Basic And Applied Research On Biomass-derived Chemical Itaconic Acid In Agriculture

Itaconic acid(IA)is regarded as one of top-valued platform chemicals,as it serves as an important feedstock or intermediate product in chemical synthesis industry due to active chemical properties.As a new renewable chemical,IA can be produced through biotechnology approach which displays low cost and broad applications.For instance,IA-based polymers are promising in agriculture owing to noticeable biodegradability.Previous studies on IA mainly focused on its production route and the synthesis of biodegradable polymeric materials.In agriculture,IA can be exploited as fertilizer unit,fertilizer release coating,and water-retaining agent.Recent years has witnessed the impressive progress in understanding the versatility of IA.Nevertheless,there is no systematical research on how IA serves as a fertilizer in agriculture.In present study,IA was exploited as a novel fertilizer.To this end,the effects of IA on the growth,physiology traits and metabolisms of crops were systematically investigated.In addition,IA-based polymer fertilizers were developed and applied in field trials.In aforementioned experiments,ion mobility spectrometry(IMS)was harnessed as a crucial monitoring technique.This study not only improves the economic value and applications of IA,but also employs IMS for metabolic analysis of crops.This work mainly includes the following aspects.1.IA is an economically important organic acid with wide applications in chemical industry and agriculture.In this study,we disentangle the physiological effects of IA on crop seedlings.Four distinct crops including corn,cucumber,sorghum and wheat were grown in soilless culture containing Hoagland's nutrient solution and one of serially diluted IA.We investigated the biomass,the activities of antioxidant enzymes,and the levels of chlorophyll and malondialdehyde(MDA)in seedlings.Results showed that low concentration of IA.(?200 mg/L)benefits crop growth and alleviates oxidative stress,as it not only improves biomass,leaf area,chlorophyll content,the activities of catalase(CAT)and peroxidase(POD),but also reduces the level of MDA,as well as the activities of ascorbate peroxidase(APX)and superoxide dismutase(SOD).IA exerts different physiological and antioxidant influences on crops.The physiological impacts of IA on crops in descending order are cucumber>wheat>corn>sorghum.Overall,IA propelled crop growth through affecting biochemical components such as antioxidant enzymes and chlorophyll.This study provides basis for future recruitment of IA as a fertilizer.2.The effects of IA on the levels of metabolites in cucumber and wheat seedlings were investigated.An online two-dimensional high-performance liquid chromatography-electrospray ionization-ion mobility spectrometry(HPLC-ESI-IMS)method was developed and applied to identify the metabolites in crops.Upon optimization of mobile phase,sheath fluid,column flow rate,spray voltage and drift tube temperature,the HPLC-IMS analytical conditions were obtained.Briefly,the separation of phenolic acids was performed in a gradient elution consisting of methanol and 0.1%acetic acid aqueous solution on a narrow diameter reverse C18 column with ammonia as sheath fluid.Acetonitrile-0.1%formic acid solution was selected as the mobile phase at a flow rate of 0.4 mL/min with gradient elution for separation of other metabolites.100 mg/L succinic acid(SA)and citric acid(CA)treatments were used as reference groups.The blank control group was treated with distilled water.In the selected conditions,the results of metabolic content in soilless cultivated crops indicated that low concentration of IA promoted the growth and development of cucumber and wheat seedlings,resulting in reduced content of maltose(MT),CA and p-hydroxybenzoic acid(HA).High concentration of IA constituted an acid stress on wheat,leading to significant accumulation of metabolites to dynamically regulate crops.Compared with the control,IA exerted similar impacts on crop metabolites to SA.This study suggests that IA may be an effective alternative to SA as a biological regulator or fertilizer.Furthermore,this sensitive and efficient