铝胁迫对烤烟生长和光合特性的影响

为明确酸性土壤条件下烟草遭受铝毒害的生理机制,以烤烟为材料,采用水培盆栽试验在营养液pH5.0条件下设置硫酸铝浓度分别为0、50、250和500μmol·L-14个处理,研究了铝胁迫对烤烟生长及光合特性的影响。结果表明:①烤烟在铝胁迫条件下根系活力明显降低;②根系鲜质量和干质量、茎叶生物量随铝处理浓度的升高而降低,且对烤烟根系生长的抑制效应大于对茎和叶的抑制效应;③铝胁迫条件下烤烟株高、茎围和单叶叶面积亦受到抑制,但对叶片长度与宽度的影响则不同,铝胁迫处理对叶片伸长没有明显影响,而对叶宽的抑制效应明显,导致受到铝胁迫的烤烟烟叶叶片狭长;④铝胁迫5 d时的烤烟叶绿素含量(质量分数)明显增加,但铝胁迫20 d时对其含量没有产生明显影响;⑤在50μmol·L-1(低浓度)铝胁迫条件下,烟叶净光合速率、气孔导度及蒸腾速率升高,而在250和500μmol·L-1(高浓度)铝胁迫条件下烟叶净光合速率、气孔导度及蒸腾速率明显降低,铝胁迫对烟叶胞间CO₂浓度没有明显影响。 

Effects of Aluminum Stress on Growth and Photosynthetic Characteristics of Flue-cured Tobacco

In order to clarify the physiological mechanism of tobacco suffered aluminum toxicity in acidic soil,the effects of aluminum stress on the growth and photosynthetic characteristics of flue-cured tobacco were studied via hydroponics experiments at 4 aluminum sulfate concentrations,0,50,250 and 500 μmol·L-1,with the nutrient solution pH of 5.0.The results showed that:1) The root vigor of tobacco decreased obviously.2) The fresh weight,dry weight of roots and the biomass of stems and leaves decreased with the increase of aluminum concentration,and the root was affected more than stems and leaves.3) Under aluminum stress,the plant height,stalk circumference and single leaf area were inhibited;however,leaf length was not affected obviously,while leaf width did,which resulted in narrow long leaves.4) The content of chlorophyll in leaves increased significantly 5 days after aluminum stress,but the influence became unobvious 20 days after aluminum stress.5) The net photosynthetic rate,stomatal conductance and transpiration rate of tobacco leaves increased at 50 μ mol·L-1,while significantly decreased at 250 and 500 μmol·L-1.However,aluminum stress did not remarkably affect the intercellular CO₂ concentration of tobacco leaves.