An Modelling Approach To Study The Effect Of Training Systems And Water Stress On The Mechanism Of Leaf Photosynthetic Physiology For Grapevine

?Object?Because of the shortage of water resources in arid areas and investigation new cultivation models for high-quality viticulture,this thesis studied the effects of different training system and water stress on the photosynthetic physiological processes of‘Zixiang seedless'grapes.The object of this study was to clarify the response of the photosynthetic physiological processes of grapes to major environmental factors and the regulation of training system and water stress.The results would deep understanding the response mechanism of grapes to environmental factors in Xinjiang areas and adopting reasonable horticultural measures.?Method?‘Zixiang seedless'grape was taken as test materia,During the growing season,Leaves photosynthetic response to light intensity and CO₂ concentration under normal irrigation and water stress condition with level trellies and high-trunk trellis were detected.The photosynthetic model was used to fit the key photosynthetic parameters.The chlorophyll,chlorophyll fluorescence characteristics,fruit quality and yield of each treated were tested.The shoot growth,leaf changes,berry develement and soil volumetric water content at depths of 10,20,30,40,60,and 100?cm?were recorded.?Results?1.Soil water content change:The soil water content of each treatment increased along with the depth increasing.The water content was the highest in the soil depth range of 60¹00cm,and the change was faint.After water stress,soil water content with high-trunk trellis was lower than the level trellies,so the water use efficiency was higher.Under normal irrigation,the soil water content changes tendency was similar in two tree trallis.2.Changes of photosynthetic in season:'Zixiang seedless'grape showed two peaks in the photosynthetic in season.The season changes in Gs was similar to the changes in Pn.The parameters Pn,Gs,Ci,and Tr of high-trunk trellies were higher than the level trellies in season.3.Photosynthetic characteristics:Water stress significantly reduced Pn,Gs,Ci,Tr‘Zixiang seedless'grape.At water stress condition,grape with high-trunk trellis water utilization rate was higher.The photosynthetic capacity of high-trunk trellis was higher than that of level trellies.The interaction between training system and water stress produced significantly effect on grape photosynthesis.4.Response to light and CO₂:According to the light and CO₂ response curve,the Pnmax,AQY and Cisat of the high-trunk trellis were higher than the level trellies.Gs and Tr of grape leaves increased with PAR.While,Ci decreased along with the increasing of PAR.Along with the increasing of CO₂concentration,Gs and Tr of grape leaves increased first and then decreased.5.Chlorophyll and chlorophyll fluorescence:There was no significant difference between the two tree shapes in chlorophyll under normal irrigation.After water stress,the content of chlorophyll a,chlorophyll b and total chlorophyll of level trellies decreased significantly,while the initial fluorescence F0 increased.The overall photochemical efficiency of high-trunk trellis was higher than that of level trellies.6.Growth and development:After water stress,the leaf dry weight,fresh weight and leaf area were significantly reduced.The dry weight,leaf area and specific leaf weight of the high-trunk trellis were significantly higher than the level trellies.During the whole growing season,the change trends of branch length and leaf number were the same.7.Fruit yield and quality:After water stress,grape yield and single berry weight of‘Zixiang seedless'decreased significantly.The yield and soluble solids content of high-trunk trelliswere higher than level trellies.Changes in training system and water conditions had a significant impact on grape yield.?Conclusion?Owing to the better light distribution,higher leaf quality,higher content chlorophyll and higher photosynthetic capacity,the canopy structure of high-trunk trellis was better than level trellies.Moreover,the water use efficiency,grape yield and quality of high-trunk trellis was better than the level trellies.