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- Author or Editor: Charles W. Heuser x
Abstract
Tissue culture propagation of Lythrum virgatum L. cv. Morden Pink was achieved from shoot tips using a modified Murashige and Skoog (MS) high salts medium. 6-Benzylamino purine (BA) at 3.0 mg/liter and naphthaleneacetic acid (NAA) at 0.1 mg/liter were optimal for shoot production. Proliferated shoots rooted and established 96% in a soilless medium under high humidity.
Abstract
The effects of the cyanogenic glycosides, amygdalin and prunasin, and their breakdown products, cyanide and benzaldehyde, on callus derived from ‘Marianna 2624’ plum (Prunus cerasifera Ehrh. × P. munsoniana Wight & Hedr.) and on that from 2 almond cultivars (P. amygdalus Batsch ‘Nonpareil’ and ‘Texas’) were compared. Prunasin (D-Mandelonitrile-β-D-glucoside) inhibited the growth of ‘Marianna 2624’ plum and ‘Nonpareil’ almond callus but not ‘Texas’ almond. Amygdalin (D-Mandelonitrile-β-D-gentiobioside) inhibited ‘Marianna 2624’ plum callus growth but promoted growth of both almond cultivars. All 3 cultivars were inhibited to the same extent by sodium cyanide, indicating that cyanide was not the differentiating inhibitory breakdown product of the cyanogenic glycosides. Benzaldehyde, another catabolite of prunasin and amygdalin, was strongly inhibitory to ‘Marianna 2624’ plum callus growth at 0.05 mm, but a concentration of 5 mm was required to inhibit similarly growth of either almond callus. The greater sensitivity of ‘Marianna 2624’ plum callus, compared to almond callus, to the cyanogenic glycosides and benzaldehyde, but not cyanide, suggests that benzaldehyde is an important factor in the almond/plum incompatibility.
Abstract
Etiolated mung bean seedlings, Phaseolus aureus Roxb., when decapitated below the cotyledons show a linear decrease with time in root initiation. The decrease does not result from a loss of endogenous auxin because IBA fails to prevent the loss. Three root promoting compounds were found in an ethanolic extract of the hypocotyl tissue, but the level of the compounds could not be consistently related to the decrease in root initiation. Glucose, fructose and sucrose are the major sugars present in the hypocotyl tissue. Total sugar decreased in a linear manner with 2.0 mg lost during the 48-hr treatm ent period. Fifty percent of the decrease in root initiation could be regained by application of glucose or fructose. Total phenolic compounds decreased 20% during decapitation but their contribution to root formation was not determined because they were not purified.
Abstract
Flower longevity (as influenced by stage of maturity at harvest), dry weight, and flower preservative were studied using cut flowers of herbaceous peony (Paeonia spp.) cultivars Felix Crousse, Festiva Maxima, John C. Lee, Mons. Jules Elie, and Richard Carvel. Flowers harvested in the tight calyx stage frequently failed to open or opening was delayed. No substantial difference in longevity between flowers harvested at the loose calyx stage or first loose petal stage was found. Those cut at the loose calyx stage maintained quality well during dry storage at 0°C for up to 4 weeks. Vase-life and days to opening differed significantly with cultivar, length of storage, and their interaction. Fresh weight increased before or during flower opening, and the increase was greater after storage than for unstored flowers. Inclusion of a floral preservative in the vase solution increased gain in fresh weight upon hydration after storage and weight throughout vase-life.
Abstract
Three lipid-like root-promoting compounds were isolated from the easy-to-root juvenile form of English ivy, Hedera helix L. The purification procedure involves extracting with methanol-chloroform and chromatography on columns of charcoal-celite, silica gel and LH-20 Sephadex. Ultraviolet and infrared spectroscopic studies suggest the presence of alcohol and nitrile functional groups. The 3 compounds are unstable and the instability is greatest when the substances are purified. In the purified state, the lipid-like compounds are colorless but become orange-yellow after breakdown. A loss of root-promoting activity occurs with the color change.
Abstract
Ethylene liberated from control and auxin-treated cuttings of Vigna radiata (L.) R. Wilcz cv. Berken was monitored for 14 hours. For root initiation, naphthaleneacetic acid (NAA) and indolebutyric acid (IBA) were the most effective with indoleacetic acid (IAA) intermediate and 2,4-dichlorophenoxyacetic (2,4-D) the least effective. No correlation was observed between the quantity of auxin-induced ethylene evolved and the number of roots formed. Decreasing the NAA solution pH from 7.0 to 3.0 reduced the evolution of ethylene but did not alter the rooting response of the cuttings. It was concluded that stimulation of adventitious root initiation by auxin is not mediated by ethylene.
Abstract
Adventitious root initiation decreased in ‘Berken’ mung bean cuttings treated with ≥ 10−4 m (2-chloroethyl) phosphonic acid (ethephon). Ethephon at 10−3 but not 10−5 m reduced root length and caused a redistribution of roots along the hypocotyl. The application of ethephon in combination with indoleacetic acid (IAA), indolebutyric acid (IBA), naphthaleneacetic acid (NAA), and 2,4-dichlorophenoxyacetic acid (2,4-D) reduced root initiation. An initial treatment of ethephon followed by NAA, or NAA followed by ethephon, inhibited root initiation to the same degree. Ethephon—whether applied at the time of cutting preparation or up to 12 hours later—inhibited root initiation to the same extent.
Abstract
Selected putative inhibitors of ribonucleic acid (RNA) synthesis (actinomycin D and 6-methylpurine) or protein synthesis (cycloheximide and puromycin) were examined for their effects on root formation in mung bean (Vigna radiata (L.) R. Wilcz.) cuttings in the presence or absence of naphthaleneacetic acid (NAA). Only 6-methylpurine completely inhibited root formation at concentrations that did not cause visible injury. Cycloheximide was most inhibitory when applied at the same time as NAA. Application of 6-methylpurine up to 12 hours after NAA uptake completely blocked root formation; thereafter its effect declined with time. This decline in response was correlated with enlargement of the nucleus and nucleolus in hypocotyl cells preparatory to cell division.
Abstract
Inconsistent results obtained with the mung bean (Phaseolus aureus Roxb.) rooting bioassay led to a reexamination of procedures. Autoclaving the double distilled water used completely eliminated the inconsistent results, but boiling and filter sterilization were not completely satisfactory. A decrease in rooting of both control and auxin-treated cuttings was noted in seedlings older than 10 and 9 days respectively. Adventitious roots were initiated within 5 days; incubation for 2 additional days did not increase rooting response. Increasing irradiance from 380 to 4080 μW/cm2 decreased rooting of both control and auxin treated cuttings.
Abstract
A histological study of the initiation and development of adventitious roots in lightgrown cuttings of mung bean (Phaseolus aureus Roxb.) showed that cell divisions leading to adventitious root initiation occurred 20–24 hours after the cuttings were taken. Cell divisions began at the same time for control and naphthaleneacetic acid (NAA) treated cuttings indicating that NAA did not alter the timing of root initiation. The root primordia for both were well developed by 48 hours and the roots began to emerge by 72 hours. Intracellular changes in the cells destine for the initial divisions first became visible histologically at 12 hours. By 16 to 20 hours considerable intracellular change was observed, including enlargement of the nuclei and nucleoli and an increase in apparent cytoplasmic staining density.