Showing papers on "Kinetin published in 1991"

Jasmonic Acid Induces Tuberization of Potato Stolons Cultured in Vitro

Abstract: The aim of the study was to assess the potential in vitro effects of jasmonic acid and kinetin on tuberization of potato (Solanum tuberosum). Of the two, the former was by far the stronger in vitro promoter of stolon tuberization. Number of tubers induced per stolon, tuberization rate, and final tuber weight were higher by factors of 2.8, 2.3, and 6.4, respectively. Bioassay sensitivity of jasmonic acid, measured in terms of the point at which the concentration for inducing tuberization was saturating, was more than 20 times greater than that of kinetin. Tuberization in both cases was associated with a decrease in rooting ability. Jasmonic acid also triggered a general state of induction throughout the stolon.

Micro- and Cutting Propagation of Silver Maple. I. Results with Adult and Juvenile Propagules

Abstract: Clonal micropropagation studies with silver maple (Acer saccharinum L.) included experiments with var- ious shoot. explant types, cytokinins, and stock plant maturation levels. These trials led to successful explant estab- lishment, axillary shoot proliferation, rooting of microshoots, and establishment of plantlets in the greenhouse. Overall, the best cytokinin tested was the phenylurea derivative TDZ. Shoot proliferation on juvenile explants was poor with kinetin, 2iP, and BA. Only zeatin at 10 µ M was comparable to TDZ. TDZ at 10 nM was optimal for both juvenile and adult nodal explants. Juvenile explants that were held in vitro for 4 months commonly had at least 60 axillary shoots that could be subculture or excised for rooting. Microshoots rooted within 2 weeks. Following rooting, silver maple plantlets could be transplanted into a growing medium and placed directly onto a greenhouse bench. Studies were also conducted on rooting stem cuttings (macropropagation). Single nodes from juvenile plants rooted under intermittent mist, regardless of auxin application; however, shoot-tip cuttings from adult trees rooted best when auxin in ethanol solution was applied. Chemical names used: N- phenyl- N' -1,2,3 -thiadiazol-5-ylurea (thidiazuron, TDZ), N- (2-furanylmethyl)-1H-purin-6-amine (kinetin), isopentenyladenine (2iP), benzyladenine (BA), (E)-2-methyl-4-(1H-purin- 6-ylamino)-2-buten-1-ol (zeatin). Silver maples are valued in the landscape because of their at- tractive foliage with its typical "maple" shape and silvery under- side, the graceful inverted vase shape of the mature trees, rapid growth that provides summer shade in a reasonably short time, and adaptability to a wide variety of soil types. The rapid juvenile growth rate is an attribute where fast shade is required (Dirr, 1977) and is also desirable in species grown under short-rotation culture conditions for the production of energy (Ranney et al., 1986). -Appropriate selection and documentation of performance for woody biomass species that grow well on secondary farmland are important to the energy future of the United States. As fossil fuels become depleted, renewable resources can be used to con- vert the sun's energy into biomass. Silver maple has been se- lected as a model species for research under the Short Rotation Woody Crops (SRWC) program, sponsored by the U.S. Dept. of Energy's Biofuels and Municipal Waste Technology Divi- sion, because of its rapid juvenile growth and other attributes as a potential woody biomass species (Ranney et al., 1986). Research that uses clonal planting stock offers advantages for the study of tree genotypes, as compared to using seedlings from open-pollinated seed orchards. Individual tree seedlings can present problems because the components of genotype and en- vironment are very difficult to separate when one is attempting to interpret the performance of a particular phenotype. Members of clones are genetically identical and, as such, can allow for

High efficiency plant regeneration from cotyledons of watermelon ( Citrullus vulgaris Schrad)

