盐胁迫对海棠生长及生理特性的影响

Effects of Salt Stress on the Growth and Physiological Characteristics of Malus Spectabilis

以八棱海棠2月龄组培苗为试验材料,采取人工模盐胁迫的方法,研究了不同质量浓度NaCl对八棱海棠生长及生理特性的影响。结果表明:随着NaCl质量浓度的增加,八棱海棠株高增量、地径增量、地上干质量、地下干质量、总干质量均呈现出下降趋势,而根冠比呈现出上升趋势,在NaCl质量浓度为8 g/L时,八棱海棠幼苗的生长受到了严重抑制,在质量浓度达到10 g/L时八棱海棠幼苗死亡;低浓度NaCl对八棱海棠叶绿素含量、光合气体交换参数、叶绿素荧光参数影响不大,在NaCl质量浓度达到8 g/L时八棱海棠光合色素含量、净光速速率、气孔导度、蒸腾速率、最大光化学效率、实际光化学量子效率、光化学猝灭系数、电子传递效率明显降低;NaCl浓度的增加会导致叶片相对电导率、丙二醛、可溶性糖含量的增加,SOD活性、CAT活性呈先升高后降低趋势。综合考虑八棱海棠生长及生理特性,确定八棱海棠的耐盐阈值为4.0 g/L。

Two-month-old tissue culture seedlings of Malus×robusta were used as experimental materials to study the effects of different concentrations of NaCl on the growth and physiological characteristics of Malus×robusta by artificial model salt stress.The results showed that with the increase of NaCl mass concentration,the plant height increase,ground diameter increase,aboveground dry mass,underground dry mass and total dry mass of Malus×robusta showed a downward trend,while the root-to-head ratio showed an upward trend,and the growth of Malus×robusta seedlings was severely inhibited when the mass concentration of NaCl was 8g/L,and the seedlings died when the mass concentration reached 10g/L.Low concentration of NaCl had little effect on chlorophyll content,photosynthetic gas exchange parameters and chlorophyll fluorescence parameters of Malus×robusta,and the photosynthetic pigment content of Malus×robusta decreased significantly when the mass concentration of NaCl reached 8g/L,and the net light velocity,stomatal conductance,transpiration rate,maximum photochemical efficiency,actual photochemical quantum efficiency,photochemical quenching coefficient and electron transport efficiency of Malus×robusta seedlings were significantly reduced when the mass concentration of NaCl was 8g/L.The increase of NaCl concentration will lead to the increase of relative conductivity,malondialdehyde and soluble sugar content of leaves,and the SOD activity and CAT activity will increase first and then decrease.Considering the growth and physiological characteristics of Malus×robusta,the salt tolerance threshold of Malus×robusta was considered to be 4.0 g/L.