Substrate and Irradiance Affect the Early Growth of the Endangered Tropical Tree Fern Dicksonia sellowiana Hook. (Dicksoniaceae)

Abstract

Abstract Dicksonia sellowiana spores were cultivated in mineral solution. After 30 days, young gametophytes were transferred to different substrates: soil rich in organic matter; coxim: coconut fiber; sterilized red soil; sterilized red soil with the addition of organic compost, to determine the best substrate for gametophytes' and sporophytes' development. Red soil with the addition of compost was the best system for growth. When sporophytes were 1.5–2.0 cm in height, they were transferred to pots containing sterilized red soil with the addition of organic compost and kept in the field for 42 days, under 75, 50, 10 and 3% of irradiance. The longest frond height, frond quantity, fresh and dry mass, and RGR were observed in plants growing in 10% of irradiance. Plants kept under 100% irradiance died after 3 days, and under 50% and 75% irradiance they died gradually after 30 days. The fresh mass/dry mass ratio was higher at 3% and lower at 30% irradiance. The levels of chlorophyll a, chlorophyll b and total ...