Arquivo da tag: simbiose

Botanist Stefano Mancuso: ‘You can anaesthetise all plants. This is extremely fascinating’ (The Guardian)

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theguardian.com

An advocate of plant intelligence, the Italian author discusses the complex ways in which plants communicate, whether they are conscious, and what his findings mean for vegans

Killian Fox

April 15, 2023

Born in Calabria in 1965, Stefano Mancuso is a pioneer in the plant neurobiology movement, which seeks to understand “how plants perceive their circumstances and respond to environmental input in an integrated fashion”. Michael Pollan in the New Yorker described him as “the poet-philosopher of the movement, determined to win for plants the recognition they deserve”. Mancuso teaches at the University of Florence, his alma mater, where he runs the International Laboratory of Plant Neurobiology. He has written five bestselling books on plants.

What’s at the root of your love of plants?
I began to be interested in plants at university. One of my tasks during my doctorate was to understand how a root growing in the soil was able to move around an obstacle. My idea was to film this movement, but I saw something different: the root was changing direction well before touching the obstacle. It was able to sense the obstacle and to find a more convenient direction. That was my first eureka moment, where I started to imagine that plants were intelligent organisms.

You refer to your field as plant neurobiology. Is this a provocation?
At the beginning, it was not at all. I started to think that almost all the claims I was hearing about the brain were valid also in plants. The neuron is not a miracle cell, it’s a normal cell that is able to produce an electrical signal. In plants, almost every cell is able to do that. The main difference between animals and plants, in my opinion, is that animals concentrate specific functions inside organs. In the case of plants, they diffuse everything through the whole body, including intelligence. So it was not a provocation at the beginning, but there was a big resistance among my colleagues to use this kind of terminology, and so after it became a provocation.

What were you hoping to achieve with your new book, Tree Stories?
What I’d like to popularise is, first, the many abilities of plants that we normally are unable to feel and understand, because they are so different from us. Second, when you tell a story about life on this planet, not talking about plants, which make up 87% of life, is a nonsense.

You argue passionately in favour of filling cities with trees. Why is this so important?
We are producing 75% of our CO₂ in cities, and the best way to remove that CO₂ is by using trees. The closer the tree is to the source of carbon emissions, the better they are at absorbing it. According to our studies, we could put around 200bn trees in our urban areas. To do that, we really need to imagine a new kind of city, completely covered by plants, without any border between nature and city.

You have a fascinating chapter about a tree stump being kept alive for decades by its neighbouring trees. What can humans learn from tree communities?
Plants are so incredibly cooperative with one another because cooperation is the most efficient way to grant the survival of species. Not understanding the strength of the community is one of [humanity’s] main errors. There was a very clever evolutionary biologist at the beginning of the last century, Peter Kropotkin, who said that when there are fewer resources, and the environment is changing, then cooperation is vastly more efficient [than competition]. This is an important teaching for us today, because we are entering a period of reduction of resources and the environment is changing because of global warming.

To what degree can plants communicate with one another? If you have a spectrum with rocks at one end and humans at the other, where do plants sit?
I would say very close to humans. Communication means you are able to emit a message and there is something able to receive it, and in this sense plants are great communicators. If you are unable to move, if you are rooted, it’s of paramount importance for you to communicate a lot. We experienced this during lockdown, when we were stuck at home and there was an incredible increase in traffic on the internet. Plants are obliged to communicate a lot, and they use different systems. The most important is through volatiles, or chemicals that are emitted in the atmosphere and received by other plants. It’s an extremely sophisticated form of communication, a kind of vocabulary. Every single molecule means something, and they mix very different molecules to send a specific message.

The idea that plants are intelligent is controversial enough, but you’ve gone one step further by claiming that plants are to some degree conscious…
It’s incredibly difficult to talk about consciousness, first because we actually don’t know what consciousness is, even in our case. But there is an approach to talking about it as a real biological feature: consciousness is something that we all have, except when we are sleeping very deeply or when we are under anaesthesia. My approach to studying consciousness in plants was similar. I started by seeing if they were sensitive to anaesthetics and found that you can anaesthetise all plants by using the same anaesthetics that work in humans. This is extremely fascinating. We were thinking that consciousness was something related to the brain, but I think that both consciousness and intelligence are more embodied, relating to the entire body.

So you can put a plant to sleep?
We are working to see if it’s possible to say that. It’s an incredibly difficult task, but we think that, before the end of this year, we will be able to demonstrate it.

As we learn more about the sophistication and sensitivity of plants, should we think twice about eating them?
It’s an interesting question. Many vegan people have written to me asking this. First, I think it’s ethical to eat plants because we are animals, and as animals we can only survive by eating other living organisms – this is a law that we cannot break. Second, it’s much more ethical to eat a plant than, for example, beef, because to produce a kilo of beef, you need to kill one tonne of plants, so it’s much better to eat directly a kilo of plants. The third point is that it’s very difficult for us to imagine being a plant, because for us being eaten is an ancestral nightmare, whereas plants evolved to be eaten, it’s part of the cycle. A fruit is an organ that is produced to be eaten by an animal.

