Creeping gloxinia is a tender climbing plant with bright pink flowers, that originated in Mexico [1]. These plants can be propagated using seeds or cuttings [2]. Creeping gloxinia varieties can be only propagated using cuttings, otherwise they would lose qualities that are characteristic to specific variety. Growth regulators are required to grow plants effectively using cuttings. Auxins are mostly responsible for plant root growth [3] and affect shoot growth [4]. Because of that most attention in this experiment was dedicated to these plant hormones, especially naphthylacetic acid (NAA).
The aim of this study is to determine the effects of different concentrations of naphthylacetic acid on creeping gloxinia plant root and shoot growth.
'Queen Letizia' and 'Queen Morta' cuttings were cut from 4-year old mother plants and were dipped for 2 seconds into four different concentrations of concentrated spirituous (50%) naphthylacetic acid solution and planted into pots filled with peat moss. Used cuttings were 5-7 cm tall of first year shoots. The measurements were carried out twice every 4 weeks.
The results can be seen in Table 1. All the cuttings rooted when the naphthylacetic acid concentration was 0,4%. By increasing the concentration of naphthylacetic acid the number of newly formed roots also increases, and most roots formed after using 0,3 and 0,4% concentration of naphthylacetic acid solution. While the longest roots formed in those cuttings which were dipped in a 0,3% concentration of naphthylacetic acid solution, but after raising the concentration to 0,4% the newly formed roots were shorter.
Significant difference of the length of newly formed shoots can be seen between varieties. While the new shoots of 'Queen Letizia' were measured between 8,8 cm and 17,7 cm, new shoots of 'Queen Morta' reached the length of 22,2 cm to 46,1 cm. Compared to control significantly longer shoots of 'Queen Letizia' were after using 0,2% naphthylacetic acid solution, while significantly longer shoots of 'Queen Morta' compared to control were after using 0,3% NAA concentration.
| No. | Treatments | 'Queen Letizia' | 'Queen Morta' | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Rooted cuttings, % | Number of roots, pcs. | Root lenght, cm | Lenght of new shoots, cm | Rooted cuttings, % | Number of roots, pcs. | Root lenght, cm | Lenght of new shoots, cm | ||
| 1. | Control | 85,2 abc | 2,7 a | 3,4 a | 8,8 a | 81,5 a | 2,2 a | 4,2 abc | 22,2 a |
| 2. | 0,1% NAA | 77,8 a | 4,9 b | 3,6 ab | 14,8 abc | 77,8 a | 4,0 b | 4,0 a | 34,2 abc |
| 3. | 0,2% NAA | 81,5 a | 5,5 c | 3,9 bcd | 17,7 c | 96,3 bc | 4,4 bc | 4,5 abc | 33,5 abc |
| 4. | 0,3% NAA | 92,6 abc | 7,2 d | 4,3 d | 14,1 abc | 92,6 bc | 5,2 cde | 5,6 c | 46,1 c |
| 5. | 0,4% NAA | 100,0 c | 7,5 d | 4,1cd | 14,5 abc | 100,0 c | 6,1e | 4,3 abc | 39,0 bc |
In conclusion we can see that higher concentrations (0,3 -0,4%) had significantly bigger impact on the rooting and number of roots of creeping gloxinia, however in 0,4 % naphthylacetic acid concentration newly formed roots were shorter. 'Queen Letizia' cuttings grew the longest shoots after using 0,2 % naphthylacetic acid concentration solution, while the longest new shots in 'Queen Morta' cuttings grew after using 0,3% naphthylacetic acid concentration.