Study On Salt Resistance Of Alfalfa Materials And Ions Distribution In Different Organs

In this study, 200 and 10 alfalfa materials were used to investigate the salt tolerance at the seedling and germinating stage, respectively. Zhongmu No.1 was used to study the impact of different salt stress on seed germination. On this basis, one salt-tolerant material and one salt-sensitive material were selected to study the contents of salt ions in roots, stems and leaves under different concentration of salt stress. The conclusions are as followed.1.Germination on the salt tolerance of 10 alfalfa materials were studied in the NaCl concentrations of 0,0.3%,0.5%,0.7%,0.9%. Germination rate, germination energy, germination index, the length of plumule and radical were measured, which decreased obviously with the concentrations of NaCl increasing. And The germination indexes of Zhongmu No.1 were measured under the different salt concentration of NaCl, NaHCO₃, Na₂CO₃. The results showed that: at the low salt concentration , germination rate, germination energy, germination index of alfalfa seeds were significant difference with the indexes of the control..And when the concentrations of NaCl≥300mmol/L,NaHCO₃≥50mmol/L,Na₂CO₃≥20mmol/L,the alfalfa seed lost the vigor completely. The inhabit of sodium salt of radical was higher than plumule.2.200 alfalfa materials under the NaCl concentration of 0, 0.3%, 0.4%, 0.5%were studied. The shape indexes(survival rate, relative height and relative biomass )and physiological indices (relative free proline content and relative membrane permeability ) were measured. ,which were evaluated by average degree of membership.with the salt concentration increasing,Survival rate, relative height and relative biomass decreased , While the content of relative proline and membrane permeability were increased. Difference obvious between different materialsThe results, which were evaluated comprehensively, suggested that the salt-tolerant materials are 2846,0104,74-24,1969,0425 and 98-4,and salt tolerance during germination and seedling ara consistent.3.The effect of NaCl on the seedling of alfalfa No.1969 was studied in different salt concentration,which were 0,0.3%,0.5%,0.7%,and 0.9%.After 30 days ,the survival rate, root length, stem length, leaf number, and Na⁺, K⁺, Ca²⁺, Mg2+ content of various organs were determined. and the K / Na, Ca / Na, Mg / Na value were analysised. The results suggested that the survival rate, root length and stem length have negative correlation with salt concentration. The content of Na+ in root, stem and leaves have positive correlation with the salt concentration, However, The content of Ca²⁺ in root, the content of K+,Mg2+ and the ratio of K/Na,Ca/Na,Mg/Na in root, stem and leaves were decreased significantly with the increasing of salt concentration, the salt stress alfalfa has significant difference with the comparison.4.The concentration of Na⁺,K⁺,Ca²⁺ in various organs of alfalfa salt- tolerant material No.1969 and salt-sensitive material No.0137 were measured under the different NaCl concentrations, which were 0, 0.1%,0.3%,0.5%. After 30 days the Na⁺, K⁺, Ca²⁺ content in the different organs were determined. The results show that the content of Na+, K+ and the K/Na ratio in the salt-tolerance material have significant differences with the salt-sensitive. There was significant difference between the salt-tolerance and the salt-sensitive materials of Ca²⁺ content in root and stem, the situation in leave were contrast. Na⁺ content in root and leaves of the salt-tolerance was lower than the salt-sensitive materials; K⁺ content and K/Na ratio of the salt-tolerance was higher than the salt-sensitive materials, the results show that the ion balance and concentration is important effective to the salt-tolerance of alfalfa.Salt-tolerant materials maintain the normal physiological and biochemical processes by regulating the ion content under the salt stress.