连作植烟土壤具有显著积累特征的两种酚酸的化感效应评价

为科学评价连作植烟土壤中具有显著积累特征的两种酚酸的化感效应,丰富现有连作障碍机理,以烤烟品种K326为试验材料,基于前期田间实测结果设置不同浓度梯度(间苯三酚:0.20、1.00、5.00 mg·kg^-1,对羟基苯甲酸0.02、0.10、0.50 mg·kg^-1)进行盆栽试验。结果表明,两种酚酸物质均显著抑制了烤烟种子萌发。间苯三酚抑制了幼苗根系的生长,且浓度越大抑制作用越强;对羟基苯甲酸对幼苗根系生长的影响表现出“低促高抑”的浓度效应。随着间苯三酚浓度的增加,叶片超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性呈上升趋势,而过氧化物酶(POD)活性呈下降趋势;随着对羟基苯甲酸浓度的增加,叶片SOD、CAT和POD活性均呈先升后降趋势。此外,两种酚酸物质均降低了烤烟幼苗叶片叶绿素含量,增加了丙二醛(MDA)含量。随着处理时间的延长,胁迫作用趋势相同。由此可知,间苯三酚和对羟基苯甲酸不同程度地抑制了烤烟幼苗的生长,且存在浓度效应。间苯三酚表现为抑制作用,浓度越高抑制作用越强;对羟基苯甲酸浓度≤0.10 mg·kg^-1时表现为促进作用,>0.10 mg·kg^-1时表现为抑制作用。对羟基苯甲酸较间苯三酚具有更强的生物毒性。本研究可以丰富植烟土壤连作障碍机理,为今后连作障碍调控提供理论依据。

Evaluation of Two Phenolic Acidifying Effects in Continuous Cropping of Tobacco Soil With Significant Accumulation Characteristics

The paper aimed to scientifically evaluate the allelopathic effects of two phenolic acids with significant accumulation characteristics of continuous cropping tobacco soil and enrich the existing continuous cropping barrier mechanism. In this study, flue-cured tobacco variety K326 was used as test material, and based on the previous field test results, different concentration gradients (phloroglucinol: 0.02, 0.10, 0.50 mg·kg^-1, p-hydroxybenzoic acid: 0.02, 0.10, 0.50 mg·kg^-1) was applied in a pot experiment. The results showed that two phenolic acids both significantly inhibited the germination of flue-cured tobacco seeds. The phloroglucin inhibited the growth of the seedling roots, and the higher the concentration, the stronger the inhibition level, while the effect of p-hydroxybenzoic acid on the root growth of the seedlings showed a concentration effect of “low promotion and high inhibition”. With the increase of phloroglucin, the activity of superoxide dismutase (SOD) and catalase (CAT) were enhunced, while the activity of peroxidase (POD) was reduced. Beside, with the increase of the concentration of p-hydroxybenzoic acid, the activity of SOD, CAT and POD increased first and then decreased. In addition, the two phenolic acids reduced chlorophyll content and increased leaf malondialdehyde (MDA) content. With the increase of treatment time, the stress effect showed the same trend. In conclusion, phloroglucin and p-hydroxybenzoic acid inhibit the growth of flue-cured tobacco seedlings to different degrees, and there exists a concentration effect. Among them, phloroglucin showed inhibition, and the higher the concentration, the stronger the inhibition; when the concentration of p-hydroxybenzoic acid was lower than 0.10 mg·kg^-1, it showed a promoting effect, and when greater than 0.10 mg·kg^-1, an inhibitory effect happened. P-hydroxybenzoic acid has stronger biological toxicity than phloroglucinol. This study can enrich the theory of relieving continuous cropping obstacle of tobacco plantation soil, and give support for continuous cropping obstacles adjustment.