Selectiom Of The Saline Resistance Of Different Cucumber Rootstocks And Root Zoot Soil Micro-ecosystem Features

Saline area of our country was about34.6million hectares, included7.6million hectares of saline arable land, accounting for one fifth of all arable land, and the native salinization type%secondary salinization and various kinds of alkaline-type were52%,40%and8%of the total saline arable land respectively. Saline area of Heilongjiang Province was almost0.667million hectares, with the increasing of soil salinization, the yield and quality of vegetables was seriously affected. Cucumber is an important vegetable crops in our country, which was vulnerable to the effects of salt stress. Studies had shown that grafting can improve the resistance and yield of vegetables. Screening salinity rootstock is one of the main research. Previous studies about the mechanism of salt tolerance of plants mostly concentrated in physiological and biochemical metabolism. The experiment explored the characteristics of the soil microbial community structure of different rootstocks, and provide the theoretical basis for to rich the salinity mechanism and improve saline land.Based on the saline content and composition of the soda saline soil in Heilongjiang and other Province, two neutral salt, NaCl and Na2SO4, and two kinds of alkaline salt, Na2CO3and NaHCO3, at three concentrations were used to treat27species of rootstocks used for cucumber. The saline resistance activity of these rootstocks at seed germination and seeding stage were evaluated and analyzed with cluster analysis. And with the comprehensive screening on fruit quality of grafted seedlings, screened the salinity cucumber rootstock varieties that apply to the area; With the four varieties rootstocks with different salt resistance as test materials, PCR-DGGE technique combined with conventional methods, through the diversity of soil microbial community structure in rhizosphere soil enzyme activities of different salinity differences and to rootstocks cucumber, cucumber rootstock proved different salinity on growth and root zone soil microbial communities characteristics. Received the following conclusions by studying:1. Through the screening of27kinds of rootstocks with germination, seedling and grafted period, they were clustered to three groups, Cucurbita moschata Duch.’Ribenxiangzhen’,’Shenlitiemuzhen’and’Huazhen108’had higher saline tolerance activity; C. moschata Duch.’Ribenxuesong’,’Molishengen’,’Huitailang’,’Qiangshitaimu’,’Zhonghuayihao’, and ’Jingxinzhenliuhao’had moderate tolerance activity, whereas C. moschata Duch.’Jingtiantaimu’,’Qingtengtaimu’,’Shenhuzhenmu’ and Cucurbita ficifolia were sensitive to saline stress. 2. Under saline stress condition, Salinity strong rootstock yield per plant, ground fresh weight, underground fresh weight and height were significantly higher salt-sensitive species and rooted cucumber,3. Under salinity stress conditions, the root zone soil catalase and dehydrogenase activity of the rootstock varieties were reduced; Later in the test, the soil urease and dehydrogenase activity of root zone salinity species’Shenlitiemuzhen’was significantly higher than that of the salt-sensitive varieties and self-rooted cucumber.4. The number of bacteria16S rDNA gene copies of ’Huazhen108’ with higher saline tolerance was significantly higher than that of the salt-sensitive varieties and self-rooted cucumber after planted50d; The number of fungi ITS gene copies of T2with higher saline tolerance was significantly higher than that of the salt-sensitive varieties and self-rooted cucumber after planted40d, the number of fungi ITS gene copies of rootstocks with higher saline tolerance was significantly higher than that of the salt-sensitive varieties, which showed the varieties advantage.5. After planting40days, there was no significant different of the root zone DGGE soil bacteria map channel number of each treatment, the Shannon-Wiener index and evenness index of Salinity resistance varieties was significantly higher than that of the salt-sensitive varieties S1, showed the changes of root zone soil bacterial community structure of the different salinity varieties. After planting50days, the soil bacteria map channel number of self-rooted cucumber was significantly higher than that of S1,the salt-sensitive varieties; the Shannon-Wiener index and evenness index of Salinity resistance varieties T2was significantly higher than that of the salt-sensitive varieties SI, showed the difference in soil bacterial community structure.In summary, through three periods of the rootstocks, the rootstock varieties with saline resistance and excellent fruit quality were screened out; there were differences in root zone microflora of different rootstock varieties, salinity stress changed the soil enzyme activities and microbial community diversity in size and structure, and then changed the quantity and richness of microbial and the growth status of cucumber.