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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

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%).

Free access

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.

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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

Abstract

Leaf explants of Sansevieria trifasciata Prain (snake plant) cultured in vitro on a modified Murashige and Skoog medium containing 0.25 mg/liter 2,4-dichlorophenoxyacetic acid (2,4-D) produced masses of meristemoids. The meristemoids formed shoots when the explants were transferred to a similar medium containing 0.3 mg/liter 6-furfurylam ino purine (kinetin). Shoots were rooted in vitro or under intermittent mist and grown as plants which appeared normal in vegetative characteristics to the parent plant.

Open Access

Hypocotyl cuttings were prepared from Ii-week-old aseptically grown seedlings of Fraser fir [Abies fraseri (Pursh) Poir.] and cultured 18 days on media containing 0 to 40 mg IBA/liter followed by transfer to the same medium without auxin. Greatest rooting (66%) occurred after treatment with 20 mg IBA/liter, whereas the greatest number of roots per rooted cutting (7.4) was noted following treatment with 40 mg·liter-1. Chemical name used: 1H-indole-3-butyric acid (IBA).

Free access

Adventitious shoots developed on cotyledons of Virginia pine (Pinus virginiana Mill.) excised from seeds germinated for 3, 6, or 9 days and cultured on media containing 0.5 to 10 mg/liter benzyladenine (BA). Shoot regeneration was greatest (46 shoots per embryo) on cotyledons from seeds germinated for 6 days and placed on medium containing 10 mg/liter BA. Shoots were excised and elongated on medium lacking BA. Following elongation, shoots were placed on media containing 0 to 40 mg/liter indolebutyric acid (IBA) for 14 days followed by transfer to the same medium lacking auxin. Without IBA treatment, percent rooting was 3% and increased to 50% for concentrations of 5 to 40 mg/liter. Rooted shoots averaged 2.0 roots per shoot without auxin treatment, 3.3 roots when treated with 5 mg/liter IBA and root number increased linearly with increased IBA concentration up to 40 mg/liter (4.5 roots). Plant lets were transferred to growing medium and acclimated successfully to greenhouse conditions.

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Hedged stock plants of four full-sib families [27-2 × 27-5, 27-3 × 27-1, 27-2 × 27-1, and 27-6 × 27-1 (designated B, G, R, and W)] of loblolly pine (Pinus taeda L.) were fertilized daily with a complete nutrient solution containing N at 10, 25, 40, 55, or 70 mg·L–1. In May, terminal softwood stem cuttings were taken and placed under intermittent mist. Families were combined to form composite poor-rooting (BR) and good-rooting (GW) families. At 0, 3, 6, 9, and 12 weeks after sticking, cuttings were evaluated for rooting and analyzed for mineral nutrient and carbohydrate content. Percent rooting by week 12 for cuttings from stock plants receiving N between 25 to 70 mg·L–1 was 28% to 33%, whereas significantly fewer (17%) cuttings from plants receiving 10 mg·L–1 had rooted. By week 12, 98% of cuttings taken from stock plants receiving N at 10 mg·L–1 were alive, while significantly fewer (81% and 82%) of the more succulent cuttings receiving 55 and 70 mg·L–1, respectively, had survived. Nearly all increases in cutting height occurred within the first 3 weeks. In contrast, top dry weight increased steadily throughout the experiment. There were no significant differences in rooting between the two composite families until week 12, when 32% of cuttings from family GW had rooted compared with 24% for family BR. Survival of cuttings was greater for the poor-rooting family (BR) (94%) than for the good-rooting family (GW) (82%) after 12 weeks. Levels of total nonstructural carbohydrates (TNC) and individual soluble sugars were initially higher in cuttings taken from stock plants that received higher rates of N, whereas the reverse was true for starch content. With the exception of sucrose, content of TNC and soluble carbohydrates generally increased over time. Starch was nearly depleted by week 3, but had increased by weeks 6 and 9. No correlation was found between TNC: N ratios and rooting percentage. Family GW contained greater quantities of myo-inositol, glucose, fructose, sucrose, total soluble carbohydrates (TSC), and TNC than did family BR. Mineral nutrient content was generally greater in cuttings taken from stock plants that received higher rates of N; these cuttings also maintained higher levels throughout the 12-week rooting period. As with the soluble carbohydrates, the good-rooting composite family (GW) contained greater amounts of all mineral nutrients than did the poor-rooting family BR.

Free access

Producing high quality rooted stem cuttings on a large scale requires precise management of the rooting environment. This study was conducted to investigate the effect of the rooting environment on adventitious root formation of stem cuttings of loblolly pine (Pinus taeda L.). Hardwood stem cuttings of loblolly pine were collected in Feb. 2002 from hedged stock plants and stored at 4 °C until setting in Apr. 2002. One hundred stem cuttings per plot in each of two replications received 45, 61, 73, 102, 147, or 310 mL·m-2 of mist delivered intermittently by a traveling gantry (boom) system. Mist frequency was similar for all treatments and was related inversely to relative humidity (RH) within the polyethylene covered greenhouse. Rooting tubs in each plot were filled with a substrate of fine silica sand, and substrate water potential was held constant using soil tensiometers that activated a subirrigation system. Cutting water potential was measured destructively on two cuttings per plot beginning at 0500 hr every 3 hh until 2300 hr (seven measurements) 7, 14, 21, or 28 days after setting. During rooting, leaf temperature and RH were recorded in each plot to calculate vapor pressure deficit (VPD). Cutting water potential and VPD were strongly related to mist application. Cutting water potential was also related to VPD. Rooting percentage had a linear and quadratic relationship with mean cutting water potential and VPD averaged between 1000 and 1800 HR. Eighty percent rooting occurred within a range of values for VPD. Data suggest that VPD can be used to manage the water deficit of stem cuttings of loblolly pine to increase rooting percentage. These results may be applicable to other species and to other rooting environments.

Free access