Abstract
Paederotella pontica is a Colchis tertiary relict species, regional narrow endemic to the Caucasus, representative of an oligotypic genus. The aim of this study was to determine dormancy-breaking requirements and develop seed germination protocol for P. pontica. Freshly matured seeds of P. pontica are morphophysiologically dormant (MPD). Mean length of seed is 820 μm, linear embryo is fully differentiated, on average 625 μm long. Penetration of tetrazolium salt indicates the permeability of seed coat and high percentage of vital seeds in capsules. Prior to root emergence, the E:S ratio increased from 0.76 to 0.9. Effects of warm and cold stratification and gibberellic acid (GA3) on embryo growth and seed germination were studied under laboratory conditions. Since cold stratification is the only requirement for the loss of MPD, the longest embryo growth occurred during this treatment and GA3 promoted MPD loss, we concluded that P. pontica seeds have intermediate complex MPD. Based on the treatment results a germination protocol is proposed: 1. Dry storage at 20°C, 2 months; 2. Cold-wet stratification at 3°C, 3 months; 3. Germination at 20/15°C day/night. Under developed conditions germination is fast, synchronous and yields to 80%.
Highlights
A Tukey post hoc test revealed that the time to overcome dormancy during the cold stratification was statistically significantly reduced when GA3 was applied during the cold stratification
Substantial difference between cold stratification (CS) and GA3+CS treatments could already be observed at the end of the first month of chilling: germination percentage of the seeds from GA3+CS treatment was much higher to compare with CS (68 versus 35%)
Results of our study showed that the seeds subjected to the 1 month of warm incubation and dry-stored seeds did not germinate at 20/15 C, indicating dormancy of both seed group
Summary
From the family Plantaginaceae includes only three species endemic to the Caucasus: P. daghestanica (Trautv.) Kem.Nath., P. pontica Protentional threats caused by natural and anthropogenic factors promote the loss of species and increase its extinction risk. Several studies showed that the rare endemic species are in particular suffer from the changes of habitat quality in comparison with widespread taxa, due to limited distributional range [3]. Little is known about seed germination ecology of the P. pontica. Giving the risk of the species loss in the native habitats posed by natural and anthropogenic threats, the knowledge of factors promoting seed germination could greatly contribute to the plant propagation and support the ex situ conservation of P. pontica. The species is listed in regional conservation reports [4, 5] as rare endemic plant need to be protected, its reproduction requirements are still poorly known. Appropriate temperature and hormonal pretreatment can both release dormancy and promote germination [8, 9]
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call