水分胁迫下高粱幼苗的生物学性状及光合参数变化

Research on the Changes of Biological Traits and Photosynthetic Parameters of Sorghum Seedlings under Water Stress

选取当前生产上较有代表性的高粱杂交种辽杂10号、辽杂19号和辽杂35号为试材,采用盆栽控水试验,调查和测定了不同水分处理对高粱幼苗物质积累、根部性状和光合参数的影响。结果表明:水分胁迫达到重度时,高粱幼苗次生根产生数量较少且死亡根数大量增加,幼苗对养分的吸收和与外界的气体交换都会严重受阻,影响生长;在水分胁迫时,高粱幼苗的根系变化活跃,中度胁迫12 d以内仍可通过自身调节保证相对稳定的总根数。随着水分胁迫的加重,高粱幼苗株高呈下降趋势,随着胁迫时间的增加新生次生根数呈抛物线状变化,死亡根数随着胁迫时间的增加呈直线增加,根冠比表现为轻度胁迫>中度胁迫>对照(ck)>重度胁迫。随着水分胁迫的加重,光合速率呈下降趋势,在轻度至中度胁迫间差异相对较小;高粱幼苗对水分的利用效率和蒸腾速率均随着胁迫的加重有所下降,水分循环速度减慢,与根系数量减少有关。

Using more representative sorghum hybrids Liaoza No .1 0,Liaoza No .1 9 and Liaoza No .35 in current production as test materials,through pot water control test,matter accumulation,root traits and photosynthetic parameters under different water treatments were investigated and determined .The results show that：When reaching severe water stress,secondary roots produce a smaller number while death root number increases substantially,and seedling nutrient uptake and gas exchange with the outside world are severely hampered,which affect seedlings′growth;during water stress,sorghum seedlings root system changes actively,and moderate stress within 1 2 days can ensure a relatively stable total root number . With the water stress exacerbation,sorghum plant height displays a downward trend,and secondary root number displays parabolic change,while the number of death root number displays increasing linear change .With the increase of stress days,shoot ratio displays moderate stress＆gt;control （ck）＆gt;severe stress .With the aggravation of stress,photosynthetic rate showed a downward trend,and there is a small difference between mild to moderate stress;water use efficiency and transpiration rate of sorghum seedlings display a declining trend with the aggravation of stress,related to the decrease of root number .