Posted on

weeds that spread seeds when you touch them

Glyphosate

Glyphosate is an herbicide. It is applied to the leaves of plants to kill both broadleaf plants and grasses. The sodium salt form of glyphosate is used to regulate plant growth and ripen specific crops.

Glyphosate was first registered for use in the U.S. in 1974. Glyphosate is one of the most widely used herbicides in the United States. People apply it in agriculture and forestry, on lawns and gardens, and for weeds in industrial areas. Some products containing glyphosate control aquatic plants.

What are some products that contain glyphosate?

Glyphosate comes in many forms, including an acid and several salts. These can be either solids or an amber-colored liquid. There are over 750 products containing glyphosate for sale in the United States.

Always follow label instructions and take steps to avoid exposure. If any exposures occur, be sure to follow the First Aid instructions on the product label carefully. For additional treatment advice, contact the Poison Control Center at 800-222-1222. If you wish to discuss a pesticide problem, please call 800-858-7378.

How does glyphosate work?

Glyphosate is a non-selective herbicide, meaning it will kill most plants. It prevents the plants from making certain proteins that are needed for plant growth. Glyphosate stops a specific enzyme pathway, the shikimic acid pathway. The shikimic acid pathway is necessary for plants and some microorganisms.

How might I be exposed to glyphosate?

You can be exposed to glyphosate if you get it on your skin, in your eyes or breathe it in when you are using it. You might swallow some glyphosate if you eat or smoke after applying it without washing your hands first. You may also be exposed if you touch plants that are still wet with spray. Glyphosate isn’t likely to vaporize after it is sprayed.

What are some signs and symptoms from a brief exposure to glyphosate?

Pure glyphosate is low in toxicity, but products usually contain other ingredients that help the glyphosate get into the plants. The other ingredients in the product can make the product more toxic. Products containing glyphosate may cause eye or skin irritation. People who breathed in spray mist from products containing glyphosate felt irritation in their nose and throat. Swallowing products with glyphosate can cause increased saliva, burns in the mouth and throat, nausea, vomiting, and diarrhea. Fatalities have been reported in cases of intentional ingestion.

Pets may be at risk if they touch or eat plants that are still wet with spray from products containing glyphosate. Animals exposed to products with glyphosate may drool, vomit, have diarrhea, lose their appetite, or seem sleepy.

What happens to glyphosate when it enters the body?

In humans, glyphosate does not easily pass through the skin. Glyphosate that is absorbed or ingested will pass through the body relatively quickly. The vast majority of glyphosate leaves the body in urine and feces without being changed into another chemical.

Is glyphosate likely to contribute to the development of cancer?

Animal and human studies were evaluated by regulatory agencies in the USA, Canada, Japan, Australia, and the European Union, as well as the Joint Meeting on Pesticide Residues of the United Nations and World Health Organization (WHO). These agencies looked at cancer rates in humans and studies where laboratory animals were fed high doses of glyphosate. Based on these studies, they determined that glyphosate is not likely to be carcinogenic. However, a committee of scientists working for the International Agency for Research on Cancer of the WHO evaluated fewer studies and reported that glyphosate is probably carcinogenic.

Has anyone studied non-cancer effects from long-term exposure to glyphosate?

Long-term feeding studies in animals were assessed by the U.S. Environmental Protection Agency (EPA) and other regulatory authorities. Based on these evaluations, they found there is no evidence glyphosate is toxic to the nervous or immune systems. They also found it is not a developmental or reproductive toxin.

Are children more sensitive to glyphosate than adults?

As required by the Food Quality Protection Act, the EPA has determined that children are not more sensitive to glyphosate as compared to the general population.

What happens to glyphosate in the environment?

Glyphosate binds tightly to soil. It can persist in soil for up to 6 months depending on the climate and the type of soil it is in. Glyphosate is broken down by bacteria in the soil.

Glyphosate is not likely to get into groundwater because it binds tightly to soil. In one study, half the glyphosate in dead leaves broke down in 8 or 9 days. Another study found that some glyphosate was taken up by carrots and lettuce after the soil was treated with it.

Can glyphosate affect birds, fish, or other wildlife?

Pure glyphosate is low in toxicity to fish and wildlife, but some products containing glyphosate may be toxic because of the other ingredients in them. Glyphosate may affect fish and wildlife indirectly because killing the plants alters the animals’ habitat.

How plants hitchhike on animal poo

From plants to poo, Kew Research Fellow Dr Si-Chong Chen reveals how seeds use animals as their free ride for dispersal…

By Katie Avis-Riordan

Plants can’t pick themselves up and move around, so they often need a little help when it comes to spreading their seeds.

Wind, water, gravity, ballistic (where the seeds are ejected by forceful and often explosive mechanisms) and animals are the main ways seeds are dispersed.

For many different plant species, dispersal increases chances of survival as the seeds are transported to more favourable environments for growth.

Plants to poo

One of the significant ways that animals disperse plant seeds is by eating and pooing them out.

Certain plant species, including many trees, enclose their seeds inside fleshy edible fruits that are appealing to hungry animals.

These fruit-loving animals are called frugivores.

‘Fleshy fruits are usually dispersed by animal ingestion,’ Kew Research Fellow Dr Si-Chong Chen says. ‘Animals gulp down the fruits without chewing the seeds, digest the fleshy pulp and defecate the seeds.’

This ingestion process of dispersal is known as endozoochory.

The plants hitchhiking a ride

‘Plants hitchhike and utilise animals as their free “bus” for seed dispersal,’ Si-Chong says.

Many tree species that produce fleshy fruits make use of seed dispersal through animal poo.

‘However, we should not neglect the fact that seeds of many plant species with dry fruits may survive animal digestive tracts and are dispersed in animal faeces,’ Si-Chong explains.

