酚酸物质对红松种子萌发及苗木生长和生理特性的影响

Abstract

通过室内模拟试验，阐明阔叶红松林中已测得含量较高的3种酚酸物质（苯甲酸、丁香酸和香草酸）对红松种子萌发及苗木生长的影响，为探索阔叶红松林内化感作用机理及解决红松更新障碍问题提供科学依据。采用培养皿培养法及室内盆栽培养法，以红松种子和3年生红松苗为试验对象，设置不同浓度（2、20、200 mg/L）苯甲酸、丁香酸、香草酸处理液，以蒸馏水为对照（CK），进行红松种子萌发试验及红松苗木生长试验，研究3种酚酸物质对红松种子发芽、苗木生长、光合色素、抗氧化酶活性、膜脂过氧化作用及渗透调节物质的影响。结果表明，（1）不同浓度3种酚酸均抑制红松种子萌发，但酚酸浓度变化仅对红松种子发芽率影响差异显著。（2）3种酚酸对红松苗木生长及物质积累抑制作用显著。浓度变化对红松苗株高及地径影响不显著，对生物量、根干重和茎干重影响显著。（3）针叶叶绿素a、叶绿素b、类胡萝卜素含量变化对酚酸处理反应一致，20 mg/L的3种酚酸均显著抑制光合色素产生，而200 mg/L丁香酸溶液及2 mg/L香草酸溶液均显著促进叶绿素a和类胡萝卜素积累。（4）酚酸处理使红松苗针叶中POD、CAT活性降低，SOD活性增加。针叶中MDA含量显著增加，200 mg/L丁香酸溶液处理组针叶MDA含量高于CK处理组70.51%。（5）不同浓度苯甲酸溶液促进可溶性糖增加，抑制可溶性蛋白增加；不同浓度丁香酸溶液促进可溶性蛋白增加，而不同浓度香草酸溶液抑制可溶性蛋白增加，二者对可溶性糖含量影响受浓度变化影响显著。苯甲酸、丁香酸、香草酸影响红松种子萌发，通过对红松苗光合色素、抗氧化酶活性及渗透调节物质的影响导致其生长受抑制、生物量减少，产生膜脂过氧化伤害。因此，解决阔叶红松林内红松更新障碍问题时，凋落物及土壤中酚酸物质的化感作用不容忽视。;Through the relevant indoor simulation experiments, this research aims to clarify the effects of three phenolic acids (benzoic acid, syringic acid, and vanillic acid) with high content in broad-leaved Pinus koraiensis forest on the seed germination and seedling growth of Pinus koraiensis, so as to provide scientific basis for exploring the allelopathy mechanism of broad-leaved Pinus koraiensis forest and solving the problem of regeneration obstacle of Pinus koraiensis. The experiment adopts petri dish culture method and the indoor potted culture method. The Pinus koraiensis seeds and triennial Pinus koraiensis seedlings as experimental object were treated with different concentrations (2, 20, and 200 mg/L) of benzoic acid, syringic acid, vanillic acid solution, and distilled water was used as control. The germination experiment of Pinus koraiensis seed and the Pinus koraiensis seedling growth test were carried out to study the effects of three phenolic acids on germination, seedling growth, photosynthetic pigment, antioxidant enzyme activity, membrane lipid peroxidation, and osmoregulation substances of Pinus koraiensis seeds. The results show that: (1) all the three phenolic acids with different concentrations had the effects of inhibiting germination of Pinus koraiensis seeds, but the change of phenolic acid concentration only had a significant difference in the germination rate of Pinus koraiensis seeds. (2) The three phenolic acids had significant inhibitory effects on the growth and substance accumulation of Pinus koraiensis seedlings. Phenolic acid concentration had no significant effect on plant height and root length, but had significant effect on biomass, root weight and stem weight. (3) The changes in the contents of chlorophyll a, chlorophyll b, and carotenoids in needles had same reaction to the phenolic acid treatment. All the three phenolic acids of 20 mg/L had significant inhibition on the production of photosynthetic pigments, while the syringic acid solution of 200 mg/L and the vanillic acid solution of 2 mg/L had significant effects on promoting the accumulation of chlorophyll a and carotenoids. (4) Phenolic acid treatment reduced the activity of peroxidase and catalase and increased the activity of superoxide dismutase. The content of malondialdehyde in needles was significantly increased, while the content of MDA in needles treated with 200 mg/L syringic acid group was 70.51% higher than that in control group. (5) Benzoic acid solutions of different concentrations could promote the increase of soluble sugar and inhibit the increase of soluble protein. Different concentrations of syringic acid could promote the increase of soluble protein, while different concentrations of vanillic acid could inhibit the increase of soluble protein. The concentration changes of both had a significant influence on the change of soluble sugar content. Benzoic acid, syringic acid, and vanillic acid affected the germination of Pinus koraiensis seeds, which led to growth inhibition, biomass reduction and membrane lipid peroxidation of Pinus koraiensis seedlings by affecting photosynthetic pigment, antioxidant enzyme activity and osmotic regulation substances. Therefore, allelopathy of phenolic acids in litter and soil should not be ignored when solving the problem of Pinus koraiensis regeneration in broad-leaved Pinus koraiensis forests.