Hydrotropism: Lessons from Ficus Elastica

The directional growth of plant roots towards water availability is what scientists call hydrotropism. The latter half of the term, “tropism,” is meant to describe the physiological response of an organism to a stimulus. Aside from any dry, technical definitions, it is through these processes that we see how an organism can adapt to a diverse situation and how efficiently it acknowledges its environment.

Yet this exact adaptive tropism is fundamental for the survival of terrestrial plants, which depend on the ability of roots to search for water and soil nutrients to survive. Hydrotropism begins with the perception of soil moisture gradients and unlike geotropism, it is not yet fully known how or which cell type on the plant’s surface senses the moisture gradient.

Although the plant originates in India, Malaysia, Java, and Sumatra, the Ficus elastica is commonly found in the Brazilian tropical lands. It usually carries a huge canopy that sometimes becomes too heavy for the plant’s survival. Cleverly, the tree throws its arms into the ground, demonstrating the versatility in its way of life, in which branches can equally function as trunks and roots in an interweaving, symbiotic design that transcends the earth.

When I first saw the Ficus beautifully standing in Ibirapuera Park in São Paulo, I was entranced by its power and the construction of its “trunks.” I could not believe that the complex brush in front of me was only one tree! Incredibly, the organism senses the scope of ground needed for its purveyance, and this is one of the greatest lessons nature can teach us about sustainable and responsible resource management.


São Paulo’s convoluted reservoir systems

São Paulo is a metropolis with more than 20 million inhabitants, making it one of the biggest cities on earth. The city is fed by a water distribution system composed by 9 reservoirs: Cantareira, Guarapiranga, Alto Tietê, Rio Grande, Rio Claro, Ribeirão da Estiva, Capivari, and Alto Cotia e Baixo Cotia. The SABESP, a state-owned water and waste management company, is responsible for the city’s distribution of water, an essential resource that cannot be humanely privatized.

It happens that one of the consequences of the city’s water crises has been the depoliticization of the problem. There is no debate over the fact that the crisis occurs in a tropical city with a high rainfall average. Thus, questions concerning the turbulent relationship between population and natural resources come back to light.

It is a long debate that has divided human thought since at least the 18th century, when the Enlightenment philosophically separated people from nature. Scientific investigations into this relationship have developed in both number and sophistication in recent years. However, the wealth of new arguments has not reduced their contentiousness, rather it has only made them more venomous, as David Harvey argued in “Population, Resources, and the Ideology of Science.”

The Malthus theory advises that population growth eventually leads to resource depletion. The land cannot provide the necessary sustenance for the growing consumption: while population grows exponentially, the land provides in a more arithmetic fashion. Any imbalance between population and resources will soon be regulated by poverty, war, and chaos.

Enter the SABESP, which has been a high profitable company since it first began courting investment. While their investors toast to their successes, everyday citizens are suffering through the worst draught in decades. Low investment, unsavory conditions of the rivers inside São Paulo, and real estate development that inhibits permeability all lead the reservoirs to dry up.


A network of suspended blue hoses helps transport water across São Paulo

Nevertheless, the water consumption by corporations is encouraged through generous incentives. Earlier last month, Sabesp released a list with more than 500 large industrial and commercial companies such as McDonald’s and Cidade Jardim Mall that get exponential discounts on water consumption in which the more they drain the less they pay–a phenomenon called “firm demand.” Despite the necessity of water for human survival, the individual right of to water access is not explicit in the 1988 Brazilian Constitution, although international organizations and covenants are fighting for such a principle. Multinational corporations like Nestle think of this natural resource as a great market to develop and try to forge a lobby in favor of water privatization.

Simultaneously, agribusiness consumes two-thirds of São Paulo’s water while city-based industry consumes another 20 percent to 30 percent while households take less than 10 percent. Which households are we talking about? Forget about the swimming pools of the upscale residences in the Morumbi district and the water it takes the wealthy to wash their SUVs. Focus on the low electric power showers and the periphery that uses them—this is the segment of society the military and police seek to exploit.

As Levi-Strauss warned in Tristes Tropiques, “Once men begin to feel cramped in their geographical, social and mental habitat, they are in danger of being tempted by the simple solution of denying one section of the species the right to be considered human.”

In which case, Large-scale development projects led by the state of São Paulo, and often conducted in the name of climate change adaptation, ultimately destabilize communities in the city who are often the most economically and politically marginalized. The solutions the state is seeking and the infrastructure it provides only perpetuates such inequality.

Among these efforts is the transposition of the Paraíba do Sul reservoir, already dried by exploratory consumption, to the Cantareira System. In essence, the trade-off of dried-out reservoirs for other dried-out reservoirs is only absorbing precious basins in the area, much to the chagrin of Rio de Janeiro. The result is that we see the two wealthiest states in Brazil contesting the same resources.


Meanwhile in Sao Paulo, SABESP is implementing a system of awkwardly suspended blue hoses networked between homes in order to bring water to residents. These hoses bring a bizarre look to the area in which Vila Madalena district’s wealthiest neighborhoods are well supplied while most of the city endures water rationing. It also does so by bringing water from a different source, switching from the Cantareira System (which is now collapsed) to the Guarapiranga reservoirs.

If São Paulo could only learn from the Ficus that grows in Ibirapuera Park in order to distribute its roots and branches more efficiently. If we can find a way to be sure that no portion of the city—neither root nor branch—suffers from a disproportional supply of water, then perhaps we can not just survive such trying times but thrive, as the Ficus thrives.


Thiago Gonçalves is an artist based in São Paulo. An installation by Thiago Gonçalves and Alejandra Bruschi entitled “Hydrotropismo” was on view at Kunsthalle São Paulo for the month of April, 2015.

[Images courtesy of Thiago Gonçalves]

This is a repost of an article that first appeared on the World Policy Blog.

July 13, 2015
Thiago Gonçalves