Studies On Physiology Characteristics Of Different Alfalfa Varieties

Forage in arid and semi-arid areas have ecological suitability, important productivity and good resistance. It has great theoretical value to select drought-resistant varieties and improve dryland cultivation on production guidance in the agriculture and animal husbandry through analysis physiological and biochemical characteristics of different stages of growth and development under dry farming condition, understand drought resistance characteristic, reveal drought-resistant mechanism.This paper based on important forage alfalfa as the study, Through study drought-Resistance of 4 foreign varieties and 1 domestic varieties of different growth stages of physiological and biochemical indexes(Pro,SOD,POD,CATactivity), water indexes(RWC,LWC,leaf water potential) , photosynthesis indexes(Pn,Tr,Ci,Gs,Chl) and chlorophyllfluorescence indexes(Fv'/Fm',ETR,qP,NPQ) under dry farming condition, Compare drought response of different varieties in the growth period, And through subordinate function analysis resistance performance of different varieties in the growth period,Use subordinate function evaluate drought-resistant adaptability of different alfalfa varieties.The result was indicated:1. physiological characteristics of different alfalfa varieties on different stages studied. The result show that Proline is extremely significant difference in the reproductive period,Branching period and budding is extremely significant higher than other 3 periods, Ameristand201+Z is extremely significant higher than other varieties, while 13Rsupreme was significant lower than other varieties.to enzyme activity, SOD, POD activity show inconsistency in different growth stages, But in the vegetative growth of alfalfa period show a higher level, Five varieties of the activity level show no significant difference.CAT activity show no significant difference in the growth period.2. water indexes of five alfalfa varieties in the period are studied, The result show that the RWC of five alfalfa varieties in the period have great differences, From turning green period to the blooming, RWC of different varieties show the trend of gradually reducing. RWC of blooming is the lowest. The determination of leaf water potential changes find water potential changes at different periods of five species show "three peak" trend, the water indexes of turning green and blooming are the best. And the analysis of water-related find that Leaf water potential and water leaves rate have the larger relevance,show significant level. And showed significant relevance with RWC.3. Different photosynthetic parameters of alfalfa varieties wered studied The result showed that The trend of Tr of different varieties in periods trends have single peak and different species is not consistent,the peak of Xinjiang Da-ye and 13Rsupreme show in budding period,it shows branching and budding are water critical period,the peak of Xinjiang Da-ye and Lobo show in branching, The other three varieties are in budding. The Tr and Pn of 13Rsupreme are keep high level,show high water demand Characteristics. Tr of Varieties in different periods was significant difference, CO2 concentration is no significant difference, 13Rsuprem is extremely significantly higher than the other four varieties. the main factors on Pn reduce of slfalfa at different times is non-stomatal .4. Various fluorescence parameters analysis indicates that trend of Fv '/ Fm' of 5 alfalfa varieties were consistent under dry farming condition, show"Swing"change,decline from 10:00 to 14:00, moderate decline at noon, no significant difference between Varieties, the trend of qP is agree with Fv '/ Fm', NPQ's change and Fv '/ Fm' On the contrary, show a single peak. max is find at 14:00 and Significant differences between the species, Ameristand201+Z's NPQ was higher than other species, as the noon temperature and light intensity increase, NPQ of five varieties of alfalfa has a rapid increase,it show that alfalfa mainly on non-radiation energy dissipation to reduce the increase photoinhibition and to protect Photosynthetic from harm. With the increase of light time, the ETR and Pn of alfalfa are on the rise, And the peaks all show at 12:00, with Pn start to decline, ETR also show a downward trend. Lobo and 13Rsupreme from performance strong ETR, which shows two species has strong photosynthetic capacity.5. Principal component analysis and regression analysis of the physiological and biochemical indexes, water indexess, photosynthetic indexes,fluorescent indexes and output indexes of branching are studied, The result show that affect of leaf water rates, leave water potential, photosynthesis and yeild are big.6. Use the average of indicators in the same period to calculation subordinate function of the indicators in the growth period. The result show that alfalfa varieties drought-resistant is the strongest of branching period, The order of branching period of 5 alfalfa varieties drought-resistant varieties are: Amerigraze 401+Z > Lobo > Xinjiang Da-ye >13Rsupreme> Ameristand201+Z.