Selection Of Superior Individual And Elementary Study On Photosynthetic Characteristic In Xanthoceras Sorbifolia Bunge

In this study, elementary study was done on diurnal viration of photosynthesis, both of which were to find adaptability of Xanthoceras sorbifolia Bunge to PAR and other environmental factors. In addition, superior trees by preliminary selection were chosen as object of study,with 4003 as CK, to further select superior individual photosynthetic physiological indexes were measured, morphological indexes and output were also considered, in order to provide theoretical basis for selective breeding, identifying superior individual and high-quality efficient cultivation of Xanthoceras sorbifolia Bunge.The main results of this study were as follows:1. Net photosynthetic rate of Xanthoceras sorbifolia Bunge presented a double—peak curve. There appeared phenomenon of"photosynthesis midday depression". There were significant positive relationships between net photosynthetic rate and transpiration rate, photosyntheticaIly active radiation, air tempreture, water utilization efficiency, there was negative relationship between net photosynthetic rate and intercellular CO2 concentration. Air tempreture, photosyntheticaIly active radiation, and air CO2 concentration were leading ecologic factors which affected photosynthesis of Xanthoceras sorbifolia. PhotosyntheticaIly active radiation was an important factor which affected net photosynthetic rate of Xanthoceras sorbifolia Bunge.2. By analysis of variance and multiple comparison it showed that there were significant difference between CK and 11 superior trees by preliminary selection in June, July and August. Pn of leaves of other 7 superior trees by preliminary selection was significantly higher than that of CK except 4043,4031,4025,4168 in June; Pn of leaves of other 10 superior trees by preliminary selection was significantly higher than that of CK except 4077 in July; Pn of leaves of other 10 superior trees by preliminary selection was significantly higher than that of CK except 4031 in August. Pn of leaves of superior trees by preliminary selection was higher than that of CK in August and July. Pn of leaves of CK and superior trees by preliminary selection in August was higher than that of them in June and July. 3.Determination of photosynthesis-light response curves indicated that LCP of CK and eleven superior trees by preliminary selection was between 60.9μmol·m-2·S-1 and 161.8μmol·m-2·S-1, LSP was between 1333.3μmol·m-2·S-1 and 1617.3μmol·m-2·S-1, WUE was between 0.023 mol·mol-1 and 0.0369 mol·mol-1. By analysis of variance and multiple comparison on LCP, LSP and WUE of CK and superior trees by preliminary selection it was found that there were significant differences among three indexes. Results showed: LCP of 4181,4168,4117,4031 was significantly higher than that of CK except CK and other 7 superior trees by preliminary selection; LSP of 4183,4117 was significantly higher than that of CK except other 9 superior trees by preliminary selection; WUE of 4043 was significantly higher than that of CK except other 10 superior trees by preliminary selection.4. After comprehensive factor was analyzed on photosynthetic indexes, comprehensive factor scores of superior trees by preliminary selection were all higher than that of CK, indicating that 11 superior trees by preliminary selection were correct. It showed that the way of selecting superior trees of Xanthoceras sorbifolia Bunge by morphological indexes was feasible. By comprehensive factor analysis on photosynthetic indexes and morphological indexes, finally eight trees , 4181, 4139, 4117, 4168, 4173, 4077, 4183, 4172 were selected as superior individual with higher economic indexes. Most of photosynthetic indexes and morphological indexes of 8 selected superior individuals were better than that of CK.