Impact of fast and slow desiccation on Garcinia imberti seed and seedling vigour

Abstract

Garcinia imberti Bourd. endemic to the southern Western Ghats is classified as endangered by the IUCN (2018). The seeds as the sole means of propagation with initial moisture content (MC) of 62.8% are sensitive to desiccation. Studies on the responses of the seed to drying require ascertaining of the critical moisture content (CMC) as a basic requisite for germplasm conservation. Responses of G. imberti seeds to fast drying with activated silica gel (25 ± 2 °C, 6 ± 1% RH) and to slow drying under laboratory conditions (28 ± 2°C, 60 ± 2% RH) were evaluated for seed and seedling vigour. When the MC was reduced to 56% by 48 hours of slow drying or 6 hours of fast drying, 75 to 90% normal seedlings were produced respectively. In the case of fast dried seed (6 hours), seed associated parameters except mean germination time showed peak values with maximum germination and enhanced root length. Below the CMCs of 16.4 and 26.3% (fast and slow drying respectively), half of the tested seeds become non viable. Thus for germplasm conservation the present study proposes 6 hour's of fast drying to retain viability and normal seedling development of G. imberti.

Conservation of Garcinia imberti Bourd. through seeds

“…Baskin and Baskin (18) reported that seed dormancy is usually allied with intrinsic factors linked to the seed itself, such as rigid and impermeability of the seed coat to gases and water, immature embryos, inhibitors, and abiotic factors like temperature, humidity, light and substrate. The G. imberti seeds when subjected to decoating, dormancy were also reduced (8). The seed decoating was efficient for avoiding the inhibitory phyto-compounds present (19).…”

“…Garcinia imberti is an evergreen, endangered tree species (7) growing up to 10 m height bearing recalcitrant seeds with high moisture content. The niche specificity is due to its patchy, specific altitudinal (600-1200 m asl) distribution, recruitment failure due to high fruit/seed predation and a prolonged period of seed dormancy (8). The major difficulty in G. imberti propagation as for many species of Garcinia genus is related to its seeds germination, dormancy and storage aspects.…”

“…The major difficulty in G. imberti propagation as for many species of Garcinia genus is related to its seeds germination, dormancy and storage aspects. Because of seed dormancy, G. imberti seeds can take 14 months in its niche to germinate due to the physical barrier of the seed coat (9,8). Niche based cues on the ecological requirements preferred by G. imberti seedlings indicated the presence of balancing nature of sunlight and misty shaded canopy.…”