Abstract:
Primulina danxiaensis, an endemic species of the Danxia landform within the Gesneriaceae
family, exhibits a narrow distribution range and a limited population size, thereby necessitating propagation
and conservation via plant tissue culture techniques. In this paper, in order to establish the tissue culture and
rapid propagation technical system of P. danxiaensis, the leaf segments of P. danxiaensis were used as
explants to screen the appropriate surface disinfection time with HgCl₂, the culture media for adventitious
bud induction, bud proliferation and rooting, as well as the transplanting substrates for tissue-cultured
seedlings. The results were as follows: (1) The optimal disinfection procedure involved a 30-second immersion in 75% alcohol, followed by a 6-minute soak in 0.1% HgCl2, achieving an 84.95% survival rate
of leaf explants. (2) For bud induction, the most effective medium was found to be 1/2MS supplemented
with 6-benzyladenine (6-BA) 2 mg·L−1 and α-naphthalene aceticacid (NAA) 0.1 mg·L−1, resulting in a
100% bud induction rate and an average of 38.35 buds per leaf explant after 40 days of culture. (3) Bud
proliferation was optimally achieved on 1/2MS medium containing 6-BA 3 mg·L−1 and NAA 0.2 mg·L−1 ,
yielding a proliferation coefficient of 7.54 over a 50-day period. (4) Rooting was successfully induced
using 1/2MS medium supplemented with NAA 0.5 mg·L−1 , leading to a 100% rooting rate and an average
of 26.28 roots per plant after 30 days. (5) The tissue-cultured seedlings were successfully acclimatized and
transplanted into three different mixed substrates: a mixture of leaf mould from Karst landform, perlite, and
vermiculite (1:1:1, V/V/V), peat soil, perlite, and vermiculite (1:1:1, V/V/V), and perlite and vermiculite (1:1,
V/V), all with a 100% survival rate and demonstrating robust growth. This study is capable of achieving
large-scale propagation of P. danxiaensis, a result that significantly contributes to both its resource
protection and utilization.