Seasonal Dynamics Of Photosynthetic Physiological Characteristics Of Pinus Koriensis In The Changbai Mountains

To explore the variation of Pinus koraiensis needles physiological state during the growth processes, and the importance of different age needles for Pinus koraiensis saplings in different periods. This paper studies the seasonal dynamic changes of photosynthetic parameters, spectral parameters, pigment content and specific leaf weight (LMA) of natural regeneration Pinus koraiensis saplings under broadleaved Korean pine forest in the Changbai Mountains. The main results were as follows:Leaf age and time were both significantly affected the photosynthetic capacity of Pinus koraiensis saplings. In September, the metabolic activities of Pinus koraiensis remains strong, this helps to absorb nutrients and the energy storage.1-year-old needles’ photosynthetic capacity had greater changes over time, indicate that the photosynthetic components had strong scalability.2-year-old and3-year-old needles’ photosynthetic parameters had smaller changes in different seasons. And their scalability were weak with the change of external environment.Along with the growing season, the photosynthetic capacity and pigment content of current-year needles were significantly increased. the photosynthetic parameters, spectral parameters, chlorophyll content and specific leaf weight (LMA) were lower with the growth of current-year needles, indicate that the growth of current-year needles need mineral elements and organic matter provided by perennial needles. But the contributions were different from needle age. From July to September, Carotenoids growth decreases along with increasing needle age, indicate that the smaller the needle age, the more sensitive response to environmental change, better able to prevent photo-oxidative damage.From June to September, except current-year needles, the normalized chlorophyll index (ChlNDI), the photochemical reflectance index (PRI) and chlorophyll, carotenoid content of Pinus koraiensis decreases along with needle age increases, All indexes of1-year-old needles had a maximum value, indicate that1-year-old needles had the largest contribution throughout the growth cycle of the Pinus koraiensis; The index of3-year-old needles went no significant change with the seasons, indicate gradually aging litter. The larger of needle age, the more of the accumulation of organic matter and other substances, the larger of specific leaf weight (LMA)The correlation was very significant between photochemical reflectance index (PRI) and photosynthetic capacity of Pinus koraiensis, So did the correlation between the chlorophyll normalized index (ChlNDI) and chlorophyll a, chlorophyll b correlation and total chlorophyll content. Therefore, in complex situations researchers can use spectral reflectance index to react photosynthetic capacity and chlorophyll content of Pinus koraiensis. Structure-independent pigment index (SIPI) and carotenoid/chlorophyll correlation is not significant, so SIPI is not widely suitable for analysis and comparison of carotenoid content.