Yesterday, I spent an hour in the greenhouse seeding four flats of seeds. I'm getting some starts ready for a project for Environmental Biophysics (details forthcoming - once I actually draft up the project proposal) and also to get some more material for grafting practice.
Seeds sown:
- 66 'Cherokee Purple' tomato seeds (Source: Territorial Seeds)
- 72 'Pumpkin-On-A-Stick' (Solanum aethiopicum) seeds (Source: Abundant Life Seeds)
- 144 Mung Bean
"Mung Bean?!"
Well, what can I say. I got side-tracked. I am raising the mung beans for a willow cofactor experiment that my plant propagation professor and I are playing around with.
I am currently a teaching assistant for Plant Propagation (HORT 251). We have been doing a series of experiments on auxin-induced rooting. Auxin is a plant hormone that induces rooting in plants. The hormone is produced in the terminal and axillary buds of a plant. Auxin moves from the shoots to the roots but not from the roots to the shoots (transfer occurs in one direction). However, auxin is not solely responsible for root induction. Rooting also requires cofactors, other chemical compounds, for auxin-induced rooting to occur.
It is commonly known that willow species (Salix sp.) root extremely easily. You can plant them vertical, horizontal, upside-down; you can weave them into sculptures or bundle them into
willow-cutting burritos, and, given moisture, they will root. One common gardening trick is to soak willow twigs in water and then use the resulting willow-infusion to water your plants, thereby increasing root development and overall plant vigor.
It is important to note that willow's rooting is not necessarily due to elevated auxin production in willows but rather in the willow cofactors. Willows contain high amounts of salicylic acid, the main ingredient in aspirin. Adding aspirin to flower water is reputed to make flowers stay fresh longer. Therefore, it could be that salicylic acid may be the rooting cofactor.
Most rooting hormone products such as Hormex consist of synthetic auxin (usually IBA or 1 H-indole-3-butyric acid) mixed with talc or other inert ingredients. The cut end of the stem is then dipped into the auxin to increase rootings (some auxin will be produced in the buds).
Dr. Kumar and I wanted to look at whether a compound could be made from willowbark and talc that would similarly induce rooting in cuttings. So, I went out and harvested some young willow branches from a large tree on campus.
We then soaked these willow branches until the buds began to swell, as we thought bud development would likely coincide with increased synthesis of auxin and cofactors. Once the buds had begun to swell, the bark was peeled from the branches and submersed in liquid nitrogen. Liquid nitrogen is -196C (-321F) and quickly freezes plant material causing plant cell walls to rupture. The bark was then put then put in a lyophilizer for 24 hours. Lyophilization removes moisture from the material by exposing the material to very low temperatures in a high vacuum.
The freeze-dried willow bark can then be ground into a powder using a coffee grinder.
Once the mung beans are big enough, we will use them to test the effect of willow-bark at different concentrations on rooting. And we will see where we can go from there.
Results from the "To Soak or Not To Soak" Eggplant Experiment
After 2 weeks, I had a 68% germination rate for the unsoaked eggplant seeds and a 92% germination rate for the soaked eggplants. Based on this small trial, I am inclined to believe that soaking the seeds for 24 hours improves germination. I will be seeding more eggplant this afternoon, so I began soaking my seeds last night.
The eggplants have become infested with thrips. The greenhouse folks have been treating them (see yellow sticky paper in photo below) but they say its a constant battle unless you want to resort to continual pesticide application.
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