| Endogenous phytohormone is a naturally occurring small molecule compounds with high biological activity,which play a role at low concentrations and regulates the whole process of plant growth and development through the interaction of hormone signaling pathways.Comprehensive and simultaneous quantitative analysis of multi-class phytohormones will elucidate the molecular mechanism of phytohormones during signal transduction and regulation of plant growth,and revolutionize the production of crops.In addition,external stimuli such as the living environment in which plants are exposed can also affect the distribution of phytohormones to regulate their ability to adapt to the environment.Light is an important environmental signal that regulates the different growth processes of plants.In these light regulation processes,multiple hormones signaling pathways are often light-regulated and affect the morphological structure and growth of plants.Hormone levels in plants can also serve as endogenous clues affecting photoreaction.The presence of hormones in plants and their levels are the key to phytohormones regulating plant growth.Therefore,accurate quantitative analysis of hormone content and time-space distribution is the key to cognitive and regulation of plant growth and development.However,due to the complexity of plant matrix,low hormone content,wide concentration range,similar structure of phytohormones,difficult to separate,hormone instability is easy to decompose in the dynamic distribution of various organs of plants,accurate and real-time analysis and detection of phytohormones in plants is also a challenge.Conventional sample pretreatment methods such as liquid-liquid extraction,solid-phase extraction,enzyme-linked immunosorbent assay,and immunoaffinity extraction do not meet the needs of ultra-trace quantitative analysis,while solid-phase microextraction(SPME)combines sampling,extraction,concentration,and injection in one step with easy automation.The use of nanomaterials with good mechanical strength and stability and large specific surface area as a solid phase micro-extraction material is the key to improving the selectivity,sensitivity and practicability of solid phase microextraction.In view of the above problems,this paper uses a solid phase microextraction method based on carbon nanofibers/carbon fibers to achieve simultaneous quantitative analysis of twelve acid-base phytohonnones by high performance liquid chromatography-tandem mass spectrometry.Different light quality treatments were set up to study the regulation effect of light quality on the content of phytohormone inendogenous and exogenous phytohormones,and provide theoretical basis for the cultivation of light-controlled facilities.The main research work has been carried out:1.Using chemical vapor deposition method,carbon nanofibers are uniformly grown on the surface of carbon fibers,and the prepared fiber has a porous structure,provides a large surface area with fast mass transfer characteristics for the enrichment of target molecules from complicated plant samples,leads to rapid adsorption/desorption process in SPME procedure.The adsorption and desorption process of SPME is completed within three minutes.2.A SPME method was established to simultaneously extract trace and ultra-trace acid-base phytohormones in plants.Through the optimization of solid phase micro-extraction parameters,chromatographic separation method and mass spectrometry detection method,the detection sensitivity reaches 0.06-5.77 ng mL-1 the recovery is 83.77-116.87%,and the relative standard deviation(RSD)is below 14.75%.The results show that the method has the advantages of easy operation,wild applicability and high sensitivity.3.Light quality and light intensity have an effect on the content of both endogenous and exogenous phytohormones in plants.In this paper,different proportions of rare earth light sources of red and blue light are used.The facilities are 6 h,12 h,18 h,24 h,36 h.After 48 h light treatment,the results showed that red light promoted the increase of ZT,KT,GA7,JA,4-CPA and SA content,and blue light increase the accumulation of 6-BA.The results of this study has certain guiding significance for the illumination control and large-scale production of the Lepidium sativum L. |
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