Study Of Low Temperatue On The Physiological Adaptability Of The Different Alfalfa Cultivars

The physiology adaptability of different 15 breeds alfalfas at 5 autumn dormancy level were studied under low temperature condition in autumn and winter. Solublesugar, freepraline, solubleprotein and POD were selected as indices, studing the change condition of every physiology index and the relationship of every physiology index and cold resistance of different Alfalfa varieties in overwintering process.1.Under low temperature condition in Autumn and Winter, the contents offreepraline in roots of different Alfalfa varieties had different change after the low temperature is coerced, the contents change was sensitive with the temprature reducing, contents change without regularity. Relevance analysis is discovered, proline contents and the winter resistance relation were not big(p>0.05). Accumulate contents of freepraline can not identify an index alone as winter resistance, only as consult index.2.Under low temperature condition in Autumn and Winter, solublesugar contents change of different Alfalfa varieties was different. Solublesugar contents had a accumulate period on 20th , September, low point appears subsequently. Which showed that the end of September was a key period of store up and supply. Henceforth, metabolize change happened. The undulating change of solublesugar appears on contents. Relevance analysis is indicated, accumulate contents of solublesugar was related to cold resistance in April 30 next year(p<0.05).3.Under low temperature condition in Autumn and Winter, the contents change of solubleprotein in roots of different 15 Alfalfa varieties without regularity. The peak value of solubleprotein contents appeared in the end of Autumn and the next Spring. Relevance analysis is indicated, contents of solubleprotein was bigger related to cold resistance in April 30 next year(p<0.05).4.Under low temperature condition in Autumn and Winter, the activity of POD in roots of different Alfalfa varieties was sensitive in overwintering process with the temprature reducing, and amplitude was bigger, the activity of POD increased, and rised to the maximal about from November till December, POD activity came down henceforth. But POD activity maintained a higher level in the next spring. Relevance analysis is indicated, there was significant difference between POD activity and cold resistance in November 16(p<0.05). Which showed that November 16 is a key period in Alfalfa overwintering process. The index of POD activity played an important role in studying Alfalfa cold resistance, and defining plants cold resistance.5.Comparing among the 15 breeds according to these physiology indices, the study indicated that the ability of cold resistance of Prairie 2, Prairie 3, Demark and A lgonquin were higher, and Pongus,Xinjina big leaf,Alfaking,Gold Empress,Empress and WL-323HQ were placed in the middle; Amerigraze401, Sanditi, Farmer'Treasure, Derby and Sitel were poor relativity.