So fruit is probably the most ethical thing you can eat, more so than, say, kale?
Maybe fruit is the most ethical, but you need to defecate on the ground afterwards, because otherwise you are breaking the cycle.

Judith Butler: To Save the Earth, Dismantle Individuality (Time)

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time.com

Judith Butler, April 21,2021

However differently we register this pandemic we understand it as global; it brings home the fact that we are implicated in a shared world. The capacity of living human creatures to affect one another can be a matter of life or death. Because so many resources are not equitably shared, and so many have only a small or vanished share of the world, we cannot recognize the pandemic as global without facing those inequalities.

Some people work for the common world, keep it going, but are not, for that reason, of it. They might lack property or papers, be sidelined by racism or even disdained as refuse—those who are poor, Black or brown, those with unpayable debts that preclude a sense of an open future.

The shared world is not equally shared. The French philosopher Jacques Rancière refers to “the part of those who have no part”—those for whom participation in the commons is not possible, never was, or no longer is. For it is not just resources and companies in which a share is to be had, but a sense of the common, a sense of belonging to a world equally, a trust that the world is organized to support everyone’s flourishing.

The pandemic has illuminated and intensified racial and economic inequalities at the same time that it heightens the global sense of our obligations to one another and the earth. There is movement in a global direction, one based on a new sense of mortality and interdependency. The experience of finitude is coupled with a keen sense of inequalities: Who dies early and why, and for whom is there no infrastructural or social promise of life’s continuity?

This sense of the interdependency of the world, strengthened by a common immunological predicament, challenges the notion of ourselves as isolated individuals encased in discrete bodies, bound by established borders. Who now could deny that to be a body at all is to be bound up with other living creatures, with surfaces, and the elements, including the air that belongs to no one and everyone?

Within these pandemic times, air, water, shelter, clothing and access to health care are sites of individual and collective anxiety. But all these were already imperiled by climate change. Whether or not one is living a livable life is not only a private existential question, but an urgent economic one, incited by the life-and-death consequences of social inequality: Are there health services and shelters and clean enough water for all those who should have an equal share of this world? The question is made more urgent by conditions of heightened economic precarity during the pandemic, exposing as well the ongoing climate catastrophe for the threat to livable life that it is.

Pandemic is etymologically pandemos, all the people, or perhaps more precisely, the people everywhere, or something that spreads over or through the people. The “demos” is all the people despite the legal barriers that seek to separate them. A pandemic, then, links all the people through the potentials of infection and recovery, suffering and hope, immunity and fatality. No border stops the virus from traveling if humans travel; no social category secures absolute immunity for those
it includes.

“The political in our time must start from the imperative to reconstruct the world in common,” argues Cameroonian philosopher Achille Mbembe. If we consider the plundering of the earth’s resources for the purposes of corporate profit, privatization and colonization itself as planetary project or enterprise, then it makes sense to devise a movement that does not send us back to our egos and identities, our cut-off lives.

Such a movement will be, for Mbembe, “a decolonization [which] is by definition a planetary enterprise, a radical openness of and to the world, a deep breathing for the world as opposed to insulation.” The planetary opposition to extraction and systemic racism ought to then deliver us back to the world, or let the world arrive, as if for the first time, a shared place for “deep breathing”—a desire we all now know.

And yet, an inhabitable world for humans depends on a flourishing earth that does not have humans at its center. We oppose environmental toxins not only so that we humans can live and breathe without fear of being poisoned, but also because the water and the air must have lives that are not centered on our own.

As we dismantle the rigid forms of individuality in these interconnected times, we can imagine the smaller part that human worlds must play on this earth whose regeneration we depend upon—and which, in turn, depends upon our smaller and more mindful role.

Love the Fig (The New Yorker)

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newyorker.com

Ben Crair, August 10, 2020

The produce section of the grocery store is a botanical disaster. Most people know that a tomato is technically a fruit, but so is an eggplant, a cucumber, and a spaghetti squash. A banana, which grows from a flower with a single ovary, is actually a berry, while a strawberry, which grows from a flower with several ovaries, isn’t a berry at all but an aggregate fruit. The most confusing classification, though, will start showing up on American shelves this month. Shoppers will find mission figs with the grapes, kiwis, and other fruit, but a clever botanist would sell them at the florist, with the fresh-cut roses. Although many people dismiss figs as a geriatric delicacy or the sticky stuff inside bad cookies, they are, in fact, something awesome: enclosed flowers that bloom modestly inward, unlike the flamboyant showoffs on other plants. Bite a fig in half and you’ll discover a core of tiny blossoms.

