Post desiccation germination of mature seeds of tea (Camellia sinensis L.) can be enhanced by pro-oxidant treatment, but partial desiccation tolerance does not ensure survival at −20 °C

The maximal potential desiccation tolerance (MPDT) of tea (Camellia sinensis) seeds has been a matter of debate for decades. Here we assessed the ability of tea seeds from three sites in China to germinate after desiccation. Desiccation tolerance was greatest in Kunming, followed by Puer and Lincang, with Kunming seeds tolerating drying to 8% moisture content (MC), or ∼0.5 water activity (aw). Such tolerance was observed in Lincang seeds only when hydrogen peroxide (H2O2) at 0.5 or 1 M was applied to seeds, indicating a stimulatory role for H2O2 in post-desiccation germination. Puer seeds exhibited MPDT of 16% MC (∼0.7 aw). Therefore, seeds from all three sites were not recalcitrant. The length of the dry season after dispersal and the high ratio of seed coat to seed mass (>0.3) support the observation of non-recalcitrant behaviour. The seeds were not immature, as the lipid signal in embryonic axes mirrored that of the cotyledons (30% oil). Even after high survival [>60% total germination (TG)] on drying to 10–13% MC, no Kunming seeds tolerated 1 month storage at −20 °C coinciding with lipid transitional changes at this temperature. The results indicate that tea seeds from China are neither recalcitrant nor storable at −20 °C.

► Different reports exist on the seed storage behaviour of tea (Camellia sinensis).
► Here, we assessed desiccation stress in tea seeds from three sites in China.
► All seed lots showed non-recalcitrant storage behaviour.
► Germination of partially dried tea seeds was enhanced by H2O2 treatment.
► However, partially dried tea seeds did not survive 1 month of storage at −20 °C.