|
Kunsten at pode frugttræer er første gang beskrevet i Antikkens Grækenland.
Ofte kan man læse at podning af frugttræer har været kendt i Kina 2000 år før f.Kr., men der er ingen dokumentation for dette. De tidligste kinesiske skrifter, der nævner noget, der kunne opfattes som podning stammer fra det 3. århundrede f.Kr.
Mere tyder på, at podning af frugttræer først er opstået i nogle kulturer, der har eksisteret i og omkring Mesopotamien, som perserne, assyrerne og sumererne. Måske kunne man pode allerede i bronze alderen.
Theophrastus er den første vi kender til, som skrev om bestøvning og planternes formering, herunder podning.
Theophrastus er født omkring 372 f.Kr. på Lesbos. Han døde 287 f.Kr. i Athen. Han var en græsk videnskabsmand og pædagog. Han var elev af Platon og Aristoteles, og efterfulgte sidstnævnte som leder for den peripatetiske skole i Athen.
Carl von Linné kaldte Theophrastos for "botanikkens far".
Hans vigtigste bidrag var hans to afhandlinger i botanik, ”Historia Plantarum” (Planternes historie) og ”De Causis Plantarum” (Årsager til plantevækst).
Bøger indeholder nøjagtige observationer af planters opbygning og indeholder praktiske oplysninger om kultivering, plantesygdomme og podning, foruden planternes anvendelse indenfor medicinen.
Bøgerne var i mere end 1.500 år hovedværker indenfor botanikken.
Herunder er et udsnit af en engelsk oversættelse af Theophrastus' ”De causis plantarum” af Benedict Einarson og George K.K. Link. 1976. William Heinemann, London.
I teksten nævner Theophrastus både podning med podekviste og knopper. Samt diskuterer forskellige forhold, der har betydning for podning.
Theophrastus beskriver en spaltepodning, hvor podekvisten bankes på plads med en hammer, og hvor frugtavlere omvikler podningen med limebark og mudder tilsat hår, for at undgå udtørring.
”Propagation in Another Tree: Grafting It remains to discuss the cases where propagation occurs in other trees, namely in twig and bud-grafts. What we have to say is simple and has (so to speak) been said already. since the twig uses the stock as a cutting uses the earth. So bud-grafting too is a kind of planting, and not a mere juxtaposition; here however it is evident that what produces both the sprout and the fruit is the generative fluid the bud possesses this when it is fitted into the stock, and getting its food from the latter produces its own type of sprout. All grafts grow rapidly because their food has already been worked up; and this applies still more to the bud-grafts, for their food is the purest and just as it is already in the fruits that are continuous with the stock. Like always coalesces readily with like, and the bud is as it were of the same variety. It is also reasonable that grafts should best take hold when scion and stock have the same bark, for the change is smallest between trees of the same kind, and what occurs is as it were a mere shift in position. For the impulse not only of the saps of the two but of the whole trees toward sprouting is then simul- taneous, so that here, when graft and scion are like and have fruit with like responses, both circumstances make the rapidity of growth reasonable. In the rest the growth is more rapid as the difference in the kind of tree, the character of the sap and the seasons of development diminishes. The seasons of grafting are also reasonable, or rather perhaps are necessarily the ones that they are, when all further sprouting in general takes place: autumn, spring and the rising of the dog-star; for we must take a graft that feels the urge to sprout. The arguments in favour of each season are much like the arguments in favour of each as a time for planting. Some persons recommend spring, the trees being still pregnant at the time of the vernal equinox, since the graft in that case will sprout at the time of the pregnancy, and mean- while the bark grows over the graft and encloses it. Others recommend the season at the rising of Arcturus, for the graft at once “takes root” (as it were) and (as it were) “seals over;” and once it has coalesced with the stock it puts forth its sprouts all at once at the coming of spring, having as it does a more powerful basis to start from. The advice to graft buds on the smoothest and youngest axils is also reasonable. For here the buds best take hold because of the smoothness and youth of the axils, since what is young is full of life and sprouts well. The stocks best fitted for bud-grafting, to put it in a word, are those with a certain stickiness in their fluid; further, those with bark that is soft and of the same kind and that have similar responses (which is why the best bud-grafting is on stocks close to the bud in nature and age). For the stickiness also establishes a hold; and when the bark is soft and similar it favours the bud equally with the bud’s own bark and makes the change no great one. In the rest the time for grafting is short because of their rapid sprouting, but lasts longer for the olive, which keeps producing buds longer. Further we are told that the new wood produced in spring stays tender and has a flow of fluid throughout the period, and the site of the graft remains moist all summer; and that with these advantages the graft grows better than that of any other tree; since some suppose that all this keeps the graft steeped in fluid for as long as four or even five months. Rain is harmful to a bud-graft, seeping in and decomposing it and killing it because of its weakness, and this is why it is considered safest to graft buds in the dog days, although nowadays some growers tie bark around the site to prevent rain from seeping in. For a twig-graft on the other band rain is helpful if the graft is not naturally moist. This is why some growers plaster it with mud and others set a pot of water over it and let the water drip, in the belief that the wound is large enough for the scion to dry out quickly unless it gets fluid. We are rightly told (1) to keep the bud and bark from getting torn and (2) to trim the insert in such a way that no core wood is exposed at the site; for when the bark is torn or the core exposed the scion dries out and perishes. This is why cultivators also first bandage the site with layers of lime bark and then plaster mud over it mixed with hair: to make the fluid remain and keep sun, rain and cold from doing any harm. So too after slitting the stock and giving the scion a wedge-like shape a they drive it in with a mallet to make the fit as tight as possible. There must also be no excess of their own fluid in the scions. This is why in the case of the vine scions are cut two days before grafting, to allow the exudation that collects at the cut first to run off and save the scion from decomposition and mould. On the other hand scions of the pomegranate and fig and of trees drier than these are grafted at once. One must choose the proper seasons for grafting with both the country and the nature of the trees in view, since some combinations are too wet, others too dry. For thin soil spring is in fact the better season; for what makes this combination appropriate is that thin soil contains but little fluid. For rich and muddy soil on the other hand the better season is autumn, since in spring there is far too much wetness to preserve the graft so long as bleeding still persists. Some set this autumnal season at thirty days. It is also reasonable that trees so grafted should bear finer fruit, especially when the scion is from a cultivated tree and the stock from a wild tree of the same bark, since the scion is better fed because the stock is strong (this is why it is recommended to plant wild olives first and later graft them with cultivated buds or twigs). For the grafts hold better to the stronger tree, and since this tree attracts more food they make it a finer producer. Indeed if one should reverse the procedure and graft wild scions on a cultivated stock, there would be a certain improvement in the wild crop but no fine fruit. Let this suffice for the discussion of planting in the sense of grafting.”
|
|