scholarly journals Plantlet formation in black and white spruce. II. Histological analysis of adventitious shoot formation in vitro

1986 ◽  
Vol 64 (5) ◽  
pp. 997-1002 ◽  
Author(s):  
Colin Rumary ◽  
Kamlesh R. Patel ◽  
Trevor A. Thorpe

Histological analysis of developmental events during adventitious shoot formation in cultured epicotyl explants of black and white spruce was carried out. Cells towards the periphery of the expiants and between the bases of the cotyledons responded to cytokinin and became meristematic. Cell division in these regions led to the formation of meristemoids and ultimately intercotyledonary adventitious shoots. These shoots developed a vascular system, which became connected to the main vascular system of the expiant. After about a month of culture, the entire expiant became meristematic and showed evidence of additional de novo shoot development. Several rings of bud primordia were found at the periphery of the expiant after about 40 days of culture. These primordia that developed in the subepidermal layers could easily be distinguished from the surrounding cells by their distinct boundaries and intense staining for nucleic acids and proteins. After 2 months of culture, the entire expiant was covered with well-developed shoots having organized apical meristems, needle primordia, and vascular systems.

HortScience ◽  
2011 ◽  
Vol 46 (12) ◽  
pp. 1661-1665 ◽  
Author(s):  
Takahiro Tezuka ◽  
Masashi Harada ◽  
Masahumi Johkan ◽  
Satoshi Yamasaki ◽  
Hideyuki Tanaka ◽  
...  

Adventitious shoots can be regenerated from the cut surface of the primary shoot and lateral branches in decapitated plants in vivo. This inherent regenerative ability of plants is useful for mass propagation. In the present study, we conducted histological observations of shoot regeneration and applied auxin and cytokinin to decapitated seedlings in four tomato cultivars. The cultivars produced different numbers of adventitious shoots after decapitation; ‘Petit’ produced the largest number of adventitious shoots (78.5 ± 10.2) and ‘Momotaro’ produced the fewest (12.1 ± 3.3). Histological observation of ‘Petit’ revealed that adventitious shoots regenerated from calli formed at the cut surface of stems. Adventitious shoot formation was inhibited by the presence of lateral branches. Shoot regeneration was prevented by application of 1-naphthaleneacetic acid to ‘Petit’. Application of 6-benzyladenine promoted shoot regeneration in ‘Momotaro’. These results suggest auxin synthesized de novo from the lateral branches inhibited shoot regeneration after decapitation and endogenous cytokinin might stimulate shoot regeneration. Chemical names: 1-naphthaleneacetic acid (NAA); 6-benzyladenine (BA)


1993 ◽  
Vol 118 (1) ◽  
pp. 151-157 ◽  
Author(s):  
Michael E. Compton ◽  
D.J. Gray

Adventitious shoots were obtained from watermelon [Citrullus lanatus (Thunb.) Matsun. & Nakai] cotyledons incubated on a modified Murashige and Skoog medium containing BA. Initial experiments comparing the effects of BA (0, 5, 10, or 20 μm) and IA4 (0, 0.5, or 5 μm) demonstrated that BA was required for adventitious shoot formation but its concentration in the medium was not critical. The addition of IAA to medium with BA increased callus production and inhibited shoot formation. However, the percentage of responding explants in the best treatment was <30%. Therefore, the manner in which cotyledon explants were prepared and seedling age at the time of explantation was examined to improve the organogenic response. The percentage of explants with shoots was improved by using explants that consisted of cotyledon bases (43%) or cotyledons cut in half longitudinally (39%). A lower percentage (16%) of cotyledons cut longitudinally into four pieces produced shoots. Explants taken from the apical half of cotyledons failed to regenerate shoots. Shoot formation was improved further by using explants from young seedlings. The percentage of explants with shoots was >90% for `Minilee', 64% for S86NE, and 50% for `Jubilee II' when explants were prepared from 5-day-old seedlings. Explants from nongerminated embryos or seedlings germinated for 10, 15, or 20 days produced fewer shoots. The effect of several cytokinins on shoot organogenesis was then examined using the optimized protocol. The percentage of explants with shoots and the number of shoots per explant were about two to four times higher when 5 to 10 μm BA was used compared to the most effective kinetin (20 μm) or thidiazuron (0.1 μm) concentration. The percentage of explants with shoots and the number of shoots per explant were greater for diploid (57% and 2.2, respectively) than for triploid (22% and 0.6, respectively) or tetraploid (20% and 0.8, respectively) lines. Chemical names used: N -(phenylmethyl)-1 H -purin-6-amine (BA); 6-furfurylaminopurine (kinetin); N -phenyl-N' -1,2,3-thiadiazol-5-ylurea (thidiazuron); 1 H -indole3-acetic acid (IAA).


