Philanthropic Plants

Some biologists consider viruses to be non-living because, unlike all other organisms, they do not have the cellular machinery to reproduce themselves. Instead, viruses insert their genetic material into the cells of other organisms, sometimes, but not always, with disastrous results for the host. Viruses, then, cannot live independently of other living things.

But no living thing can survive independently of other living things, any more than people can survive without other people or companies can survive without other companies. A clear example is the dependency of plants on the fantastically complex community of bacteria, fungi, protists, viruses, and microscopic animals that lives in the soil around the plant’s roots. To get some idea of the complexity of this so-called rhizosphere community (rhizo for roots), consider that just one teaspoon full of it contains more bacteria than there are stars in the Milky Way, and that no more than 1% of bacterial species in any such spoonful have yet been identified. Naturally then, we cannot claim to have anything close to a full understanding of this tiny community.

However, we do know two important things. First, the rhizosphere community is crucial in supporting the life of the plant. The community decomposes dead plant matter, and underlying rocks, releasing vital nutrients such as phosphorous and nitrogen. Without the rhizosphere community, all of these nutrients would eventually become locked up in dead plant matter, and the plants would die. That’s a pretty good example of the interdependency of living things.

Second, plants deliberately feed the rhizosphere community. To explain. When plants photosynthesize, they convert water (from the soil) and carbon dioxide (from the air) into carbohydrates, all powered by sunlight. The carbohydrates are then used to make more plant. Thus, plants work extremely hard to maximize their rate of photosynthesis, carefully growing their stems and leaves to maximize light capture; carefully growing their root systems to maximize water capture; and carefully balancing their investments in roots vs leaves to stay balanced, in order to maximize their overall growth rate. Their carbohydrates, then, are much needed and hard won. And yet plants pump a decent fraction of those carbohydrates into the rhizosphere. Why?

They don’t do it by mistake. Billions of years of plant evolution have resulted in a wide array of extremely sophisticated cellular mechanisms regulating every process occurring within every plant. It is impossible to imagine that plants have never worked out a way to stem an uncontrolled leakage of carbon from their roots. Neither do they do it because they have excess carbon to vent. One can always find a use for excess carbon, just as one can always find a use for excess money. Plants could build better protection against herbivores, in the shape of spines or protective chemicals; or against pathogens, in the shape of a more active immune system. They could grow taller, in order to capture more light; or grow deeper roots, in order to capture more water and nutrients. Any in any case, if plants really do not need the excess carbohydrate, why put the effort into making it in the first place?

The only believable explanation for the leakage of carbon into the rhizosphere is that plants are deliberately fertilizing the rhizosphere community because the benefits of doing so outweigh the costs. The costs include the direct cost of the carbon, the indirect cost of fertilizing potentially troublesome nasty stuff like pathogenic bacteria, and the opportunity cost of what else the plants could do with the carbon. The benefit is – presumably – a denser, faster, more diverse rhizosphere community that is better at returning nutrients to the plant. Fertilize the community a little and it fertilizes you a lot.

We can split the fertilization into two categories, targeted and generic. An unambiguous example of targeted fertilization is the carbon fed to those soil fungi: the mycorrhizae. Mycorrhizae form very close symbiotic relationships with plant roots, either wrapping the roots or, more commonly, actually penetrating the roots to form specialized exchanges structures that look like blood capillaries. The rest of the mycorrhizae consist of dense networks of fine threads that infuse the whole of the rhizosphere. The mycorrhiza gets lots of carbon in a highly useful form (glucose), rather than having to break down plant matter; whereas the plant gets a greatly increased supply of nutrients, especially phosphorous, which otherwise would diffuse toward the plant roots only slowly.

Interestingly, the plant-mycorrhizae symbiosis has all the hall marks of outsourcing as we see it in business. The plant selects the most efficient partners available to them, for example by beginning relationships with several then dropping the less efficient through time (think, tendering). The plant uses a complex signalling approach in order to drop the multiple levels of security that would usually keep fungi out of the roots (think, giving swipecards and email accounts to your contract staff). The plant ramps the relationship up and down through time in line with supply and demand for carbon (think, zero-hour contracts). To hedge their bets, individual mycorrhizae often form working relationships with many individual plants (think, broadening your customer base). In so doing, they unwittingly l linking the fates of, those multiple plants in ways that ecologists have barely begun to explore. Presumably, outsourcing unwittingly links the fates of companies also.

Targeted fertilization – ecological outsourcing – is easy to understand. But we also see a large amount of what looks like generic fertilization, in the form of easily-useable carbon that is leaked straight into the soil as ‘root exudates’ without any obvious target. This is the ecological equivalent of taking some of your profits out in cash and throwing out the front door. I don’t know if any company has ever done this. But I get the impression it is not the norm.

Now, companies do give to local charities. But this differs from the what plants do. Giving to a local charity is targeted fertilization, whereas generic fertilization would mean giving money to anyone or anything. Also, companies give to charities for PR or, sometimes, for ethical reasons. As far we we know, plants don't do ethics or PR. Therefore, generic fertilization must have evolved purely because it is in the best interest of the individual plant.

Does this imply that companies also could benefit from the generically fertilizing their local community? According to ecological theory it depends on scale. It pays to give to the local community only when it remains close to (ideally dominated by) you, in the same way that a plan dominates its rhizosphere community. In this circumstance, you fertilize the community a little and it fertilizes you a lot. By contrast, I am not aware of a clear example of animals deliberately fertilizing the community, presumably because animals are highly mobile. When you are mobile, or your community is mobile, you fertilize the community a little and it fertilizes everyone a tiny bit, including your competitors. The economic implication is that companies that depend intimately on a local community, for example for customers, suppliers and labour, could, in theory – and in the long term – benefit from fertilizing that community, even in a completely non-targeted way. There are possible examples in the famous 19th century British philanthropists who utterly transformed the local communities on which they depended for labour, building everything from schools, to houses, to hospitals. There is little doubt that philanthropy was driven mostly by religious and ethical concerns, but the dramatic business success of the philanthropists implies that fertilization was also an excellent long-term business strategy. Naturally, that business success meant that the philanthropists could fertilize their communities all the more. It is hard to think of a more virtuous circle.

By contrast, in our increasingly globalized world, ecological theory would predict that the business benefits of fertilization will disappear for most companies. The exceptions will be the very small, who remain hyper local, and the handful of very large companies for whom the whole world is one large local community. According to ecological theory then, the Philanthropy of the Gates, Pages and Zuckerbergs of this world will benefit not just their local communities – that is, the whole world! – but their parent companies also. Joseph Rowntree, one feels, would approve.

© 2017 Drew Purves All Rights Reserved