Abstract:

In this paper,growth in height,caliper,and biomass,and dynamic changes of the δ¹³ C and δ¹⁵ N 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,δ¹³ C and δ¹⁵ N,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 δ¹³ C and δ¹⁵ N 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 δ¹³ C and δ¹⁵ N values of 　“source”　 organ had a significantly negative correlation with the height,caliper,and the positive correlation with biomass.The δ¹³ C,δ¹⁵ N value of 　“sink”　 organ had a significantly positive correlation with the plant height,caliper,and biomass.The δ¹³ C,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.

Key words: Populus×, euramericana&lsquo, Nanlin 895', exogenous Ca²⁺, biomass, &delta, ¹³ C, &delta, ¹⁵ N