Effects Of Several Types Of Acid Stress On The Growth Of Alfalfa In The Germination Period

In this study,6 alfalfa varieties were used as plant materials. The seed germination test was respectively carried out under acid-iron stress, acid-aluminum stress and acid-manganese stress (pH 4.5), and statistical analysis was conducted on the indices of alfalfa germination characteristics, root growth characteristics and physiological. The tolerance of acid-iron, acid-aluminum and acid-manganese stress in the germination period and seedling growth stage was evaluated comprehensively, which provided a reference for the selection and identification of resistance varieties of alfalfa. The main conclusions are as follows:1. Two factor analysis of variance showed that the concentration of acid-iron ions had a significant effect on the germination index, vigor index, the root length, the actual analysis area, the root surface area and root volume of 10d alfalfa, but had no significant effect on the root indices of 20d alfalfa. The concentration of acid-aluminum ions had a significant effect on germination potential, germination rate, germination index, vigor index, the root length, actual analysis area, root surface area, average root diameter and root volume of 10d and 20d Alfalfa. The content of free proline, MDA, relative electrical conductivity and relative chlorophyll of the 20d alfalfa were significantly influenced by the stress concentration of acid-iron and acid -aluminum ions. The concentration of acid-manganese ions had a significant effect on germination potential, root length, actual analysis area, root surface area and root volume of 20d Alfalfa, but had no significant effect on the root indices of 10d alfalfa.2. Through the correlation analysis and the principal component analysis, the 20 acid-iron resistance indexes can be simplified to relative electrical conductivity and average diameter of root of 20 d alfalfa; the 20 acid-aluminum resistance indexes can be simplified to germination potential and root surface area of 10 d alfalfa; the 20 acid-manganese resistance indexes can be simplified to germination index, root surface area of 10d, root length of 20d alfalfa. The simplified screening indexes for alfalfa with acid-iron, acid-aluminum and acid-manganese tolerance need to be verified by a large number of alfalfa varieties.3. Through the analysis of Rank Sum Ratio statistical analysis, WL440 and WL712 were high acid-iron, acid-aluminum and acid-manganese tolerance; and WL363 were acid-iron, acid-aluminum and acid-manganese sensitive. But the tolerance ability of all varieties of alfalfa to acid iron, aluminum and acid manganese stress is not the same.