The Research On The Radiation Breeding Of Acer Ginnala‘Flame'

Red-leaf plants,with beautiful leaf color,beautiful posture and colorful color with seasonal changes,not only beautify the appearance of the city,but also give people visual and spiritual enjoyment,and become a new economic growth point in the field of greening Acer ginnala‘Flame'arbor or arboret,belongs to Acer?Aceraceae?.Its trunk is straight and clean.The leaves of the spring shoots are purplish red,the leaves are dark green in summer,and the autumn leaves are red as flame.The flowers are milky white,samara are bright-red,so it is has a strong ornamental value.Because of its cold and drought tolerance,it has become a profound developing value garden tree species in the north of China.Until now,there were few researches on the breeding of Acer ginnala‘Flame',and mainly used traditional breeding methods.Therefore,selecting and breeding mutants with landscaping ornamental value by using different breeding technique would become an important thing in garden breeding.In this research,the seeds of Acer ginnala‘Flame'were radiated with different does of ⁶⁰Co-?,to produce mutants and have a seed germination experiment.Morphology and physiology characteristics,photosynthetic and fluorescence characteristics were used to study the effects of ⁶⁰Co-?on young seedlings.Results showed that:?1?Radiation treatments have a significant impact on the seed germination of Acer ginnala‘Flame'.After dormant seeds were radiated,the germination rate,germination potential,germination index,emergence rate and survival rate of the seeds decreased significantly with the increase of radiation dose.With the increase of radiation dose,the germination rate,germination potential and emergence rate of the seeds increased firstly and then decreased,and the germination index and survival rate of the plants decreased gradually after the seeds were treated with radiation during the germinating period.?2?The semi-lethal of the dormant seed of Acer ginnala‘Flame'was about 51.98Gy,and the suitable radiation dose was between 20Gy and 200Gy.The semi-lethal of the germinating seed was about 95.14Gy,and the suitable radiation dose was between 20Gy and 100Gy.?3?Radiation treatments have a significant impact on the morphology of Acer ginnala‘Flame'seedlings.The plant height,internode length,leaf length,leaf width,leaf area and leaf number of seeded seedlings decreased with the increase of radiation dose.?4?Radiation treatments have a significant impact on the physiological index of Acer ginnala‘Flame'seedlings.With the increase of radiation dose,the MDA content and relative electrical conductivity of seedlings increased,and the proline content increased firstly and then decreased,and reached the maximum under 20Gy irradiation.After the dormant seeds treated by radiation the chlorophyll content of seedling leaves in summer was not significantly different from that of the control.After germinating seeds were radiated,the total chlorophyll content of seedling leaves increased firstly and then decreased with the increase of radiation dose.The maximum value reached at 20Gy radiation treatment,which was 126.67 higher than that of the control.?5?After dormant seeds were radiated,the LSP and AQY of the seedlings of Acer ginnala‘Flame'increased firstly and then decreased with the increase of radiation dose,and reached the maximum at 20Gy radiation,which were 5.48%and 8.26%higher than those of the control respectively.The net photosynthetic rate?PN?and transpiration rate?TR?of the seedlings of Acer ginnala‘Flame'increased firstly and then decreased with the increase of radiation dose.The stomatal conductance and intercellular CO₂concentration decreased with the increase of radiation dose.When the radiation dose reached 200Gy,the values of each index decreased to the lowest.After germinating seeds were radiated,the AQY of the seedlings of Acer ginnala‘Flame'increased firstly and then decreased with the increase of radiation dose.The values of AQY in 20Gy and 40Gy radiation treatments were 5.73%and 0.84%higher than those of the control respectively.The net photosynthetic rate,stomatal conductance,transpiration rate and intercellular CO₂ concentration of the seedlings of Acer ginnala‘Flame'decreased gradually with the increase of radiation dose.?6?After germinating seeds were radiated,the values of Fo?DIo/RC and ABS/RC were significantly higher than those of the control group.The values of Fv/Fo?Fv/Fm??_Po??_o and?_Eoo were significantly lower than those of the control group.The value of Fm is negatively correlated with the radiation dose.?7?The suitable radiation treatment could delay the leaf shedding,and the excessive radiation dose could cause the leaf to fall off earlier.