There are reasons to think that moringa has one of the most potent cancer chemopreventive agents known, but, like so many moringa properties, there are still no clinical trials in humans. Read on for more details.
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The main planting out of the trees was in summer of 2014. While the plants are small, it’s necessary to baby them along. A forgetful neighbor is notorious for not tying up his goats well, and his three goats can often be seen around town, dragging their ropes behind them, standing in a tree munching on leaves or in someone’s yard eating their tomato plants. They seem to like trotting up the hill to the Collection, and my heart stops every time I see them. Some species are still very small and one goat mouthful would set them back considerably. Even though Moringa is very palatable, all of the plants have escaped being eaten so far. It is trite among moringaphiles to make a big deal out of moringa growth rates, but I can't help it. The photos of M. drouhardii and M. hildebrandtii are a seedlings from mid-2014 and they are already taller than me (to my infinite relief- bigger trees are less susceptible to goats, ants, etc.). See photos below. Here is a story that illustrates how perfect the climate and soil are here for moringas. I collected seed of Moringa borziana in southeastern Kenya in 1997. The seeds sprouted in 1998 and were kept very small in the greenhouse in Missouri until last year. I planted it out in late 2014 and immediately the powerful tropical sun burned the stem. This happens commonly in plants that have been grown in the shade and then are planted in full sun. It often helps to “compass” plants by keeping track of which side faced south and has therefore built up more sun resistance. Moringas almost never complain about sun, so in this case I hadn’t bothered. I wondered what to do, because the stem was dying from the tip down. Should I dig it up, disturbing the plant even more, or let it settle in? Large Moringa borziana tubers in the wild sit with their apices well below the soil level. The upper parts of the tubers always have abundant scars from old, dead stems. So I had reason to think that the the little M. borziana could re-sprout from below ground. I buried the tuber a little deeper and made the water basin a little wider, and sat back to wait. Two months later, the plant was over 50 cm tall, bigger than it has ever been, so a major success and a huge relief! The big accomplishment of February was to finish the inventory of the plants in the botanical garden, assigning each a unique number so I can keep track of them in my records. Each plant gets three labels, two metal ones and one plastic one. The plants are still small to attach the labels with nails to the trunk, which I will do as soon as possible, but in the meantime we need to be very paranoid about keeping track of the identity of the trees, given that they lose so much value for research if the identity is lost. The next step is a map of all of individuals, so that if a label is lost it is still possible to reconstruct the ID. There are a few botanical garden apps for just such situations, but I haven't found one I'm entirely happy with yet. So we're still in the stage of babying the trees, but we're getting there. In a few years, the trees should pretty much take care of themselves, but in the meantime the Collection is already meeting its goal of driving moringa research.
I was worried that it would be hard to grow Moringa peregrina here. The rainfall here is about 750 mm per year, considerably higher than in most of the places where Moringa peregrina grows. Also, I was worried about a moringa catch-22: Moringa peregrina plants can take a long time to grow aerial stems in pots, but I didn’t want to plant them out in the ground in the botanical garden until they grow aerial stems. Like many species of Moringa, Moringa peregrina has a tuberous juvenile stage. It grows, often for many years, as just a tuber underground, throwing up slender shoots every year that then die back to the tuber. Only after the tuber reaches a certain size does the plant form an aboveground stem that does not die back every year. Even in the first few years this stem can still die back all the way to the tuber if there is a very severe drought. But eventually the stem remains year after year, the beginning of the life of the plant as a tree. With a little patience, though, and relatively large pots, the M. peregrinas have started to form large enough above ground stems, 10-40 cm tall, that I feel confident about putting them out in the ground. Other species, like Moringa concanensis or M. drouhardii grow in dense tropical dry forest. They compete well with weeds and other forest plants. Moringa peregrina often grows on bare rocky slopes where they are the only tree in the landscape. Not accustomed to competition, I wanted to make sure that the peregrinas would do well when planted out. I was also worried that the relatively high humidity here would be a problem. It doesn’t rain 8 months of the year here, but we are so close to the coast that the humidity is always high. So I was concerned that the plants might be vulnerable to fungal infection and rot. Once the plants are established and growing in pots, though, we have had no losses, and they are doing just as well as all the other species. So, in June we made a trial planting of four M. peregrinas of various provenances on the driest, most exposed portion of the ridge that runs through the collection lot. It seems like the perfect place for the drought-loving M. peregrina. Their aboveground growth has been slow to date—the tallest plants are just 40 cm tall—and I suspect they are busy allocating resources to roots. But they are holding their own and producing aboveground growth much faster than I have ever seen in pots. So we declared the planting a success and in September started about 10X10 meters of a steep, west-facing slope for planting out more Moringa peregrina. Because Moringa peregrina grows in the open, we wanted to plant them out on the most competition-free slope possible. The Taminco company here in Mexico very kindly donated 20 liters of metamsodium, a soil fumigant. After a good rain had soaked the soil, we diluted the metamsodium, which in this case came under the evocative trade name of Mercenario, and poured it into the soil. We watered it in and then covered the entire parcel with plastic and weighted down the plastic around the edges. After a month, we took off the plastic and let the soil air out. Metamsodium is wonderful because it kills absolutely everything—weed seeds, plants, nematodes, fungi, provided that it is sufficiently concentrated and goes deep enough. After a month’s airing out, we noted with a little dismay that there were some Antigonon vines coming back from their underground tubers. This is a horrible weed that roots everywhere and produces very firmly rooted tubers everywhere. The vine itself is fragile so it is impossible to pull the tubers out. A perfectly designed weed but a nightmare to control as it reaches up, sometimes overnight, to grab onto the moringas and smother them. This is almost certainly not the fault of the Mercenario but our not watering in the fumigant well enough on in all areas.
Undaunted, we whacked back the Antigonon and planted out a little over a dozen Moringa peregrina saplings to see how they do. Now, just a few days after transplanting, they look great, with no transplant shock apparent. Given that it grows in fairly readily accessible places like the Golan, Egypt, etc., someone else must grow M. peregrina in the Americas, but I don’t know of anyone. Check back and hopefully in a few years in this space I will be telling stories about the first flowering and fruiting of M. peregrina here, so far from their native habitat. A major research milestone for the collection. The idea of the collection is to gather the widest diversity of Moringa germplasm in the world together in one place. Once this diversity is gathered, then it is possible to start answering our questions about moringa—what is the most nutritious species? Having identified the species, we can start looking for the most nutritious individual, or variety, or population of that species. We can compare the cancer chemopreventive agents across the members of the collection or their glucoregulatory activity. But we need the trees growing and healthy, and we need them large. We need them large to be able to harvest the leaves, flowers, fruits, wood, seeds, or whatever part needs study.
So, it was a major success that, just 7 months after the initial planting out, I was able to harvest leaf tissue from 55 individuals from 11 species plus one interspecific hybrid of Moringa representing 46 different localities or seed sources. I sent these samples to collaborator Renuka Sankaran, of Lehman College/ City University of New York. Renuka is a specialist in nutritional aspects of edible plants, especially protein and mineral nutrition. Along with her student Scott Macbeth, they will screen these samples to start looking for the “best of the best” Moringa in terms of nutrition. We’ll keep you posted on our findings. |
AuthorDr. Mark E. Olson is a researcher at Mexico's national university and an expert on the biology of the genus Moringa Archives
November 2018
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