If you wish to have Aztekium . . . (Seed propagation) By Piotr Swiatoniowski.

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The genus Aztekium is one of the most famous sort of cactus, and unfortunately also the one which is most difficult to grow. The problems in its cultivation refer principally to extremely slow growth but also to some other special requirements that make these plants laborious to raise even in their native land of Mexico. However, it is obvious that Aztekium ritteri and Aztekium hintonii are really extraordinary examples of the Earth's flora and they deserve coping with difficulties in their cultivation. A few years ago I decided to take up some experiments in growing Aztekium from seeds and grafting it on different stocks. I would like to present my conclusions to you. I hope that this information will be helpful for beginning growers, and it will give occasion to overcome the doubts which still exist. First of all, it is desirable to check all seeds because many of them can be imperfectly developed or crushed. It is reasonable to sow only these grains which are felt with a finger tip as possessing spherical form, and not being just flakes, because these ones won't germinate. There is no danger to damage a seed if you perform this activity delicately. This is after picking that the seeds reveal the best germination. Afterwards the seeds should be protected against the development of any fungus. The best treatment in this case is soaking them for about fifteen minutes in the 0.1 % solution of quinosol ( C9H7ON * KHSO4 ), and later when they dry up, additionally in the common seed dressing. The first compound doesn't mitigate the energy of the germination in the case of Aztekium in contradiction to seeds of Parodia and some other genus. Frequently applied potassium permanganate ( KMNO4) is not sufficiently effective, and very often the seeds treated with it are assaulted by white spawn of Fusarium moniliforme var. subglutinans. Considering of the best breeding ground for the seedlings it turned out that due to danger of extension of fungus or alga and the dimension of the seed, all requirements are fulfilled by pure sand, broiled in about 150C. All attempts at the application of gelatine and blotting paper ended with worse results, and in the first case there occurred very fast development of some Aspergillaceae inside the gelatine. It is rather the river sand that should be used because the common sand usually contains grains of limestone which very fast change the pH degree of water into the alkaline. As a matter of fact, Aztekium grows generally in the habitat on this type of breeding ground but investigations performed by Sociedad Mexicana de Cactologia A.C. proved that in the case of Aztekium ritteri the pH equalled about 5.5 degrees. Thus it would be very clever to use, for the seedlings, distilled water that is free of any biological pollution, with the addition of some acid and good fertilizer in the ordinary concentration. Sometimes it may seem that the fertilizer changes the pH of water, but it is dangerous to add more acid even if the acidiameter indicates a new degree of pH. The good solution is rather to use mineral acids as sulphuric acid (H2SO4) because some organic acids, for example formic acid ( HCOOH ) manifest tendency to crystallization after a few weeks. The acidimeters used in aquaristics are very precise. It is important to remember that distilled water usually has got less than 7 degrees of pH, though it should be neutral according to chemical literature. After all these quite complicated preparations we can set about the proper sowing of seeds. I recommend the only really effective method, consisting the application of hermetic jars, which is well known to all growers. It is not necessary to mention all advantages of this procedure related to separation of the seedlings from biological pollution, almost 90% humidity of the air, easy increase of temperature, lack of vaporization ... The seeds begin to germinate usually after 5 days in the controlled level of 25C, and the whole process advances quite steadily for next two weeks, but most seedlings appear before the end of first 10 days. Lower temperature slows down the growing, but the temperature which is too high at the outset is also disadvantageous because the seeds can be overheated and don't germinate completely. Of course, this process depends on much more parameters and factors that are difficult or almost impossible to determine. The seedlings of Aztekium ritteri are almost always spherical in contrast to these of Aztekium hintonii that can be as well ball shaped, discus shaped or even elongated, regardless to the mother plant. These ones that are the last to germinate, grow worst and at the lowest speed. Unfortunately, it will be very difficult to check if this original shape has any direct relationship with the proportions of the definite specimen. In the habitat there indeed exist this kind of differences, but especially in the case of Aztekium hintonii. In spite of the large germination power, the seedlings are very sensitive for the first two months and many of them perish because of several factors. There can be mentioned three main agents here : too high concentration of the fertilizer, too high temperature and too strong light. I carried out some simple experiments and it turned out that always when any of the above mentioned agents was too high, the seedlings were turning glassy and olive green. The modification of the pH gives the same result in the case of too acid water but alkaline medium involves something like slow drying up of the seedlings. Taking into consideration the proper temperature, my experiences proved that for a few weeks after germination it shouldn't overstep the limit of 28C and it is better to keep it at this level for almost two months. Later the seedlings become stronger and even the temperature of 45C is harmless for them, though this one is probably too high and it can, of course, slow down the growth. Then they become very hard and extremely resistant to the lack of water. There is one more very interesting reason for wasting away of the seedlings, and it is easy to observe. Because of their spherical shape and very slow process of photosynthesis, the seedlings which germinated upside down aren't able to change their position contrary to seedlings of other cacti and they are destined to die. This fact is very striking from the evolution point of view because it seems to constitute some kind of imperfection. On the other hand, it is manifest that this spherical shape certainly tends towards the reduction of transpiration under difficult conditions. Sometimes it is important to help these usually few unfortunate seedlings to survive. In connexion with these special conditions, it is certainly better and much easier to propagate Aztekium under artificial light that gives also a lot of warmth. Hence, traditional bulbs can be better than colder fluorescent lamps. Unfortunately, special electric bulbs for flowers are still inaccessible in my country, and therefore I cannot estimate their advantages and disadvantages. In such quasi - laboratory conditions the seedlings should grow well but it takes many years before they overstep 10 mm in diameter if they haven't been grafted. Aztekium hintonii differs in this respect, because it grows several times faster than smaller Aztekium ritteri. Text : Piotr Swiatoniowski (p.swiatoniovsky@interia.pl). Photos : George S. Hinton The author, Piotr Swiatoniowski (p.swiatoniovsky@interia.pl), would like to get in touch with growers of Pterocacti and Austrocylindropuntia.