三种有机酸对马尾松种子萌发及幼苗的化感作用

Allelopathic Effects of Three Organic Acids on Seed Germination and Seeding Growth of Pinus massoniana

以3种浓度的棕榈酸、硬脂酸和邻苯二甲酸对马尾松种子和一年生幼苗进行处理,探讨各处理对马尾松种子萌发和幼苗生长、生理及土壤特性的化感效应。结果表明,除硬脂酸和低浓度棕榈酸对发芽率具有促进作用外,其余处理均对种子萌发产生抑制作用,以邻苯二甲酸抑制作用最显著,同时,邻苯二甲酸对芽苗生长也具有抑制效应,且抑制作用随浓度的增加而增强。3种有机酸对马尾松幼苗苗高、地径、生物量和过氧化物酶(POD)具有低促高抑效应,邻苯二甲酸对超氧化物岐化酶(SOD)具有不显著促进作用,棕榈酸和硬脂酸则呈低促高抑效应,并在低浓度时达显著水平。1 mg/mL和0.5 mg/mL的3种有机酸会导致丙二醛(MDA)含量升高,并在1 mg/mL时达显著促进作用。硬脂酸对土壤多酚氧化酶、磷酸酶具有显著抑制作用,对脲酶具有低促高抑效应,而棕榈酸和邻苯二甲酸对以上3种酶分别具有促进、抑制和低促高抑效应。3种有机酸除对土壤pH值、全磷和速效钾具有显著影响外,对土壤其他理化性质均无显著影响。研究表明,3种有机酸类化感物质对种子萌发、幼苗生长和土壤主要理化性质均有一定影响,化感效应与有机酸种类、浓度及受体生长时期有关,总体以邻苯二甲酸对种子萌发、芽苗和幼苗生长的抑制作用最强,硬脂酸对土壤酶活和土壤理化特性影响较显著,推测实际生产中的硬脂酸和邻苯二甲酸是影响马尾松天然更新的主要物质之一。

The seeds and annual seedlings of Pinus massoniana were treated with 3 concentrations of palmitic acid,stearic acid and phthalic acid,and the allelopathic effects of each treatment on seed germination,seedling growth,physiology and soil characteristics were investigated.The results showed that,except for stearic acid and low concentration palmitic acid,the other treatments had inhibitory effects on seed germination,and the inhibitory effect of phthalic acid was the most significant.At the same time,phthalic acid also had inhibitory effect on sprout growth,and the inhibitory effect increased with the increase of concentration.The three organic acids had a low promoting and high inhibiting effect on seedling height,ground diameter,biomass and peroxidase(POD),while phthalic acid had no significant promoting effect on superoxide dismutase(SOD),palmitic acid and stearic acid had a low promoting and high inhibiting effect,and reached a significant level at low concentrations.The three organic acids at 1 mg/mL and 0.5 mg/mL resulted in an increase in malondialdehyde(MDA)content,which was significantly promoted at 1 mg/mL.Stearic acid significantly inhibited soil polyphenol oxidase and phosphatase,and had low promotion and high inhibition effect on urease,while palmitic acid and phthalic acid had promotion,inhibition and low promotion and high inhibition effect on the above three enzymes,respectively.The three organic acids had significant effects on soil pH value,total phosphorus and available potassium,but had no significant effects on other soil physical and chemical properties.The results showed that the allelopathic effects of the three organic acids had certain effects on seed germination,seedling growth and main physical and chemical properties of soil,and the allelopathic effects were related to the type and concentration of organic acids and the growth period of the receptors.In general,the inhibitory effects of phthalic acid on seed germination,sprout and seedling growth were the strongest,while the effects of stearic acid on soil enzyme activity and soil physical and chemical properties were more significant,suggesting in the actual production these two substances were one of the main substances that affected the natural regeneration of Pinus massoniana.