It has been very wet in England recently, and on waking up I noticed this creeper outside the window exuding droplets of sap. The creeper in question is an Akebia and the process is called guttation. When the water potential in the roots is less than that in the soil, water enters the plant. At night the stomata (leaf-pores) in most plants are closed to reduce water-loss, so the excess water is exuded via the xylem (pipes in the plant’s plumbing), leaving through special glands called hydathodes. A bit of useful stuff, like sugars and minerals, is lost with the waste water, but the main thing is to keep the water-balance right.
Plants go to immense pains to access and conserve water, but when there is too much of it they tend not to hoard: they return it to the environment. And in the whole of the natural world, resources like water, carbon, nitrogen – you name it – are regulated by the systems and organisms that need them.
Standing there in my pyjamas, I had the thought, trite though it may be, that the Akebia was offering me an object lesson in economy. In the West, many people have too much. Their cupboard-pressure may be too high.
Then I recalled this cantata (“I Have Enough”) composed by Johann Sebastian Bach, that wise old bird: