Abstract:
In order to explore the optimal calcium concentration for seedling growth of
Pinus sylvestris var. Mongolica in sandy land, the three-year seedlings of
Pinus sylvestris var. Mongolica were used into a soil culture trial with 6 calcium concentration gradients by 6 replications for each treatment, to investigate the changes of relevant indices such as seedling growth, photosynthetic parameters, chlorophyll fluorescence parameters, water use efficiency of
Pinus sylvestris var. Mongolica seedlings in sandy land under different exogenous calcium concentrations. The results showed that the plant calcium content in the leaves of
Pinus sylvestris var. Mongolica seedlings increased with the increase of calcium gradient, which was significantly more than that without calcium treatment. Calcium application promoted the growth of
Pinus sylvestris var. Mongolica seedlings in sandy land with the optimal calcium concentration rangeing from 50 to 100 mg kg
−1. When over the optimal value, the growth and biomass of
Pinus sylvestris var. Mongolica seedlings in sandy land showed downward trends with the increase of calcium concentration. Calcium also enhanced the synthesis of photosynthetic pigment of
Pinus sylvestris var. Mongolica seedlings, increased the photosynthetic parameters of the plant, and promoted the accumulation of soluble sugar and starch. The most significant effects of those indices affected by the calcium concentrations were between 50-100 mg kg
−1. Moreover, calcium application affected the chlorophyll fluorescence characteristics of
Pinus sylvestris var. Mongolica seedlings. When the calcium concentration reached 400 mg kg
−1, the maximum photochemical efficiency of PSⅡ was less than 0.8, causing the stress phenomenon. In addition, calcium application significantly improved the water use efficiency of
Pinus sylvestris var. Mongolica seedlings as well, showing the highest water use efficiency was obtained at the calcium concentration of 400 mg kg
−1. These results suggested that the optimal calcium concentration of
Pinus sylvestris var. Mongolica seedlings in sandy land had to maintain at 50-100 mg kg
−1. Too high or too low calcium concentration would inhibit the growth and development of
Pinus sylvestris var. Mongolica seedlings in sandy land.
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