Studies On The Factors Affected The Foundation Of Populus×Euramericana Cv. Zhonghuahongye Sterile Breeding

Populus×euramericana cv. Zhonghuahongye is trained from a sport of Populus×euramericana cv. Zhonglin2025. Zhonghuahongye grow fast and can change its leaves/ color in deferent seasons, so it is a fine species with ornamentality and wood production. Due to the development with short time and the lack of quantity, it is difficult to meet market demand only by conventional breeding methods. Although tissue culture is an effective method of achieving rapid propagation and used for many different seedlings, the tissue culture about Populus×euramericana cv. Zhonghuahongye had not been reported. In this paper, the factors led to the browning in the foundation of Populus×euramericana cv. Zhonghuahongye sterile breeding line during establishment of rapid propagation system is studied.0.15% mercuric chloride, 2% sodium hypochlorite and 30mg/L antibiotic were used separately to disinfect the Populus×euramericana cv. Zhonghuahongye's stem and leaves with different time. Inoculated with the same medium, statistic the rate of pollution and observe the conditions of growth. The results showed that: the stem treated with 0.15% mercuric chloride for 10 minutes grow well and with low polluted percent; whereas the stem treated with 2% sodium hypochlorite for 20 minutes grow better than mercuric chloride treated but with higher polluted percent; and antibiotic can't take effect on explants/ disinfection within 30 minutes. Leaves treated with 0.15% mercuric chloride for 8 minutes grow well with low polluted percent, whereas the leaves treated with 2% sodium hypochlorite for 12 minutes grow better than mercuric chloride treated with higher polluted percent, and antibiotic can't take effect on explants/ disinfection within 20 minutes.We also studied the factors which caused explants browning. Treated with low temperature and combination with the method of the simple culture medium raise in pretreatment made a low rate of explants browning; and the low rate of explants browning also can be obtained by rocking with PVP and Vc mixture solution before disinfect the explants, and treated with Vc will get a better effect.In the factors of causing brown of medium, pH is obviously. The trend can be described that the lower pH the lower browning rate during pH5.0～pH6.5. The browning trend caused by inorganic salt concentration also can be described as the lower percent of inorganic salt the lower rate of browning; And the higher percent of agar the lower rate of browning when agar concentration in 5.0～6.5g/L. Low concentration of sugar was in favors of reducing browning rate. The lowest browning rate obtained by culture with 2% sugar in the test. Active carbon can affect the rate of browning obviously but the concentration must be appropriate and the lowest browning rate obtained added 0.3% of the active carbon per liter medium. We found in the primary stage, the seedlings in dark can effectively reduce the rate of browning spend 10 days. Temperature also affects the rate of browning. To a certain extent, the higher temperature, the more serious of browning. So low-temperature may be better to reduce browning; The light intensity in 1000lx～3000lx can not cause an obvious effect for the browning rate.The time of bottle transfer affects not only the rate of browning, but also the degree of browning. Shorten the bottle transfer cycle was effective to reduce the rate of browning and the degree of browning.