A Preliminary Study On Mutagenesis With EMS Of Northern Highbush Vaccinium

Vaccinium L., Ericaceae vaccinium spp., was a perennial evergreen or deciduous shrubs or small shrubs. There were about 450 species all over the world, mostly distributed in tropical regions on the open hillside, and part of them distributed in the Northern Hemisphere subtropical and temperate regions. There were about 91 species and 28 variants grew in Chin, respectively distributed in the eastern, central, from south to southwest and northeast regions of China. At present, people paied more and more attention to vacciniums because of its potential economic value and its good medicinal and health value.At present, vacciniums, which were adapted to China’s southern tropical regions, were mostly rabbit vacciniums and southern Highbush vacciniums. But it was small in fruit size or poor in fresh quality. Northern highbush vacciniums can also cultivate in China’s southern and northern regions. It had some superiority, such as big in fruit size, excellent in fresh quality and beautiful leaves in autumn. However, northern highbush vacciniums were deciduous shrubs and originated in northern regions. Their roots were slender and distributed very shallow, mainly distributed within the range of 10 cm to 60 cm of topsoil. So, northern highbush vacciniums were poor in the resistance of drought stress and waterlogging stress. The whole plant would die after dipping in the wate for dozens of hours. In the south of China, they were often continuous-high-temperature and continuous-heavy-rain in summer. All of them can easily cause adverse consequences of the Northern highbush vacciniums. Among Northern highbush vacciniums, Bluecrop and Darrow had strong ability to adapt environment. The test did mutagenesis on Bluecrop and Darrow with traditional means of chemical mutagenesis. Then we carried out researches on mutagenic materials with drought stress and waterlogging stress, and did preliminary explorations on mutagenic materials for enhanced resistance.Under aseptic conditions, The test used different concentrations of EMS solution to soak the tissue culture shoot tips of Bluecrop and Darrow, washed them clean, then inoculated them on modified WPM medium. Observed and analyzed the performance of materials in their growth process and filtered out possible mutated materials. Then treated materials with drought stress, waterlogging stress and salt stress, determined some related physiological indexes, and compared the changes in resistance to adversities of mutagenic groups treated with EMS. We hoped to conclude whether there were possible variants in the groups and provide basic data for vaccinium breeding research. The test was divided into the following four parts:1. The vitro shoots of Bluecrop and Darrow were treated with EMS. The results showed that:(1)In vitro conditions, the best combination of EMS mutagenesis was EMS treated vitro shoots for four hours with the concentration was 3%. In the combination, the mortality rates approached to 50%. (2) After EMS treatment, the growth and differentiation of vitro shoots of Bluecrop and Darrow were jagged. The vitro shoots got dwarfed, stems got thicker and reddened, leaves turned yellow, leaf vein got reddened, leaf trichomes increased, the branching capability of vitro plants at the base weakened and the branching capability of lateral branches enhanced, main branches grew as well as lateral branches and so on. (3) When the vitro shoots of Bluecrop and Darrow with EMS treatment grew to plants, it appeared some variations, including main branches and lateral branches grew at the same time, the growing capacity of lateral branches enhanced and the growth pattern of leaves changed from alternate to opposite.2. When Bluecrop and Darrow plants treated with EMS grew to 10 cm, they were treated in drought stress. According to physiological indexes, including MDA content, free proline content, soluble carbohydrate content, the activity of SOD, and total chlorophyll content in different soil moisture contents, we study whether there were possible variants in the mutagenic groups. The results showed that:(1) With the exacerbation of drought stress, MDA content, free proline content, the activity of SOD in normal blueberries groups and mutagenic blueberries groups were up firstly and later down. When the soil moisture content was 50%, they were increased to the maximum. While the soluble sugar content and total chlorophyll content were felling all the time. (2) Under drought stress, compared with normal groups, the changing rate of MDA content and soluble sugar content in the two mutagenic groups has slowed, proline content was higher, SOD activity was lower and the total chlorophyll content did not change obviously. (3) According to principal component analysis, during drought stress, the proportion of the indicators to reflect drought tolerance among normal and mutagenic groups in descending order as follows:soluble carbohydrate content, the activity of SOD, total chlorophyll content, MDA content and free proline content. (4) Based on the physiological and principal component analysis, we concluded that the drought tolerance in the mutagenic groups of the two varieties was higher than their normal groups, and maybe there were some variants with enhanced drought resistance in mutagenic groups.3. To study the effects on waterlogging resistance of Bluecrop and Darrow, regenered plants groups, which grew to 10 cm, were treated with waterlogging stress. The results showed that:(1) With the exacerbation of drought stress, in normal blueberries groups and mutagenic blueberries groups, MDA content, free proline.content, soluble sugar content and the activity of SOD were rising on the whole, and they were up to the maximum at the 28 days. While chlorophyll content was falling. (2) According to principal component analysis, during waterlogging stress, the proportion of the indicators to reflect waterlogging tolerance among normal and mutagenic groups in descending order as follows:soluble carbohydrate content, free proline content, the activity of SOD, MDA content and total chlorophyll content. (3) Based on the physiological and principal component analysis, We concluded that the waterlogging tolerance in the mutagenic groups of the two varieties was higher than their normal groups, and maybe there were some variants with enhanced waterlogging resistance in mutagenic groups.4. To study the effects on salt resistance of Bluecrop and Darrow, regenered mutagenic plants groups, which grew at 10 cm, were treated with salt stress. According to some physiological indexes of leaves, we knew that:(1) With the exacerbation of drought stress, in normal blueberries groups and mutagenic blueberries groups, MDA content, soluble sugar content and the activity of SOD were rose first, fell later, then rose again, and then fell again. Free proline content was rose slowly at first and then fell slowly. Chlorophyll content was falling slowly all the time. (2) According to principal component analysis, during salt stress, the proportion of the indicators to reflect salt tolerance among normal and mutagenic groups in descending order as follows: soluble carbohydrate content, MDA content, free proline content, total chlorophyll content and the activity of SOD. (3) Under salt stress, there were significant changes in physiological indicators among mutagenic groups and normal groups. Combined with principal Component Analysis results, we concluded that the salt tolerance in the mutagenic groups of Bluecrop and Darrow were higher than their normal groups, and maybe there were some variants with enhanced salt resistance in mutagenic groups.