There’s nothing like a trip to the bramble patch to remind you that nature is one tough place to make a living. Just securing enough berries to make a batch of jam involves dealing with a host of natural obstacles. There are competitors (birds, animals and of course, other pickers), predators (mosquitos), pests of all types, and then of course the various defenses of the plants themselves. It’s these that have my particular attention this morning, as I still have a few blackberry barbs stuck under my fingernails.
Plant defenses are interesting things to ruminate on, as it were. You won’t be surprised to learn, given who I am, that I think about them several times a week. Especially now in the early summer when salad greens are so abundant. For me, a consummate plant predator, the pleasure of a good salad is twofold. First there’s the sheer delight of the epicure, since I love those hot and bitter flavors. Second is the satisfaction of the conqueror, since I’m all too aware that the same chemicals that produce those bitter flavors (alkaloids) are also meant as a defense mechanism. Toxins are what they are, a feeble attempt to poison me. Knowing that, it’s often all I can do to keep from blurting out something like: “Ha! Nice try escarole! But you’re going to have to do a lot better than that if you’re going to take down a mammal my size! I actually enjoyed it!” (outbursts like that really embarrass the wife in restaurants). Though in truth alkaloids really are meant more for insects. They’re plant-made pesticides, of which we consume some 1500 milligrams each day (man-made pesticides account for 0.1 milligrams of our total daily pesticide intake). Good thing our guts are chock-a-block with defenses of our own, mostly in the form of toxin-disassembling enzymes, which are not only plentiful, they’re adaptable to new and different types of toxins (one of the evolutionary advantages to being a free-ranging, new food sampling omnivore).
Yet our digestive defenses don’t protect us from everything, and there are some toxins present in fruits and vegetables that really can do us harm. Potatoes are rich in compounds called glucoalkaloids, nerve toxins that can make us sick in high enough concentrations (which is why any green portions of potatoes should always be avoided). Red kidney beans contain poisons called lectins which cause gastrointestinal inflammation and vomiting if we don’t destroy them first, which we do, through another extraordinary evolutionary countermeasure we humans have come up with: cooking.
Of course blackberry shrubs don’t work that way. They prefer the direct approach: stabbing weaponry. Which I have to confess has always confused me, since the whole purpose of making a fruit in the first place is supposedly so that animals will consume them, thus carrying the seeds to new locales. I’ve heard it said that the reason blackberries have thorns is because the teeth of big animals destroy their delicate seeds. Thus thorns are a blackberry shrub’s way of saying: Birds welcome, large mammals need not apply. Whether this has been proven scientifically or is just idle speculation, I honestly don’t know.
Suffice to say that at the very least the plant world is sending us mixed messages. Stone fruits like peaches, cherries, plums, pears and prunes are further examples. They say to us: do what you will with the fruit, just watch how you treat the seeds, bub. A message they back up with cyanogenic glycoside, a compound in the stones that creates hydrogen cyanide if they’re chewed (otherwise they’ll pass straight through the digestive system without causing any harm, should you swallow one). So who’s running the show here? Them or us? The more I think about this kind of thing, the more I really start to wonder.