关键词: 南瓜, 南瓜, 净光合速率, 蒸腾速率

Abstract:

The goal of this study was to evaluate the reasonable fertilizer of nitrogen application on Cyclobalanopsis glauca container seedlings. Plant height, basal diameter, and chlorophyll content, photosynthetic parameters were investigated in the C. glauca container seedlings grown in five nitrogen environments (0, 0.184, 0.629, 1.074, and1.518 mg/cm3). Plant height, basal diameter, main root length, biomass accumulation and quality index were significantly affected by nitrogen concentrations, with the maximum was observed in nitrogen level of 0.629 mg/cm3 (average: plant height=15.17 cm, basal diameter=3.39 mm, main root length=16.7 cm, quality index=0.38). The diurnal process of photosynthetic rate of C. glauca exhibited a double peak curve in which the main peak appeared around 11:00 and the second around 15:00. This indicated an obvious phenomenon of midday depression of photosynthesis, while higher photosynthetic rate (5.56 μmol CO2/(m2?s)) was maintained at midday in the plants grown in middle nitrogen environments (0.629 mg/cm3) than other treatments. Moreover, the efficiency of energy conversion of open PSⅡ (F′v/F′m), photochemical efficiency of PS II, and photochemical quenching (qP) were highest in the plants grown in middle nitrogen environments (0.629 mg/cm3). The soluble sugar content of root, stem and leaf was highest when plants grown in middle nitrogen level (0.629 mg/cm3) among the five treatments. Root nitrogen, stem nitrogen, leaf nitrogen and chlorophyll content increased in increased nitrogen concentrations. Leaf nitrogen was significantly higher than root and stem nitrogen concentration. We concluded that 0.629 mg/cm3 nitrogen was the optimum with exponential fertilization technique in the cultivation of C. glauca container seedlings.