Studies On The Photosynthetic Physiological Characteristics And Drought Tolerance Of Three Species Of Lonicera

The photosynthetic physiological characteristics and drought tolerance under the humanlconditions for three species of Lonicera japonica (Lonicera japonica ‘Chinensis’, Lonicera tellmanianaand Lonicera x heckrotti) were studied. The results showed that:(1) According to parameters of the established response characteristic curve of photosynthesis tothe light, the conclusions were drawn tha the photosynthesis capability of three species of Lonicerajaponica was: Lonicera japonica ‘Chinensis’＞Lonicera x heckrotti＞Lonicera tellmaniana. They allhad different abilities of using light and different light adaptation range, the order was as follows:Lonicera japonica ‘Chinensis’＞Lonicera x heckrotti＞Lonicera tellmaniana. And the light energyconversion efficiency of three species of Lonicera japonica varied in the order: Lonicera japonica‘Chinensis’＞Lonicera x heckrotti＞Lonicera tellmaniana.(2) The curves diurnal variation of net photosynthetic rate of three species of Lonicera japonicapresented two peaks, there was obvious photosynthetic depression. And the curves diurnal variation oftranspiration rate and water use efficiency of three species of Lonicera japonica also presented twopeaks, whereas the curves diurnal variation of light use efficiency of three species of Lonicera japonicashowed “V” type change trend.(3) The interrelation between the net photosynthetic rate of three species of Lonicera japonica andthe physiological and ecological factors is not same, and the main factors were stomatal conductance,intercellular CO2concentration and photosynthetic active radiation(4) According to the changes of physiological and biochemical parameters under drought stress forthree species of Lonicera japonica, the conclusions were drawn that: leaf water potential and content ofchlorophyll of three species of Lonicera japonica decreased, and the relative electric conductivity andthe content of MDA persistently increased, while the activity of SOD, the activity of POD, the contentof soluble protein and praline showed “first and decreased afterwards” by the increase extent of droughtstress.(5) According to the changes of chlorophyll fluorescence parameters under drought stress for threespecies of Lonicera japonica, the results showed that minimal fluorescence (Fo) and non-photochemicalquenching coefficient (qN) increased by the increase extent of drought stress. Whereas maximalfluorescence (Fm), potential photochemical efficiency of PSⅡ (Fv/Fo), maximal photochemicalefficiency of PSⅡ (Fv/Fm), effective quantum yield of PSⅡ photochemistry (Y), apparent electrontransport rate (ETR) and photochemical quenching coefficient (qP) gradually decreased.(6) According to changes in physiological and biochemical parameters and chlorophyllfluorescence parameters, the drought-tolerance ability of three species of Lonicera japonica underdrought stress condition have been evaluated with subordinate function method. The results are asfollowing: Lonicera japonica ‘Chinensis’＞Lonicera x heckrotti＞Lonicera tellmaniana.