Effects Of Exogenous Hormones On The Growth And Development Of Lilium Lancifolium And Bulbils

Lilium lancifolium,as a wild species for both medicine and food,has a huge market potential.Bulbs propagation,as the foundation of lily industry,has a healthy and sustainable influence.L.lancifolium can sprout bulbils on the leaf axils of the stem,which fall off naturally after maturation.The use of bulbil to propagate is not only simple and homogeneous,but also can greatly improve the efficiency of bulb propagation.It has been widely used in agricultural production.In this study,we first used RT-PCR technology to detect the virus in bulbil of L.lancifolium;then,explored the effects of different exogenous hormone treatments on the phenotype of L.lancifolium and its bulbil;determined the content of endogenous hormones at different developmental stages of bulbil,and analyzed the dynamic changes of endogenous hormones during the formation of bulbil.The main results are as follows:(1)RT-PCR method was used to detect the virus in the leaves,underground scales and the upper,middle and lower parts of the same strain of L.lancifolium.The results showed that there were LMo V viruses in the leaves and scales,but no LMo V viruses were detected in the three parts of the bulblets,indicating that the bulbils did not carry the virus.(2)Comparing with CK,the plant height,internode length,bud length and width which was spraied by GA3 has increased by 69.73%,58.81%,29.15% and 37.16%,flowering date was advanced by half a month,and the bulbil after GA3 treatment broke dormancy and germinated directly on the mother plant.Comparing with CK,the plant height,internode length,flower bud length and width under PAC treatment decreased by 77.06%,69.86%,30.91% and 8.93% respectively.As a plant growth retardant,it can be widely used in ornamental plant cultivation.Compared with CK,the stem diameter,internode length and number of bulbil increased by 16.13%,28.23% and 27.76% respectively.NPA treatment improved the efficiency of bulbil differentiation and significantly increased the number of bulbil,but this treatment could affect the polar transport of auxin,resulting in curl of leaves and deformity of flower buds.IAA treatment had little effect on the phenotype of L.lancifolium.but promoted the formation of adventitious roots of bulbils.(3)The content of endogenous hormones in different developmental stages of bulbil was determined.It was found that the contents of IAA,JA-me,GA3 and ABA fluctuated greatly,and the contents of IAA and ABA were higher at different stages.The content of endogenous JA-me decreased during the initiation of bulbil,which may inhibit the germination of bulbil,while the content of IAA,GA3 and ABA increased,which may have a positive effect on the germination of bulbil.The content of endogenous IAA and ABA was highest in the middle of stem,JA-me was the highest in the upper part,and GA3 was the highest in the lower part of non-growing bulbil.The changes of endogenous hormones did not increase or decrease with the treatment of two hormones and their corresponding inhibitors.GA3 treatment increased the content of endogenous hormones.A large increase in the content of endogenous GA3 during bulbil initiation may be a factor affecting the germination of bulbil.As a reproductive organ,bulbil can produce high-quality virus-free seed bulbs and establish a breeding system for good varieties.This experiment provides a new idea for the actual production of bulbil reproduction through the treatment of exogenous hormones.The purpose is to establish a method to regulate the growth of bulbil,provide some new ways and ideas for the production of lily seed bulbs,and provide a basis for further excavation of related genes of bulbil formation.