Abstract: Cotyledons of various ages from seedlings of eight watermelon (Citrullus vulgaris) cultivars were cultured on MS medium supplemented with different combinations of phytohormones. High frequency shoot regeneration (60.0–92.0%) was induced from 5-day-old cotyledons of cultivars cultured on MS medium containing 5.0 mg/l 6-benzylaminopurine (BA) and 0.5 mg/l indole-3-acetic acid (IAA). Multiple shoot buds elongated on MS medium containing 0.2 mg/l kinetin (KT) and 5–10 shoots per expiant could be recovered depending on the cultivars. Elongated shoots rooted on MS medium with 0.1 mg/l α-naphthalene acetic acid (NAA). Zeatin riboside (ZT) had a similar efficiency as BA in shoot induction, and it was significantly more functional than 2-isopentenyladenine (2iP) or kinetin (KT). Cotyledons from 5-day-old seedlings were the most responsive to shoot induction.

Rapid in vitro propagation of Aloe barbadensis Mill

Abstract: Axillary bud development and adventitious bud formation was obtained with decapitated shoot explants of Aloe barbadensis Mill. Maximal bud growth and rooting of shoots was obtained on a modified medium of Murashige and Skoog supplemented with 5 μM IBA. More adventitious and axillary buds developed on nutrient media supplemented with IBA than with NAA. Axillary buds but not adventitious buds developed with IAA in the medium. Morphogenesis was inhibited by 2,4-D. Kinetin, benzyladenine and thidiazuron were toxic to the explants and did not stimulate the development of axillary of adventitious buds. The optimal temperature for bud growth and development was 25°C. Axillary bud growth and the formation of adventitious buds was slowed down at 10°C and totally inhibited by 30°C. The optimal sucrose concentration was 3% with the inhibition of bud growth and development by higher sucrose levels.

Effect of plant growth regulators on somatic embryogenesis in leaf cultures of Coffea canephora.

Abstract: The effects of plant growth regulators on somatic embryogenesis were studied in leaf cultures of Coffea canephora. The maximum number of somatic embryos were obtained on media that contained only cytokinin as a plant growth regulator. All of the auxins tested (NAA, IBA, IAA and 2, 4-D) inhibited the formation of embryos. The optimal concentration of each cytokinin (2-iP, BA and kinetin) for somatic embryogenesis was 5 μM. Under optimal conditions, each explant formed more than 100 embryoids with little callus and few adventitious roots. Embryoids were formed only at the cut edges of the leaf discs. Cytokinins were absorbed only at the cut edges of leaf discs that were in contact with the medium, and were not transported to other parts of the explant.

Low sugar and osmotic requirements for shoot regeneration from leaf pieces of Solanum melongena L.

Abstract: Uniform leaf pieces of egg-plant, Solanum melongena L., were cultured in Murashige and Skoog's medium containing 2 mg l-1 kinetin and varying sugar levels. Glucose or fructose at 44 mM was optimal in inducing shoot regeneration compared to sucrose. Sucrose at 11 and 22 mM induced more shoot organogenesis than at lower or higher levels. An additional 22 mM mannitol with 22 mM sucrose enhanced shoot regeneration significantly more than 22 mM sucrose alone. The dual role of sugar as carbon and osmotic source in shoot regeneration from leaf explants of egg-plant is discussed.

Plant regeneration from stem and petal of carnation ( Dianthus caryophyllus L.)

Abstract: Plants were regenerated via adventitious shoot initiation from petal explants of carnation (Dianthus caryophyllus L.) cultivars Crowley Sim, Ember Rose, Orchid Beauty, Red Sim, White Sim and from stem segments of Crowley Sim, Red Sim, White Sim. Differences in cultivar response were observed, with White Sim being the most responsive for both explant types. Plants were also regenerated from receptacles of this cultivar. The effect of different cytokinins on regeneration from petal and stem explants of cultivar White Sim was compared. Thidiazuron was more effective than 6-benzylaminopurine or kinetin. In stem explants, morphogenic capacity was determined by the developmental stage of the explant. Highest percentage of shoot formation was observed in the youngest stem segments, on all the cytokinins tested. Stem-derived plants grew faster than petal or receptacle-derived plants and produced normal, flowering plants eight to ten months after culture.

