In Vitro Propagation and Reintroduction of Paphiopedilum wardii Sumerh.

Abstract

Paphiopedilum wardii Sumerh. is an endangered and rare terrestrial orchid threatened with extinction in the wild due to anthropogenic activities. Asymbiotic germination provides a useful way for ex situ conservation, for reintroduction in the wild, and for commercial demand. The 180-day seeds after pollination had highest germination rate with 65.33%, and 1/2MS supplemented with 0.5 mg l⁻¹ NAA, 10% coconut water, and 1.0 g l⁻¹ activated charcoal was a suitable medium. Hyponex N026 medium containing 1.0 mg l⁻¹ NAA, 1.0 g l⁻¹ peptone, 10% CW, and 1.0 g l⁻¹ AC was most suitable for subculture of plantlets. Hyponex N016 medium containing 1.0 mg l⁻¹ NAA, 1.0 g l⁻¹ peptone, 100 g l⁻¹ banana homogenate, and 1.0 g l⁻¹ AC was suitable for plantlets’ growth in vitro. The plantlets 5 cm in height were transplanted in mixture media [2: 1: 1 (v/v) Zhijing stone for orchids/sieved peat/shattered fir bark]. Survival rate of 92.33% was obtained after 180 days in a greenhouse. 10,000 plantlets in vitro were obtained. We used the 1000 plantlets propagated in vitro to reintroduce into one habitat and two sites outside the species range. The 180-day transplanted seedlings were reintroduced into habitat at Gaoligong Mountain in Yunnan or alien forest habitats at Yangchun and Guangzhou in Guangdong, which had a higher survival percentage than 90-day or 360-day transplanted seedlings. About 2 years after transplantation, around 30% of plants that survived flowered from seedlings transplanted for 360 days at all three reintroduction locations. At Gaoligong Mountain, Lushui, 32% of flowering plants produced fruits and seeds.