Abstract: Biochar was widely used for improving low-yield farmland and restoring heavy-metal polluted soil, but its application might have potential toxicity to plants. In order to reveal the potential toxicity of biochar, this paper took biochar extracts from different origins and with different concentrations to treat seedling of Brassica campestris; and detected relevant indexes of seed germination and seedling growth. The results showed that biochar extracts of distillers grain and pearwood had significant effect on seed germination and seedling growth of B. campestris, but there were significant differences among different kinds and different concentrations of biochar extracts. ① The original biochar extracts of wine lees and pearwood all could significantly decrease seed germination (P<0.05), but their diluted extracts could improve seed germination, especially the seed germination rate treated with pearwood diluted biochar extract and wine lees biochar extract after 50 times dilution  were 16.67% and 8.33% higher than those of the contrast, respectively. ② Biochar extracts could improve seedling height and root activity. The seedling heights and root activities of the plants treated with the original biochar extract were obviously higher than those of the contrast (P<0.05). The improving effect of wine lees biochar extract was lower than that of pearwood biochar extract. ③ Biochar extracts could increase the chlorophyll content, photochemical efficiency (Fv/Fm), actual quantum yield (PSⅡ) and apparent photoelectron transfer rate (ETR) of seedling leaves, and these parameters increased with the increasing of biochar extract concentrations, while biochar extracts could significantly decrease malondialdehyde (MDA) contents (P<0.05), and they increased with the decreasing of extract concentrations, indicating both wine lees biochar extract and pearwood biochar extract could increase seed germination, seedling root activities and fluorescence effect, but the effect of wine lees biochar extract was lower than that of pearwood biochar extract.

Key words: biochar, extract, Brassica campestris, germination, fluorescence parameters

摘要： 生物炭被广泛应用于低产地改良以及重金属污染土壤修复，但是其应用可能对植物存在潜在毒性。为了揭示生物炭的潜在植物毒性，用不同来源、不同浓度生物炭浸提液对小白菜种子进行处理，检测种子萌发以及幼苗生长相关指标。结果显示，酒糟生物炭和梨木生物炭浸提液对小白菜种子萌发以及幼苗生长具有明显作用，但不同生物炭浸提液以及不同浓度浸提液影响差异较大。①酒糟生物炭和梨木生物炭浸提液原液均显著降低小白菜种子萌发(P<0.05)，但稀释后的浸提液却促进小白菜种子萌发，尤其是稀释50倍后梨木炭浸提液和酒糟炭浸提液处理的小白菜种子萌发率分别比对照高16.67%和8.33%；②生物炭浸提液可提高小白菜幼苗株高和根系活力，尤其浸提液原液处理的植株株高、根系活力显著高于对照(P<0.05)；酒糟生物炭浸提液的促进作用明显低于梨木生物炭；③生物炭浸提液均可提高小白菜幼苗叶片叶绿素含量、光化学效率（Fv/Fm）、实际量子产量（ΦPSⅡ）和表观光电子传递速率（ETR）等，且供试植株幼苗叶片叶绿素含量、Fv/Fm、ΦPSⅡ、ETR等随生物炭浸提液浓度增加而增加；但酒糟浸提液对小白菜幼苗叶片荧光作用的影响低于梨木生物炭浸提液；④生物炭浸提液能显著降低幼苗丙二醛含量 (P<0.05)，且其随生物炭浸提液浓度增加而降低。由此表明，酒糟生物炭和梨木生物炭浸提稀释液均可提高小白菜种子萌发率及幼苗根系活力，增强幼苗叶片的荧光作用，但酒糟生物炭浸提液的影响作用低于梨木生物炭。

关键词: 生物炭, 浸提液, 小白菜, 萌发, 荧光参数