重金属胁迫对小麦光合产物输配影响的示踪动力学研究

应用示踪动力学方法研究了不同浓度的 3种重金属离子 (Cu2 +、Cd2 +和Hg2 +)胁迫对小麦幼苗叶片光合产物输配影响。结果表明 ( 1 )Cu2 +、Cd2 +和Hg2 +能明显使小麦倒一叶光合产物输出速率常数k10 随其胁迫浓度的增大逐步减小 ;随Cu2 +、Cd2 +和Hg2 +胁迫浓度的升高 ,小麦倒二叶光合产物的输出速率常数k10 均表现为先上升后下降的趋势 ,表明重金属胁迫能影响小麦叶片光合产物从叶内的输出。 ( 2 )较低浓度 ( 50mg L)的Cu2 +、Cd2 +就使小麦倒一叶和倒二叶k2 1和k12 大幅度降低 ,尤其当Cu2 +浓度达 1 50mg L时 ,k2 1和k12 均等于零 ;1 0 0mg L的Hg2 +胁迫使倒一叶k2 1和k12 大幅度降低 ,50mg L的Hg2 +胁迫也使倒二叶k2 1大幅度降低 ,表明重金属胁迫能影响小麦叶片光合产物在叶内的分配代谢。 ( 3 )Cu2 +、Hg2 +和Cd2 +能明显抑制光合产物向根系的积累

USING TRACE KINETICS TO STUDY THE EFFECT OF HEAVY METAL STRESS ON THE TRANSPORTATION AND ALLOCATION OF PHOTOSYNTHATE IN WHEAT

The trace kinetics was used to study the effect of different concentration of Cu 2+ \,Cd 2+ \,Hg 2+ stress on the transportation and allocation of photosynthate in wheat.The results showed as follows.(1) With the concentration of Cu 2+ \,Cd 2+ and Hg 2+ increasing,the export rate constant of photosynthate in the first leaf from top of wheat decreased.The export rate constant of photosynthate in the second leaf from top of wheat increased when Cu 2+ \,Cd 2+ and Hg 2+ was in lower concentration range,and it decreased when the Cu 2+ \,Cd 2+ and Hg 2+ was in higher concentration range, indicating that Cu 2+ \,Cd 2+ \,H 2+ \-g stress might affect the export of photosynthate in the leaves of wheat.(2) The lower concentration (50mg/L) of Cu 2+ and Cd 2+ stress caused the k 21 and k 12 of the first and second leaf from top to decrease significantly,especially with the Cu 2+ concentration of 150mg/L. The k 21 and k 12 of the first and second leaf from top decreased to 0. 100mg/L Hg 2+ stress caused the k 21 and k 12 of the first leaf from top to decrease significantly.50mg/L Hg 2+ stress also caused the k 21 of the second leaf from top to decrease significantly, indicating that Cu 2+ \,Cd 2+ \,Hg 2+ stress might also affect the metabolism and allocation of photosynthate in the leaves of wheat.(3) Cu 2+ \,Hg 2+ and Cd 2+ stress could inhibit the accumulation of photosynthate in roots.