The Study Of Alfalfa Tissue Culture And Ultra-Weak Luminescence At Electric Field

In order to innovate alfalfa seed resources, we studied for different varieties of alfalfa tissue culture under high voltage field conditions. The cotyledon and hypocotyl of alfalfa is treated with electric field combined with tissue culture technology. We adopted the orthogonal experimental design and set up three levels, in order to study the influence of explant callus induction rate. The results indicated that the optimal concentration combination of callus induction is 2,4-D:1.8mg/1, 6-BA:0.3mg/l; the condition of the highest callus induction rate is frequency 3.85kHz, field strength 2kV/cm, time 20min after 7days cultivation of hypocotyl. After 20days,20min treatment has promoted hypocotyl apoptosis; therefore the condition of the highest hypocotyl callus induction rate is frequency 3.85 kHz, field strength 2kV/cm, time 15min. In addition, we found that explant lignification degree is higher after electric field treatment.Ultra weak luminescence (UWL) is a biophysical phenomenon, closely relating organisms themselves and their environments. In this paper, in order to investigate the effect of temperature on ultra weak luminescence value (UWL) of the different alfalfa seedlings, we set 3℃,4℃,5℃, indoor temperature, and randomly select a certain number of seeds to germinate. Subsequently, germination rate, germination potential and germination index are presented, and measure UWL at different temperatures for different germination stage. Similarly, put the four kinds of seedlings that is grown at different time respectively at room temperature, 10℃,5 ℃,0℃,-5 ℃ for four hours, and then measure their UWL. The results show that:at indoor temperature,5℃,4℃, the germination rate of 2006-YL-2 variety is the highest, and the germination potential of Zhongcao No.3 are highest. But at 3℃, the germination rate of 2006-YL-2 variety is maximum, and the germination potential of YL-702 is the highest. At the same temperature, the UWL of different alfalfa varieties present a certain variation tendency with prolongation of germination period. At 4℃, UWL relates to the germination potential. At the same day a few more seeds germinate, UWL smaller. UWL of 2006-YL-2, Zhongcao No.3 generally decreases with the decrease of the temperature at the same state. But UWL of Zhongmu No.l, YL-702, Post Mark first decrease, increases and then decreases. According to the practical experience, the order of cold resistance is 2006-YL-2>Zhongcao No.3>YL-702>Post Mark. It is shown that UWL of susceptible cold variety is higher than cold resistance variety at the same low temperature (below 0℃). At room temperature,10℃,5℃, UWL of 2006-YL-2 and Zhongcao No.3 generally decreases with the short of seedling growing. However at 0 ℃, UWL of 2006-YL-2 and Zhongcao No.3 generally increases and then decreases. At-5 ℃, they all decrease then increase.Amino acids are the basis of alfalfa nitrogen metabolism. At dormant period, the content of Pro amino acid is higher than germination early and mid’ for2006-YL-2 and Zhongcao No.3. That is presented pro amino acid relates to cold resistance. By comparing amino acids content between Zhongcao No.3 and 2006-YL-2 during germination, it is shown that GLU, GLY, ALA, CYS, VAL, TYR, PHE, LYS content of 2006-YL-2 during germination do not reduce but increase. It is concluded this relates to cold resistance during germination. Subsequently, YL-702 amino acid content during germination was compared, thereby further validate:GLU, GLY, ALA, CYS, VAL, TYR, LYS relate to cold resistance during germination.