In this paper,growth in height,caliper,and biomass,and dynamic changes of the δ13C and δ15N value in the vegetative organs of Populus × euramericana‘Nanlin 895’cuttings were investigated in response to different concentrations of exogenous Ca2 + treatments. The experimental results showed that different concentrations of exogenous Ca2 + were able to promote the plant growth; the height,caliper,and biomass increments were all greater than the control after spraying exogenous Ca2 + ,among which the 200 mg·L -1 Ca2 + concentration exhibited the best effect. Compared with the control, the average of the height,caliper and biomass treated with 200 mg·L -1 Ca2 + increased by 14. 82% ,18. 01% ,and 19. 7% respectively. The stable isotope,δ13C and δ15N,enrichment capacity of the Populus × euramericana‘Nanlin 895’ cuttings were affected by different concentration exogenous Ca2 + to various degrees. With the Ca2 + concentration increased (0,2,20,100,200,300 mg·L -1),the δ13C and δ15N values of the leaf,stem and root presented a gradual increase at low concentrations,and then slowly declined at high concentration,with the maximum value appeared at the concentration of 200 mg·L -1 Ca2 + . The distribution of δ13 C and δ15 N value in the plant complied with the principle that the "sink" organ was more than the"source"organ. The correlation analysis showed that both the δ13C and δ15N values of"source" organ had a significantly negative correlation with the height,caliper,and the positive correlation with biomass. The δ13C, δ15N value of"sink"organ had a significantly positive correlation with the plant height,caliper,and biomass. The δ13C, δ15 N value dynamic changes of different vegetative organs reflected to a certain extent accumulation and redistribution patterns of the photoassimilates in the"source"and"sink"organs of Populus × euramericana ‘Nanlin 895’cuttings in response to exogenous Ca2 + concentration.

Using Populus×euramericana Nanlin 895 cuttings as experimental materials,we investigated the effects of exogenous Ca2+ on its growth situations and photosynthetic parameters after foliar-spraying at 20 days.The experimental results were that:(1)With the Ca2+ concentration increasing,the Pn,Tr,Gs,Ci in the leaf was presented gradually trends of increase first,and then decrease without exception.The value of Ci would reach to maximum when the concentration of Ca2+ treatment was 20 mg/L.However,the value of Pn,Tr,Gs would reach to the peak when the concentrations of exogenous Ca2+ was 200 mg/L.Compared with the control test,the difference was quite obvious,and it increased by 22.34 %,57.76 %,105 %,respectively.(2)The exogenous Ca2+ treatment could promote height of the plant and caliper growth of Populus×euramericana Nanlin 895 cuttings.The otherness was remarkable or extreme noticeable at the side of control test.Thereinto,the stimulative role of 200 mg/L Ca2+ treatment was the best one,and the height and caliper increased by 25.74 %,70.15 %,separately.In a word,the proper concentration of exogenous Ca2+ treatment could improve the photosynthetic conditions.Consequently,the growth of Populus×euramericana Nanlin 895cuttings were accelerated effectively.