Effect Of Simulated Nitrogen Deposition On Cupressus Lusitanica Seedlings

This paper investigates the impacts of different concentrations of nitrogen deposition onseedlings of two-year-old Cupressus lusitanica from the perspective of seedling growth andphotosynthetic physiological. The results showed as follows:1. With the increase of nitrogen deposition input, the stem base diameter and height of Cupressuslusitanica seedlings show a trend of gradually decrease after the first increase. In the short term,nitrogen depositions of different concentrations all promote the growth of the stem base diameterand height of seedlings, which are most seriously affected by medium nitrogen deposition.Specific leaf area of seedlings is gradually increased with the increase of nitrogen depositioninput. The treatment of high concentration is the most favourable to the specific leaf area.2. The root weight, root length, root surface area and root volume of Cupressus lusitanicaseedlings are all gradually decreased with the increase of the concentration of nitrogen deposition.However the root average diameter of seedlings is increased firstly and then decreased with theincrease of nitrogen deposition input. The treatments of low and medium concentration bothimprove the root average diameter of seedlings. In the opposite, the treatment of highconcentration is disadvantageous to the root average diameter. Seedlings roots with the treatmentof nitrogen deposition are given priority to with fine roots instead of a long taproot.3. The photosynthetic pigment content of seedlings is increased with the addition of theconcentration of nitrogen deposition. Chla/Chlb values of seedlings under deal with nitrogendepositions of different concentrations are higher than that of control seedlings, and that of lownitrogen deposition are the highest.4. At the beginning of the experiment nitrogen deposition of different concentrations played arole in helping seedlings photosynthesis to increase. However with the increasing of nitrogendeposition input, high nitrogen deposition gradually displays inhibitory effect, plus low andmedium nitrogen depositions are advantageous all the time. The promoting effect of mediumnitrogen deposition is greater than low nitrogen deposition.5. Nitrogen depositions of different concentrations all improve Cupressus lusitanica seedlingsFv/Fm and Fv/F0values, which are affected the best by medium nitrogen deposition. Furthermore,nitrogen deposition significantly impact stronger on Fv/F0value than Fv/Fm value.