title: 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.
abstract: 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 (a(w)). Such tolerance was observed in Lincang seeds only when hydrogen peroxide (H₂O₂) at 0.5 or 1M was applied to seeds, indicating a stimulatory role for H₂O₂ in post-desiccation germination. Puer seeds exhibited MPDT of 16% MC (∼0.7 a(w)). 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.
authors.affiliation: Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of Sciences, 132 Lanhei Road, Kunming 650201, China.
authors.forename: Hongying
authors.initials: H
authors.lastname: Chen
authors.forename: Hugh W
authors.initials: HW
authors.lastname: Pritchard
authors.forename: Charlotte E
authors.initials: CE
authors.lastname: Seal
authors.forename: Jayanthi
authors.initials: J
authors.lastname: Nadarajan
authors.forename: Weiqi
authors.initials: W
authors.lastname: Li
authors.forename: Shixiong
authors.initials: S
authors.lastname: Yang
authors.forename: Ilse
authors.initials: I
authors.lastname: Kranner
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects*; D002152:Calorimetry, Differential Scanning; D028241:Camellia sinensis / Q000187:drug effects / Q000196:embryology* / Q000502:physiology*; D002681:China; D003080:Cold Temperature; D003890:Desiccation; D005843:Geography; D018525:Germination / Q000187:drug effects*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D016877:Oxidants / Q000494:pharmacology; D010938:Plant Oils / Q000032:analysis; D012639:Seeds / Q000187:drug effects / Q000196:embryology*; D014867:Water
chemical_list: D016877:Oxidants; D010938:Plant Oils; D014867:Water; D006861:Hydrogen Peroxide