Oculation
Okulation is a type of plant refinement in which only a dormant bud ("noble eye") is used from the noble rice . This eye of the noble variety is inserted into the base (or mother plant) with a small piece of the surrounding bark.
Period of implementation
For most inoculation methods, the bark of the base must have the seasonal property of dissolving . Methods that “push the eye behind the bark” can only be used in the vegetation phase, because at this time the cambium between the bark and wood is growing and a thin film of weakly connected cells is created. This period extends from the end of May to September.
The weather plays a significant role here, as more dryness prevents the eye from growing. If necessary, this problem can be remedied with irrigation and urea spraying. This difficulty exists in all of the time it takes for the eye to grow.
At the time of collection, the buds of the noble rice must be mature; for buds of the current year this is often only given in July. If you want to graft earlier, the vines have to provide the buds from the previous year. This is only possible if the vines have been cut in the dormant vegetation and stored in a cool, dark and moist place until they are processed.
In Central Europe, the grafted bud usually does not sprout until the following spring when the budding occurs late; in areas with a longer vegetation period, sprouting can occur in the same year. A "focus on the driving eye" occurs particularly early in the year and significantly shortens the period of development.
Implementation of the finishing
During the actual inoculation, the eye is cut flat out of the precious rice with the inoculating knife , to a length of approx. 1–2 cm for roses and approx. 2–4 cm for fruit. It is an advantage if you leave a small leaf stalk on the noble eye, on which the small noble eye can be better held and which is later used to monitor success. Then a cut is made on the base with a very sharp knife, which loosens the bark in such a way that the precious eye can be used accordingly. For this purpose, special tongues are used on the knives made for this work to loosen the bark without damage.
The finishing must now be closed, either with foil tape, raffia or special quick release fasteners to protect it from dirt, drying out and mechanical damage. The closure presses the eye firmly against the cambium of the base and thus ensures rapid growth, which occurs after 14 days in favorable weather. The finishing process should take place as quickly as possible so that the interfaces and especially the precious eye do not dry out.
Success control: One to three weeks after inoculation you can see on the leaf stalk whether the grafting has been successful. If the leaf stalk still looks plump and bright and falls off when touched lightly or has already fallen off by itself, the refinement can be described as successful. The successful combination of the two cambium components now supplies the noble eye with nutrients and the old leaf stalk can initially still receive water; at the same time, however, the usual separation begins at the point where the leaf is shed, through further special tissue formation, until the stalk finally falls off. However, if the petiole has dried up (appearance thin and dark) and it does not fall off even with a light touch, the refinement has not been successful: the eye could not establish a connection with the cambium of the base; in this case, however, post-processing is still possible.
To protect against the cold, the refining point is piled up with earth in winter. In spring, the winter protection is removed and the plant that is still above the grafted eye is cut off. Due to the sap pressure of the base, the eye drives out, the newly created plant reaches z. B. with bush roses in autumn a salable quality.
In the case of roses , the planting takes place at the level of the root neck, in the case of fruit trees at a height of approx. 10–15 cm above the ground in the annual, woody shoot.
Known oculation variants
T-Okulation
With the T-Okulation, a T-shaped cut is made on the surface with the knife: First, a two-centimeter long cross-section is made, which only cuts through the bark, which is a few millimeters thick. The next step is to make a longitudinal cut that is two to four centimeters long and is flush with the cross section. With the help of a special loosener of the grafting knife , the two bark wings are then pulled up without damage, so that the bark can be carefully loosened to the left and right. The previously cut eye is inserted into the slot that has been cut out, pushed down a little so that it lies firmly in the bark pocket, and the bark is folded back again.
Inverted T-ooculation
In order to avoid water running into the incision, the reverse T-ooculation is performed. The transverse slot is set below the longitudinal slot so that the image is an upside-down T. This method is used for citrus plants , for example , but is otherwise rarely used.
Plate inoculation
In the case of plate inoculation, an approximately square piece of bark around the noble eye is lifted off. Likewise, a square area of the same size is freed of bark on the noble rice and the noble eye is placed there. This method is successfully used on walnut and hickory .
For this work there is a special, two-blade walnut refining knife that cuts out a strip of bark that is exactly 3 cm wide.
Ring inoculation
In principle, the ring location works like the plate location. However, a whole ring of bark is loosened from the noble rice and attached to a suitable, bark-free spot on the base.
Chip refinement
→ See chip processing
Chip refinement also only uses a bud, but in contrast to other forms of budding, chip refinement does not depend on the detachability of the bark and can therefore also be used during the vegetation break. For this purpose, a wood chip or chip of the same shape is cut out of the noble rice and the base . The chip consists (on the noble rice) of the bud, the surrounding bark and a portion of the underlying wood. This complete chip is placed in the suitably cut notch in the base and fastened with raffia or rubber band; When processing in spring, the gaps still have to be filled with tree wax , this is not necessary with summer processing .
Nicolier
If there is an incompatibility between the noble variety and the base, a thin plate of a third variety can be placed between the two, with which both are compatible. This process is called nicoling .
literature
- Donnchadh Mac Cárthaigh, Wolfgang Spethmann (ed.): Krüssmanns wood propagation . Parey Berlin, 2000, pp. 154ff. ISBN 3-8263-3221-0
