Analysis on Leaf Morphology and Photosynthesis Physiology of Polyploidized Populus yunnanensis Seedlings

ObjectiveThe morphological and photo-physioligical difference caused by genome dosage of different ploidies Populus yunnanensis were investigated, in order to provide theoretical guidance for P.yunnanensis polyploid breeding.MethodPolyploid P. yunnanensis seedlings were obtained which were used as materials to determine the leaf size, leaf thickness, palisade tissue thickness, stomata characteristics and chlorophyll content compared with diploid P. yunnanensis. ResultThe results showed that all the leaf sizes of mosaic and tetraploid were larger than diploid. The leaf thicknesses of mosaic and tetraploid were 1.16 times and 1.41 times of that of the diploid, while the palisade tissues of mosaic and tetraploid were 1.10 times and 1.23 times thicker than that of the diploid. The stomata number of polyploidized leaf surface in per unit visula field was obviously fewer than that of the diploid, but the volum was larger than that of the diploid. The total chlorophyll contents in mosaic and tetraploid were respectively 127% and 141% of that of diploid. The net photosynthesis ratios of mosaic and tetraploid were faster than that of the diploid, while the stomatal conductance and transpiration rate of diploid were little different from the diploid, and the intercellular CO2 concentration in the diurnal variation process did not change significantly in these materials.ConclusionThe obvious genetic dose-effect was put up after the chromosome number increased. The theoretical basis and practical guidance were offered by the research and the important material foundation were provided for polyploidized P. yunnanensis clone as well.