Dissertation
Dissertation > Agricultural Sciences > Gardening > Fruit trees gardening > Pome > Pear

Photosynthetic Characteristics Research and Fruit Quality Determination of Different Tree Shape on Korla Fragrant Pear

Author MeiChuang
Tutor LiJiang; ZuoWeiMing
School Xinjiang Agricultural University
Course Horticulture
Keywords Korla Fragrant Pear Photosynthetic Characteristics photosynthetically active radiation diurnal variation seasonal variation
CLC S661.2
Type Master's thesis
Year 2012
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In this reasearch, Korla fragrant pear was the test material,researching on photosynthetic characteristics and light distribution in crowns of different tree shape at different time. Determinating the fruit quality of two tree shape under different tree age condition. The results are as follow:1. The variance analysis in diurnal variation of photosynthetic gas exchange parameters of two kinds of tree shape at different time showed no difference. The Pn under four kinds of processing showed a bimodal curve of the asymmetry. The antemeridian peak value was about eleven o’clock, maximum value reached15.5μmol·m-2·s-1, the midday depression of photosynthesis phenomenon appeared at noontime, these phenomenon were mainly double impacted by stomatal and non-stomatal factors. The seasonal variation amplitude of Pn showed a big chang. During the full fruit period, the delayed-open central leader shape tree had obviously higher net photosynthetic rate mean than the open center shape tree at each stage, then the aging stage, the open center shape tree showed higher photosynthetic use efficiency than the evacuation.2. The light saturation point of two kinds of tree shape at different time varied from900μmol·m-2·s-1to1200μmol·m-2·s-1, the light compensation point varied from25.0μmol·m-2·s-1to33.2μmol·m-2·s-1. The utilization rate of strong light on the delayed-open central leader shape tree was higher than on the open center shape tree at full fruit period, but it was opposite at aging stage. Concentration response curve of Pn-COi was similar to its light response curve, in response to the initial stage. CO2concentration was main limiting factor of photosynthesis. CO2saturation point under four kinds of processing varied from1125μmol·m-2·s-1to1180μmol·m-2·s-1, the CO2using range of delayed-open central leader shape tree was more wider at full fruit period, but CO2utilization rate of open center shape was stronger at aging stage.3. The Pn value of leaves increased with leaf chlorophyll content increasing and were positively correlated with the level of the correlation coefficient R20.978,0.958,0.944,0.895. In addition, the photosynthetic pigment index of different tree shape had great differences, the unit total leaf chlorophyll content was obviously higher on delayed-open central leader shape tree than on open center shape tree at full fruit period. Pn and SLW of four kinds of processing showed positively related level and correlation coefficient R2value were0.8441,0.8916,0.8544,0.9425. There was no difference among four kinds of processing on SLW.4. The photosynthetically active radiation changes of two kinds of tree shape in different directions in the overall trend:low-high-low, different tree shape showing the instability of plus or minus, usually after14:00noon, photosynthetically active radiation began to decrease slowly. Three-dimensional distribution of generally showed two trends. The photosynthetically active radiation distribution of delayed-open central leader shape tree obey rules that degressive tendency from crown peripheral to trunk bore and gradually increasing from crown bottom to top. Then that of open center shape tree obey rules that gradually increasing from crown peripheral to trunk bore and degressive tendency from crown upper to lower layer. The LAI mean value of delayed-open central leader shape tree were significantly higher than open center shape tree in different directions, the LAI mean value at aging stage was higher than full fruit period, this was caused by pear leaves more gathered and cascaded in the pruning process at aging stage.5. Fruit quality determination of two tree shape indicated that some important quality index such as single fruit weight, fruit shape index, soluble solid of the open center shape tree were higher than that of the delayed-open central leader shape tree, but the stone cells content of fruit to open center shape tree was significantly lower than evacuation hierarchical shape tree. The fruit quality determination in two tree age conditions obtained that the peeled hardness and stone cells content in aging stage were higher than in full fruit period, its vitamin C content was extremely significantly lower than full fruit period, so the fruit quality of the full fruit period was superior to the aging stage. We should make the orchard update on time to increase economic efficiency in the process of production.

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