不同耕作条件下玉米光合特性的差异

摘要

Maize were studied in this research to test the diurnal variation of photosynthetic performance,inclu-ding net photosynthetic rate,stomatal conductance,transpiration rate and intercellular CO2 concentration under con-servation tillage technology and conventional tillage technology,to compare the differences of photosynthetic charac-ters of maize under different tillage types. The results showed that the maximum value of net photosynthetic rate of maize under different tillage types occurred 11:00 as well as stomatal conductance of maize under different tillage types,the maximum value of net photosynthetic rate were 30. 61,27. 30 μmol/( m2·s) respectively,the maximum value of stomatal conductance were 0. 20,0. 19 mmol/(m2·s) respectively;the diurnal variation of transpiration effi-ciency of maize under protective tillage was a bimodal curve,and the maximum value of transpiration rate of maize under technology of conservation tillage and conventional tillage occurred 15:00 and 11:00 , the specific value of that were 5. 81,6. 05 mmol/(m2·s). respectively;the diurnal variation of transpiration efficiency of maize under tra-ditional tillage was only a single peak,and the maximum value of transpiration rate of maize under traditional tillage occurred 11:00,the specific value was 4. 82 mmol/(m2·s),and there were no significant change between the two type tillage at other sampling points. Diurnal variation of intercellular CO2 concentration showed decrease firstly and then increase. Net photosynthetic rate of maize under conservation tillage technology higher than conventional tillage technology. Given this,from the view of the photosynthetic efficiency,conservation tillage technology systems can re-place the traditional tillage type in south Tumochuan Plain in Inner Mongolia.%为廓清不同耕作措施下玉米光合效率的差异性,利用Li-6400光合作用测定系统对保护性耕作和传统耕作措施下玉米净光合速率( Pn)、气孔导度( Gs)、蒸腾速率( Tr)和胞间CO2浓度( Ci)等光合性能指标的日变化进行了测定。结果表明：保护性耕作玉米和传统耕作玉米净光合速率和气孔导度最高值都出现在11：00时,净光合速率最高值分别为30.61,27.30μmol/(m2·s),气孔导度最高值分别为0.20,0.19 mmol/(m2·s)；保护性耕作玉米蒸腾速率的日变化曲线呈双峰型,2个峰值分别出现在11：00和15：00时,其峰值分别为5.81,6.05 mmol/(m2·s),传统耕作玉米蒸腾速率的日变化曲线呈单峰型,峰值出现在11：00时,其峰值为4.82 mmol/(m2·s)；在其他时间点2种耕作类型玉米的日变化曲线大体趋势一致。胞间CO2浓度的日变化曲线呈先下降后上升的变化趋势。表明保护性耕作玉米的净光合速率明显高于传统耕作玉米。鉴于此可以推断,从光合效率的角度看,在内蒙古土默川南部保护性耕作模式可以替代常规耕作模式。