Castor Bean Results

Lee silkwood at
Sun Mar 28 03:19:32 EST 1999

Hi everyone;
I did a small assignment on Ricinus communis (Castor bean) callus 
efficiency on different explants and I would like to share my results as 
well as qestions.

First, does anyone out there whether Ricinus is a recalcitrant plant? I 
realised I need a good objective/aim to back me up for initiating callus 
from Ricinus to get high grades!

Here are my results:
The Plant Preservative Mixture (PPM) sent from Plant Cell Technology
(email: jhnlung at was very effective in curbing
contamination. I used PPM to surface sterilise the Castor seeds and
incorporated into media. I even coughed and sneezed in front of PPM media
to prove myself. The PPM media remained clear. I strongly recommend PPM
for all tissue culture work. Moreover, investigations show that PPM did
not inhibit any growth in any way. If only we can use PPM as

I found out that after plunging the naked Castor bean into MS + 0.1mg/L
NAA produced monstrous, tumour-like seedlings in two weeks. The roots
look like porcupine and some were callusing from the roots!!! Ugly!

Lastly, the roots was the best to induce callus formation. Beautiful
friable callus in MS + 1mg/L NAA + 1 mg/L Kinetin.

I do have a few queries though. Our teacher has stressed that she would
like us to have a more accurate method to quantify callus formation in
cell suspension and solid media rather than based on visual such as 100%
callus, 75% callus.

I am thinking of using chemicals (nitric acid, chromic acid) to dislodge
the callus from the explant, then measure the weight of that callus. Do
you have any other ideas?
Weighing the callus+explants is out because I forgot to pre-weigh the 
explant before I started on my experiment! Any suggestions?

Also, I've noticed that the axillary buds and shoot tips which I've
excised sprouted enormous leaves in MS + 1 mg/L NAA + 1 mg/L Kinetin. One
of them was SSSOOO big, it was just like a huge caterpillar with callus
all over!!!. Gross!. I hope it's not vitification!!
My question is, why did leaves just sprung out of nowhere from the
axillary buds?? Is it because the buds have some sort woken up from their
dormancy to sprout?? I find that incredible. It can't be direct
organogensis, right?

By the way, do you know whether Castor is a 'recalcitrant' plant?
silkwood at

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