| Summary: | 碩士 === 國立臺灣大學 === 森林學研究所 === 88 === The objective of this study was aimed to ascertain the effects of light intensity and phosphorus fertilizer on the growth and field performance of Pasania ternaticupula seedlings. Three-month old seedlings of P. ternaticupula were applied with 0, 60, 90, 120, 150 kg ha-1 phosphorus fertilizer, respectively, combined with 300 kg ha-1 nitrogen fertilizer and 100 kg ha-1 potassium fertilizer, while seedlings were grown under 44%, 58% relative light intensity, and full daylight, respectively.
The results showed that the one-year old seedlings grown in relative light intensity of 58% full daylight had biggest items in height growth, total leaf area, average leaf area, total dry mass, dry mass of roots, stem and leaves, and Dickson quality index. However, leaf area ratio（LAR）, specific leaf area（SLA）, leaf weight ratio（LWR）, dry weight partition to leaf , and chlorophyll concentration of seedlings were increased as shading intensity increased. Root-top ratio, dry weight of roots, and the stomata density were increased in the higher light intensity environment. The light intensity significantly affected the growth and morphology of seedlings.
The responses of total weight, dry weight of roots and leaves, Dickson quality index showed that the 60 kg ha-1 P level was optimal. The concentration of P in seedlings was increased as the amount of P fertilizer increased. The first year field performance of the seedlings after out-planting was also affected by light intensity during nursery stage. The seedlings grown under relative light intensity 44% had highest height growth in first year in field might be due to the scattered trees that shading the planted seedlings. However, P fertilizer did not affect the performance of the seedlings in the field.
The results of this study showed that suitable shading had an advantage in dry mass production of P. ternaticupula seedlings; however, the optimal amount of P for the seedlings was as low as 60 kg/ha. In summary, the best scheme to cultivate P. ternaticupula seedling is to apply 60 kg ha-1 of phosphorus fertilizer and a relative light intensity 58% of full daylight.
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