盐胁迫下丛枝菌根真菌对生菜生长和生理特性的影响

于盆栽条件下设0、50、100和150 mmol/L NaCl处理,对生菜(Lactuca sativa Hort.;品种"芳妮")接种丛枝菌根(arbuscular mycorrhizae, AM)真菌摩西管柄囊霉(Funneliformis mosseae),测定生菜的株高、茎粗、根系活力、叶片相对电导率和防御性酶活性.结果表明,随NaCl浓度的增加,生菜根系AM真菌侵染率逐渐降低;生菜株高、茎粗、根系活力、超氧化物歧化酶(superoxide dismutase, SOD)活性、过氧化物酶(peroxidase, POD)活性也呈下降趋势,而叶片电导率显著提高.于低盐浓度(特别是50 mmol/L NaCl)处理下,接种AM真菌显著提高了生菜的茎粗、株高和根系活力,降低叶片电导率,并提高叶片SOD和POD酶活性.结论认为,较低盐浓度胁迫下,接种AM真菌可通过提高根系活力和防御性酶活性、降低细胞膜质透性而缓解盐胁迫对植株的伤害,提高植物的耐盐性.

Effects of Arbuscular Mycorrhizal Fungi on Growth and Physiological Indices of Lettuce under Salt Stress

Lettuce (Lactuca sativa Hort. cv.'Fang Ni') seedlings grown in pots and added with different concentrations of NaCl solutions were inoculated with arbuscular mycorrhizal (AM) fungus Funneliformis mosseae. Plant height, stem diameter, root activity, leaf relative conductivity, and defense enzyme activity of lettuce were measured. The results showed that, with the increase of NaCl concentrations, the colonization percentage of AM in lettuce roots decreased; plant height, stem diamete, root activity, superoxide dismutase (SOD) and peroxidase (POD) activity also decreased, while leaf relative conductivity increased significantly (P<0.05). Under the lower NaCl concentration(especially under 50 mmol/L NaCl) treatments, AM fungal inoculation increased lettuce stem diameter, plant height, root activity, and POD and SOD activities of lettuce, while decreased leaf relative conductivity. Under certain salt stress conditions, inoculation of AM fungi may play a role in alleviating salt injury by increasing root activity and defense enzyme activity, and decreasing membrane permeability.