Pilot Study On Young Root Architectur Of Axis Root Type Alfalfa With Analysis Of Drought Tolerance Capacity

Root system is the medium between plant and soil,capturing water and nutrient from soil is the main function of the root,but root architectural features has important effects on the root's ability to capture water and nutrient.Based on root,the text focus young alfalfa (Medicago sativa L.) on root morphology structure, agronomic traits, grouping and naming of root architectur, and using the indexes of drought resistance to analysis the capacity of drought resisitance of different root architectur in the arid and sim-arid regions of the Loess Plateau.The results show:1. There are distinctly difference among alfalfa cultivars in length and diameter of the main root, length and diameter of the max-secondary root, the number of the Lat.root, volume of root system and dry weight of root. Under same condition of dry farming, development ability of the max-secondary root mainly depend on plant of alfalfa cultivars, bearing a trait of inheritance.2.Based on correlation coefficient of root morphology indexes, dry weight of root is positively correlative with diameter of the main root,length and diameter of the max-secondary root, And length of the max-secondary is positively correlative with diameter of the max-secondary root.3. The root morphology and agronomic traits were evaluated using grey relevancy and decision making method of with information of Fuzzy Mathematics. The results showed that indexes of root morphology had the highest weight than of agronomic traits.4.Passing discussion partition and naming of root architectur, confirmation of root architectura must represent root morphplogy character and space character so that root indexes must be selected strictly. Lastly, root is confirmed as representative indexes for dividing root architectural, which will divide young Alfalfa root system to four groups,namly Architecturâ… : thin diameter and small acute angle; Architecturâ…¡: thin diameter and big acute angle; Architecturâ…¢; thick diameter and small acute angle; Architecturâ…£: thick diameter and big acute angle.5. Using drought resistant indexes to analysis shows that the drought resistant capacity of root architectur will be divided two different drought resistant groups with strongness and feebleness. Architecturâ… and Architecturâ…¢are belong to the strong drought resistant group with the more containing water, the smaller relative permeability of cell memberance and the more content of free praline; Architecturâ…¡and Architecturâ…£are belong to the feeble drought resistant group with the more containing water, the bigger relative permeability of cell memberance and the littler content of free praline.6. Based on different drought resistant capacity of root architectur, different drought resistant capacity of tested alfalfa cultivars belonged to different root Architectur will be conferred.