干旱胁迫下厚朴幼苗的生理指标及次生代谢产物对保水剂的响应

Responses of physiology and secondary metabolites in Magnolia officinalis seedlings to super absorbent polymers under drought stress

以1年生紫油厚朴(Magnolia officinalis)为试验材料,采用盆栽试验,设置了多功能型、钠盐型、钾盐型3类保水剂处理和空白对照,分别进行干旱和不干旱处理,研究紫油厚朴幼苗抗氧化酶活性、膜脂过氧化程度和次生代谢产物对干旱胁迫的响应.结果表明:干旱胁迫下,丙二醛(MDA)和超氧阴离子(O-·2)含量在4组处理中均显著增强(P<0.05),过氧化氢(H2O2)含量和过氧化氢酶(CAT)、过氧化物酶(POD)、超氧化物岐化酶(SOD)和抗坏血酸过氧化物酶(APX)4种抗氧化酶的活性均增加,且均在空白对照和钠盐型保水剂组中分别达到显著差异水平(P<0.05);可溶性蛋白、脯氨酸和可溶性糖的积累量在干旱胁迫下均有不同程度的增加(P<0.05);次生代谢产物——厚朴酚与和厚朴酚的积累量均有不同程度的上升,二者在钠盐型保水剂组中未增加,而在钾盐型保水剂组显著增加.综上所述,钾盐和多功能型保水剂处理在厚朴幼苗受到干旱胁迫时渗透调节物质积累增多,抗氧化酶活性提高,膜脂过氧化程度减轻,叶片的抗旱性增强;更重要的是适度干旱和适量钾肥有利于主要药效成分厚朴酚与和厚朴酚的积累.

To investigate the effect of super absorbent polymer( SAP) on physiology of Magnolia officinalis,3 types of SAPs,including sodium( Na),potassium( K) and multifunctional( X) were added to one-year-old seedlings,and changes in antioxidant enzyme activities,lipid peroxidation and accumulation of osmoregulation substances in both drougt( D) and regularly irrigated groups were recorded. Results showed that contents of malondialdehyde( MDA) and O-·2significantly increased in 4 drought groups( P < 0. 05). H2O2 and all enzymes including catalase( CAT),peroxidase( POD),superoxide dismutase( SOD) and ascorbate peroxidase( APX) in leaves increased significantly in groups of control under drought( N + D) and Na-SAP under drought( Na +D). Accumulations of soluble protein,proline and soluble sugar all increased under drought stress( P < 0. 05). Under drought stress,magnolol and honokiol levels elevated to some extent except staying the same in group Na + D,however,their levels increased significantly in groups of K + D. In conclusion,both K-and X-SAPs ameliorated drought stress for M. officinalis seedlings in terms of accumulated osmoregulation substances,enhanced activities of antioxidant enzymes,and mitigated membrane lipid peroxidation. More importantly,the main medicinal componds,magnolol and honokiol increased when K- SAP was applied.