大白菜根系分泌物对幼苗自毒作用的研究

A study on the autotoxicity of root exudates of chinese cabbage on seedlings

[目的]目前连作障碍已经成为限制十字花科蔬菜生产最主要的原因之一,探究大白菜根系分泌物对自身幼苗生长产生的影响,可为解决大白菜栽培过程中的连作问题以及大白菜自毒作用的研究提供理论依据。[方法]本研究以大白菜品种‘金麒麟’为试验材料,在室内进行水培,共设置8组处理:CK1(1/2 Hoagland营养液)、CK2(1/2 Hoagland营养液+活性炭)、T1(根系分泌物收集液)、T2(根系分泌物+活性炭)、T3(根系分泌物稀释2倍)、T4(根系分泌物稀释3倍)、T5(根系分泌物稀释4倍)、T6(根系分泌物稀释5倍),分析不同稀释倍数的根系分泌物对大白菜幼苗生长性状、生理生化指标和叶片质膜完整性的影响,探讨大白菜根系分泌物的自毒作用机理。[结果]与稀释后的各处理相比,T1处理导致大白菜幼苗的生物量显著减少,较CK1处理地上部鲜重显著降低了84.82%,根系活力较CK1处理显著减少了40.16%,损伤了根系结构;叶绿素含量减少32%以上,MDA含量增加,过氧化氢和超氧阴离子的积累增加,并对叶片质膜完整性造成破坏;与T1处理相比,T2添加活性炭与根系分泌物稀释各处理对幼苗的伤害均有所减轻,同时,大白菜幼苗自身可以通过提高渗透调节物质含量以及抗氧化酶活力来降低自毒作用所造成的伤害。[结论]大白菜根系分泌物对幼苗存在自毒作用,影响幼苗生长,而添加生物活性炭和稀释培养液在一定程度上可以减轻大白菜根系分泌物对幼苗的自毒作用造成的影响。

[Objective]Continuous cropping obstacles are one of the main factors limiting the production of cruciferous vegetables.This study investigated how the root exudates of Chinese cabbage affected its own seedling growth,providing both practical and theoretical basis for addressing continuous cropping issues and understanding autotoxicity in Chinese cabbage.[Method]The Chinese cabbage variety'Jin qi lin'was used as the experimental material and the experiment was conducted hydroponically indoors.A total of eight treatment groups were set up:CK1(1/2 Hoagland nutrient solution),CK2(1/2 Hoagland nutrient solution+activated carbon),T1(root exudates collection solution),T2(root exudates+activated carbon),T3(root exudates diluted twice),T4(root exudates diluted three times),T5(root exudates diluted four times),and T6(root exudates diluted five times).The study analyzed how different dilution ratios of root exudates affected the growth characteristics,physiological and biochemical indicators,and leaf plasma membrane of Chinese cabbage seedlings.The mechanisms of autotoxicity caused by of root exudates in Chinese cabbage were studied.[Results]Compared to the diluted treatments,the T1 treatment led to a significant reduction in seedling biomass.Compared to CK1,T1 treatment reduced the fresh weight of the shoots by 84.82%and root vitality by 40.16%,causing structural damage to the roots.Additionally,chlorophyll content decreased by over 32%,while MDA levels,hydrogen peroxide,and superoxide anion accumulation increased,compromising leaf membrane integrity.However,compared to T1,the addition of activated carbon(T2)and the dilution of root exudates(T3~T6)alleviated the damage to seedlings.Moreover,cabbage seedlings mitigated autotoxic damage by increasing the content of osmoregulatory substances and the activity of antioxidant enzymes.[Conclusion]The root exudates of Chinese cabbage exhibit autotoxic effects that inhibit seedling growth.However,adding bioactive carbon and diluting the root exudate solution can partially alleviate the autotoxic effects.