RESUMO

In this study, we successfully cryopreserved cotyledonary somatic embryos of diploid and triploid Arachis pintoi cytotypes using the encapsulation-dehydration technique. The highest survival rates were obtained when somatic embryos were encapsulated in calcium alginate beads and precultured in agitated (80 rpm) liquid establishment medium (EM) with daily increasing sucrose concentration (0.50, 0.75, and 1.0 M). The encapsulated somatic embryos were then dehydrated with silica gel for 5 h to 20% moisture content (fresh weight basis) and cooled either rapidly (direct immersion in liquid nitrogen, LN) or slowly (1 degree C per min from 25 degree C to -30 degree C followed by immersion in LN). Beads were kept in LN for a minimum of 1 h and then were rapidly rewarmed in a 30 degree C water-bath for 2 min. Finally, encapsulated somatic embryos were post-cultured in agitated (80 rpm) liquid EM with daily decreasing sucrose concentration (0.75 and 0.5 M) and transferred to solidified EM. Using this protocol, we obtained 26% and 30% plant regeneration from cryopreserved somatic embryos of diploid and triploid cytotypes. No morphological abnormalities were observed in any of the plants regenerated from cryopreserved embryos and their genetic stability was confirmed with 10 isozyme systems and nine RAPD profiles.

Assuntos

RESUMO

Tropical Ilex species have recalcitrant seeds. This work describes experiments demonstrating the feasibility of long-term conservation of Ilex brasiliensis, I. brevicuspis, I. dumosa, I. intergerrima, I. paraguariensis, I. pseudoboxus, I. taubertiana, and I. theezans through cryopreservation of zygotic rudimentary embryos at the heart developmental stage. The embryos were aseptically removed from the seeds and precultured (7 days) in the dark, at 27 +/- 2 degrees C on solidified (0.8% agar) 1/4MS medium, [consisting of quarter-strength salts and vitamins of Murashige and Skoog (1962) medium] with 3% sucrose and 0.1 mg/l Zeatin.The embryos were then encapsulated in 3% calcium alginate beads and pretreated at 24 h intervals in liquid medium supplemented with progressively increasing sucrose concentrations (0.5, 0.7 5 and 1 M). Beads were dehydrated for 5 h with silicagel to 25% water content (fresh weight basis) and then placed in sterile 5 ml cryovials. Then the beads were either plunged rapidly in liquid nitrogen were they were kept for 1 h (rapid cooling) or cooled at 1 degrees C min(-1) to -30 degrees C. Then the beads were immersed in liquid nitrogen for 1 h (slow cooling). The beads were rewarmed by immersion of the cryovials for 1 min in a water bath thermostated at 30 degrees C. Finally, beads were transferred onto culture medium (1/4MS, 3% sucrose, 0.1 mg/l zeatin, solidified with 0.8% agar) and incubated in a growth room at 27 +/- 2 degrees C under a 14 h light (116 micromol. m(-2) x s(-1))/ 10 h dark photoperiod. Maximum recovery percentages between 15 and 83% (depending on de the species and the treatment) were obtained with the cryopreserved embryos.

Assuntos

RESUMO

Tropical Ilex species have recalcitrant seeds. This work describes experiments demonstrating the feasibility of long-term conservation of Ilex brasiliensis, I. brevicuspis, I. dumosa, I. intergerrima, I. paraguariensis, I. pseudoboxus, I. taubertiana, and I. theezans through cryopreservation of zygotic rudimentary embryos at the heart developmental stage. The embryos were aseptically removed from the seeds and precultured (7 days) in the dark, at 27 +/- 2 degrees C on solidified (0.8% agar) 1/4MS medium, [consisting of quarter-strength salts and vitamins of Murashige and Skoog (1962) medium] with 3% sucrose and 0.1 mg/l Zeatin.The embryos were then encapsulated in 3% calcium alginate beads and pretreated at 24 h intervals in liquid medium supplemented with progressively increasing sucrose concentrations (0.5, 0.7 5 and 1 M). Beads were dehydrated for 5 h with silicagel to 25% water content (fresh weight basis) and then placed in sterile 5 ml cryovials. Then the beads were either plunged rapidly in liquid nitrogen were they were kept for 1 h (rapid cooling) or cooled at 1 degrees C min(-1) to -30 degrees C. Then the beads were immersed in liquid nitrogen for 1 h (slow cooling). The beads were rewarmed by immersion of the cryovials for 1 min in a water bath thermostated at 30 degrees C. Finally, beads were transferred onto culture medium (1/4MS, 3% sucrose, 0.1 mg/l zeatin, solidified with 0.8% agar) and incubated in a growth room at 27 +/- 2 degrees C under a 14 h light (116 micromol. m(-2) x s(-1))/ 10 h dark photoperiod. Maximum recovery percentages between 15 and 83% (depending on de the species and the treatment) were obtained with the cryopreserved embryos.(AU)

