Biological effects of electron beam to target turning X-ray (EBTTX) on two freesia (Freesia hybrida) cultivars

Abstract

Electron beam to target turning X-ray (EBTTX) is an emerging irradiation technology that can potentially accelerate the breeding process of plants. The biological effects of EBTTX irradiation on the two freesia cultivars (the red freesia and the purple freesia) were investigated by establishing an irradiation-mediated mutation breeding protocol. The germination rate, survival rate, plant height, leaf number and area, root number and length of the two freesia cultivars decreased following different irradiation doses (25, 50, 75, and 100-Gy). A high irradiation dose exhibited stronger inhibition effects on these plant growth parameters, and the survival rate of the two freesia cultivars was 0.00% following the 100-Gy irradiation treatment. The median lethal dose (LD50) based on survival rates was 54.28-Gy for the red freesia and 60.11-Gy for the purple freesia. The flowering rate, flower number, and pollen vigor were significantly decreased by irradiation treatment. At 75-Gy irradiation, the flowering rate, flower number and pollen viability of the two varieties reached the minimum, exhibiting strong inhibitory effects. Meanwhile, 75-Gy irradiation significantly decreased the chlorophyll content and increased the malondialdehyde (MDA) content of the two freesia cultivars. Furthermore, as the irradiation dose increased, the changes in the micro-morphology of the leaf epidermis and pollen gradually increased according to a scanning electron microscope (SEM) analysis. These results are expected to provide useful information for the mutation breeding of different freesia cultivars and other flowering plants.

Biological effects of gamma-ray radiation on tulip (Tulipa gesneriana L.)

“…The influence of the irradiation on physiological activities and chromosomal damage resulted in a decrease in plant survival ( Manju & Gopimony, 2009 ; Kiong et al, 2008 ). In addition, a high gamma-ray radiation dose can damage cell membrane integrity and permeability to inhibit the nutrient and water uptake, thus causing interference with plant growth and and physiological activities ( Li et al, 2021 ).…”

“…Numerous researchers have reported that gamma rays affect the morphology of treated plants ( Yue & Ruter, 2020 ; Li et al, 2021 ; Asare et al, 2017 ). Indeed, this study also found that plant height and flowering rate decreased significantly ( P < 0.05) with increasing doses of γ-ray irradiation.…”

“…2 ). This is because that irradiation causes DNA breakage in plant cells, further leading to various types of damage to plant cell division and development processes, and plant growth ( Amirikhah et al, 2019 ; Li et al, 2021 ).…”

“…After 63 d of cultivation, the flowering rate was measured. Additionally, 0.25 g fresh leaves of tulip were extracted with 80% acetone aqueous solution to determine the contents of both chlorophyll a and b using UV spectrophotometer at 665 and 649 nm ( Li et al, 2021 ). The MDA content in these samples was determined with the thiobarbituric acid reaction using the procedure developed by Chen et al (2020) .…”

“…Several methods are widely applied to enhance seed breeding in ornamental plants, including cross breeding, selective breeding, monadic breeding and polyploid breeding ( Kishi-Kaboshi, Aida & Sasaki, 2018 ; Ahn et al, 2020 ). However, most of these techniques have some disadvantages, such as a long breeding period and heavy workload ( Li et al, 2021 ). Since it has been an important tool to induce mutations and increase the genetic variability in plant breeding, mutation breeding can effectively solve these drawbacks ( Kishi-Kaboshi, Aida & Sasaki, 2018 ).…”