According to their research, published Sept. 23 in Current Biology, plants actually do have a way of talking to each other. Their messages come embedded in the form of airborne chemicals known as volatile organic compounds (VOCs), which transfer information among plants.
The big finding in the study is what Kessler calls “open-channel communication.” Based on their genotypes, different plants have different smells. But when plants come under attack from pests like the goldenrod leaf beetle, their smells – carried by VOCs – become more similar.
“So they kind of converge on the same language, or the same warning signs, to share the information freely,” Kessler said. “The exchange of information becomes independent of how closely related the plant is to its neighbor.”
The research found that neighboring plants pick up on warning VOCs and prepare for the perceived threat, such as an oncoming insect pest. Said Kessler: “A (VOC) emitted by one plant can be picked up by another plant, and they can either ready their defenses or they may actually directly induce those defenses.”
However, their goodwill toward plant neighbors only works on an if-you-see-something-say-something basis and when, as a result of the communication, pest pressure is equally distributed across the plant population. Plants in populations without herbivores do not freely share information with their neighbors. Instead, they maintain a private channel with their closest kin through VOC emissions that induce resistance – but only in those relatives or plant parts distant from the damage site on the same plant.
“We code our language if we want to keep it private, and that’s exactly what happens there, but on a chemical level,” Kessler said. “That analogy is striking and not what we expected.”
When people pose the old question about whether a tree falling in an empty forest makes a sound, they presuppose that none of the other plants in the forest are listening in. Plants, supposedly, are silent and unhearing. They don’t make noises, unless rustled or bitten. When Rachel Carson described a spring bereft of birds, she called it silent.
But these stereotypes may not be true. According to a blossoming batch of studies, it’s not that plants have no acoustic lives. It’s more that, until now, we’ve been blissfully unaware of them….. read more at the Atlantic
Early this spring, Rice University evolutionary biologist Scott Egan stood in a patch of live oak scrub habitat in South Florida and scanned the trees for something he’d never seen outside his lab — a wispy, orange vine twining itself around swollen stems or pea-sized growths on the underside of oak leaves.
Rice University bioscientists have discovered the first example of a parasitic plant attacking a parasitic insect on a shared host plant. Cassytha filiformis, also known as love vine, feeds off of galls, the natal chambers of parasitic wasps.
Egan needed visual confirmation of something he and his students noticed in the lab a few months earlier: love vine, a parasitic plant, latching onto and feeding off of not the tree itself, but the tumor-like growths made by his favorite insects, gall wasps.
“I went to spots where I knew that my gall-formers and the vines were, and I just blurred my eyes across the tops of the trees,” Egan said, re-enacting the moment he scanned the forest. “And, once you have seen it, you can’t not see it. I’m like, ‘Oh. It’s everywhere. I can’t not find it, on this branch, or on this one or this one.”
For Egan, who has spent 17 years studying gall-forming insects and logged thousands of miles collecting samples from oak forests across a dozen U.S. states, it was a revelation.
“I had never seen this,” Egan said. “But the fact that no one, as far as we know, had ever documented this was incredible because biologists have studied each of these — the vines and the insects — for more than a century.”
In ecological parlance, the find was a new trophic interaction between two species, meaning that one was feeding off the other. “Basically, you have a parasitic plant attacking a parasitic insect inside of another host, a host they share,” he said.
Interesting, white flowers are white to attract pollinators at night, several orchids I’ve owned have a scent that is very strong after dark but barely there during the day.
We find that the floral scent of the orchid Gymnadenia conopsea differs between day and night, and the increase in scent from day to night is stronger in populations with nocturnal pollination. This is the first study to report genetic variation in floral scent emission rhythms within the same species, and this is an important first step to understand the evolution of floral scent.
…. But a review by scientists from the University of Exeter and the Kunming Institute of Botany (Chinese Academy of Sciences) found plants use a host of techniques long known to be used by animals.
These include blending with the background, “disruptive colouration” (using high-contrast markings to break up the perceived shape of an object) and “masquerade” (looking like an unimportant object predators might ignore, such as a stone).
“It is clear that plants do more than entice pollinators and photosynthesise with their colours—they hide in plain sight from enemies too,” said Professor Martin Stevens, of the Centre for Ecology and Conservation on Exeter’s Penryn Campus in Cornwall.
“From ‘decoration’, where they accumulate things like dust or sand on their surface, to disruptive coloration, they use many of the same methods as animals to camouflage themselves.
“We now need to discover just how important a role camouflage has in the ecology and evolution of plants.”