西蓝花(Brassica oleracea var.italica)是我国重要的蔬菜作物之一,其种子主要源于进口,亟需开发属于我国的创新型品种.为探究高能重离子束对西蓝花的当代生物学效应,本研究采用碳离子束辐照西蓝花种子,检测其幼苗期的生长指标、抗氧化酶活性、光合指标和叶绿素荧光等参数.结果表明:100~500 Gy的辐照对种子的萌发没有显著影响,600 Gy显著抑制其萌发.100~600 Gy辐照后根长、芽长、苗高、叶面积总体上随剂量增加而降低.碳离子束辐照西蓝花的半致死剂量(Median lethal dose,LD50)为415.89 Gy,使根长减半的剂量为495.12 Gy.辐照后幼苗的超氧化物歧化酶(Superoxide dismutase,SOD)和过氧化物酶(Peroxidase,POD)活性均高于对照,过氧化氢酶(Catalase,CAT)的活性低于对照,400 Gy辐照后丙二醛(Malondialdehyde,MDA)含量显著升高.随吸收剂量的增加光合色素(叶绿素a、叶绿素b和类胡萝卜素)呈现先升高再降低的趋势,最高值出现在300 Gy处.净光合作用、蒸腾速率和气孔导度均与吸收剂量负相关,辐照后非光合淬灭系数显著升高.结果表明,重离子束辐照抑制了西蓝花植株的生长,影响了抗氧化酶活性和光合作用.本研究为西蓝花的重离子束辐照诱变育种提供了基础数据.
Brassica oleracea is one of the important vegetable crops in China.Its seeds are primarily imported.Hence,developing innovative varieties belonging to China is an urgent requirement.Since broccoli is a cross-pollinated crop systematic selection and cross-breeding are challenging,and the application of radiation mutagenesis breeding in broccoli has not been reported.In this study,the seeds of Brassica oleracea were irradiated using carbon ion beams to investigate the biological effects of these beams on broccoli.The growth indices,antioxidant enzyme activity,photosynthetic indices,and chlorophyll fluorescence were detected at the seedling stage.The results revealed that irradiation with 100-500 Gy exhibited no significant effect on the germination of Brassica oleracea,while the germination of seeds was significantly inhibited at 600 Gy.After irradiation with 100-600 Gy,the root length,shoot length,seedling height,and leaf area decreased with the increase in irradiation dose.The Median lethal dose(LD50)of Brassica oleracea irradiated using a carbon ion beam was 415.89 Gy,and the dose that halved the root length was 495.12 Gy.After irradiation,the activities of superoxide dismutase(SOD)and peroxidase(POD)were higher than that of the control plants,while the activity of catalase(CAT)was lower than that of the control plants.The content of malondialdehyde(MDA)increased significantly at a dose of 400 Gy.The photosynthetic pigments(chlorophyll a,chlorophyll b,and carotenoids)showed an increasing trend initially,and then a decreasing trend with an increasing irradiation dose,and the highest value was detected at a dose of 300 Gy.Net photosynthesis,transpiration rate,and stomatal conductance exhibited a negative correlation with irradiation dose,while the non-photosynthetic quenching coefficient exhibited a significant increase after irradiation.The findings indicated that heavy ion beam radiation inhibited the growth of broccoli plants and affected the activity of antioxidant enzymes and photosynthesis.The study provided basic data for the radiation mutation breeding of Brassica oleracea.