酚酸化感作用对栝楼生理特性及根际微生态的影响

酚酸类物质对植物产生明显化感作用,威胁植物生长和加工产品质量。以栝楼(Trichosanthes kirilowii Maxim.)为研究对象,通过室内盆栽试验,在土壤中添加3种不同浓度(0,50,100,150,200 mg/kg,分别为CK、T1、T2、T3、T4)的对羟基苯甲酸(pHBA)、苯甲酸(BA)、肉桂酸(CA)处理液,研究酚酸对栝楼生理和土壤特性的影响,阐明酚酸化感作用的强度和规律。结果表明：(1)T1浓度pHBA能够促进栝楼根系伸长,根鲜重增长率可达19.25%;BA影响栝楼生物量的积累,T4浓度下可抑制鲜重和根鲜重至CK的35.17%和58.38%;T4浓度下CA对株高和根长的抑制效果最为明显,最大降幅达到66.19%和63.13%。(2)高浓度pHBA能降低根系活力,最大抑制率为33.55%;BA对根系活力的化感效应与浓度呈正相关,最大抑制率为47.41%。3种酚酸对蒸腾速率的作用效果略有不同,但高浓度下均表现为抑制作用。(3)pHBA与CA提高SOD、POD活性,下调CAT活性;BA使SOD、POD、CAT活性都被抑制,分别降低47.42%,59.07%,45....

Effects of Phenolic Acidification on Physiological Characteristics and Rhizosphere Microecology of Trichosanthes kirilowii Maxim.

Phenolic acids can have a significant allelopathic effect on plants, threaten plant growth and processing product quality. Trichosanthes kirilowii Maxim. was used as the study object. Through the indoor pot experiment, five different concentrations (0, 50, 100, 150, 200 mg/kg, designated as CK, T1, T2, T3, T4) of p-Hydroxybenzoic acid (pHBA), Benzoic acid (BA), and Cinnamic acid (CA) treatment solutions were added to the soil to study their effects on the physiology and soil characteristics of T. kirilowii, and the intensity and law of the allelopathic effect of phenolic acid were elucidated. The results showed that: (1) pHBA at T1 concentration can promote the elongation of the root system of T. kirilowii, and the growth rate of root fresh weight can reach 19.25%; BA affects the biomass accumulation of T. kirilowii, and at T4 concentration, it can inhibit the fresh weight and root fresh weight to 35.17% and 58.38% of the control group; under T4 concentration, CA have the most obvious inhibitory effect on plant height and root length, with the largest decrease of 66.19% and 63.13%. (2) Low concentration of pHBA could enhance root vigor, while high concentration inhibited it, the maximum inhibition rate was 33.55%; the allelopathic effect of BA on root vigor was positively correlated with the concentration, and the maximum inhibition rate was 47.41%. The effect of phenolic acid on transpiration rate and root vigor were slightly different, but the treatment of 150-200 mg/L showed obvious allelopathic inhibitory effect. (3) pHBA and CA improved SOD and POD activity and downregulated CAT activity; BA inhibited the activity of SOD, POD and CAT, which decreased by 47.42%, 59.07% and 45.43%, respectively. The degree of lipid peroxidation of the T. kirilowii membrane increased under all three phenolic acid stresses, but the damage was relieved as the stress time prolonged. (4) Phenolic acid stress significantly changed the soil microecology, and the activities of urease and invertase in the soil were more sensitive to it, and the microbial structure changed from bacterial to fungal. The same concentration of benzoic acid had the deepest allelopathic effect on T. kirilowii cultivation, followed by p-hydroxybenzoic acid and the weakest was cinnamic acid. Therefore, reduction of the phenolic acid content in the soil is conducive to alleviate the allelopathic effect of the T. kirilowii, enhance the viability of the T. kirilowii, and thus improve the yield and quality of the T. kirilowii.