‘To be able to survive the digestive tracts of the animals ingesting it, the seed has to have some form of strong protection, such as a seed coat resisting digestion.’

The seed-pooing animals

So which animal species help disperse seeds in this way?

All major groups of vertebrates, including mammals, birds, reptiles and fish, are involved.

Even well-known carnivores such as wolves occasionally eat seeds and other plant material.

Large-bodied frugivores, like tapirs, cassowaries and elephants, are important seed dispersers.

‘But if we zoom in to particular regions, some local animals can be so important to the keystone species (species which have a large impact on their natural environment and significantly affect a high number of other organisms) in seed dispersal, such as many species of birds, bats and primates,’ Si-Chong says.

‘Also, large grazers, such as cattle and horses, mow the grass mainly for plant leaves and unintentionally ingest a large number of seeds.’

When an animal chews the seeds rather than swallow them whole, dispersal fails as the seeds are killed.

In our native woodlands, badgers help spread the seeds of yew trees (Taxus baccata) to more open areas in their poo.

These black-and-white creatures swallow the yew berries but only digest the fruit pulp, leaving the seeds to pass through their digestive system intact and grow into new trees.

Did you know? Yew berry seeds are poisonous to humans and most mammals, but the fruit’s bright red colour helps badgers and other suitable woodland creatures find and eat them.

Some invertebrates that are big enough to swallow seeds, like crickets, slugs and snails, may ingest and disperse them, but this is not common.

Double dispersal

Sometimes seeds pass through not just one animal but two!

Secondary seed dispersal happens when a predator devours another animal that has eaten the seeds, such as birds of prey that feed on small seed-eating lizards.

This increases the distance the seeds are carried before they are finally deposited. But the seeds have to be tough enough to survive digestive tracts, twice over.

Benefits of poo dispersal

The most important benefit of seed dispersal through animal poo is distance.

‘Plants cannot move, so they hitchhike by spores, pollen and seeds,’ Si-Chong says. ‘The “bus” can be wind, water, animals and so on.

‘Hitchhiking in animal digestive tracts can bring them to generally long distances. This is also why large-bodied animals are important seed dispersers – they eat a lot and travel far!’

Why does distance matter?

Being dispersed further away from the parent plants means the seeds are carried to an environment with less competition with parents and siblings, better light conditions, avoidance of predators and pathogens, and an opportunity to colonise new habitats.

Another positive is that some seeds get higher germination rates after going through digestive tracts because digestion removes the physical layers or chemical compounds that inhibit seed germination.

Challenges and damages

Seed dispersal through animal poo is defined as a form of allochory, meaning the plant relies on external entities for dispersal.

This is opposed to autochory, when dispersal is achieved by the plant’s own means.

Dispersal by poo relies on the survival of the seed-ingesting animals within the ecosystem.

Another challenge these plants face is the possibility that the seeds won’t survive the physical and chemical process of digestion.

Though there may be challenges, these clever plants continue to use their hitchhiking skills to migrate and flourish.

Scientists reveal that plants can feel when we touch them

It’s something that plant lovers have long suspected, but now Australian scientists have found evidence that plants really can feel when we’re touching them.

Not only that, but different sensations trigger a cascade of physiological and genetic changes, depending on the stimulation the plants are receiving, whether it’s a few drops of rain, or a little soft pat, which is probably the coolest thing we’ve heard all week.

“Although people generally assume plants don’t feel when they are being touched, this shows that they are actually very sensitive to it,” said lead researcher Olivier Van Aken from the University of Western Australia.

“While plants don’t appear to complain when we pinch a flower, step on them or just brush by them while going for a walk, they are fully aware of this contact and are rapidly responding to our treatment of them,” he added.

But first thing’s first, let’s not get ahead of ourselves and anthropomorphize the crap out of this situation, as we humans love to do. Although this whole thing sounds super adorable and touchy feely, plants don’t have brains and they don’t “think”.

We also don’t have evidence to suggest that they actually “feel” in any way resembling our perception of the sense.

That said, previous research has shown that plants do have pretty good awareness of their surroundings. For example, they can “hear” when they’re being chewed on by insects, and release chemicals to stop it. And they’re also able to communicate with each other via a subterranean “internet” of fungus.

While there’s no visible response to any of this stimulus, what this input does is help the plant stay aware of its surroundings and prepare itself for any potential danger, or get ready to take advantage of changing weather conditions.

One thing the scientists found was that spraying water droplets on plants caused them to change the expression of thousands of genes – a dramatic physiological response that started within minutes of the stimulus and stopped within half an hour.

“We were able to show that this response was not caused by any active compounds in the spray but rather by the physical contact caused by water drops landing on the leaf surface,” says Van Aken.

Curious to know how else they might respond, the team also found that gently patting the plants or touching them with tweezers could trigger a similar physiological cascade. So could a sudden shadow falling over their leaves.

All of this information could be essential to plants survival in the wild, the researchers explain in the journal Plant Physiology.

“Unlike animals, plants are unable to run away from harmful conditions. Instead, plants appear to have developed intricate stress defence systems to sense their environment and help them detect danger and respond appropriately,” says Van Aken.

Importantly, the study also identified two proteins that could switch off the plant’s touch response. In the future, this could help plants in controlled environments, such as greenhouses, from changing their genes and responding to “false alarm” stimuli.

One study on its own obviously isn’t enough to overhaul our understanding of plant stimulation perception, and more research is needed to replicate the finds. But for now, maybe we should all be more thoughtful when we’re prodding and poking our plants, or blocking their light with our giant human heads.

The good news? Singing seems to be pretty safe. “As yet, there’s no evidence to back the idea held by some people that the vibrations caused by just talking to plants has a strong enough effect to move plants,” Van Aken told Peter Spinks from the The Age.