[Effects of light intensity on growth and content of active components of Uncaria rhynchophyll]

The aim of this study was to study the effects of different light intensity on the growth,biomass accumulation and distribution,chlorophyll content and effective components of Uncaria rhynchophylla seedlings,and explore the suitable light intensity conditions for artificial cultivation of U. rhynchophylla seedlings. Three-year-old U. rhynchophylla seedlings were used as experimental materials. Four light intensity levels( 100%,70%-75%,30%-35%,5%-10%) were set up with different layers of black shading net. With the decrease of light intensity,the results showed that the plant height,basal diameter and biomass( root,stem,leaf and hook) of U.rhynchophylla seedlings exhibited the trend of " increase-decrease". Under 70%-75% light intensity,the plant height,basal diameter,biomass( root,stem,leaf,hook) of U. rhynchophylla seedlings were significantly higher than those of other treatments( P< 0. 05);under 5%-10% light intensity,the plant height,basal diameter and biomass( root,hook) of U. rhynchophylla seedlings were significantly lower than those of other treatments( P<0. 05). With the decrease of light intensity,the chlorophyll content of U. rhynchophylla seedlings increased gradually: under 100% light intensity,the chlorophyll content of U. rhynchophylla seedlings were the smallest,while under 100% light intensity,its chlorophyll content was the highest. With the decrease of light intensity,the contents of rhynchophylline and isorhynchophylline in different organs of U. rhynchophylla seedlings varied: under 30%-35% light intensity,the contents of rhynchophylline and isorhynchophylline in hooks and rhynchophylline content in stems were the highest; under 5%-10% light intensity,the contents of rhynchophylline and isorhynchophylline in leaves and stems of U. rhynchophylla were the highest. In conclusion,70%-75% light intensity is suitable for seedling growth and biomass accumulation,and 30%-35% light intensity is suitable for the accumulation of effective components in U. rhynchophylla seedlings.