Assuntos

RESUMO

In vitro regeneration of shoots from leaf explants of the Paradise tree (Melia azedarach L.) was studied. Three different portions (proximal portion, distal portion and rachis of the leaflets) of three developmental stages (folded, young still expanding and completely expanded) of leaves of 10-15 year old plants of seven genotypes were cultured on Murashige and Skoog (1962) medium (MS) supplemented with 1 mg x l(-1) benzylaminopurine (BAP) + 0.1 mg x l(-1) kinetin (KIN) + 3 mg x l(-1) adenine sulphate (ADS). The rachis of the leaflets of the completely expanded leaves was found to be the most responsive tissue, in most of the genotypes employed. Shoot regeneration occurred in leaf explants of all the genotypes tested. The best genotype for shoot regeneration was clone 4. Rooting was induced on MS medium supplemented with 2.5 mg x l(-1) 3-indolebutyric acid, IBA, (4 days) followed by subculture on MS lacking growth regulators (26 days). Complete plants were transferred to soil.

Assuntos

RESUMO

In vitro regeneration of shoots from leaf explants of the Paradise tree (Melia azedarach L.) was studied. Three different portions (proximal portion, distal portion and rachis of the leaflets) of three developmental stages (folded, young still expanding and completely expanded) of leaves of 10-15 year old plants of seven genotypes were cultured on Murashige and Skoog (1962) medium (MS) supplemented with 1 mg x l(-1) benzylaminopurine (BAP) + 0.1 mg x l(-1) kinetin (KIN) + 3 mg x l(-1) adenine sulphate (ADS). The rachis of the leaflets of the completely expanded leaves was found to be the most responsive tissue, in most of the genotypes employed. Shoot regeneration occurred in leaf explants of all the genotypes tested. The best genotype for shoot regeneration was clone 4. Rooting was induced on MS medium supplemented with 2.5 mg x l(-1) 3-indolebutyric acid, IBA, (4 days) followed by subculture on MS lacking growth regulators (26 days). Complete plants were transferred to soil. (AU)

Assuntos

RESUMO

In vitro regeneration of shoots from leaf explants of the Paradise tree (Melia azedarach L.) was studied. Three different portions (proximal portion, distal portion and rachis of the leaflets) of three developmental stages (folded, young still expanding and completely expanded) of leaves of 10-15 year old plants of seven genotypes were cultured on Murashige and Skoog (1962) medium (MS) supplemented with 1 mg x l(-1) benzylaminopurine (BAP) + 0.1 mg x l(-1) kinetin (KIN) + 3 mg x l(-1) adenine sulphate (ADS). The rachis of the leaflets of the completely expanded leaves was found to be the most responsive tissue, in most of the genotypes employed. Shoot regeneration occurred in leaf explants of all the genotypes tested. The best genotype for shoot regeneration was clone 4. Rooting was induced on MS medium supplemented with 2.5 mg x l(-1) 3-indolebutyric acid, IBA, (4 days) followed by subculture on MS lacking growth regulators (26 days). Complete plants were transferred to soil.

