Promoting the application of pinus thunbergii Parl. toward enhancing the
growth and survival rates of post-germination somatic plantlets
Abstract
There is a growing need for nematode-resistant Pinaceae species
seedlings to cope with the degradation of global coniferous forests due
to the prevalence of pine wilt disease. One of obstacle of Pinaceae
species plantlets commercialization is the regeneration plantlets from a
controlled, sterile environment to the field while maintaining a high
survival rate. The low survival rate of plantlets transferred from a lab
to soil is mainly because of the quality of plantlet which makes
commercialization challenging. For this paper, we investigated the
factors that influence the growth of post-germination somatic
regeneration plants (SRPs) to promote the application of
nematode-resistant of Pinus thunbergii. The results indicated
that, for rooted plantlet, a suitable liquid medium (1/2 WPM),
transplantation stroma (perlite and vermiculite =1:1), and carbohydrate
(20 g/L sucrose) were effective for promoting the growth of SRPs. While,
for unrooted plantlets, 1 ug/L of brassinolide enhanced plantlets growth
and rooting. In the laboratory domestication stage, under light spectrum
treatments, blue light (B) significantly promoted the longitudinal
growth of shoots, while red light (R) was of benefit for the improvement
of root growth. The optimal combination of R/B was the 8:2. After this
domestication culture, SRPs of Pinus thunbergii could be directly
transplanted to the field with a higher survival rate (85.2%). This is
the first report on domestication of conifer regeneration plants, that
will increase the possibility of afforestation of Pinaceae or other
woody plants. In addition, it contributes to breeding project of pine
resistance to pine wilt disease.