All kinds of critters, not only humans, frequent fig trees, but the plants owe their existence to what may be evolution’s most intimate partnership between two species. Because a fig is actually a ball of flowers, it requires pollination to reproduce, but, because the flowers are sealed, not just any bug can crawl inside.* That task belongs to a minuscule insect known as the fig wasp, whose life cycle is intertwined with the fig’s. Mother wasps lay their eggs in an unripe fig. After their offspring hatch and mature, the males mate and then chew a tunnel to the surface, dying when their task is complete. The females follow and take flight, riding the winds until they smell another fig tree. (One species of wasp, in Africa, travels ten times farther than any other known pollinator.) When the insects discover the right specimen, they go inside and deposit the pollen from their birthplace. Then the females lay new eggs, and the cycle begins again. For the wasp mother, however, devotion to the fig plant soon turns tragic. A fig’s entranceway is booby-trapped to destroy her wings, so that she can never visit another plant. When you eat a dried fig, you’re probably chewing fig-wasp mummies, too.

The fig and the fig wasp are a superlative example of what biologists call codependent evolution. The plants and insects have been growing old together for more than sixty million years. Almost every species of fig plant—more than seven hundred and fifty in total—has its own species of wasp, although some commercial fig production favors varieties that do not require pollination. (They are grown from cuttings and produce fruit without any seeds.) But codependence hasn’t made the fig and the fig wasp weak, like it can with humans. The figs and fig wasps’ pollination system is extremely efficient compared with that of other plants, some of which just trust the wind to blow their pollen where it needs to go. And the figs’ specialized flowers, far from isolating them in an evolutionary niche, have allowed them to radiate throughout the natural world. Fig plants can be shrubs, vines, or trees. Strangler figs sprout in the branches of another tree, drop their roots to the forest floor, and slowly envelop their host. The branches of a large strangler fig can stretch over acres and produce a million figs in one flowering. Figs themselves can be brown, red, white, orange, yellow, or green. (Wild figs are not as sweet as the plump and purple mission figs you buy at the farmers’ market.) And their seeds sprout where other plants’ would flounder: rooftops, cliff sides, volcanic islands. The fig genus, Ficus, is the most varied one in the tropics. It also routinely shows up in the greenhouse and the garden.

The variety and adaptability of fig plants make them a favorite foodstuff among animals. In 2001, a team of researchers published a review of the scientific literature and found records of fig consumption for nearly thirteen hundred bird and mammal species. One of the researchers, Mike Shanahan—a rain-forest ecologist and the author of a forthcoming book about figs, “Gods, Wasps, and Stranglers”—had spent time studying Malaysian fig trees as a Ph.D. candidate, in 1997. He would sometimes lie beneath a huge strangler fig and record its visitors, returning repeatedly for several days. “I would typically see twenty-five to thirty different species,” Shanahan told me. “The animals would include lots of different squirrel species and some curious creatures called tree shrews. There would be some monkeys and a whole range of different bird species, from tiny little flowerpeckers up to the hornbills, which are the biggest fruit-eating birds in Asia.” There were also pigeons, fruit doves, fairy bluebirds, barbets, and parrots. As the biologist Daniel Janzen put it in “How to Be a Fig,” an article from 1979, “Who eats figs? Everybody.”

With good reason, too. Figs are high in calcium, easy to chew and digest, and, unlike plants that fruit seasonally, can be found year-round. This is the fig plant’s accommodation of the fig wasp. A fig wasp departs a ripe fig to find an unripe fig, which means that there must always be figs at different stages. As a result, an animal can usually fall back on a fig when a mango or a lychee is not in season. Sometimes figs are the only things between an animal and starvation. According to a 2003 study of Uganda’s Budongo Forest, for instance, figs are the sole source of fruit for chimpanzees at certain times of year. Our pre-human ancestors probably filled up on figs, too. The plants are what is known as a keystone species: yank them from the jungle and the whole ecosystem would collapse.

Figs’ popularity means they can play a central role in bringing deforested land back to life. The plants grow quickly in inhospitable places and, thanks to the endurance of the fig wasps, can survive at low densities. And the animals they attract will, to put it politely, deposit nearby the seeds of other fruits they’ve eaten, thereby introducing a healthy variety of new plants. Nigel Tucker, a restoration ecologist in Australia, has recommended that ten per cent of new plants in tropical-reforestation projects be fig seedlings. Rhett Harrison, a former fig biologist, told me that the ratio could be even higher. “My inclination is that we should be going to some of these places and just planting a few figs,” he said.

Fig trees are also sometimes the only trees left standing from former forests. In parts of India, for instance, they are considered holy, and farmers are reluctant to chop them down. “Diverse cultures developed taboos against felling fig trees,” Shanahan told me. “They said they were homes to gods and spirits, and made them places of prayer and symbols of their society.” You can’t really taste the fig’s spiritual aura in a Fig Newton, but it shines in the mythologies of world religions. Buddha found enlightenment under a fig tree, and the Egyptian pharaohs built wooden sarcophagi from Ficus sycomorus. An apple tree might have cost Adam and Eve their innocence, but a fig tree, whose leaves they used to cover their nudity, gave them back some dignity. If only they had preferred figs in the first place, we might all still live in Eden.

*This article has been revised to clarify the fact that not all fig plants require pollination to produce edible fruit.