Construction Of Two Supramolecular Plant Hormone Delivery Systems And Their Application In Regulating Plant Growth

Agriculture is the basis of national survival.With the continuous development of the world's agriculture and the continuous expansion of the population,there is an urgent need for technological innovation of traditional agricultural chemicals(including fertilizers,pesticides,hormones et al.)to effectively increase the yield of crops.On the other hand,the low utilization rate and serious premature release of traditional agricultural chemicals or slow-release agricultural chemicals have placed a great burden on the living environment of mankind.Therefore,we are committed to utilize dynamic,smart and controllable supramolecular systems to construct a series of novel supramolecular phytohormone delivery systems which were able to permit phytohormone release under specific stimuli to efficiently promote plants growth.To resolve different agricultural problems,two different supramolecular phytohormone delivery systems with excellent phytohormone controllable and accurate release abilities were constructed.In this paper,we mainly discussed the construction process,controlled release behavior and plant growth regulation ability of these new supramolecular plant hormone delivery systems:In the first part,We first utilized supramolecular controlled delivery system to deliver plant hormone,in which the controllability of our system was greatly enhanced compare to traditional agricultural slow-release systems.A large loading capacity carrier pyridine modified hollow mesoporous silica nanoparticle(HMSN-Py)was utilized to load gibberellic acid(GA3),and water soluble carboxylate ammonium salt pillar[5]arene functionalized ultra-small Fe3O4 nanoparticles(WP[5]A-Fe3O4)were chosen as nanovalves.WP[5]A-Fe3O4 could cap on the surface of HMSN-Py to prevent hormone leakage(this GA3 loaded supramolecular delivery system was denoted as GA3-HMSN/Fe3O4).Importantly,the host-guest interaction could be disrupted by acid or alkane p H,butanediamine(BDA)and ultrasound stimuli to open up the nanovalve.The experimental results demonstrated that GA3-HMSN/Fe3O4 could accurately release GA3 under specific condition,and obvious plant growth promotion effect by GA3-HMSN/Fe3O4 was also firmly proven.In the second part,we chosen one kind of pyridine modified metal-organic framework(MOF)that is Ui O-66-Py as carrier to deliver salicylic acid(SA).Because of the good host-guest interaction between water-soluble pillar[5]arene and Py and the rigid skeleton of WP5,WP5 were utilized to assemble with Py on the surface of Ui O-66-Py as valve(The prepared SA loaded supramolecular system was denoted as SAUi O-66-WP5).Under the stimulus of BDA,SA-Ui O-66-WP5 will open up its valve permitting SA release and therefore weaken the stress effect of plants induced by drought.From the experimental results,we can know that this novel supramolecular phytohormone SA-Ui O-66-WP5 not only could accurately control the release process of SA but also show excellent drought stress releasing ability for plants.