Actinidia Kolomikta(Rupr.& Maxim.)Maxim Variegated Leaf Formation And Photosynthetic Function

In this test,formation law of variegated leaf was observed firstly,formation period and position of variegated leaf were confirmed.And then,epidermal cells,leaf structure,chloroplast development and pigment content were studied,and analysed the relationship among optical properties,leaf structure and pigment content,physiological reasons of leaf coloring was clarified.On this basis,photosynthetic characterization and photoprotective mechanism of variegated leaf was studied,and the maintenance and perfection mechanism of photosynthetic function in variegated leaves was revealed primarily.According to physiological changes,transcriptome of variegated leaves will be analyzed to mine related genes with anthocyanin biosynthesis and photoprotection,which will provide theoretical basis for elucidating the molecular mechanism of leaf coloring reason and acclimative mechanisms of photosynthesis to structure changes.The experiment results were as follows:1.Variegated leaves of Actinidia Kolomikta associated flower development during florescence.Formation period of variegated leaf was after flower buds emerge（Mid-May）,and variegated leaf will not form after a week of flowering（Early-June）.Formation position of variegated leaf located at fourth node to fifteenth node from base of fresh shoot,variegated leaf was on the top of flower bud.2.The palisade tissue cells of variegated leaves were loose compared with green leaves,intercellular air spaces were observed,and thickness of variegated leaf was higher than green leaf.Palisade tissue from variegated leaf contained few and abnormally developed chloroplasts,and normal chloroplasts were distributed mostly in sponge tissue.Reflectance in variegated leaves was higher than in green on adaxial surfaces,but the reflectance of variegated leaves was similar to green leaves on abaxial surfaces.Chlorophyll content of variegated leaf maitained high level relatively,and the anthocyanins content of red leaf was higher than green leaf.Colored reason of variegated leaf was due to leaf structure,pigment content and kinds,so variegated leaf of A.Kolomikta may be compound type.3.The net photosynthetic rate（P_n）of variegated leaves was 80～94%of green leaves,they have no significant difference,stomatal conductance（g_s）and intercellular CO₂ concentration（C_i）of variegated leaves was higher than green leaf.The maximum photosystem II efficiency（F_v/F_m）,efficiency of electron flow beyond Q_A（ET₀/TR₀）,and actual efficiency of PSII in variegated leaf were significant than green leaf.The quantum use efficiency of the abaxial surface was higher than the adaxial surface in variegated leaves.Therefore,maintenance of photosynthetic function in variegated leaves may be due to thickness at late development stage of variegated leaves,higher g_s,C_i and photochemistry activity.4.Under highlight condition,F_v/F_m of variegated and green leaf decreased significantly,but drop amplitude of light green leaf was highest,and white and red leaf was the lowest.The actual efficiency of PSII（ΦPSII）,excitation capture efficiency of the open PSII centers（F_v’/F_m’）and photochemical quenching（qP）in variegated leaf were higher than green leaf,but drop amplitude of these parameters in variegated leaf were also higher.Non-photochemical quenching（NPQ）decreased significantly as stress developed in variegated leaf,NPQ of green leaf increased gradually,and accumulation of H₂O₂ of variegated leaf was higher than green leaf.Therefore,photooxidation reason of variegated leaf at late development stage may be that excessive excited energy was not dissipated effectively although incident light was reflected partly.5.Analysis on of the leaf transcriptome during different development stage was carried out using the Illumina/Solexa RNA-Seq method,related genes with flavonoids biosynthetic pathway and heat shock protein were found.Then the expression levels of anthocyanin biosynthetic genes and related photoprotective genes were analysed.