Effect Of Different Trellis Systems On Leaf Photosynthetic Characteristics And Berry Yield And Quality Of Greenhouse Grape

The photosynthetic characteristics as well as fruit yield and quality of the greenhouse Summer Black seedless grapes under facilities condition with different trellis systems was investigated in this research,and the advantages and disadvantages of the vertical trellis and pergola on the cultivation of greenhouse grapes were evaluated.The Li-6400 xt portable photosynthesis meter was adopted to measure the photosynthesis parameters,such as Net photosynthetic rate（Pn）,Transpiration rate（Tr）,Stomatal conductance（Gs）,and Intercellular CO₂ concentration（Ci）.All indicators of fruit quality were measured and the yield was investigated during the fructescence.The major research results were shown as follows:1.The diurnal change of Pn of grapes in greenhouse under different trellis systems: unimodal curve at each stage could be seen regarding the diurnal variation of the Pn value of the vertical trellis cultivated grape leaves,while bimodal curve during the fruit spreading growth stage,and unimodal curve during the fruit coloring and frutescence could be observed with regard to that of the pergola cultivated grape leaves;the diurnal variation of the Pn value and the mean decreased from the fruit spreading growth stage to the fruit coloring to frutescence;the whole-day Pn under the pergola was higher than that under the vertical trellis cultivation at all stages,and the chlorophyll content in the leaves was higher than that in the vertical trellis cultivated leaves.2.The seasonal change of Pn in various sites of the greenhouse grape leaves under different trellis systems: unimodal curves could be seen in terms of the seasonal change of Pn in various sites of the grape leaves under vertical trellis and pergola;the differences in the Pn value among various sites of grape leaves under pergola cultivation were smaller than those under vertical trellis cultivation;while the Pn values in various sites of the grape leaves under pergola cultivation were higher than those under the vertical trellis cultivation at all stages.3.The results of correlation analysis of Pn in various sites of Summer Black seedless grape leaves under two trellis systems with other factors indicated that,Pn was positively correlated with Gs and chlorophyll content in an extremely significant manner,it was significantly positively correlated with the photosynthetically active radiation（PAR）,and was significantly negatively correlated with the Ci;and Ci was negatively correlated with other factors.4.The mature Summer Black seedless grapes under pergola cultivation had greater single panicle weight,single grain weight,as well as longitudinal and transverse diameters than those under vertical trellis cultivation,with the differences being significant.5.The mature Summer Black seedless grapes under pergola cultivation had remarkably higher contents of soluble solids,total sugars and pericarp anthocyanin than those under vertical trellis cultivation,while the fruit firmness and total acid were markedly lower than those under vertical trellis cultivation,and the difference in the Vc content in the grapes under the two trellis systems was not significant.6.The pergola cultivated grapes had notably greater mean single panicle weight than that of the vertical trellis cultivated ones,in addition,the mean fruit panicle number in each line was also greater than that under vertical trellis cultivation;therefore,the grape yield under pergola cultivation was outstandingly higher than that under vertical trellis cultivation.The difference between the estimated yield and the actual yield was not great.7.The problems existing in the local greenhouse grape production were concluded in accordance with the investigation results,and suggestion and development strategies for solving these problems were proposed based on the practical conditions.