污泥热碱液提高小青菜抗逆性及品质的机制

Mechanism underlying the improvement of stress resistance and quality in Brassica chinensis by alkaline thermal hydrolysate of sewage sludge

干旱、盐等非生物胁迫是限制植物生长发育的主要环境因子。近年来,城市生活污泥排放增加。污泥经碱性热水解技术处理,其产物热碱液中含有丰富的钙和有机氮养分。为研究污泥热碱液对蔬菜作物逆境抗性的影响,实现污泥资源化利用,本研究以小青菜(Brassica chinensis)为材料,通过盆栽试验,设置无胁迫、干旱胁迫和盐胁迫3种生长条件,同时设置不施氮、施用污泥热碱液及施用尿素3个处理,探讨污泥热碱液对叶菜生长和抗逆性的影响。结果表明:无胁迫条件下,与施尿素相比,施热碱液促进小青菜增产43.3%,显著降低硝酸盐含量,提高可溶性糖、可溶性蛋白质及维生素C含量;在干旱胁迫和盐胁迫下,施用热碱液增加土壤中水溶态钙和交换态钙含量,有效提高小青菜钙吸收量,并进一步促进脯氨酸积累,降低丙二醛含量,显著提高干旱胁迫下过氧化氢酶活性(8.6%)以及盐胁迫下过氧化物酶活性(70.4%),缓解逆境胁迫。将污泥热碱液应用到蔬菜生产中,可减少化肥投入,提高作物产量和品质,增强抗逆性,也为有效无害化、资源化利用城市生活污泥提供了一种新途径。

Abiotic stresses such as drought and salinity are the major environmental factors hindering plant growth and development.The discharge of municipal sewage sludge has been increased in recent years.The sewage sludge can be treated using alkaline thermal hydrolysis technology.The product alkaline thermal hydrolysate(ATH)contains abundant calcium and organic nitrogen nutrients.To investigate the effects of ATH on the resistance of vegetables against environmental stresses and accomplish the recycling of sewage sludge,Brassica chinensis was subjected to three stress treatments(no stress,drought stress,and salt stress)and three fertilization treatments(no fertilizer,ATH,and urea)in a pot experiment.The results showed that the application of ATH enhanced the yield of B.chinensis by 43.3%compared with urea application without abiotic stress.ATH application reduced nitrate content and increased the contents of soluble sugar,soluble protein and Vc in B.chinensis.Under drought stress and salinity stress,ATH application increased the contents of water-soluble calcium and exchange calcium in the soil and increased the calcium uptake of B.chinensis.ATH promoted the accumulation of proline and decreased the content of malondialdehyde.Furthermore,ATH significantly increased the activity of catalase by 8.6%under drought stress and the activity of peroxidase by 70.4%under salt stress,and thus alleviated the stress caused by adverse environments.The application of ATH to vegetable production can reduce fertilizer input,improve yield,quality and stress resistance of crops,and consequently is a new way for effective,harmless and resource utilization of municipal sewage sludge.