铝胁迫对马尾松幼苗根系形态及活力的影响

Effects of aluminum stress on Pinus massoniana seedlings root morphology and activity

采用砂基栽培,研究不同铝胁迫强度（0、50、100、150、200μmol.L-1）和胁迫时间（30d、60d和100d）条件下,对马尾松（Pinus massoniana）幼苗单株根长、根干重、根系质膜透性、根系吸收总面积、活跃吸收面积和根系活力的影响。结果表明：低水平胁迫（0~50μmol.L-1）对马尾松幼苗根系生理指标影响较小;中等水平胁迫（100μmol.L-1）是马尾松根系生长和活力变化的转折点;重度胁迫（150~200μmol.L-1）条件下,根系生理指标呈现大幅度下降变化趋势。根长、根质量、质膜透性和根系活力可作为马尾松幼苗根系受铝毒害的鉴定指标。短时间（〈30d）根际供铝,马尾松幼苗适应能力较强,根系生长抑制不明显;栽培30d以上时,马尾松根部对铝胁迫的响应随胁迫时间的增加而加剧。

By the method of sand culture,this paper studied the effects of different concentration（0,50,100,150,and 200 μmol·L-1）aluminum（Al）on the root length,root dry weight,root plasma membrane permeability,root total absorption area,root active absorption area,and root activity of Pinus massoniana seedlings after 30,60,and 100 days of treatment.Low concentration（0-50 μmol·L-1）Al had less impact on the physiological characteristics of root system,medium Al stress（100 μmol·L-1）was the turning point for the root growth and activity,while high Al（150-200 μmol·L-1）decreased the root physiological indices markedly.Root length,root mass,root plasma membrane permeability,and root activity could be used as the identification indices of Al toxicity during the seedling stage of P.massoniana.When the rhizosphere Al treatment was less than 30 days,the P.massoniana seedlings had stronger adaptability,and the root growth was less inhibited;when the stress was longer than 30 days,the root responses would be more severe with extending stress time.