Growth regulator and axillary bud position effects on in vitro establishment of Vitis rotundifolia

Abstract: Four muscadine grape (Vitis rotundifolia Michx.) cultivars (Carlos, Noble, Regale, and Tarheel) were evaluated for their ability to be cultured in vitro. Axil1ary buds were placed on Murashige and Skoog medium as modified by Chee. Different levels of benzylaminopu rine ((BA) 0.5 to 10.0 µ M), kinetin ((KIN) 0.5 to 5.0 µM), and thidiazuron ((TDZ) 0.5 to 11.3 µM), and different explant positions were evaluated for their effect on in vitro explant establishment and shoot production. Thidiazuron (2.3 to 4.5 µM) alone or in combination with BA (1.0 to 5.0 µ M) or KIN (1.0 or 5.0 µM) was effective for establishing axillary buds. Similar levels were also effective for pro- moting shoot proliferation. Explants originating from the 10 basal nodes of a shoot with at least 25 nodes gave better shoot proliferation than explants originating from the 10 distal nodes. Chemical names used: 6-benzylaminopurine, 6-furfurylaminopu. rine (kinetin):N -phenyl- N'- l,2,3 -thiadiazol-5-y lurea (thidiazuron).

Nodule culture and regeneration of Eucalyptus grandis hybrids.

Abstract: Callus of three superior Eucalyptus grandis hybrids was induced from immature inflorescences, floral parts, shoot tips, zygotic embryos, and hypocotyl explants on various auxin (2,4-D or NAA) and cytokinin (kinetin) supplemented media Hypocotyl callus initiated on 4 mg/l NAA and 1 mg/l kinetin formed massive nodular structures, and shoots and roots after four weeks on hormone free-medium Callus from all other expiants turned brown and died upon transfer to hormone free or reduced hormone media The nodular structures originating from hypocotyl-callus were maintained by subculture for over three years and retained the ability to form thousands of shoots Shoots were successfully rooted (98% rooting) and plantlets developed were transferred to mist-greenhouse and then to greenhouse conditions with 95% survival Plantlets were grown for six months in the greenhouse without sign of abnormal growth

Plant Regeneration and Genetic Variability from Tissue Cultures of Sunflower (Helianthus annuus L.)

Abstract: Adventitious buds were induced from in vitro culture of sunflower (Helianthus annuus L) cotyledons Four inbred lines (G1, G2, G3 and HA89), an open pollinated variety (‘Argentario’) and two hybrids with specific genetic markers were used Cotyledons were cultured in vitro on MS medium (Murashlge and Skoog 1962) containing various concentrations of kinetin and indole 3-acetic acid (IAA) The quantitative interactions between auxin and cytokinin, the age of the cotyledons and the 2,3,5-triiodobenzoic acid (TIBA) treatments have been found to influence shoot regeneration The plantlets, after rooting, were successfully established on soil Qualitative variation was noted in self-pollinated progeny of plants regenerated from culture of two inbreds Chimerism in regenerated plants was indicated by sectoring of the genetic markers Some culture-induced variant phenotypes were similar to known spontaneous mutation in sunflower but others have been not yet described Preliminary data indicate that most of them may have single-gene recessive inheritance

Changes in Cytokinins before and during Early Flower Bud Differentiation in Lychee (Litchi chinensis Sonn.)

