In Vitro Technologies for American Chestnut (Castanea dentata (Marshall) Borkh) Conservation

Abstract

American chestnut (Castanea dentata), a native species of eastern North America, is an economically important deciduous hardwood tree that has been designated as endangered in Canada. The population of American chestnut trees has dwindled significantly across Southern Ontario due to chestnut blight and many of the surviving trees continue to show blight disease symptoms. American chestnut requires efficient strategies for propagation and preservation for species recovery. The objective of this study was to develop a long-term plant conservation program using micropropagation and cryopreservation protocols. An in vitro technology using a liquid-based temporary immersion system (TIS) was developed for micropropagation of American chestnut. The highest rate of shoot multiplication was observed in cultures grown in the DKW (Driver and Kuniyuki 1984) basal medium supplemented with 2.2 µM 6-benzylaminopurine and 1.0 µM gibberellic acid. More than 95% of proliferated microshoots, about 40–50 mm in size, developed roots after 30 days of culture within bioreactor vessels containing DKW basal medium supplemented with 15 µM 3-Indolebutyric acid. Rooted plantlets transplanted to the greenhouse had a survival efficiency of 82% after one month of growth. The cryopreservation protocol for germplasm preservation was developed through droplet vitrification of shoots. Optimal regeneration of shoot tips occurred from explants precultured on stepwise concentrations of sucrose and subsequent dehydration in PVS3 for 30 min. Cryopreserved shoot tips were regenerated to whole plants using pre-optimized conditions of micropropagation. This study confirms the potential of TIS for micropropagation in ex situ conservation and reintroduction of endangered American chestnuts and possibly other woody plant species.

Effects of culture medium composition on the <italic>in vitro</italic> growth of stem cuttings of <italic>Kirengeshoma koreana</italic> Nakai, a rare species in Korea

“…WPM is the most commonly used basal culture medium for woody plants (Liu et al, 2022). Among the Hydrangeaceae family, micropropagation studies of two Hydrangea macrophylla cultivars have been reported, and the explants were cultured on B5 basal culture medium (Khaing et al, 2018).…”

Myrtaceae in Australia: Use of Cryobiotechnologies for the Conservation of a Significant Plant Family under Threat

“…Likewise, there are relatively few reports of successful cryopreservation using shoot tips of woody tropical species, but survival of 70% or more following cryopreservation has been reported for Parkia speciosa, Trichilia emetica, Carica papaya, Citrus aurantium, Citrus suavissima and Manihot esculenta [124]. Shoot tips from in vitro cultures have been also been used to cryopreserve the fungal-blight affected Castanea dentata (Fagaceae) [131]. Application of antioxidants such as vitamins C and E during pretreatment and recovery may help to increase survival and regrowth after cryopreservation of both shoot tips [132] and seed embryonic axes [133].…”

Propagation of Azerbaijani chestnut by tissue culture

“…For example, in the Genus, it completely surrounds the fruit or fruits of the recurrent type, the number of which ranges from 1-3, and has 2-4 leaves. When the cupula matures, it opens through these flaps (Liu et al, 2022).…”