Study On The Absorption And Mobility Of Exogenous Al³⁺ In Hydrangea Macrophylla

Hydrangea macrophylla（Thunb.）Rer.is an aluminum accumulating plant with high ornamental value,which is favored by domestic and foreign markets for its beautiful ornamental characters and excellent adaptability.As one of the essential elements in flower color regulation,Al³⁺plays an important role in blue flower formation and plant growth and development.In order to effectively regulate Hydrangea macrophylla sepals color and growth and to furthest minimize environmental pollution,this paper studied the effects of genotype and temperature on the absorption of Al³⁺in Hydrangea macrophylla,the dynamic changes of the absorption of Al³⁺in plants and the mobilities of Al³⁺between tissues in different parts of plants on the ground,and the related aluminum-tolerant genes of Hydrangea macrophylla‘Bailmer’variety were screened by q RT-PCR technology.The main contents and results of this study were as follows:1.In this study,the Al³⁺contents of sepals and leaves of 13 different genotypes of Hydrangea macrophylla were measured and then studied the difference of aluminum tolerance among different genotypes.The results showed that the Al³⁺content of No.4genotype was significantly higher than that of the others,and it belonged to the aluminum-tolerant variety.The Al³⁺content of No.8 genotype was significantly lower than that of the others,and it belonged to the aluminum-intolerant variety.2.The effects of three different temperatures on the growth,development and absorption of Al³⁺in Hydrangea macrophylla‘Bailmer’were studied by measuring the relevant physiological indexes of growth and development,chlorophyll fluorescence parameters and the absorption of Al³⁺in Hydrangea macrophylla‘Bailmer’variety.The results showed that23°C was beneficial to Al uptake in leaves and sepals and plant growth.3.The Al³⁺contents of sepals and leaves under different times in Hydrangea macrophylla‘Bailmer’variety were measured and then studied the dynamic trend of aluminum absorption over time.The results showed that the change trends of Al content was similar between sepals and leaves,and both increased first,then decreased,and rose finally.Al uptake rates in sepals and leaves increased rapidly in the early stage,reached the peak at12h,then decreased rapidly,and finally stabilized.4.By analyzing the trends of aluminum contents in old leaves and new leaves of Hydrangea macrophylla‘Bailmer’variety under aluminum application treatment and aluminum non-application treatment（CK）the mobility of Al³⁺in plants was studied.The results showed that there was no transfer of Al³⁺between old leaves and new leaves,and between leaves and sepals.5.Through existing literatures,combining with third-generation transcriptome sequencing results and using q RT-PCR technology,finally,13 related Al stress genes HmALMT,HmALS3.1,HmALS3.2,HmSTOP,HmNIP5-1,HmNIP7,HmPALT1,HmVALT,HmGDI,HmASR,HmTSJT1,HmABCA1,HmABCD1 were screened and obtained from Hydrangea macrophylla‘Bailmer’variety,these genes were expressed in different parts in response to aluminum stress,thus which were involved in the transport,transshipment and storage of aluminum ions.