干旱对三个春小麦品种根系呼吸及产量的影响

potted plant experiment was conducted under the rain-shelter to investigate effects of water lack on root respiration and yield in three spring wheats. Three wheats of plant were selected: ‘Heshangtou’ (H), ‘Gaoyuan602’(G) and ‘Longchun8275’(L). Two water treatments were employed including well-water supply (W, 75%~80% of field water capacity) and drought stress (S, 45%~50% of field water capacity). For every pot, the root respiration and rhizosphere microbial respiration showed the “low—high—low” tendency during he whole growth period, and the average value of antiquity variety H is the highest and modern variety L is the lowest. But specific root respiration (the root respiration of unit biomass) and specific root rhizosphere microbial respiration (root rhizosphere microbial respiration of unit biomass) were higher in variety G. The root to shoot ratio of three varieties in S were higher than in W. For both G and L, the root to shoot ratio were lower than H significantly. Daily root respiration carbon and daily exudation carbon (RE) were the main part of total carbon consumption (CT), and results showed the percentage of RE to CT exceed 50, even exceed 100 during the mature stage, and RE of G and L were lower than H significantly. For G and L, the ratio of daily photosynthetic rate of entire plant (PT) to CT (PT /CT) were higher than H significantly. The higher gain yield and higher assimilative matter use efficiency of L is the main factor in variety subrogation.