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  • Author or Editor: Frank A. Blazich x
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Abstract

Many studies have been reported on the propagation of Ilex species by stem cuttings (1, 2, 3, 4, 5) but none have appeared on the influence of ambient temp on the rooting process. The following investigation was undertaken to study the effects of 3 ambient temp on rooting holly stem cuttings.

Open Access

Two experiments investigated the relationship of light and temperature in seed germination of Fraser fir [Abies fraseri (Pursh) Poir.]. Irradiation during the warm portion of 9/15 hr thermoperiod of 20/10C and 30/20C increased germination percentages after 42 days, and the degree of stimulation depended on the timing of the light exposures. A 1-hr exposure was most effective during the latter part of the warm portion of the thermoperiods, and varying the time of irradiation had the greatest effect at 20/10C. The involvement of phytochrome in this photomorphogenic response was ascertained by demonstration of red/far-red reversibility.

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Cones of six provenances (Escambia Co., Ala., Santa Rosa Co., Fla., Wayne Co., N.C., Burlington Co., N.J., New London Co., Conn., and Barnstable Co., Mass.) of Atlantic white cedar [Chamaecyparis thyoides (L.) B. S. P.], were collected Fall 1994 (Alabama, North Carolina, New Jersey, and Connecticut), Winter 1995 (Massachusetts), or Fall 1995 (Florida). Cones were dried for 2 months, followed by seed extraction and storage at 4°C. Seeds were then graded and stratified (moist-prechilled) for 0, 30, 60, or 90 days. Following stratification, seeds were placed at 25°C or an 8/16-hr thermoperiod of 30°/20°C with daily photoperiods of 0, 1, or 24 hr. Germination was recorded every 3 days for 30 days. Temperature, stratification, and light had significant effects on germination. However, responses to these factors varied according to provenance. Averaged over all treatments, the Alabama provenance exhibited the greatest germination (61%), followed by the Florida provenance (45%), with the remaining provenances ranging from 20% to 38%. However, there were specific treatments for each provenance that resulted in germination > 50%. The three southern provenances (Alabama, Florida, and North Carolina) required 30 days of stratification for maximum germination. They did not exhibit an obligate light requirement, but photoperiods ≥ 1 hr increased germination greatly over seeds in darkness. In contrast, the northern provenances (New Jersey, Connecticut, and Massachusetts) had an obligate light requirement. These provenances only required 30 days stratification with continuous light for maximum germination. When subjected to a 1-hr photoperiod, seeds from the northern provenances required longer durations of stratification for maximum germination. Regardless of the length of stratification, the New Jersey provenance required a 24-hr photoperiod to maximize germination. When averaged over all treatments, total germination for each provenance was greater at 30°/20°C than 25°C (43% vs. 31%).

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Seeds of six provenances (Escambia Co., Ala.; Santa Rosa Co., Fla.; Wayne Co., N.C.; Burlington Co., N.J.; New London Co., Conn.; and Barnstable Co., Mass.) of Atlantic white-cedar [Chamaecyparis thyoides (L.) B.S.P.] were stratified (moist-prechilled) for 0, 30, 60, or 90 days at 4 °C. Following stratification, seeds were germinated at 25 °C or an 8/16-hour thermoperiod of 30/20 °C with daily photoperiods at each temperature of 0 (total darkness), 1, or 24 hours. The germination of nonstratified seed did not exceed 18%. Seeds germinated at 25 °C required 60 to 90 days stratification to maximize germination. In contrast, 30 days stratification maximized germination at 30/20 °C. Regardless of stratification duration, germination was generally lower at 25 °C than at 30/20 °C for each provenance. Averaged over all treatments, seeds of the Alabama provenance exhibited the greatest germination (61%), followed by those from Florida (45%), with the remaining provenances ranging from 20% to 38%. However, specific treatments for each provenance induced germination >50%. Germination of seeds not exposed to light was <8%, in contrast with 48% and 55% germination for daily photoperiods of 1 and 24 hours, respectively. Seeds from each of the provenances, except for Alabama, exhibited an obligate light requirement when germinated at 25 °C. At 30/20 °C, the North Carolina, New Jersey, Connecticut, and Massachusetts provenances required light for germination, whereas the Alabama and Florida provenances did not.

Free access

Abstract

Eastern white pine (Pinus strobus L.) and Japanese black pine (Pinus thunbergii Pari.) seedlings were grown under 4 photoperiods with 5 rates of 18N-2.6P-10.0K (18N-6P205-12K2O) Osmocote fertilizer applied at radicle emergence. Seedlings of both species grown under 16 and 20 hour photoperiods at fertilizer rates of 1.78 and 3.56 kg/m3 were taller and had greater dry weight than seedlings grown under 8 and 12 hour photoperiods and higher rates of fertilizer (5.34 and 7.12 kg/m3). With both species, short days inhibited height growth and dry weight accumulation and this effect could not be overcome by increasing the fertilizer rate.

Open Access

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.

Open Access

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.

Open Access

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.

Open Access

Abstract

Rooting of Fraser fir [Abies fraseri (Pursh) Poir.] stem cuttings decreased as stock plant age increased from 5 to 12 to 22 years. Indolebutyric acid (IBA) at 5000 ppm increased rooting of cuttings from 12- and 22-year old trees.

Open Access

Abstract

Leaves, upper stems and lower stems of Ilex crenata cv. Convexa cuttings were analyzed for N, P, K, Ca, and Mg at 3 day intervals for 27 days during intermittent mist propagation. No mobilization of nutrients from the upper portions of a cutting into the base was noted during the root initiation period.

Open Access