Abstract: Lychee (Litchi chinensis) has been analyzed for cytokinins in buds before and after flower bud differentiation, using reversephase high performance liquid chromatography in combination with Amaranthus bioassay and gas chromatography-mass spectrometry-selected ion monitoring. Four cytokinins, zeatin, zeatin riboside, N6-(δ2-isopentenyl)adenine, and N6-(δ6-isopentenyl) adenine riboside, were detected in buds. There was an increase of cytokinin activity in the buds during flower bud differentiation. In dormant buds, the endogenous cytokinin content was low, and the buds did not respond to exogenous cytokinin application. Application of kinetin promotes flower bud differentiation significantly after bud dormancy. These results are interpreted as an indication that the increase in endogenous cytokinin levels during flower bud differentiation may be correlative rather than the cause of flower bud initiation.

In vitro plant regeneration via somatic embryogenesis from root culture of some rhizomatous irises

Abstract: A method for plant regeneration of Iris via somatic embryogenesis is described. Root and leaf pieces from in vitro-grown plants of several genotypes of rhizomatous Iris sp. were cultured in vitro. Callus induction occurred only on root cultures incubated under low light intensity (35 μmol m-2 s-1) on two induction media containing 2,4-D (4.5 or 22.5 μM), NAA (5.4 μM) and kinetin (0.5 μM). Somatic embryos developed after transfer of callus onto four regeneration media containing 9 or 22 μM BA, or 5 μM kinetin and 2 μM TIBA or 9 μM BA and 4 μM TIBA. Plantlets could be obtained from these somatic embryos. Genotypic differences were found both in callus induction and somatic embryo formation, with I. pseudacorus responding better than I. versicolor or I. setosa. Cytological analysis performed on root tips of 80 regenerated plants revealed that two of the I. pseudacorus regenerants were tetraploid.

Culture conditions for induction of green plants from barley microspores by anther culture methods.

Abstract: With barley a large variation in frequency of plant formation from microspores of spikes from the same plant has been observed. The highest frequency of plant formation was obtained when culturing anthers in the dark on a high Ficoll medium containing 2,4-D and kinetin to induce proembryo (or callus) formation. Subsequently the proembryos or calli were cultured in dim light on a high Ficoll-high sugar medium containing IBA and kinetin. Finally the embryos were transferred to a starch agar medium. A maximum of 13 green plants were obtained from microspores of a single anther.

Shoot, root and flower morphogenesis on tomato inflorescence explants

Abstract: Regeneration of de novo shoots, roots and flowers has been obtained on inflorescence explants of tomato (Lycopersicon esculentum Mill.). Indole-3-acetic acid (IAA), indole-3-butyric acid (IBA) and α-naphthaleneacetic acid (NAA) were added in a 3×3×3 factorial combination with kinetin, each at 0.001, 0.1 and 10 μM concentrations. Direct shoot formation occurred on media with 10 μM kinetin and 0.001 μM IAA or NAA. Root formation was observed on media with 0.1–10 μM IAA, IBA or NAA. Flower formation occurred on elongated shoots with several leaves on media with 10 μM IAA and 0.1 μM kinetin. Shoot organogenesis was increased by substituting 10 μM zeatin or N6-benzyladenine (BA) for kinetin. Eleven tomato cultivars were tested for their ability to undergo de novo shoot regeneration on the improved medium. All tomato cultivars were capable of shoot morphogenesis with a mean number of shoots per explant that ranged from 1.3 (‘Red Alert’) to 5.3 (‘Large Red Cherry’). Histological studies revealed that active cell divisions occurred in subepidermal and cambial tisue during the first week of culture. Meristematic centers of dividing cells were evident by day 14, and well-developed shoot apices and leaf structures were observed on 50% of the explants 28 days after culture initiation.

