Abstract
Cytokinin activity was indicated in roots of Chrysanthemum morifolium Ramat, cv. Polaris cultured using a nutrient film technique and assayed at 3 stages of plant development: young, actively growing; mature flowering; and senescing with dried flowers.
Gibberellin A3 (GA3: 1, 3, or 5 (μg/shoot), 6N-benzyladenine (BA: 1, 3, or 5 μg/shoot), or both were applied to the flowering shoots of a white hybrid Phalaenopsis orchid (Leda) when they were 2 to 3 cm (stage 1, no flower primordial long at high temperature (30 °C day/25 °C night). When flowering shoots were treated with GA3, alone, deformed flowers were more frequent with increasing GA3 concentrations. The occurrence of GA3-induced deformed flowers was prevented by BA at the same dose as GA3 when applied 4 days after GA3 treatment. BA (1, 3, or 5 μg/shoot) was also applied 4 days before (time 1) or 4 days after (time 2) GA3 (1 (μg/shoot) treatment for regulating plant characteristics. The application of BA at 1 or 5 μg/shoot to stage 1 flowering shoots at time 2 resulted in short internodes between florets, whereas BA application at time 1 had no effect. Simultaneously, BA at 1 or 5 μg/shoot applied at time 1 or time 2 to stage 2 (5 to 6 cm long, two- to three-flower primordia) flowering shoots also shortened internode length between florets as compared to GA3 alone. When a stage 1 flowering shoot was given BA (3 or 5, but not 1 μg/shoot) and then treated with GA3 4 days later, flower count was slightly reduced as compared to treating with (GA3 alone. However, a high dose of BA applied at time 1 or time 2 on stage 2 flowering shoots had no effect on flower count. Chemical names used: N-(phenylmethyl)-lH-purine-6-amine [benzyladenine (BA)], gibberellic acid (GA3).
Abstract
Axillary shoot proliferation from cranberry (Vaccinium macrocarpon Ait.) nodes in vitro was correlated positively with glyphosate [(N-(phosphonomethyl) glycine,(Gly)] and isopentenyladenine (2iP) concentrations. Maximum proliferation was caused by 3.7 × 10−3 m Gly or 1.5 × 10−4 m 2iP. Shoot proliferation was reduced when combined at levels above 1.9 × 10−3 m Gly and 7.4 × 10−5 m 2iP. Gly and 2iP reduced shoot and root dry weight. Indoleacetic acid (IAA) did not significantly affect shoot proliferation or shoot and root growth at concentrations of 5.7 × 10−6 m and 5.7 × 10−5 m. Gly induced basal swelling of shoots and reduced leaf size. These characteristic Gly effects were not altered by 2iP or IAA. Gly may be a useful addendum for in vitro shoot proliferation and a tool for the investigation of meristem initiation and development.
Abstract
Application of 6-(benzylamino)-9-(2-tetrahydropyranyl-9H-purine (PBA); 6-benzylamino purine (BA); and ethyl 5-(4-chlorophenyl)-2H-tetrazole-2-acetate (PP528) to seedlings of Macadamia tetraphylla L. in the greenhouse resulted in sprouting of axillary buds. PBA and BA were more effective than PP528. No axillary buds sprouted on untreated seedlings.
Abstract
Current-year branches in the uppermost whorl of unsheared balsam fir [Abies balsamea (L.) Mill.] trees were dipped 1, 2, or 3 times at weekly intervals in 0, 125, 250, 500, or 1000 ppm BA + 0.5% Buffer-X surfactant, starting every 2 weeks between 9 June and 18 Aug. 1982. BA applied once during June and early July increased lateral bud number and branch diameter in 1982, and increased lateral shoot production while decreasing lateral and whorl shoot elongation in 1983. The degree of response increased with increasing BA concentration, the greatest effect being obtained with 1000 ppm applied on 24 June when untreated branches had attained about 70% of their final length. Multiple applications were no more effective than a single application and caused phy to toxicity. The results indicate that BA application may be a useful method for increasing crown density in balsam fir Christmas trees.
Abstract
Multiple shoots of Chinese chestnut (Castanea mollissima Blume), produced in vitro from axillary buds of juvenile shoots, were successfully rooted and transplanted to the greenhouse. Benzyladenine (BA) at 0.44 μM promoted the proliferation of axillary shoots, but 4.44 μM and 44.4 μM of BA inhibited buds from sprouting and promoted callus growth. Zeatin at 4.56 μM, induced longer and more vigorous shoots than BA, but did not promote the multiplication of axillary shoots. Rooting was achieved by a 1 sec basal dip of excised microshoots in 9.8 mM or 14.8 mM indolebutyric acid (IBA) solution. The treated shoots were transferred to a plant growth regulator-free medium in flasks or to plastic flats containing sand under high humidity. Roots developed within 30 days in both rooting regimes.
Abstract
Protoplasts were isolated from potato Solanum tuberosum L. leaves (‘Russet Burbank’) and plated in cell layers containing either BA, kinetin, or 2iP at concentrations of 0, 0.005, 0.05, or 5.0 mg·liter−1. After 17 days in culture, plating efficiencies were determined and BA at the 0.5 and 0.05 mg· liter−1 concentrations was associated with significantly higher plating efficiencies than the other two sources. The methodology for following development of individual protoplasts is discussed. Chemical names used: N-(phenylmethyl)-1H-purin-6-amine (BA); N-(2-furanylmethyl)-1H-purin-6-amine (kinetin); and N-(3-methyl-2-butenyl)-1H-purin-6-amine (2iP).
BA and GA4+7, were applied to vegetative, mature Rudbeckia hirta plants at the beginning of long days (LD). There were no synergistic effects, but BA inconsistently affected branching and had no effect on flowering. Floral initiation of the terminal inflorescence was promoted by GA4+7, although axillary inflorescences were not. Increasing GA4+7 levels decreased the time to terminal inflorescence anthesis. However, the interval between the terminal and second axillary inflorescence anthesis was increased. The net result was no significant effect on the time to second axillary inflorescence anthesis. Gibberellins may enhance the LD effect on the apical meristem of Rudbeckia, but axillary meristems, which initiate later, remained unaffected. Chemical names used: benzyladenine (BA), gibberellin4+7, (GA4+7).
Benzyladenine (BA) applied postbloom at 125 and 250 mg·liter-1 thinned `Empire' apple (Malus domestica Borkh.) trees below commercial crop levels but thinned less than thidiazuron (THI) at 62 and 125 mg·liter-1. Ethephon (ETH) applied up to 250 mg·liter-1 reduced fruit set only slightly. When BA was tank-mixed with ETH, thinning was the same as with BA alone. Although THI thinned more, BA resulted in a larger increase in fruit weight. Seed development was nearly eliminated by THI, but was unaffected by either BA or ETH. Thinner effects on foliar nutrient concentrations were associated with changes in fruit load but not shoot growth. The effects of BA and ETH on fruit-flesh nutrient concentrations were similar to their effects on foliar nutrient concentrations. Although THI thinned strongly and produced large changes in foliar nutrient concentrations and seed count, THI resulted in virtually no changes in fruit-flesh nutrient concentrations. Chemical names used: N-(phenylmethyl)-1 H-purine-6-amine (benzyladenine); 2-chlorophosphonic acid (ethephon); N-phenyl-N'-1,2,3-thiadiazol-5-ylurea (thidiazuron).