from COLAS Group, Veolia Water and the Total Foundation.