scholarly journals Improving Ex Vitro Rooting and Acclimatization Techniques for Micropropagated American Chestnut1

2020 ◽  
Vol 38 (4) ◽  
pp. 149-157
Author(s):  
Allison D. Oakes ◽  
Hannah C. Pilkey ◽  
William A. Powell

Abstract Limited rooting and acclimatization success when micropropagating certain hardwood tree species may hinder conservation efforts of certain threatened and endangered species. Restoration efforts for such trees, such as the American chestnut [Castanea dentata (Marsh.) Borkh.], require a massive number of plantlets to be produced by micropropagation for testing, initial distribution, and orchard establishment. Therefore, increasing the number and quality of lab-produced plantlets is a key research focus. After previously determining that an ex vitro rooting system produced significantly more robust plantlets, we examined extending the time in elongation medium, rooting substrates, exogenous auxin applications, root-promoting substrate soaks, submerging the cut site, and light intensity. The most effective methods included seven weeks in elongation medium, using Jiffy peat pellets soaked in water as the rooting substrate, cutting off callus while submerged, then dipping in 0.31% IBA rooting gel, and placing plantlets in low light of 60 μmol·m-2·s-1 after rooting. By increasing the number of roots and improving acclimatization success, we can ensure that many more blight-tolerant American chestnuts will be available for field studies and eventual public distribution. Demonstrating the ecological safety and blight survival of these trees will help restore this foundational tree species and assist future restoration efforts for other threatened species. Index words: Rooting, ex vitro, American chestnut, Castanea dentata, IBA, substrate. Species used in this study: American chestnut, [Castanea dentata (Marsh.) Borkh.]. Chemicals used in this study: IBA (indole-3-butyric acid).

1989 ◽  
Vol 67 (12) ◽  
pp. 3457-3469 ◽  
Author(s):  
Frederick L. Paillet ◽  
Philip A. Rutter

American chestnut was introduced at West Salem, Wisconsin, about 1880 and had begun to replace native tree species in adjacent oak-hickory woodland before 1930. Chestnut is now an important canopy species over about 20 ha of forested ridge extending north and south of the original plantation. A smaller area of less than 5 ha is dominated by chestnut in both the canopy and understory. Chestnut seedlings and small saplings are more numerous along woodland edges and in recently disturbed soil, they are rare in the interior of ungrazed pasture and entirely absent from intensively grazed areas adjacent to chestnut-dominated woodland. Random sampling of recently established seedlings indicates that from 1 to 5 seedlings/(year ∙ ha) became established in undisturbed woodland between 1986 and 1988. The general pattern of chestnut distribution indicates the importance of woodland edges in chestnut propagation and the effects of livestock grazing in excluding chestnut. Replacement of native species by chestnut appears to have occurred in two steps: isolated groups of trees became established at favorable locations, after which many additional chestnut stems became established in the understory. The recent discovery and treatment of blight indicates that the West Salem site may not be available for study of blight-free chestnut in the future.


FLORESTA ◽  
2011 ◽  
Vol 41 (1) ◽  
Author(s):  
Paulo César Poeta Fermino Júnior ◽  
Andrea Raposo ◽  
Jonny Everson Scherwinski-Pereira

O enraizamento de espécies arbóreas é bastante complexo devido à maturidade dos tecidos. O objetivo deste trabalho foi avaliar o efeito de AIB no enraizamento ex vitro de brotos micropropagados a partir de plantas jovens de Tectona grandis L. em dois substratos, bem como da porção do broto para enraizamento. Foram utilizados brotos multiplicados in vitro inteiros, ou excisados ao meio (porção apical e basal), submetidos a imersão por 10 segundos em soluções contendo diferentes concentrações de AIB (0, 100, 1000, 2000, 4000 mg.L-1) e plantados em bandejas plásticas contendo vermiculita ou Plantmax® como substratos. O enraizamento ex vitro ocorreu em todos os tratamentos, inclusive na ausência de AIB. O maior número de raízes e o maior crescimento relativo do caule foram observados para os tratamentos com o uso de AIB, em ambos os substratos. O enraizamento ocorreu em 100% dos explantes de origem apical e basal, em ambos os substratos. O enraizamento ex vitro de brotos micropropagados de T. grandis é viável a partir de plantas jovens, e a taxa de multiplicação é duplicada com o seccionamento dos brotos em porções apical e basal.Palavras-chave:  Teca; produção de mudas; micropropagação; condição ex vitro; porção do broto. AbstractEx vitro rooting and acclimatization of micropropagated plantlets of Tectona grandis. The rooting of tree species is very complex due to the maturation of tissues. The objective of this study was to evaluate the effect of IBA on ex vitro rooting of micropropagated shoots from juvenile plants of Tectona grandis L. into two substrates, as well as the portion of the shoot to root. Shoots multiplied in vitro were used with whole or excised shoots (apical and basal) submitted to immersion for 10 seconds in solutions of IBA (0, 100, 1000, 2000, 4000 mg.L-1) and planted in plastic trays containing vermiculite or Plantmax ® as substrates. The ex vitro rooting occurred in all treatments, even in the absence of IBA. The largest number of roots and higher relative growth of the stem were observed in all treatments with IBA in both substrates. The survival of acclimatized plantlets occurred in all treatments. Rooting occurred in 100% of explants from apical and basal origin in both substrates. The ex vitro rooting of micropropagated shoots of T. grandis is feasible from juvenile plants and the multiplication rate is duplicated when shoots are cutin apical and basal portions.Keywords: Teak; seedlings; micropropagation; ex vitro condition; portion of the shoot.


Castanea ◽  
2020 ◽  
Vol 85 (2) ◽  
pp. 232
Author(s):  
Robert G. Laport ◽  
David Smith ◽  
Julienne Ng

1998 ◽  
Vol 18 (3) ◽  
pp. 283-305
Author(s):  
Louisiana Lush ◽  
George P. Cernada ◽  
A. K. Ubaidur Rob ◽  
Mohammed Shafiq Arif ◽  
Minhaj Ul Haque ◽  
...  

This article presents the results of a number of operations research studies (OR) of family planning services provided by a new cadre of female village-based family planning workers in Punjab Province, Pakistan. This cadre of workers, recruited nationwide, have been trained to visit women in their villages to provide information and family planning services. The studies were conducted as part of a broad program of technical assistance to the Government of Pakistan. Surveys investigated the quality of their training as well as attitudes among clients to the new program. They found that the program is developing well but there is room for improvement, particularly in counseling and training. Additional field studies are ongoing and recommendations for change have been incorporated in training and supervision. The program is expanding on a national scale.


2005 ◽  
Vol 84 (1) ◽  
pp. 69-79 ◽  
Author(s):  
Linda D. Polin ◽  
Haiying Liang ◽  
Ronald E. Rothrock ◽  
Mutsumi Nishii ◽  
Deborah L. Diehl ◽  
...  

2005 ◽  
Vol 25 (5) ◽  
pp. 450-456 ◽  
Author(s):  
Danilo D. Fernando ◽  
Javonna L. Richards ◽  
Julie R. Kikkert

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