磺胺二甲基嘧啶与环丙沙星对小麦种子萌发和幼苗生长的影响

为研究抗生素胁迫对小麦种子萌发和幼苗生长发育的影响，选取磺胺二甲基嘧啶（Sulfadimidine,SM2）和环丙沙星（Ciprofloxacin,CIP）两种典型抗生素为研究对象，采用水培方法，通过测定不同浓度的两种抗生素对小麦种子芽和根的生长抑制率、幼苗生物量、根系形态和根系活力指标，分析比较了两种抗生素对小麦种子和幼苗的生态毒性差异。结果表明： 0.1~2.0 mg·L^-1的SM2和0.1~1.0 mg·L^-1的CIP能够促进小麦种子根和芽的生长，当SM2浓度达到10.0 mg·L^-1、CIP浓度达到5.0 mg·L^-1时，两种抗生素开始对小麦种子根长产生抑制作用，并且随着浓度的增大抑制作用显著增强；两种抗生素对作物种子根长的抑制效应强于芽长； 0.1 mg·L^-1的SM2促进小麦幼苗生长以及干物质积累，但随着SM2浓度增大，小麦幼苗生长受到抑制，根系生物量以及根系性状（总根长、平均直径）显著降低； CIP对小麦幼苗生长、干物质积累和根系性状均具有抑制作用，并且随着CIP浓度的增大抑制作用增强； SM2和CIP均抑制小麦根系活力，随着抗生素浓度的升高小麦根系氧化还原力降低，根系活力逐渐减弱。研究表明，SM2和CIP会在小麦根系不断积累，影响小麦正常生长，CIP对小麦幼苗生态毒性相对更强，0.1 mg·L^-1CIP即会抑制小麦幼苗生长。

Effects of sulfadimidine and ciprofloxacin stress on seed germination and seedling growth of wheat

To study the effect of antibiotic stress on wheat seed germination and seedling growth and development, two typical antibiotics-sulfadimidine(SM2) and ciprofloxacin(CIP)-were selected as research objects in this experiment. The effects of the two antibiotics with different concentrations on the growth inhibition rate, seedling biomass, root morphology, and root activity were studied using hydroponics. The ecological toxicity of two antibiotics for wheat seeds was analyzed and compared. The results showed that 0.1~2.0 mg·L^-1 SM2 and 0.1~1.0 mg·L^-1 CIP could promote the growth of wheat seed roots and buds. However, when the concentration of SM2 reached 10.0 mg·L^-1 or the concentration of CIP reached to 5.0 mg·L^-1, it began to inhibit the growth of wheat seed roots. The inhibition increased significantly with the concentration. The inhibitory effect of the two antibiotics on the root length of wheat seeds was greater than that on the root length of buds. A low concentration of SM2(0.1 mg·L^-1) promoted the growth, dry matter accumulation, and root development of wheat seedlings but with the increased SM2 concentration, the growth of wheat was inhibited, and root biomass and root characteristics(total root length and average diameter) significantly decreased. In the experimental concentration range, CIP inhibited the growth of wheat seedlings, dry matter accumulation, and root characteristics, strengthening with the increase of CIP concentration. In the experimental concentration range, the two antibiotics inhibited the root activity of wheat. With the increase of antibiotic concentration, the redox ability of wheat roots and root activity decreased. In general, SM2 and CIP accumulate continuously in the root system of wheat and affect its normal growth. CIP is relatively more toxic to wheat seedlings, and even 0.1 mg·L^-1 CIP can inhibit their growth.