Effects of synthetic cytokinins on levels of endogenous cytokinins and respiration patterns of Beta vulgaris cells in suspension

Abstract: Respiration patterns and growth of cytokinin-dependent cell suspensions ofBeta vulgaris L., precultured in media with or without three different synthetic cytokinins [benzyladenine (BA), kinetin (KIN), and thidiazuron (TDA)], were compared. The content of endogenous cytokinins, especially zeatin and isopentenyladenine, as well as the dry mass yield, were dependent on the kind of synthetic cytokinin present in the culture medium and decreased in the following order: thidiazuron, kinetin, benzyladenine, no cytokinin. The apparent capacity of the alternative pathway, as measured after blocking of the cytochrome pathway by cyanide, was inversely proportional to the content of endogenous cytokinins. Some synthetic cytokinins (e.g., benzyladenine), when exogenously applied, are known to inhibit selectively the alternative pathway. However, this does not necessarily imply that the mechanism of action of endogenous cytokinins on the respiration pattern is limited to a single effect on the alternative pathway. Multiple effects on oxidative processes cannot be excluded.

In vitro culture of adult and juvenile bud explants of Passiflora species

Abstract: Cultivar E23, an F1 hybrid of P. edulis and P. edulis f. flavicarpa is usually propagated by shoot-tip grafting. Various media were tested to evaluate the potential of E23 for in vitro propagation. Adult tissue was difficult to culture and did not respond to media containing low (<10 µM) concentrations of growth regulators. Growth of adult buds on intact stem sections was promoted by 1 week of dark incubation on MS basal medium plus 150 µM 2iP, 200 µM adenine sulphate and 17.1 µM IAA (3 mg l−1), and further developed into shoots on MS medium plus 4.9 µM 2iP (1 mg l−1) and 5.7 µM IAA (1 mg l−1). By contrast, juvenile shoots of E23, and Passiflora species: edulis f. flavicarpa, edulis, alata, caerulea, mollissima, coccinea, herbertiana and suberosa grew rapidly on MS medium plus 10 µM kinetin and 5 µM IAA. Rapid multiplication was achieved on MS plus 20 µM BA, 10 µM kinetin, 5 µM IAA, and roots initiated on MS plus 5 µM IAA.

Somatic embryogenesis and plant regeneration of squash Cucurbita pepo L cv. YC 60

Abstract: Plant regeneration from tissue cultures of summer squash, Cucurbita pepo L., cv. YC60, has been observed. Somatic embryos organized from shoot apex derived callus cultured on Murashige and Skoog (MS) medium supplemented with 1.2 mg/l 2,4,5-trichlorophenoxyacetic acid, 0.8 mg/l benzylaminopurine, and 0.1 mg/l kinetin. Embryos developed into plantlets by transfer of immature somatic embryos to MS medium with 0.05 mg/l NAA and 0.05 mg/l kinetin. Regenerated plants appeared morphologically normal and set fruits with seeds which could germinate normally.

Somatic embryogenesis in asparagus: the role of explants and growth regulators

Abstract: The explant used to initiate embryogenic callus and the growth regulators used in subsequent induction (IM) and embryo development media (EDM) both influenced rate of somatic embryo development and conversion to plantlets in asparagus. Embryogenic callus derived from spear-cross sections (SS), in vitro crowns (IVC) and lateral buds (LB) was cultured on IM of MS salts and vitamins with 2, 4-D or NAA at 0, 0.01, 0.1, 1.0 or 10 mg/l and kinetin at 0, 0.1, 1.0 or 10 mg/l. The auxin 2,4-D at 1–10 mg/l, in combination with kinetin at 0–1 mg/l, in IM induced the highest frequency of embryos after four weeks; callus derived from SS, IVC and LB had means of 394, 382, and 344 small globular embryos, and 4, 11 and 9 bipolar embryos per gram of callus, respectively. After 6 weeks on EDM, 128, 116 and 51 bipolar embryos (4–7 mm in length) occurred per gram callus and 4.5, 1.4 and 2.1 embryos converted for IVC, SS and LB, respectively. NAA at 1–10 mg/l, in combinations with kinetin 0–1 mg/l, yielded means of 64, 175 and 225 small globular embryos per gram callus on IM for SS, IVC and LB, respectively. NAA promoted a higher rate of embryo development: means of 27, 54 and 91 bipolar embryos per gram callus for SS, LB and IVC, respectively, on EDM. There were 0.5, 9.4 and 11.9 plantlets from these respective callus sources. There was no difference between kinetin levels of 0–1 mg/l on callus growth and embryogenesis, whereas, 10 mg/l in IM was inhibitory.

