Features of sterilization of various explants of rhododendrons (Rhododendron L.) and their introduction in vitro

Abstract

Purpose. To establish the influence of sterilization conditions and the type of explants for obtaining aseptic culture of representatives of the genus Rhododendron (L.).
 Methods. Biotechnological, laboratory, analytical, statistical.
 Results. It was found that for 70 % of the concentration of the soap solution and exposure for 10–15 minutes with three washes, it is possible to obtain additional sterile seeds up to 33 %, and seedlings 29 %. The most effective treatment was with a concentration of primary sterilizer of 50 %, which provided additional sterile seeds of 37 % and seedlings – 31 %. The worst was a solution of primary sterilizer 20% for which sterile seeds amounted for 15 % and seedlings for 8 %. At a concentration of 35 %, and exposition for up to 10 minutes it is possible to reach seed sterility of 78 % and seedlings of 65 %, of which viable seeds 67 % and viable seedlings 57 %, which was one of the best results of the studied treatments. The lowest rates of sterile explants were observed in the treatments with hydrogen peroxide (H2O2). Seeds were only 23 % sterile and seedlings 12 %. Seed viability was up to 14 %, and seedlings up to 34 %. The results of the studies indicate that with the combined use of 35 % Bilyzna and 50 % Bradofen, it is possible to obtain sterile seeds from 83 to 95 % and seedlings from 83 to 91 %. In addition, viable explants in this combination were founding in seeds from 76 to 85 %, and in seedlings from 67 to 82 %. The most effective combination is 35 % Bilyzna and 50 % Bradofen for 10 minutes of exposure. Sterility was 94 % in seeds and 90 % in seedlings, viability: 83 and 80 %, respectively. It is worth noting the lack of necrotic tissue in seedlings.
 Conclusions. Regardless of the concentration, the most optimal exposure was 10–15 minutes. Depending on the type of explant and the use of the primary sterilizer, a higher percentage of sterile seeds was obtained compared to seedlings. The mercury dichloride concentration of 0.4 % and 0.2 % provided a low percentage of viable explants for both seeds and seedlings. In the latter, its use led to partial burns of the leaf surface. Therefore, the use of mercury dichloride 0.4 % and 0.2 % was not appropriate for sterilization of plant material of the genus Rhododendron (L.). The most effective way to sterilize the seeds of the genus Rhododendron (L.) is to use a 35% solution of Bilyzna for 10 minutes. Seedlings should be sterilized for 8 minutes, and the increase leads to a higher percentage of necrotic material.