Assuntos

RESUMO

In vitro regeneration of shoots from leaf explants of the Paradise tree (Melia azedarach L.) was studied. Three different portions (proximal portion, distal portion and rachis of the leaflets) of three developmental stages (folded, young still expanding and completely expanded) of leaves of 10-15 year old plants of seven genotypes were cultured on Murashige and Skoog (1962) medium (MS) supplemented with 1 mg x l(-1) benzylaminopurine (BAP) + 0.1 mg x l(-1) kinetin (KIN) + 3 mg x l(-1) adenine sulphate (ADS). The rachis of the leaflets of the completely expanded leaves was found to be the most responsive tissue, in most of the genotypes employed. Shoot regeneration occurred in leaf explants of all the genotypes tested. The best genotype for shoot regeneration was clone 4. Rooting was induced on MS medium supplemented with 2.5 mg x l(-1) 3-indolebutyric acid, IBA, (4 days) followed by subculture on MS lacking growth regulators (26 days). Complete plants were transferred to soil.

RESUMO

In vitro plant regeneration from nodal segments (containing one axillary bud) of seven species of the genus Ilex (I. argentina, I. brevicuspis, I. dumosa, I. microdonta, I. pseudoboxus, I. taubertiana and I. theezans) were readily achieved through three steps: 1) shoot regeneration by in vitro culture of nodal segments in MS medium at 1/4 strength, plus 3% sucrose and 0.65% agar (1/4MS) and 0.5 microM BA (45 days of culture); 2) Induction of rooting from regenerated shoots with 1/4MS (solidified with 2.5 g.L-1 "Phytagel") with 7.3 microM IBA (7 days) and, 3) subculture of shoot on a fresh medium (1/4MS lacking plant growth regulators) during 21 days. Shoot regeneration of other three species (I. aquifolium, I. brasiliensis and I. integerrima) were also obtained by in vitro culture of nodal segments. Shoot regeneration of I. aquifolium, I. brasiliensis, I. integerrima, I. microdonta, I. pseudoboxus, and I. taubertiana were also obtained by culture shoot tips on 1/4MS and 0.5 microM BA. Shoot regeneration from meristems of I. argentina, I. brevicuspis, I. dumosa, and I. theezans were readily achieved by in vitro culture on the same medium.

Assuntos

RESUMO

In vitro plant regeneration from nodal segments (containing one axillary bud) of seven species of the genus Ilex (I. argentina, I. brevicuspis, I. dumosa, I. microdonta, I. pseudoboxus, I. taubertiana and I. theezans) were readily achieved through three steps: 1) shoot regeneration by in vitro culture of nodal segments in MS medium at 1/4 strength, plus 3 sucrose and 0.65 agar (1/4MS) and 0.5 microM BA (45 days of culture); 2) Induction of rooting from regenerated shoots with 1/4MS (solidified with 2.5 g.L-1 "Phytagel") with 7.3 microM IBA (7 days) and, 3) subculture of shoot on a fresh medium (1/4MS lacking plant growth regulators) during 21 days. Shoot regeneration of other three species (I. aquifolium, I. brasiliensis and I. integerrima) were also obtained by in vitro culture of nodal segments. Shoot regeneration of I. aquifolium, I. brasiliensis, I. integerrima, I. microdonta, I. pseudoboxus, and I. taubertiana were also obtained by culture shoot tips on 1/4MS and 0.5 microM BA. Shoot regeneration from meristems of I. argentina, I. brevicuspis, I. dumosa, and I. theezans were readily achieved by in vitro culture on the same medium.(AU)

Assuntos

RESUMO

In vitro plant regeneration from nodal segments (containing one axillary bud) of seven species of the genus Ilex (I. argentina, I. brevicuspis, I. dumosa, I. microdonta, I. pseudoboxus, I. taubertiana and I. theezans) were readily achieved through three steps: 1) shoot regeneration by in vitro culture of nodal segments in MS medium at 1/4 strength, plus 3 sucrose and 0.65 agar (1/4MS) and 0.5 microM BA (45 days of culture); 2) Induction of rooting from regenerated shoots with 1/4MS (solidified with 2.5 g.L-1 "Phytagel") with 7.3 microM IBA (7 days) and, 3) subculture of shoot on a fresh medium (1/4MS lacking plant growth regulators) during 21 days. Shoot regeneration of other three species (I. aquifolium, I. brasiliensis and I. integerrima) were also obtained by in vitro culture of nodal segments. Shoot regeneration of I. aquifolium, I. brasiliensis, I. integerrima, I. microdonta, I. pseudoboxus, and I. taubertiana were also obtained by culture shoot tips on 1/4MS and 0.5 microM BA. Shoot regeneration from meristems of I. argentina, I. brevicuspis, I. dumosa, and I. theezans were readily achieved by in vitro culture on the same medium.