In vitro studies of the submerged angiosperm Ruppia maritima : auxin and cytokinin effects on plant growth and development

Abstract: Axenic tissue cultures ofRuppia maritima L. were established and propagated clonally in vitro from terminal rhizome segments collected from Tampa Bay, Florida, USA. Cultures were maintained in a base medium consisting of synthetic seawater supplemented with half-strength Murashige and Skoog salts and 1% sucrose at pH 5.6. The effects of five cytokins [6-furfurylaminopurine (kinetin), 6-benzylaminopurine (BAP), 2-isopentyladenine (2iP), 6-(4-hydroxy-3-methyl-but-2-enylamino) purine (zeatin), andn-phenyl-n′-1,2,3-thidiazol-5′yl urea (thidiazuron)] and one auxin [napthalene acetic acid (NAA)] on explant growth and development were investigated. Cytokinin additions resulted in a 3- to 4-fold increase in nodal production, branching, and biomass ofR. maritima after 12 wk in culture. Cultures responded in a dose-dependent manner to 2iP but exhibited broad dose-response curves to kinetin, BAP, zeatin, and thidiazuron. NAA addition resulted in increased leaf and internodal lengths, but reduced the number of leaves per node and the rhizome biomass. The addition of NAA almost completely suppressed root growth in media without cytokinins and had an antagonistic effect on nodal production and branching in cytokinin-supplemented media.

High frequency of plant regeneration from hypocotyl explants of Brassica carinata A. Br.

Abstract: An efficient tissue culture system for high frequency of plant regeneration from hypocotyl explants of Brassica carinata was developed via manipulation of culture medium and selection of explants. Explants grown on medium containing combinations of 2 mg l-1 BA and 0.01 mg l-1 NAA or 4 mg l-1 kinetin and 0.01 mg l-1 2,4-D regenerated shoots at 100% frequency. High frequency shoot regeneration occurred only from explants originating from 6 to 7-day-old but not younger or older seedlings. Explants showed higher regeneration capacity at the distal end than the proximal end, and the upper segment was more regenerative than the lower segment of hypocotyl. Regenerants were rooted on half-strength growth regulator-free medium, acclimatized and developed into normal, fertile plants.

Agrobacterium rhizogenes Mediated Transformation of the Forage Legumes Medicago sativa and Onobrychis viciifolia

Abstract: Three cultivars of M. sativa and one cultivar of 0. viciifolia were evaluated for their response to inoculation with A. rhizogenes strain A4T (containing pRiA4b). A cultivar-dependent response was observed in M. sativa with 94%, 25%, and 4% of infected stem expiants producing transformed roots in the cultivars Vertus, Regen-S, and Rangelander, respectively. In O. viciifolia cv. Hampshire Giant, an explant-dependent response was observed with 78% and 50% of seedling cotyledon and hypocotyl expiants responding, respectively. Leaf expiants failed to produce transformed roots. Transformed roots showed plagiotropic and negatively geotropic growth on hormone-free agar MS medium. Production of transgenic shoots from O. viciifolia root cultures occurred spontaneously. Recovery of transgenic plants from M. sativa cv. Rangelander was achieved by transfer of callus (induced on UM medium containing 2 0 mg dm"3 2,4-D and 0-25 mg dm"3 kinetin) to MS medium containing 0-5 mg dm"3 BAP and 0 05 mg dm"3 NAA. Cultured roots of both species synthesized opines (agropine and mannopine). Extensive morphological variation was observed in plants of M. sativa (clone Al) and O. viciifolia (clone A4T1) established in the glasshouse. DNA sequences homologous to TL-DNA and TR-DNA were present in root clones and regenerated plants.