Effects Of DA-6 On Growth And Fruiting,endogenous Hormones And Photosynthetic Physiology Of Camellia Oleifera

Camellia oleifera Abel.was a unique economic tree species in our country.It had a long history of cultivation and consumption.It occupied a very important position in Chinese forestry.It had high comprehensive utilization value and excellent economic,ecological and social comprehensive benefits.DA-6（N,N-diethyl aminoethyl hexanoate）was a widely used plant growth regulator,which had a good effect on increasing the yield and quality of economic forests.In this experiment,the 8-year-old C.oleifera of‘Changlin 53’was used as the object,and five DA-6 treatment concentrations（5 mg/L,10 mg/L,15 mg/L,20 mg/L,25 mg/L）were set.The effects of different treatments on growth and fruting,endogenous hormones and photosynthetic physiological indexes of C.oleifera were analyzed,to study the growth physiological response and the effect of increasing yield and quality of C.oleifera applying DA-6,the optimum application concentration of DA-6 was selected,aiming to provide a certain theoretical basis for the efficient yield of C.oleifera technical support.The main findings and conclusions were as follows:1.DA-6 treatment effectively promoted the growth of C.oleifera.Compared with the control group,the spring shoot length,spring shoot diameter,autumn shoot length,autumn shoot diameter,leaf area,leaf length,leaf width,and leaf circumference of C.oleifera were significantly improved.The optimal concentration of each index was 20 mg/L,10 mg/L,10mg/L,10 mg/L,15 mg/L,10 mg/L,20 mg/L,20 mg/L,respectively.Compared with the control group,it increased by 26.5%,5.3%,32.5%,24.2%,7.9%,5.6%,8.8%,6.3%,respectively.2.DA-6 treatment also had positive effects on the yield and quality of C.oleifera fruits.The yield per plant,fruit quantity per plant,fruit weight per plant,oil yield per plant,fruit diameter,fruit high,dry seed rate,dry kernel rate,seed oil content,fresh fruit oil content,fruit setting rate,soluble sugar,sucrose,reducing sugar,soluble protein and starch content of different treatments were significantly increased compared with the control.The optimal concentration of each index was 15 mg/L,15 mg/L,10 mg/L,15 mg/L,20 mg/L,15 mg/L,15 mg/L,10 mg/L,15 mg/L,15 mg/L,15 mg/L,15 mg/L,15 mg/L,15 mg/L,15 mg/L,15mg/L.Compared with the control,it was increased by 18.6%,15%,4.7%,46.5%,7.8%,5.4%,13.5%,6.3%,4.0%,23.6%,28.8%,32.1%,20.9%,21.1%,26.1%,15.1%respectively.3.DA-6 treatment also had certain effects on endogenous hormones in C.oleifera seeds.In different stages of C.oleifera fruit development,different treatments had different effects on different hormones.Overall,DA-6 treatment increased the contents of IAA,ZR and GA₃ in seeds during the whole fruit development period of C.oleifera,while the ABA content was decreased during the slow and fast growth stages of C.oleifera fruit development,and during the fruit oil transformation and ripening stages had been improved.DA-6 treatment also had a certain effect on the proportions of the four endogenous hormones in C.oleifera seeds,and the proportions of each hormone were affected by DA-6 differently.DA-6 treatment reduced ABA/IAA,ABA/GA₃ and ABA/ZR in seeds and improved IAA/ZR,ZR/GA₃ and IAA/GA₃.4.DA-6 treatment also had a positive effect on the photosynthetic physiology of C.oleifera.The application of DA-6 to C.oleifera can significantly increase the chlorophyll fluorescence indicators such as Fo,Fm,Fv/Fm,Y（II）,q N,q P,ETR;DA-6 treatment also increased the net photosynthetic rate,transpiration rate,stomatal conductance and intercellular CO₂concentration of C.oleifera.DA-6 treatment also significantly improved chlorophyll a,chlorophyll b and chlorophyll in C.oleifera leaves;DA-6 treatment also increased soluble sugar and soluble protein in C.oleifera leaves.The effect of different concentrations of DA-6 on C.oleifera was different,which indicated that the response of each index to DA-6 concentration was different.On the whole,with the increasing concentration of DA-6,the increasing range of each index showed a trend of low-high-low.The effects of low and high concentrations of DA-6 on the growth and fruiting,endogenous hormones and photosynthetic physiology of C.oleifera were relatively weak,and the effective concentration range of DA-6 was concentrated in 10-20 mg/L.Based on comprehensive analysis of all indexes,the optimal concentration of DA-6 applied in C.oleifera of‘Changlin 53’was 15 mg/L.