Abstract: [Objective] Dalbergia odorifera is one of the rare tree species for timber forest in our country,and there is an increasing demand for its seedlings. Aiming to explore the influence of shade on growth, development, morphology and physiological characteristics of D. odorifera seedlings, this paper could provide a sound theoretical foundation for the control of light environment on forestry seedling cultivation.[Method] Five shade treatments including 0%(T₀), 40%(T₁), 60%(T₂), 80%(T₃) and 95%(T₄) were set to annual D. odorifera seedlings for four months. Growth index (i.e. ground diameter, seedling height, and leaf number) of D. odorifera seedlings were measured every 15 days during the experiment. The plant biomass, specific leaf weight, chlorophyll content (Chl), net photosynthesis rate (P_n), intercellular CO₂ concentration (C_i), stomatal conductance (G_s), and transpiration coefficient (Tr) were measured at the end of the treatment.[Result] The results showed that the ground diameter, seedling height and biomass of D. odorifera seedlings descend gradually with the increase of shade degree and the extension of treatment time, indicating the weakened growth of D. odorifera seedlings. The increment of seedling height and ground diameter in T₄ treatment was 7.7 cm and 1.0 mm and which was 39.2% and 35.6% of T₀ treatment respectively during the test process. The dry matter accumulation, specific leaf weight, quality index and root/shoot ratio were significantly decreased with the increase of shade degree, indicating that shade inhibited the growth and development of D. odorifera seedlings. On the contrary, the shade markedly increased the Chl b and Chl a content of leaf and water content for all plant organs, while the Chl a/Chl b and P_n were decreased. These results demonstrated that the increase of shade level could cause a decline of photosynthetic use efficiency, and then leading to a slower growth and development rate and a descend in the deposit rate of D. odorifera seedlings.[Conclusion] The results and relevant studies showed that the D. odorifera seedlings were suitable to breed under the full light in seedling stage based on comprehensive analysis on the growth and physiological morphology indexes.

Key words: Dalbergia odorifera, shade, container seedlings, growth, morphology physiology