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The Introduction

Please read first the article on Camellia seed and seedlings under the topic 'Description'.

This experimental work was induced by Dr Jean Creze in France. He has developed a method to micrograft buds into seedlings, in order to get rid of virus which has indeed infected most Camellia plants. I visited him some time ago and he was so generous to demonstrate his procedure. He gave me all his material and I will certainly post this and his results here at the internet. Most his material is in French, with wich language I have difficulties. But be patient, it is on its way. To my knowledge his approach is the first successful attempt to get rid of Camellia virus. As I understand, one can now buy a virus free 'Ville de Nantes' (which is often variegated in the leaves) at Mr. Thoby's place in Carquefou.

The graft into a developing seedling seems to be a quick method in order to establish a new plant of a given cultivar. With grafting, you need a scion or shoot of the wanted cultivar, and an understock, normally a robust and vital C. japonica or C. sasanqua. The understock is cultivated for about two years. There are several methods of grafting, each requires skill and knowledge. Most grafts can only be done at certain development stages of the understock. Since germinating plants are available all the year, one is not bound to special seasons when the graft is done into the seedling as the understock. When the graft fails, both the scion and the seedling can be reused for a further attempt. The union between the two parts can occur within three weeks. The reasons are:

My experience with this technique is only 4 weeks, and certainly the results described here are all preliminary. I will give more information as soon as I feel to have success with different appraoches. So far I will give the details of the presently most successful method, the graft of the scion into a cleft of the epicotyledon.

The Equipment

  1. A scalpel or a very sharp small knife
  2. A small gas burner
  3. Hard grafting wax as used for grafting grapes
  4. A small metal loop (inoculating loop, 3mm), nichrome wire
  5. Sterile water (best cooked in a pressure cooker)
  6. A germinated Camellia in the unfolded state
  7. A scion, not too soft

Seedling Grafts

by Klaus Peper

This experimental work is devoted to Dr. Jean Creze, France.
who advised me into the micro graft technique.

The Illustration

A. The germinated Camellia seed, or the understock. Note that the Epicotyledon ends with the first forerunner leave (fl). B. The cut scion. C. The cut portion of Epicotyledon. D. The united graft with indicated wax. E. Inoculating loop with handle.

The Procedure

A. Cleft graft into the Shoot

The shoot is quite thin, and only thin scions can be applied. According to my experience, the epicotyledon is a safer place to graft. Even in nature, the seedling can reduce the fluid supply to the shoot (for several reasons), and instead the sleeping axillary eyes at the axil of the cotyledon stalks may become active.

B. Cleft graft into the Epicotyledon

It appears that the most active and vigorous tissue is located in this region.

  1. Take a seedling in the unfolded stage, with prior cut root and established in a single pot.
  2. Remove the surface soil until the seed and the cotyledon stalks are above ground.
  3. Cut with a scalpel the shoot at an appropiate level as indicated in Fig. A. The level depends on the diameter of the scion.
  4. Take the terminating bud of the scion shoot and remove all leaves except the highest one.
  5. Produce a wedge in the scion shoot with two cuts as indicated in Fig. B. Soak the cut end into sterile water.
  6. Do a vertical cut 4-5mm into the seedling right into the hypocotyledon, as indicated in Fig. C.
  7. Heat the wire loop (Fig. E.) in a gas burner and transfer a small amount of water to the surface of the cut understock.
  8. Insert the scion into the understock.
  9. Heat the loop again and transfer hot wax to the union. The plant readily accepts the wax and gives the union the necessary stability. The water prevents the hot wax to enter the cleft.
  10. Note the day of operation and put the pot into a closed cabinet with 100% humidity.
  11. Inspect the graft twice a week. Remove any auxiliary shoot which may arise from the cotyledon leaf stalk axils.
  12. Wait at least 3-4 weeks. Retry if the union is not successful.

C. Cleft grafting into the Hypocotyledon

In this method the cut through the seedling is done just underneath the cotyledon stalks. It is tempting to try this since here the shoot is thickest, and would fit best thicker scions. However, the hypocotyledon seems to be very short in Camellias (2-3mm), and a cut just above the stalks gives equal thickness.

D Cleft grafting into the root

According to my preliminary results, this method is only partly effective, since it seems that the root tissue builds up callus at a reduced rate in comparison with the shoot tissue.

E. Flat bud grafting on the epicotyledon

This is very much the technique of Dr. Jean Creze. He found out the right wax to use, and introduced the trick with the water 'glue'. Jean does all his work under sterile conditions, which demands equipment and skill which is not available to everybody. However, it appears that perfect sterility is not necessary, although clean handling is obligatory.

  1. Surround the epicotyledon with wax, using the inoculating loop.
  2. Select a dorminating, but already elongated vegetative bud of the cultivar, e.g., at early winter.
  3. Surround the basis of the bud also with wax.
  4. Cut both waxed areas with a sharp knife, perpendicular to the shoot axis.
  5. Put sterile water on top of the cut understock.
  6. Position carefully the bud on the understock.
  7. Melt the wax with the hot wire loop together.
  8. Further treatrment is like in A.

I have done this operation several times and hope that the buds will thrive after a while. The two cuts have to be done exactly perpendicular, otherwise the bud will fall down. Thank you Jean!

The preliminary Results

21. 8. 1996. I have done about 30 operations so far since I started a month ago. I have 11 successfully united grafts, wax removed, in the young plant culture room. So far there is no sign of new shoot. The most successful procedure was so far the method B, graft into the epicotyledon, and to a lesser degree grafts into the shoot and into the root. The flat graft according to Dr. Creze failed in all cases. Dr. Creze did his grafts in November, with dormant, but elongated buds. I certainly will retry this and report.

It appears that at least the knife and the water must be sterile: I have detected fungus hyphens in the graft cleft.
I lost several plants because of an infection with small black flys, the larvae of which live in the soil and readily enter plant wounds, eating the tissue. I have them quite often in the young culture room, where they are not very harmful because the plants are not wounded. Most damage was done to the seeds in the seed nurse technique (see seeds in the topic: Camellia Description).

2. 9. 1996. I found that the operated seedling is easily infected by fungus like Botrytis: The spliced part of the understock turns brown and becomes soft. The graft is a failure, but can be recut and regrafted.

Now I have adopted the following procedure:
The seedling is completely removed from the soil and washed with normal water. The graft is done on the bare-rooted plant. This is much easier to handle than to operate with the plant in soil, where I have infected, in several plants, the operation area with contaminated soil.
The graft is repotted in sterile medium ( 30 minutes in a pressure cooker). The graft area and the seed is well above the surface of the medium. Thus air is allowed to reach the hypocotyledon, which is the most sensitive part to be infected with fungus.
I recommend to sterilize the seed before sowing with Chavel water, and sow them into sterilized potting medium, in order to get rid of any fungus and pests.

DEC 96: I now have successful (i.e., growing) grafts with all procedures, including the flat graft. However, many grafts were successful in the unification, but failed to grow. In most cases this was due to infection of the seedling. In order to make seedling graft a successful procedure, we have to experiment more to make this method safer. As soon as I have more experience, I will post them here.
Meantime start your own grafts and and report!
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