HPLC-ESI-IMS method developed in this study could be applied for rapid separation and identification of metabolic components in crops,and provide insights for further development of IA application in agriculture.3.To disentangle the influences of IA on the metabolites of different varieties of cucumbers,two distinct cucumber seeds were treated with IA.The growth,endogenous hormones and amino acids in cucumber seedlings were examined.In addition,CA,SA and IA treatments were performed by soaking of seeds and subsequent irrigation.In this study,CA and SA treatments were regarded as reference groups.Results showed that IA treatment improved seed germination rate.Low concentration(200 mg/L)of IA effectively boosted leaf area,biomass accumulation,stem cell,the content of indoleacetic acid(IAA)or indolebutyric acid(IBA),and amino acids in the leaves of cucumber seedlings.However,IA attenuated the formation of salicylic acid(SCA)and abscisic acid(ABA).By contrast,high concentration(400 mg/L)of IA inhibited above biochemical phenotypes.The impacts of IA on cucumbers were cucumber 1>cucumber 2.Compared with SA and CA,IA exerted similar levels of influences relative to SA.This study not only provides insights for further elucidation of underlying mechanism but also sets a stage for fully exploiting IA as a novel fertilizer.4.To extend the applications of IA in agriculture,two new compound fertilizers(PDIU and CPPDIU)were designed and developed based on I A,urea(UR)and KH2PO4.The properties of PDIU and CPPDIU were analyzed by fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM),and X-ray diffraction(XRD).The effects of PDIU and CPPDIU on plant growth,and the levels of N and P were investigated.Results showed that these two low-cost compound fertilizers,PDIU and CPPDIU,not only demonstrated significant water-retaining properties,but also benefited the growth of stem and leaf.The soil water retention rates of PDIU and CPPDIU placed in soil for 30 d were improved by 6.95%and 4.98%,respectively.Additionally,PDIU and CPPDIU increased the length(28.68%,42.17%)and weight(35.29%,64.71%)of stem,leaf area(81.50%,112.72%)and fresh weight(67.12%,49.32%),total fresh weight(44.27%,33.58%)and fresh-dry ratio(13.26%,15.27%)of leaf,respectively.These newly developed fertilizers also significantly increased the accumulation of nutrient elements N,P,K as well as the N-P ratio in leaves of cucumber seedlings.Under PDIU and CPPDIU conditions,the content of N were enhanced by 6.4-fold,5.8-fold,and P were increased by 31.05%,10.17%,as well as K were boosted by 4.71-fold,0.47-fold in cucumber leaves,respectively.Collectively,IA can be exploited as a novel fertilizer,and it has found broad applications in environmental protection,agriculture and horticulture.5.To further exploit IA as a fertilizer,a new controllable slow-release fertilizer CKDIU was developed.The fertilizer CKDIU was based on IA,biochar,urea and KH2PO4.In this study,the adsorption of KH2PO4 was optimized,and the chemical properties were characterized by FTIR,SEM and XRD.Additionally,water absorption,water retention and slow release properties of CKDIU were examined.Specially,the effects of CKDIU on plant growth,N and P content were investigated.Results showed that CKDIU is a long-acting slow-release fertilizer,and the N released rate was 23.64%after being incubated in water for 24 d in water.Notably,CKDIU manifested typical crystal shape,high water absorption rate(1.91 g/g)and water retention rate(63.21%and 28.73%,at 15 d and 30 d,respectively).More importantly,CKDIU can significantly promote the growth of stem and leaf of cucumber seedlings.In fact,it can substantially improve the growth of stem diameter,stem weight,leaf area,leaf fresh weight and total fresh weight by 27.13%,59.38%,82.71%,78.95%and 55.91%,respectively.Furthermore,this CKDIU fertilizer significantly facilitated the accumulation of N and P,and increased the ratio of N-P in cucumber seedlings.The content of N and P were increased by 6.15-fold and 0.18-fold,and the ratios of N/P and N/K were 202.51 and 74.45,respectively.Clearly,CKDIU holds considerable potential for management of cucumber seedlings.In conclusion,IA can be exploited as slow-release fertilizers.