e-Magazine about exotic forms of Cactaceae
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CULTIVAR / КУЛЬТИВАР e-Magazine about exotic forms of Cactaceae ENGLISH / RUS-(Win1251) | |||||
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Trying to discover the most productive method of obtaining variegated forms of cacti, I decided to apply the two types of mutagens: chemicals and radiation. The goal was to understand the effectiveness of each separate mutagen as well as their combination upon the sprouting seeds of different cacti. As a chemical agent I used water-soluble iron hydroxy acetate salt (CH3COO)2FeOH. I used a 1% solution for watering. As a radiation mutagen I utilized ultra-violet (UV) lamp Q-145 Medicor. The distance between the UV lamp and the seeds did not exceed 4 cm, and exposure time varied from 30 to 90 seconds for different kinds of cacti. The seeds were UV exposed 24 hours after having been sown. Then they were sprayed with distilled water of room temperature, because they had been heated up to 50-60 °C as a result of the UV exposure. After that, all the seeds were kept into a propagator under white fluorescent tubes placed at the height of about 20 cm and set at a 12 hours/day cycle. The temperature in the propagator was not exceeding +29°С at the daytime and was not falling below +19 °С at night. As shown in the table below, the above-mentioned impacts and their combination have influenced seeds of different species unequally. Seeds were sown on March 1, 2000.
Analyzing the data, you can see that some species have an increased sensitivity to the iron ions (Fe2+). This may be explained by lack of iron microelements in the species habitats. The excess of iron caused plastid mutations in these species. As a result of my previous experiments, seeds of many Astrophytum taxa (photo 3) and their hybrids produced colored sprouts after being UV exposed from the distance of 12-15 cm for 15 minutes. Exactly the same amount of UV exposure caused colored sprouts of some Gymnocalycium in one of my later experiments: Gymnocalycium glaucum VS48, Gymnocalycium guanchinense, Gymnocalycium ritterianum P219. But this didn't affect the vast majority of the sowed species: Gymnocalycium bayroanum GN88-69/169, Gymnocalycium catamarcense VS67, Gymnocalycium ferrari GN95-633/2515, Gymnocalycium friedrichii (Gymnocalycium michanovichii v. friedrichii), Gymnocalycium friedrichii v. pirarettaense (Gymnocalycium michanovichii v. pirarettaense), Gymnocalycium michanovichii v. melocactiformis, Gymnocalycium monvillei ssp. achirasense v. kainradliae GN90-270/886, Gymnocalycium monvillei v. colaratum GN96-318a/32086, Gymnocalycium mucidum P36, Gymnocalycium neuhuberi GN89-77, Gymnocalycium riojense GN93-586/2364, Gymnocalycium striglianum, Gymnocalycium uruguaense, Lobivia arachnacanta v. albiflora, Neoporteria wagenknechtii v. multiflora. Though in another experiment several kinds of Lobivia were affected: Lobivia acanthoplegma v. pilosa, Lobivia chrysantha, Lobivia leucorhodon. However, there were just a few colored sprouts amongst these Lobivia and they perished in several days. The rest of the sprouts in this experiment were green: Acanthocalycium violaceum, Gymnocalycium mazanense, Gymnocalycium mihoga, Lobivia backebergii v. oxyalabastra, Lobivia backebergii v. purpurea, Lobivia cardenasii, Lobivia cintiensis, Lobivia famatimensis v. haematantha, Lobivia haematantha v. rebutioides, Lobivia leucomalla, Lobivia maximiliana, Lobivia oyonica, Lobivia pentlandii, Lobivia saltensis, Lobivia scoparia, Lobivia sp. 'Red flowers', Lobivia wessneriana, Matucana haynei v. perplexa KK1459, Rebutia violaciflora, Submatucana formosa, Submatucana sp. 'Lamellini'.
As the next attempt to initiate plastid mutations, the sowing was UV exposed from the distance of 15 cm for 16 minutes per day. Seeds of each species were exposed separately for three days after the first single sprouts had appeared. The length of the UV exposure, as well as the power, remained unchanged in the three days. The results were a little bit surprising. Seeds of Gymnocalycium damsii f. rubra had almost 100% germination, but the sprouts were green. Seeds of Gymnocalycium bodenbenderianum f. variegata showed 5% germination. They also did not show any variegate features even two months later. There were no colored or cristate sprouts among those of two interspecific hybrids F1 between variegated plants of Gymnocalycium michanovichii v. friedrichii f. variegata x Gymnocalycium michanovichii f. 'Hibotan Nishiki' and Gymnocalycium michanovichii f. 'Hibotan Nishiki' x Gymnocalycium michanovichii v. fridrichii f. variegata. In contrast, the non-exposed seeds of these two hybrids gave 30% and 5% variegated sprouts correspondingly. Therefore, it can be concluded that UV rays are capable to rehabilitate existing mutations. I also want to mention that in this case not only plastid mutations, but also nuclear DNA inside the germ cells were rehabilitated. Although seems unbelievable, but it happened in the experiment. As a result of the experiment, Gymnocalycium eyrupleurum (photo) affected by the iron (III) salt produced plastid mutations, but after the combined treatment by the iron (III) salt and the UV radiation mutations did not occur. UV rays initiated plastid mutations of G. artigas hybr. (photo), but the combination of UV and iron salt had no effect. The iron salt produced plastid mutations of Melocactus sp 'Holland' (photo). Mutations also appeared when the effect was combined, i.e. the iron salt and UV radiation. Walery Kalishev, Chelyabinsk, Russia, mailto: e-mail | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