1981 ◽  
Vol 59 (5) ◽  
pp. 870-874 ◽  
Author(s):  
Sara Von Arnold ◽  
Tage Eriksson

Isolated embryos of Pinus contorta Dougl. ex Loud, were induced to form adventitious buds on a cytokinin-supplemented medium. Further development of the buds required transfer to a cytokininless medium. Both bud induction and development were stimulated by a dilution of the basal culture medium and best growth was obtained if the buds were isolated from the original tissue when stem elongation had started. The growth of these isolated adventitious shoots was further stimulated by adding activated charcoal to the diluted medium. A small percentage of the shoots have been rooted. The capacity for bud formation varied among seeds collected from different regions of British Columbia. This method for induction of adventitious buds on embryos was also applicable to explants of young seedlings.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 560d-560
Author(s):  
Dennis P. Stimart ◽  
John C. Mather

Cotyledons from developing embryos 6 to 8 weeks old of Liatris spicata (blazing star) were cultured on Murashige-Skoog (MS) medium containing 0, 0.4, 4.4, and 44.4 μ M benzyladenine (BA) or 0, 0.2, 2.2, and 22.2 μ M thidiazuron (TDZ) to induce adventitious shoot formation. The highest percent of cotyledons forming shoots with highest shoot counts was on medium containing 2.2 μ M TDZ. Vitreous shoots formed on medium with 22.2 μ M TDZ. Callus derived from cotyledons and cultured on medium containing 4.44 μ M BA or 2.2 μ M TDZ formed adventitious shoots with highest shoot counts on 4.44 μ M BA. Adventitious shoots derived from cotyledons and callus were rooted on MS medium with 5.0 μ Mindole-3-butyric acid, acclimatized and grown ex vitro. All micropropagated plants appeared similar to each other.


HortScience ◽  
1996 ◽  
Vol 31 (1) ◽  
pp. 154-155
Author(s):  
Dennis P. Stimart ◽  
John C. Mather

Cotyledons from developing 6- to 8-week-old embryos of Liatris spicata (L.) Willd. (blazing star) were cultured on Murashige and Skoog medium containing 0, 0.4, 4.4, or 44.4 μm BA or 0, 0.2, 2.2, or 22.2 μm TDZ to induce adventitious shoot formation. The highest percentage of cotyledons forming the most shoots was on medium containing 2.2 μm TDZ. Cotyledon-derived callus cultured on medium containing 4.4 μm BA formed ≈16 times more adventitious shoots than on 2.2 μm TDZ. Adventitious shoots derived from cotyledons or callus produced roots when placed on MS medium containing 5.0 μm IBA. Regenerated plants that flowered in the field appeared homogeneous. Chemical names used: N6-benzyladenine (BA), thidiazuron (TDZ), indole-3-butyric acid (IBA).


HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 471B-471
Author(s):  
Agustin Huerta ◽  
Ramon Dolcet-Sanjuan

Adventitious shoots and viable plants were regenerated from bell pepper (Capsicum annuum L.) cultivars and dihaploid lines (DHLs) obtained from F1 hybrids via androgenesis (Dolcet-Sanjuan et al., in press). Hypocotil and cotyledon sections from in vitro-germinated seeds were used as explants. A modified MS medium (Murashige and Skoog, 1962) supplemented with IAA (0 to 3.2 μM) and BAP (0 to 100 μM) was used in a 3-week-long shoot primordia induction phase. Shoot elongation was best performed in the same basal medium, but supplemented with silver thiosulfate and GA3. Shoots were regenerated from eight selected DHLs (`C213', `C215', `C218', `C2123', `C2125', `C3111', `C3113', and `P493') and two cultivars (`Padrón' and `Yolo Wonder'). The percentage of cotyledon sections with shoot primordia after the induction phase was not genotype-dependent and always higher than with hypocotil sections (93.4% and 17.9%, respectively). The number of shoot primordia per responsive cotyledon section was also higher than with hypocotil sections (3.3 and 1.7, respectively). The genotype had a significant effect on the number of shoots regenerated per responsive cotyledon (1.1 to 5.5) or hypocotil (0.5 to 3.5) section. All adventitiously regenerated plants were fertile. This adventitious shoot regeneration protocol is being used to obtain transgenic plants from sweet bell pepper genotypes.


2014 ◽  
Vol 71 (4) ◽  
pp. 269-274
Author(s):  
Andrzej Gatz

Adventitious shoots differentiated directly from explant tissue without intermediate callus on all types of examined explants (shoot tip, cotyledonary node, cotyledon and hypocotyl) of <em>Capsicum annuum</em> L. cv. Bryza. First cell divisions took place as early as after 3 days of explant culture within epidermal and subepidermal layers of explants, and in the case of cotyledon also within mesophyll cells located near epidermis. Mitotic activity in these layers led to the formation of meristemoids (meristematic centres). In all types of studied explants, meristematic centres appeared approximately at the same time (after about 7 days of culture). In the second week bud primordia began to differentiate from meristematic centres. Subsequently some of shoot primordia developed into leaves and leaf-like structures (mainly on cotyledon explants), and also into adventitious buds with well developed apical meristem and leaf primordia.


Plant Science ◽  
1995 ◽  
Vol 110 (1) ◽  
pp. 155-164 ◽  
Author(s):  
A. Wilmink ◽  
B.C.E. van de Ven ◽  
J.B.M. Custers ◽  
Y. Nöllen ◽  
J.J.M. Dons

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