Morphological Variations in Buddleia Induced by Gamma Ray Irradiation

Abstract

<jats:p><jats:italic>Buddleia</jats:italic> species is commonly used as a perennial for landscaping as a result of its heavy flowers and long bloom period. However, this species has a few concerns such as lack of flower color, excessive growth, and an invasive nature. Attempts to improve <jats:italic>Buddleia</jats:italic> using conventional breeding methods have resulted in limited success. In this study, mutagenesis by gamma ray irradiation was used to induce genetic variations. In vitro shoot tips of two <jats:italic>Buddleia</jats:italic> cultivars, <jats:italic>B. davidii</jats:italic> ‘Potters Purple’ and <jats:italic>Buddleia</jats:italic> ‘Lochinch’, were exposed to 0 to 150 Gy gamma rays and then recovered in Murashige and Skoog (MS) medium supplemented with 2.5 μM benzyladenine (BA). Shoots that recovered from the gamma ray treatment were rooted in half-strength MS medium with 0.5 μM naphthalene acetic acid (NAA) and grown in the greenhouse. The growth of shoot tips was inhibited after they were exposed to gamma rays. An average of 50.8% of shoots treated with 50 Gy gamma rays were recovered, whereas only 9.7% and 6.5% of shoots recovered when exposed to 100 and 150 Gy gamma rays, respectively. After transfer to the greenhouse, a few plants showed reduced growth with some dying before they reached the flowering stage. Various variations including characteristics of leaves (shape, size, hairs), stems (shape, internode length, branching), flowers (color, size, and structure), and plant stature were observed. This research demonstrates that in vitro mutation induction using gamma ray irradiation could be a useful protocol to develop new cultivars or genetic materials for further breeding of <jats:italic>Buddleia</jats:italic> or other related species.</jats:p>

Induced Variation in Tetraploid Rudbeckia subtomentosa ‘Henry Eilers’ Regenerated from Gamma-irradiated Callus

“…The low r 2 value for all variables reflects the variability of our data. Similar to our study, variability in morphological traits in response to radiation dose has also been observed in gamma-irradiated shoot tips of Buddleia cultivars (Dai and Magnusson, 2012). Given the random nature of mutation treatments to DNA, this is not unexpected.…”

“…Radiation can affect plant height by reducing the number of nodes and the length of internodes (Gottschalk and Wolff, 1983). Radiation has been used as a tool to induce mutations for the development of commercial varieties in many crop species, particularly the forages as well as in ornamental crops such as Chyrsanthemum (Dao et al, 2006), Dendranthemum grandiflorum (Datta et al, 2001), Nelumbo nucifera (Arunyanart and Soontronyatara, 2002), Rosa hybrida (Arnold et al, 1998;Gupta and Shukla, 1971;van Harten, 1998), and Buddleia (Dai and Magnusson, 2012).…”

Morphological, cytological and molecular variations induced by gamma rays in Chrysanthemum morifolium ‘Donglinruixue’

“…Some researchers hypothesised that the plasma membrane and cytosolic enzyme systems suffer damage that can lead to inhibition of plant growth and development under high dose of radiation (Fu et al, 2000;Anandhi et al, 2013). We observed that irradiation also caused a series of morphological variations in leaves and flower shapes (Dai and Magnusson, 2012).…”

Evaluation of Plant and Flower Characteristics of selected 15-Gy irradiated Phalaenopsis aphrodite

“…A similar finding was reported by Srivastava and Mishra (2005), who spotted smaller flowers in Hibiscus rosa-sinensis plants exposed to gamma irradiation. Other reports indicated that varied flower sizes were observed across gamma-irradiated plants, such as in chrysanthemum (Lamseejan et al, 2000), Calisthepus chinensis (Anwar et al, 2020) and Buddleia (Dai and Magnusson, 2012). Additionally, fewer flowers ranging from three to four were produced in contrast to the control plants with five to eight flowers (Table 1).…”