Abstract: [Objective] Ormosia henryi is listed as the precious timber species under state protection (category ii). For providing a theoretical basis of water supply according to demand of O. henryi seedlings at different growth stages, we conducted this study on the water consumption rule of O. henryi seedlings at different growth stages under different water supply and on the effect of water supply conditions to growth and physiological processes of O. henryi seedlings, to save water, reduce nutrient loss and improve seedlings quality. [Method] We conducted a potting experiment in which six relative water content gradients were set, that is, of 90%,80%,70%,60%,50% and 40%, controlled by weighing filling water method. The water consumption dynamic per a seedling and the growth, physiological and biochemical indices of one-year-old O. henryi were measured with six different substrate moisture contents. [Result] In the six different water regimes, both the daily and monthly water consumption of O. henryi seedlings were smaller at early growth stage (15-76 d) and later growth stage (185-231 d), while the water consumption was bigger in fast growth period (77-184 d). The daily water consumption presented two peak periods, they were 92-107 d and 139-169 d, respectively. The biggest daily water consumption ranged from 10.12 mL to 18.84 mL. The monthly water consumption of 5-month-old seedlings (136-169 d) was biggest, ranging from 307.62 mL to 565.26 mL. The total water consumption of seedlings increased with increase of soil moisture content in the range of 40%-80%, and when the relative water content was 80%, the total water consumption of seedlings was biggest, with 3870.99 mL water. The growth and physiological indices of seedlings existed significant differences (P<0.05) in the six different water regimes. When the relative water content was 80%, the height, ground diameter, biomass and root indicators of O. henryi seedling were all better than the other water treatments, and the total chlorophyll content was higher, and the malondialdehyde content, SOD activity, proline content and soluble sugar content were lower than the other water regimes. It was shown that too high or too low relative water content inhibited growth of the seedlings. In synthetic consideration of seedling growth, physiology and water consumption characteristics, the relative water content of 80% was best for cultivating the high quality seedlings of O. henryi, and also realizing the efficient use of water. [Conclusion] Different water supply significantly affect the water consumption, growth and physiology of O. henryi seedlings at different stages. It is benefit for cultivating O. henryi seedlings in the relative water content of 80%, in which the height, ground diameter, biomass and root indicators of O. henryi seedling are superior to other water treatments, and the physical performance also is the best. In terms of the overall quality of seedlings, according to the water consumption rule of O. henryi seedlings under 80% relative water content, we have formulated the optimization irrigation system for O. henryi container seedlings at different growth phases, that is, the irrigation water volume per month is 178.35,232.47,469.98,436.59,565.26,367.35 and 329.55 mL when the seedlings age is 15-45, 46-76, 77-107, 108-138, 139-169,170-200 and 201-231 d, respectively.

Key words: Ormosia henryi, water supply, water consumption quantity, growth characteristics, physiology characteristics, irrigation system