Different Nitrogen On Quercus Aquifolioides Seeding Growth And The Effect Of Photosynthetic Response

Nitrogen deposition on plant growth has important influence on the increase of nitrogen content in the atmosphere,and will reduce the resistance of plant photosynthesis,etc.,this study three years Quercus aquifolioides seedlings as the research object,different simulation nitrogen effects on seedling growth and development.Urea,ammonium sulfate and Nitrogen source for urea,ammonium sulfate and potassium nitrate and mixed nitrogen two of the three kinds of nitrogen source,respectively according to the ratio of 1:1 the way;N application rate,respectively is:N₆₀(60kg·hm^-2·a^-1),extended(120kg·hm^-2·a^-1),N₁₈₀(180kg·hm^-2·a^-1),nitrogen level,with no added nitrogen as the control（CK）,respectively,NO₃^--N、MDA、Pro、SS and SPDA,and other physiological indexes,Tr、Gs、Pn、Ci and photosynthetic indexes such as seedling light response curve,and aims to extract can effectively improve the suitable concentration of nitrogen and Quercus aquifolioides growth,effectively improve photosynthetic and physiological characteristics of seedlings,promote seedling growth,increase the Quercus aquifolioides resistance.At the same time,the nitrogen fertilization in seedling cultivation for Tibet provide certain theory reference and practice guidance.Results show that compared with not adding nitrogen fertilizer,nitrogen fertilizer application in N₆₀～N₁₂₀can effectively increase the seedling growth,photosynthesis and resistance,and with the n application rate increased to a certain concentration,seedling growth and development will be crimped,seedling photosynthesis also declined,and reduces the resistance of the seedling.When nitrogen for potassium nitrate,ammonium sulfate=1:1seedling growth and best exists significant difference with other processing,shows mixed nitrogen is more advantageous to seedling growth and development;When for potassium nitrate nitrogen,the proline content of seedling minimum and no significant difference under different n application levels,nitrogen of urea,ammonium sulfate=1:1,potassium nitrate,ammonium sulfate=1:1 seedlings the content of malondialdehyde than the control group were decreased 49.13%、50.87%shows moderate mixed nitrogen fertilizer can increase the resistance of seedlings and the better.When nitrogen of urea:potassium nitrate=1:1 n concentration for extended(120 kg·hm^-2·a^-1),the seedlings of the highest net photosynthetic rate,nitrogen of urea,ammonium sulfate=1:1 the highest chlorophyll content of seedling leaves,are increased in the control group of 170%shows that this processing next to a greater extent,improve the photosynthetic ability of seedlings;Elected to take nitrogen concentration for extended(120kg·hm^-2·a^-1),light response curve of right Angle hyperbolic concluded that after correction model to simulate hybrid seedlings under n treatment can better use the photosynthetic active radiation.In general,when n application for extended(120kg·hm^-2·a^-1),nitrogen treatment of mixed nitrogen,seedling growth,photosynthesis and the best.