Friday, October 24, 2014

Breaking seed dormancy in Sacred Lotus, Nelumbo nucifera

I love Sacred Lotus. The flowers are beautiful and have an intoxicating fragrance that will always remind me of swimming in (crocodile free) water holes in the Kimberley region of north-west Australia. I grow several types which I purchased from Blue Lotus Water Garden at Yarra Junction. This nursery-come-water gardens stocks ornamental Lotus with skinner rhizomes than the big fat edible types but I'll find some bigger eating varieties one day. In the meantime, it's worth growing them for the aesthetic value of the leaves and flowers alone.

Sacred Lotus is propagated by division of the sausage-like rhizomes which is extremely easy. Not so easy is propagation by seed. None of the specimens I've grown have ever produced seed, or more precisely, the seeds in the pods are always empty. Last year there were two filled seeds in a specimen purchased from Blue Lotus and I have been saving these up for germinating and growing on. The difficulty with the Lotus propagation from seed is breaking through the hard thick coat of the seed which can prevent germination from occurring in even optimum conditions.

Lotus seeds - about the size of a pea

I looked up ways to break Nelumbo dormancy and have followed instructions from the following website to the letter -

The key points made by the author are as follows (taken directly from the webpage):

"The secret for speeding up the germination process is to remove this protective cover without harming the internal seed. Many methods of doing this have been described in the literature (including soaking in concentrated sulfuric acid for 5 hours), but the method I use is easily available to every one. The primary tool is a pair of pliers which has the usual pipe grip cutout at the business end. The pliers are used to get a firm grip on the seed within the oval pipe grip section of the pliers. The seed is very tough and you do not have to grip the seed so hard as to crack it. The seed is then rubbed along a rough surface to wear away part of the seed coat. The preferred surface is a medium grit sand paper laid flat on a table, although a concrete surface or file can be used. The optimum grit size for the sandpaper is # 80, although a finer grit (higher number) can also do the job. It just takes more rubbing and the sandpaper wears out sooner. You will then appreciate how hard the seedcoat really is.
There are two areas where the seed scouring can take place: on the side or at the dimpled end. I prefer the side because the progress of the rubbing (or sanding) is more uniformly determined. When scouring the side, rub the seed in one area only. This will produce a shiny flat surface as the rubbing proceeds. This surface should be inspected frequently to check the process of the wearing away process. At first, the surface is a uniform black color. As the rubbing proceeds, a thin white line circle or oval will appear, depending on the seed type. This indicates the breaking through of the junction between the two fused seed coats. At this point you can stop the rubbing"

The photos below show my preparation of the seed. In order to maintain a warm temperature for soaking I've placed the seed in a jar in Breville Yoghurt  Maker which has a heated coil running through it to incubate yoghurt. (These are quite handy for germinating seed too but that's another story). We'll see how this goes and I'll post on how these Nelumbo seeds progress. Finger crossed.

Pre-scarification withe sandpaper

Post-scarification with sandpaper

Floating in a jar in the Yoghurt Maker Lid on - good luck seeds!


First Lotus leaves of spring

No comments:

Post a Comment