Assuntos

RESUMO

In vitro plant regeneration from nodal segments (containing one axillary bud) of seven species of the genus Ilex (I. argentina, I. brevicuspis, I. dumosa, I. microdonta, I. pseudoboxus, I. taubertiana and I. theezans) were readily achieved through three steps: 1) shoot regeneration by in vitro culture of nodal segments in MS medium at 1/4 strength, plus 3

sucrose and 0.65

agar (1/4MS) and 0.5 microM BA (45 days of culture); 2) Induction of rooting from regenerated shoots with 1/4MS (solidified with 2.5 g.L-1 [quot ]Phytagel[quot ]) with 7.3 microM IBA (7 days) and, 3) subculture of shoot on a fresh medium (1/4MS lacking plant growth regulators) during 21 days. Shoot regeneration of other three species (I. aquifolium, I. brasiliensis and I. integerrima) were also obtained by in vitro culture of nodal segments. Shoot regeneration of I. aquifolium, I. brasiliensis, I. integerrima, I. microdonta, I. pseudoboxus, and I. taubertiana were also obtained by culture shoot tips on 1/4MS and 0.5 microM BA. Shoot regeneration from meristems of I. argentina, I. brevicuspis, I. dumosa, and I. theezans were readily achieved by in vitro culture on the same medium.

RESUMO

Plant regeneration in Arachis pintoi was obtained via two developmental pathways: organogenesis and somatic embryogenesis. Organogenic callus cultures were initiated from pieces of leaf on MS medium supplemented with NAA or 2,4-D in combination with BA, KIN or 2iP. The most suitable combination for plant regeneration through organogenesis was an initial medium composed of 10 mg/l NAA+1 mg/l BA followed by transfer of the callus to a shoot induction medium (MS+1 mg/l BA). Rooting of regenerated shoots was readily achieved by culture on MS+0.01 mg/l NAA. Embryogenic callus cultures were initiated from pieces of leaf on MS medium supplemented with PICL in combination with KIN, ZEA, BA or 2iP, and the most suitable combinations were 20 mg/l PICL+1 mg/l BA or 2iP. When pieces of embryogenic callus were subcultured on MS+1 mg/l BA, somatic embryos were differentiated and developed further into well-developed plants in MS+1 g/l AC followed by MS medium devoid of plant growth regulators.

RESUMO

Plants were regenerated from leaf explants of Centrosema brasilianum cultured in vitro. Callus and buds were produced on Murashige and Skoog medium (MS), 0.8% agar, 0.1 mg/l NAA and 1 mg/l BAP. Regeneration of multiple shoots was achieved by transferring callus onto fresh medium containing 0.01 and 1 mg/l of NAA and BAP, respectively. Shoots formed roots upon transfer to MS with 0.01 mg/l NAA. Plantlets were succesfully transferred to soil. Leaf-derived calli of Centrosema arenarium, C. macrocarpum, C. pascuorum, C. pubescens, and C. virginianum did not produce shoots when cultured in vitro.

RESUMO

In vitro regeneration of plants from both cotyledon-, and leaf - derived calli of Lotononis bainesii Paker was studied under defined nutritional, hormonal and environmental conditions. Explants from both, cotyledons from seedilings of 4 days old and fully expanded leaves from mature plants, were cultured on MS medium containing 0.8% agar and supplemented with 0.01, 0.1, and 1 mg/1 concentrations of naphthaleneacetic acid (NAA) and 0.1, 1, and 3 mg/1 levels of benzyladenine (BA) in various combinations. Multiple shoot (on an average 4 shoots per callus) regeneration from primary callus occurred within 15 to 35 days of culture in most of the media tested. Although the best medium for shoot regeneration from cotyledon-derived callus contained NAA and BA at 1, and 0.1 mg/1 levels, respectively, maximal shoot regeneration from leaf-derived calli was achieved by using NAA and BA at 0.01 and 0.1 mg/1, respectively. Roots were induced to differentiate by transferring the regenerated shoots onto a medium lacking growth regulators.